CN114374312A

CN114374312A - Driving device, method for adjusting self current of driving device and system based on driving device

Info

Publication number: CN114374312A
Application number: CN202011098404.0A
Authority: CN
Inventors: 费小泂
Original assignee: Cool Silicon Semiconductor Technology Shanghai Co ltd
Current assignee: Cool Silicon Semiconductor Technology Shanghai Co ltd
Priority date: 2020-10-14
Filing date: 2020-10-14
Publication date: 2022-04-19

Abstract

The invention relates to a driving device, a method for adjusting self current of the driving device and a system based on the driving device. The driving device comprises a power supply input terminal and a potential reference terminal, and further comprises a constant current unit which can provide driving current for a load so as to implement constant current driving on the load. The first bypass unit of the drive is connected between the supply input and the potential reference. On the premise that the multiple stages of driving devices are connected in series, when the driving current set by any one driving device is mismatched with the driving currents set by the rest driving devices, the first bypass unit of any one driving device adaptively adjusts the current flowing through the first bypass unit, so that the input currents flowing into different driving devices under the series architecture are equal.

Description

Driving device, method for adjusting self current of driving device and system based on driving device

Technical Field

The invention mainly relates to the field of constant current driving of loads, in particular to a driving device, a method for adjusting self current of the driving device and a system based on the driving device.

Background

In the field of constant current driving of a load, a pulse modulation technique is commonly used in the industry to change the time width of the load on or off within a certain period of time, and at the same time, the current flowing through the load during the load on is required to be a constant current value, thereby realizing the change of the average current flowing through the load. If the output current from the current source driving the load is fixed, the driving of the load is called current-fixed driving. If the output current from the current source driving the load is variable, the driving of the load is called current programmable driving. The difficulty is that the output current always deviates from the target value.

In the prior art, data transmission is generally performed by cascading four communication lines, and the use of a clock signal line and a data signal line and a load signal line and an output enable signal line is the most typical four-wire communication example. Whether four-wire communication or two-wire communication using only clock signal lines and data signal lines or other multi-wire communication, the communication process can be realized by requiring very strict timing coordination between signals with different attributes transmitted on different signal lines. In an application example of replacing multi-line communication, the single-line serial transmission scheme is adopted, single-line transmission only needs a single communication line as the name suggests, and the method has the advantages of simple wiring and elimination of timing matching elbow caused by traditional multi-line communication. In the field of constant current driving of loads, when the number of loads and matched current sources is large, a new driving scheme capable of solving the current deviation is urgently needed to be designed.

Disclosure of Invention

The present application relates to a drive device comprising:

a power input terminal and a potential reference terminal;

a constant current unit which can supply a driving current to the load to perform constant current driving on the load;

a first bypass unit connected between the power input terminal and the potential reference terminal;

under the premise that the multiple driving devices are connected in series, when the driving current set by any one driving device is mismatched with the driving currents set by the rest driving devices, the first bypass unit of any one driving device adaptively adjusts the magnitude of the current flowing through the first bypass unit so as to ensure that the input currents of any one driving device and the rest driving devices are equal.

The above-mentioned drive device: the system also comprises a data transmission module and a pulse width modulation module;

the data transmission module is used for receiving communication data;

the pulse width modulation module forms a pulse width modulation signal according to duty ratio information contained in the communication data, and the on-off state of a constant current unit connected with the load in series is controlled by the pulse width modulation signal.

The above-mentioned drive device: the data transmission module is used for forwarding communication data;

the multi-stage driving device receives communication data in a cascading mode: after each stage of driving device receives the communication data, the communication data belonging to the stage is extracted and the rest of the received communication data is forwarded to the next stage which is in cascade connection with the driving device.

The above-mentioned drive device: the first bypass unit of any one driving device synchronously adjusts the voltage drop between the power supply input end and the potential reference end of any one driving device while adjusting the current of the first bypass unit:

and clamping voltage drops of different driving devices with mismatched driving currents at different voltage values.

The above-mentioned drive device: a capacitive device is connected between the power input terminal and the potential reference terminal.

The above-mentioned drive device: the mechanisms causing the mismatch include at least:

the manufacturing process links for manufacturing the driving devices cause manufacturing differences among different driving devices; or

The temperature of different driving devices is not consistent when the driving devices work.

The above-mentioned drive device: when the voltage drop between the power supply input end and the potential reference end of the driving device is not lower than the first threshold voltage set by the first bypass unit: the first bypass unit is turned on, otherwise the first bypass unit is turned off.

The above-mentioned drive device: the second bypass unit is connected between the power supply input end and the potential reference end;

when the voltage drop between the power supply input end and the potential reference end of the driving device is not lower than the second threshold voltage set by the second bypass unit: the second bypass unit is turned on, otherwise the second bypass unit is turned off.

The above-mentioned drive device: the first bypass unit comprises a three-end adjustable shunt reference source and a resistor which are connected in series between the power supply input end and the potential reference end; the first threshold voltage is determined by the minimum working voltage required when the three-terminal adjustable shunt reference source is conducted.

The above-mentioned drive device: the second bypass unit comprises a zener diode between the power input terminal and the potential reference terminal;

the second threshold voltage is determined by a threshold voltage of the zener diode at reverse breakdown.

The application relates to a method for adjusting self current of a driving device, which is characterized by comprising the following steps:

the driving device includes: a power input terminal and a potential reference terminal; a constant current unit which can supply a driving current to a load;

the method comprises the following steps: connecting the multi-stage driving devices in series;

in the multi-stage driving device, the current of the first bypass unit in the driving device with larger driving current is smaller, and the current of the first bypass unit in the driving device with smaller driving current is larger;

therefore, the first bypass unit of each driving device can self-adaptively adjust the current flowing through the first bypass unit, so that the input currents flowing into all the driving devices are equal.

The method comprises the following steps: a voltage drop exists between the power supply input end and the potential reference end of each driving device; the larger the driving current, the smaller the voltage drop of the driving device; the smaller the drive current, the larger the voltage drop of the drive device.

The method comprises the following steps: when the voltage drop between the power supply input end and the potential reference end of the driving device is not lower than the first threshold voltage set by the first bypass unit: the first bypass unit is turned on, otherwise the first bypass unit is turned off.

The method comprises the following steps: the second bypass unit is connected between the power supply input end and the potential reference end;

The method comprises the following steps: the first bypass unit comprises a three-end adjustable shunt reference source and a resistor which are connected in series between the power supply input end and the potential reference end, and a specified voltage or a preset voltage is input to the voltage reference end of the three-end adjustable shunt reference source; the first threshold voltage is determined by the minimum working voltage required by the three-terminal adjustable shunt reference source when the three-terminal adjustable shunt reference source is conducted.

The method comprises the following steps: the second bypass unit comprises a zener diode connected between the power input terminal and the potential reference terminal;

The method comprises the following steps: the driving device is also connected with a capacitance device between the power supply input end and the potential reference end;

and when the voltage drop between the power supply input end and the potential reference end of any driving device is lower than a first threshold voltage, the constant current unit and the first bypass unit of any driving device are turned off, and a capacitance device of any driving device is charged.

The method comprises the following steps: the system also comprises a data transmission module and a pulse width modulation module; the data transmission module receives communication data;

the pulse width modulation module forms a pulse width modulation signal according to duty ratio information carried by communication data, and the on-off state of a constant current unit connected with the load in series is controlled by the pulse width modulation signal.

The method comprises the following steps: the data transmission module is used for forwarding communication data;

The present application relates to a drive device comprising:

a power input terminal and a potential reference terminal;

a constant current unit which can supply a driving current to a load;

the constant current unit and the first bypass unit are in parallel connection;

among the series-connected multi-stage driving devices, the current of the first bypass unit in the driving device with larger driving current is smaller, and the current of the first bypass unit in the driving device with smaller driving current is larger;

therefore, the first bypass unit of each driving device can self-adaptively regulate the current flowing through the first bypass unit, so that the input currents flowing into all the driving devices are equal.

The above-mentioned drive device: a voltage drop exists between the power supply input end and the potential reference end of the driving device;

the larger the driving current is, the smaller the voltage drop of the driving device is;

the smaller the driving current, the larger the voltage drop of the driving device.

The above-mentioned drive device: when the voltage drop between the power supply input end and the potential reference end of the driving device is not lower than a first threshold voltage set by the first bypass unit: the first bypass unit is turned on, otherwise, the first bypass unit is turned off;

the first bypass unit comprises a three-end adjustable shunt reference source and a resistor which are connected between a power supply input end and a potential reference end in series; the first threshold voltage is determined by the minimum working voltage required when the three-terminal adjustable shunt reference source is conducted.

The above-mentioned drive device: the driving device is also connected with a capacitance device between the power supply input end and the potential reference end;

and when the voltage drop between the power supply input end and the potential reference end of any driving device is lower than a first threshold voltage, the constant current unit and the first bypass unit of any driving device are turned off to charge the capacitive device of any driving device.

the data transmission module is used for receiving communication data;

The present application relates to a system comprising:

a plurality of driving devices connected in series in a power supply mode to form a row;

each of the driving devices includes:

a power input terminal and a potential reference terminal;

a constant current unit which can supply a driving current to a load;

the data transmission module receives and forwards communication data;

the pulse width modulation module forms a pulse width modulation signal according to duty ratio information contained in the communication data, and the on-off state of a constant current unit connected with the load in series is controlled by the pulse width modulation signal;

in the system:

the multistage driving device receives communication data in a cascading mode, and after each stage of driving device receives the communication data, the multistage driving device extracts the communication data belonging to the stage and forwards the received rest other communication data to the next stage connected with the multistage driving device in a cascading mode;

in the multi-stage driving device, when the driving current set by any one driving device is different from the driving currents set by the rest driving devices, the first bypass unit of the any one driving device adaptively adjusts the current flowing through the first bypass unit, so that the input currents flowing into the different driving devices are equal.

The system comprises the following steps: the first bypass unit of any one driving device synchronously adjusts the voltage drop between the power supply input end and the potential reference end of any one driving device while adjusting the current of the first bypass unit:

and clamping voltage drops of different driving devices with different driving currents at different voltage values.

The system comprises the following steps: in each drive device:

the first bypass unit comprises a three-end adjustable shunt reference source and a resistor which are connected between a power supply input end and a potential reference end in series; and when the voltage drop between the power supply input end and the potential reference end is not lower than the minimum working voltage required by the conduction of the three-end adjustable shunt reference source, the first bypass unit is switched on.

The system comprises the following steps: in each drive device:

the second bypass unit comprises a voltage stabilizing circuit connected between the power input end and the potential reference end, and is switched on when the voltage drop between the power input end and the potential reference end is not lower than the critical voltage of reverse breakdown of the voltage stabilizing circuit.

The system comprises the following steps: each drive device is further connected with a capacitive device between the power supply input terminal and the potential reference terminal.

The system comprises the following steps: the load comprises a light emitting diode.

The system comprises the following steps: the drive device is designed in the form of a drive chip.

The present application relates to a drive device comprising:

the voltage drop exists between the power input end and the potential reference end;

a constant current unit which can supply a driving current to a load;

when the voltage drop is not lower than a first threshold voltage set by the first bypass unit, the first bypass unit is conducted, the driving device enters a first working mode, and the constant current unit is started at the moment;

when the voltage drop is lower than a first threshold voltage set by the first bypass unit, the first bypass unit is turned off, the driving device enters a second working mode, and the constant current unit is forbidden;

the multistage drive devices are connected in series:

on the premise of a first working mode, if the driving current set by any one driving device is different from the driving currents set by the rest other driving devices, the first bypass unit of any one driving device can adjust the magnitude of the current flowing through the first bypass unit so as to ensure that the input currents of any one driving device and other driving devices are equal;

and simultaneously, the voltage drop of any one driving device is adjusted, so that the voltage drops of different driving devices with different driving currents are clamped at different voltage values.

when the voltage drop is not lower than a second threshold voltage set by the second bypass unit, the first bypass unit and the second bypass unit are both conducted, the driving device enters a third working mode, and the second threshold voltage is greater than the first threshold voltage.

The above-mentioned drive device: the first bypass unit comprises a three-end adjustable shunt reference source and a resistor which are connected in series between a power supply input end and a potential reference end; the first threshold voltage is determined by the minimum working voltage required by the conduction of the three-terminal adjustable shunt reference source;

the second bypass unit comprises a zener diode connected between the power input terminal and the potential reference terminal;

The above-mentioned drive device: each driving device is also connected with a capacitance device between the power supply input end and the potential reference end;

when the driving device enters the second working mode, the capacitor device of the driving device entering the second working mode is charged.

The above-mentioned drive device: each driving device also comprises a data transmission module and a pulse width modulation module;

the data transmission module is used for receiving communication data;

The above-mentioned drive device: each driving device also comprises a data transmission module, and the data transmission module is used for transmitting communication data; the multi-stage driving device receives communication data in a cascading mode: after each stage of driving device receives the communication data, the communication data belonging to the stage is extracted and the rest of the received communication data is forwarded to the next stage which is in cascade connection with the driving device.

The above-mentioned drive device: on the premise of the first operation mode, the current of the first bypass unit in the driving device with larger driving current is smaller, and the current of the first bypass unit in the driving device with smaller driving current is larger.

Drawings

To make the above objects, features and advantages more comprehensible, embodiments accompanied with figures are described in detail below, and features and advantages of the present invention will become apparent upon reading the following detailed description and upon reference to the following figures.

Fig. 1 is an embodiment using a current source module in an architecture in which a plurality of driving devices are connected in series.

Fig. 2 is an embodiment without using a current source module in an architecture in which a plurality of driving devices are connected in series.

Fig. 3 is an example of transmitting communication data by a single line in a mode in which multi-stage driving apparatuses are cascade-connected.

Fig. 4 shows an example of communication data transmission asynchronization in a mode in which multi-stage driving devices are cascade-connected.

Fig. 5 illustrates an example of the multi-stage driver transmitting communication data using a return-to-zero code as a communication protocol.

Fig. 6 is a diagram of a drive device with a data transfer module receiving duty cycle data and current regulation data.

Fig. 7 is a topology schematic of a drive arrangement with a first bypass unit and a second bypass unit.

Fig. 8 is a general schematic diagram of the input current waveform of the driving device in solving the current mismatch problem.

Fig. 9 is an example of a diode that may or may not emit light when the load driven by the driving device.

Fig. 10 is an embodiment in which multiple loads driven by the same driver are controlled by pulse width modulated signals.

Fig. 11 is an example of optional electronic components of the first bypass unit and the second bypass unit in the driving apparatus.

Fig. 12 is an alternative example of a first bypass unit with a three terminal adjustable shunt reference source in a drive arrangement.

Detailed Description

The invention will be more fully described with reference to the following examples. The solutions obtained by a person skilled in the art without making any inventive step are within the scope of protection of the present invention.

Referring to fig. 1, a master node, not shown, needs to transmit data DT to a slave node, such as a drive device 100. The communication of the master and slave nodes allows for the use of standardized communication protocols or customized non-standardized communication protocols. The master node and the slave node are respectively provided with an interface circuit or a communication module for realizing data communication. Currently, data communication is more common in which a plurality of transmission lines, for example, four, are used to transmit communication signals: the clock signal line and the data signal line and the loading signal line and the output enable signal line work together, communication data are sequentially transmitted in series and are matched with each other through four-line signals to control the slave nodes of all levels of connection. A communication protocol using only data lines and a clock line and a latch line for a total of three lines is also a mainstream communication scheme of the display technology. In an alternative example, two-wire transmission is used, and the two-wire transmission of the data line and the clock line is a compromise between the number of data lines and the transmission rate. Although the general multi-wire protocol is suitable for communication between a master node and a plurality of cascade-connected slave nodes and communication data is transmitted, the alternative single-wire communication technology is more suitable for transmission of the communication data, and the single-wire protocol has the advantage that only a single data wire is required for transmission of the cascade data. Data transmission in the form of a return-to-one code or zero code is the most common in the case of single-wire transmission, and manchester coding is also associated with the single-wire transmission scheme. The communication mode under single-wire transmission conditions typically requires the slave node to have a data forwarding function: for example, when each slave node receives communication data transmitted by the master node, it needs to extract the data source belonging to its own unit first, and forward other data sources not belonging to its own unit to the next-stage slave node connected in cascade with it. The communication aspect requires a cascade connection relationship between the driving apparatuses 100.

Referring to fig. 1, the power input terminal VCC is generally defined as a power supply terminal for driving each functional module in the apparatus 100, and then the total input current flows from the power input terminal VCC. The potential reference terminal GND is defined as the potential reference terminal of the driving device 100, and the total output current flows out of the potential reference terminal GND. In the industry, the driving device can be designed into a driving circuit in a discrete form and can also be designed into a driving chip with high integration level.

Referring to fig. 1, a plurality of driving devices 100 are arranged in one or more columns in a power supply path. The first driver 100 in each column as the head of the column has its power supply input VCC coupled to the positive power supply VP, while the last driver 100 in the end of the column has its potential reference GND coupled to the negative power supply VN. The power supply input of the following driver is also arranged in each column to be coupled to the potential reference of the preceding driver. In the present example, the supply input VCC of a second driver 100 is coupled to the current outlet, i.e. the potential reference GND, of the adjacent first driver 100, as in the first column. The power supply input VCC of the third driver 100 in the first column is connected to the current drain, i.e. the potential reference GND, of the adjacent second driver 100. And it may for example be provided in the first column that the supply input VCC of a fourth driver 100 is coupled to the current outflow, i.e. potential reference GND, of an adjacent third driver 100. The supply input VCC of the last driver 100 in the first column is coupled to the current drain, i.e. the potential reference GND, of the penultimate driver 100. For example, a supply input VCC of the penultimate drive 100 can be coupled to a current outlet, i.e., a potential reference GND, of the penultimate drive 100 in the first column. Thus, it can be seen that: the power input of the rear drive in each column is coupled in a power supply relationship to the potential reference of the adjacent front drive until all drives in each column are connected in series or superimposed between the positive VP and negative VN poles of the external power supply. As an alternative, a capacitance CZ can also be provided between the supply input VCC and the potential reference GND of each drive. The output current of the previous driving device in each column is considered as the input current of the next driving device, or the input currents of all driving devices in each column are considered to be equal, which is determined by the serial structure of all driving devices 100.

Referring to fig. 1, a current source module PCS is provided on the supply lines of each column of drive devices, such as the first column, to maintain the input current of each drive device 100 in the first column at a predetermined value. In the first column, the respective driving devices 100 and the current source modules PCS are connected in series between the positive electrode and the negative electrode of the power supply source. The input current of any one of the driving devices in each column is equal to the output current of the current source module PCS, and the same is true for the first column on the left side and the second column on the right side.

Referring to fig. 1, at the stage that the previous frame of communication data received by each driver 100 is refreshed to the next frame of communication data to update the respective communication data of each driver 100, the current adjustment data received by the current source module PCS is also refreshed by frame so that the output current of the current source module PCS is also refreshed by frame and flows to the driver. The input current to each drive device is updated from a predetermined value corresponding to the current adjustment data for the previous frame to a predetermined value corresponding to the current adjustment data for the next frame. Note that the current adjustment data of the previous frame is decoded from the communication data of the previous frame and the current adjustment data of the next frame is decoded from the communication data of the next frame. At this time, both the current source module PCS and the driving device include a communication interface circuit or a communication module for realizing the transmission and reception of communication data, and only the communication data received by the current source module PCS is defined as current regulation data according to the purpose. The current source module PCS may define an input current of the driving device. If the communication interface circuit or communication module is omitted from the current source module PCS, the current output is fixed, i.e. the current source module PCS naturally does not need the signal output DO and the signal input DI.

Referring to fig. 1, there are various drawbacks that are difficult to overcome using the current source module PCS. First, the current adjustment data is part of the complete data, and occupies additional data bits per frame of data, which results in data bloat, and also reduces the data refresh rate of the communication data sent to each driving device 100. The current source module PCS furthermore carries an additional high cost burden, in particular the very high accuracy of the current it requires. In addition, the current source module PCS is an electronic component with completely different functional properties relative to each driving device connected in series, and voltage fluctuation of an external power supply between the positive electrode VP and the negative electrode VN can be borne by the current source module PCS in most scenes, so that the current source module PCS is easily overheated and damaged. It is highly necessary to omit the current source module PCS which has various disadvantages, as will be described later.

Referring to fig. 2, the explanation is still made using a cascaded multi-stage driving apparatus 100. Note that the cascade drive devices described above are arranged in a row in the power supply system, i.e., the drive devices are connected in series. The master node transmits communication data to each stage of driving device, and the master node may use a server or a microprocessor or the like as a data transmitting terminal. When transmitting communication data to a plurality of driving apparatuses and the like in the cascade form: the signal output DO of a preceding or previous driving means may be arranged to be coupled to the signal input DI of a subsequent or next driving means via a coupling capacitor C.

Referring to fig. 2, the driving apparatuses 100 are communicatively connected in cascade. The signal input terminal DI of the first driving device 100 in the first row receives the communication data from the master node. Also provided in the first column is that the signal output DO of the preceding stage drive means is coupled to the signal input DI of the following stage drive means. For example, in a first column, the signal input DI of a second driver 100 is coupled to the so-called signal output DO of an adjacent first driver 100, i.e. a driver of a preceding stage. In the case of a cascade of several drives, for example, in the first column, the signal input DI of a third drive 100 is coupled to the so-called signal output DO of an adjacent second drive 100, i.e. a preceding drive. In the case of a cascade of several drives, for example, in the first column, the signal input DI of the fourth drive 100 is coupled to the so-called signal output DO of the adjacent third drive 100, i.e. the previous drive. The last actuator 100 in the first column as the column tail may have its signal output DO floating if it is the final actuator of the actuators, and the signal output DO of the column tail actuator 100 may continue to deliver the communication data to the subsequent stage if it is not the final actuator of the actuators.

Referring to fig. 2, the driving apparatuses 100 are communicatively connected in cascade. Also provided in the second column is that the signal output DO of the preceding driver is coupled to the signal input DI of the following driver. For example, in the second column, the signal output DO of a second driver 100 is coupled to the so-called signal input DI of an adjacent first driver 100, i.e. a subsequent driver. In the case of a cascade of several drives, for example, in the second column, the signal output DO of a third drive 100 is coupled to the so-called signal input DI of an adjacent second drive 100, i.e. a subsequent drive. In the case of a cascade of several drives, for example, in the second column, the signal output DO of a fourth drive 100 is coupled to the so-called signal input DI of an adjacent third drive 100, i.e. a subsequent drive. The last drive device 100 in the second column as the column tail allows to receive the communication data originating from the last drive device 100 in the first column, and the same last drive device 100 in the second column as the column tail also allows to receive the communication data originating from the master node. The communication data of the first row on the left side is transmitted from the head of the row to the tail of the row, and the communication data of the second row on the right side is transmitted from the tail of the row to the head of the row.

Referring to fig. 3, taking data transmission in the return-to-zero code format as an example: suppose N (N is a positive integer greater than 1) drivers are connected in cascade and are assigned communication data of D1 to DN, respectively. After the first driver receives the communication data D1 from the master node, the first driver will receive the communication data D2-DN but the first driver will forward the communication data D2-DN to the second driver, which will only hold the communication data D1. The second driver also receives the communication data D2-DN but the second driver forwards the communication data D3-DN to the third driver, which retains only the communication data D2. Likewise, the third driver will receive the communication data D3-DN but the third driver will forward the communication data D4-DN to the fourth driver, which retains only the communication data D3. And so on until the final driving device 100 at the end of the column receives the communication data DN. The complete data DT comprising D1-DN is not seen to be synchronously assigned to the N drive devices 100 of the cascade connection. It is also known that the multistage drive receives communication data in a cascade connection: after each stage of driving device receives the communication data, the communication data belonging to the stage is extracted and the rest of the received communication data is forwarded to the next stage which is in cascade connection with the driving device.

Referring to fig. 3, taking a three-stage driving apparatus (in the case of N ═ 3) as an example, twenty-four bits of communication data are allocated to each driving apparatus. After the first driving device receives the first twenty-four bit data sent by the master node, the first driving device receives the second twenty-four bit data sent by the master node, but considering that the total number of bits required by the first driving device reaches the expected number, the first driving device directly forwards the second twenty-four bit data to the second driving device. The first driver receives the third twenty-four bit data from the master node again, and then the third twenty-four bit data is forwarded to the second driver according to the forwarding rule, because the total number of bits required by the second driver is met, and the second driver is allocated to the second driver, then the second driver continues to forward the third twenty-four bit data to the third driver.

Referring to fig. 3, the disadvantage of asynchronous communication data of N driving apparatuses 100: if the communication data includes the current adjustment data for changing the magnitude of the driving current IS sent to the driving device, the driving device that receives the communication data first changes the magnitude of the driving current IS after receiving the communication data, and the driving device that receives the communication data then also changes the magnitude of the driving current IS after receiving the communication data. In the stage of refreshing the previous frame of communication data received by each driving device 100 to the next frame of communication data: for example, after the first driving device in the front of the cascade position, i.e., the first driving device 100 in the row, refreshes the communication data of the next frame to change its driving current IS, the driving devices in the back of the cascade position, i.e., the driving devices 100 in the row, have not yet refreshed the communication data of the next frame, obviously, the driving current IS of the driving device 100 in the back of the row IS still determined by the communication data of the previous frame. So that the drive currents IS provided by the drive means in different cascade positions are different. If it is specified that the drive current set by any one of the drive devices and the drive currents set by the remaining other drive devices should be equal, the difference between the drive current set by any one of the drive devices and the drive currents set by the other drive devices is a mismatch. Based on the consideration that the N driving devices 100 are connected in series, in an alternative example, the driving currents IS provided by all the driving devices 100 are equal to ensure that the input currents flowing into the different driving devices are equal. Conversely, if there IS a difference between the driving currents IS provided by different driving devices, a current mismatch may be caused in the series configuration because the input currents of all the series-connected driving devices 100 of the series configuration should be identical. The drive current IS will be described further below.

Referring to fig. 5, the data transmission in the return-to-zero code format allows the use of a RESET signal RESET. The reset signal is a long low level which is substantially easy to detect in many cases. Each driving device 100 receives the RESET signal RESET and then directly forwards the RESET signal RESET to other driving devices 100 in the next stage of the cascade. Each driving device 100 receives the RESET signal RESET and triggers updating of its own communication data. If the RESET signal RESET IS used as the refresh time point for triggering the driving current IS, the advantage IS that the time difference between the data refresh time points of the N driving devices 100 connected in series can be reduced, but the RESET signal IS still transmitted from the driving device located at the front of the cascade to the driving device located at the back of the driving device. Therefore, the driving device that receives the reset signal first changes the magnitude of the driving current IS of itself after receiving the reset signal, and the driving device that receives the reset signal later also changes the magnitude of the driving current IS of itself after receiving the reset signal. That is, the refresh time points of the communication data of the N driving devices are still asynchronous, and the cascade current still has the potential threat of mismatch. If the main node sends a reset signal, all the driving devices connected in cascade are reset, decode the communication data received by the driving devices, refresh and execute the communication data, complete a data refresh period, and return to a data receiving preparation state.

Referring to fig. 4, in view of the asynchronous communication data of the N driving apparatuses 100: the driving device which receives the communication data receives the reset signal first, delays slightly and then changes the magnitude of the driving current IS of the driving device, and the driving device which receives the reset signal later and the driving device which receives the reset signal first change the value of the driving current IS as synchronously as possible. Note that data transmission in the return-to-one code encoding format or data transmission in the return-to-zero code encoding format, manchester code, and the like all generate asynchronous phenomena.

Referring to fig. 4, for example, the first driving apparatus 100 receives the RESET signal RESET and delays the time period T1 to change its driving current IS. The second driving device 100 receives the RESET signal RESET and delays the time period T2 to change its driving current IS. The third driving device 100 receives the RESET signal RESET and delays the time period T3 to change its driving current IS, and so on. The nth driving apparatus 100 has no delay. The more forward the cascade position, the longer the period of time the drive needs to be delayed: the N drive devices may refresh their respective drive currents IS in near synchronization. The driving device needs to be configured with an additional timer to perform the delay timing. The rules of this example are: the communication data refreshing IS enabled to be effective at the same time by delaying all the driving devices as much as possible, and the N driving devices refresh the respective driving currents IS at the same time as much as possible because the communication data comprises the current regulation data. It should be emphasized that, whether the reset signal or the further delay is used, the time difference between the effective communication data refresh time points of the N driving apparatuses 100 is reduced or slowed down, and the current mismatch problem cannot be completely solved.

Referring to fig. 6, the data transmission module COM of the driving device has a decoding function, includes a decoder, and can decode the input serial data according to a predetermined communication protocol, for example, the driving device can decode the first type of data or decode the second type of data from the received communication data. In fact, whether the first type data or the second type data is the first type data or the second type data, the decoder restores the signals with the preset coding rules in the communication data into the common binary data, and the restored data have slight differences in use so that the naming rules are different. The data transmission module COM is essentially the interface circuit or communication module mentioned above, which can implement data communication. The first type of data includes current adjustment data that can adjust the magnitude of the drive current and the second type of data includes data containing duty ratio information or pulse width modulation data.

Referring to fig. 6, a programmable constant current unit is provided. The adjustment scheme of the magnitude of the driving current IS provided by the constant current unit CS1 IS diversified. The first type of data decoded by the driving device 100 and allocated to the constant current unit CS1 is represented as D1-CS in the drawing. When receiving the communication data, the data transmission module COM IS used to decode the first type of data, such as the current adjustment data, and the first type of data IS used to fine-tune or adjust the magnitude of the constant current IS of the constant current unit. That is, the data transmission module may receive communication data containing the first type of data, and the first type of data is transmitted to the constant current unit CS 1. The binary values are well known in the art and therefore will not be described herein.

Referring to fig. 6, the constant current unit and the current source are also called as a constant current source module (current source) and the generated stable reference current or constant current IS regarded as the driving current IS. The load or the light source and the constant current source module are connected in series, so that the current of the load or the light source and the constant current source module can be stabilized, and the aim of constant current control can be fulfilled. Or the current mirror structure is matched with the constant current source module to enable the current flowing through the current mirror to be either equal to the reference current or proportional to the reference current, the current mirror (Current mirror) is a specific form of the constant current source module, the mirror current of the current mirror is equal to or proportional to the input reference current, and the characteristic is that the mirror current flowing through the current mirror is copied or copied to the reference current input to the current mirror according to a certain proportion. Causing a mirror current to flow through the load or light source may also implement constant current driving of the load or light source. In the present application, but any circuit capable of generating a stable reference current or a constant current may be included in the definition of the constant current unit CS1, constant current source modules such as a voltage-to-current converter are all examples of the constant current unit or current source. It is understood that the circuit topology of the constant current unit or current source generating a constant output current shown in the figure is not unique in nature but rather is diversified.

Referring to fig. 6, allowing the driving apparatuses and other communication circuits to be cascaded with each other also allows the driving apparatuses to be cascaded with each other so that they each have a data forwarding function. One of the core functions of the driving device is to drive a single-path load or a plurality of paths of loads matched with the driving device and perform constant current driving according to requirements. The data transmission module configured in the driving device is provided with a decoder, and decodes the input serial data according to a preset communication protocol and decodes various data from the received communication data. In an alternative example, the data decoding function and the data forwarding function are provided as an example to explain the mechanism of the data transmission module COM for receiving and forwarding the communication data. The signal input terminal DI receives communication data provided from outside, and the decoder needs to decode or decode the data information carried in the communication data, and the data decoding means can restore the data in the pre-coding format that the driving device cannot directly use to a conventional binary code that is easy to recognize and execute. The decoded binary code may be buffered in a register, and additional buffer space or latches may be used to hold the decoded data, taking into account that data refreshing of the register may be faster and often times more recent. The encoding formats such as Manchester encoding and decoding technology, normalization code encoding and decoding technology, return-to-zero encoding and decoding technology and the like are suitable for a single-wire data transmission protocol or a communication protocol of a data transmission module.

Referring to fig. 6, a so-called data transfer module COM is used to regenerate or forward data, and to perform a so-called data forwarding task, such as transmitting communication data to a rear drive. The simplest forwarding mode of the data transmission module COM is transparent transmission, that is, communication data received by the signal input terminal DI is allowed to be directly output from the signal output terminal DO, and then the driving devices or other communication circuits connected in cascade are respectively extracted from the single data line to communication data which are consistent with the self address and belong to the self address according to the address allocation rule. As an alternative forwarding scheme, communication data belonging to each stage of driving device needs to be counted in a coordinated manner, each stage of driving device retrieves the communication data belonging to the stage from each frame of communication data and then forwards the rest of the received other communication data to a next-stage communication data receiver cascaded with the driving device, where the next-stage communication data receiver may be a next-stage driving device or other communication circuits. For example, each stage of driving device needs to cooperate with counting whether the total number of bits of the communication data belonging to the stage is completely received, and the result of the counting is that once the communication data belonging to the stage of driving device is decoded and completely received, the data transmission module COM is triggered to forward the communication data received at the signal input terminal DI off from the signal output terminal DO. The data forwarding process also allows for shaping of the data: because the communication data has the signal attenuation problem in the forwarding stage of the multi-stage driving device, the signal distortion attenuation is more serious when the cascade number of the driving devices is more, so the communication data can be shaped when being forwarded. If the return-to-zero code or the return-to-one code requires that the high level or the low level of each bit of communication data meets the preset duty ratio in the transmission process, in order to ensure that the communication data is not attenuated, the duty ratio of the high level or the low level of each bit of communication data can be reconstructed in the transmission process. Shaping forwarding is equivalent to: each bit of data with a preset duty ratio is received and decoded by the data transmission module COM, and the duty ratio of each bit of data is modified by the data transmission module COM until the duty ratio is restored to the preset duty ratio. That is, the predetermined duty ratio of each bit of data received by the signal input end DI of the data transmission module COM is roughly equal to the actual duty ratio of each bit of data forwarded and output by the signal output end DO of the data transmission module COM, and the signal attenuation distortion is recovered by shaping the data. As an alternative forwarding scheme, an encoder may also be configured for the data transmission module COM and a re-encoding technique may be used to implement forwarding: after the communication data is decoded and temporarily stored in the storage space of the data transmission module COM, the temporarily stored data is recoded by the coder capable of recoding the binary data again and output, and the relay function of decoding and storing the data and recoding the data according to the preset coding format ensures that the data can be smoothly transmitted. Data forwarding is within the scope of the prior art.

Referring to fig. 6, the driving device 100 includes a power supply input terminal VCC and a potential reference terminal GND, and also sets a LOAD and a constant current unit CS1 connected in series between the power supply input terminal VCC and the potential reference terminal GND. Note that current flows in from the power supply input terminal VCC and out from the potential reference terminal GND. The driving apparatus 100 is, for example, a driving circuit that can perform constant current driving on a load such as a conventional diode or a light emitting diode or a resistor, and is, for example, a battery charge management circuit that manages a load such as a rechargeable battery as a driving device. In addition to the various components mentioned above, the drive device 100 in the industry is an optional item rather than a necessary item: it is also allowed that the driving apparatus 100 integrates a protection circuit such as an over-temperature protection or a start-up protection or an electrostatic protection or an instantaneous voltage protection or a spike current leakage circuit, a bandgap circuit, an oscillator, a power-on reset circuit, a clock circuit, a communication module, or the like. In terms of constant current driving of the load, the modules or circuits all belong to necessary or optional parts of the driving device, and especially when the driving device is a driving chip with high integration level, the description thereof is omitted because the contents are well known by those skilled in the art.

Referring to fig. 6, the driving current IS generated by the constant current unit CS1 IS usually pulse width modulated in driving the LOAD, and the pulse width modulation module MOD shown in the figure can generate a pulse width modulation signal PWM and IS used to control the on/off of the constant current unit IS. The drive current IS, at this time of full amplitude, IS loaded onto the LOAD in a repetitive pulse sequence that IS switched on or off: the driving current IS applied to the LOAD when the driving current IS on, for example, when the PWM signal PWM has a high logic level, and the driving current IS cut off from the LOAD when the driving current IS off, for example, when the PWM signal PWM has a low logic level. Pulse width modulation is within the scope of the prior art. The communication data received by the drive device includes a second type of data, pulse width modulated data and is represented as D1-GS in the figure. The drive device confirms and gives the duty ratio of the drive current IS to be outputted to the LOAD according to the second type data matched to the LOAD, and the drive current IS modulated on and off periodically at the given duty ratio. In other words, the pulse width modulation module MOD forms a so-called pulse width modulation signal PWM from the second type of data carrying the duty ratio information, and the on or off state of the constant current unit CS1 connected in series with the LOAD is controlled by the pulse width modulation signal PWM. The complete communication data received by the driving apparatus 100 includes the high data segment and the low data segment, and the first type data and the second type data can be selected from the high data segment and the low data segment of the communication data respectively or vice versa. If the driving current of the LOAD is 80mA and the on-time duty ratio determined by the pulse width modulation signal is 75%, the equivalent average current is 80 × 75% — 60 mA. If the driving current output by the driving device is adjusted to 60mA through the communication data and the duty ratio of the on-time determined by the pulse width modulation signal is 70%, the equivalent average current of the driving current adjustment is 60 multiplied by 70 percent to 42 mA. The constant current unit can flexibly program current.

Referring to fig. 7, a non-programmable constant current unit is provided. The magnitude of the driving current IS provided by the constant current unit CS1 IS programmed into the constant current unit CS1 in advance, for example, the magnitude of the driving current IS usually determined before the driving device of the driving chip type IS shipped. In this case, the first type of data, originally expressed as D1-CS, is negligible, and the driving current need not be edited and modified online in this example by communicating data. Note that the manufacturing process links for manufacturing the driving device 100 are likely to cause manufacturing differences between different driving devices: for example, some driving devices have different driving currents due to not being shipped from the same lot, for example, some driving devices have different driving currents due to slight changes in the manufacturing process, and for example, parameters such as the sizes or doping concentrations of some transistors or electronic elements in a constant current unit including many semiconductor transistors and electronic elements have deviations, etc., all of which are likely to cause the driving currents of different driving devices not to be identical. Furthermore, drive current mismatch can be caused by inconsistent operating temperatures of the drive devices.

Referring to fig. 7, in an alternative example, a first bypass unit SH1 is connected between the power supply input terminal VCC and the potential reference terminal GND as shown. The effect of the so-called first bypass unit SH1 is set on the premise that the multistage drive 100 is connected in series (fig. 3): when there IS a mismatch between the driving current IS set by any driving device and the driving current IS set by other driving devices, the first bypass unit SH1 in any driving device adaptively adjusts the magnitude of the current flowing through itself to ensure that the input currents of any driving device and other driving devices are equal or to ensure that the input currents flowing in different driving devices are equal.

Referring to fig. 3, in an alternative example, an N-level driving device is taken as an example. In the serial link of the driving devices, it can be assumed that the driving device 100 at the head of the column IS deviated from the design rule to make the driving current IS 11mA, for example, it can be assumed that the driving device 100 at the middle IS deviated from the design rule to make the driving current IS 10mA, and for example, it can be assumed that the driving device 100 at the tail of the column IS deviated from the design rule to make the driving current IS 13 mA. There IS no doubt that there IS a drive current mismatch between the drive current IS of the first-row drive device 100 and the drive currents of the middle-row and the last-row drive devices 100, for example, they should all be the same desired current value. The difference between the driving currents IS provided by different driving devices in the series configuration of the driving devices may cause the disorder of the cascade current ISE, and the input currents of all the series driving devices 100 in the series configuration should be identical.

Referring to fig. 3, the multi-stage driving apparatus is connected in series: when there IS a mismatch between the driving current IS set by any one of the driving devices, such as the first driving device 100, and the driving current IS set by the other driving devices, such as the last driving device, the first bypass unit SH1 in the any one of the driving devices, such as the first driving device 100, IS required to adaptively adjust its current so as to ensure that the respective input currents flowing into the different driving devices are equal. For example, if the driving current IS set by the head-of-column driving device 100 IS lower than the driving current IS of other driving devices, such as the tail-of-column driving device, the so-called first bypass unit SH1 in the head-of-column driving device should increase the current to equalize the input currents of the head-of-column and tail-of-column driving devices. If the driving current IS set to the first-row driver 100 IS higher than the driving current IS set to the second-row driver, the so-called first bypass unit SH1 in the first-row driver should reduce its own current to equalize the input currents of the first-row and second-row drivers and equalize the input currents to the cascode current ISE. The principle is that the smaller the driving current, the larger the current of the first bypass unit SH1 in the driving device, and at the same time, the smaller the current of the first bypass unit SH1 in the driving device with the larger driving current. The first bypass unit SH1 is required to be able to regulate its current itself.

Referring to fig. 3, the multi-stage driving apparatus is connected in series: when there IS a mismatch between the driving current IS set by any one of the driving devices, such as the third driving device 100, and the driving current IS set by the other driving devices, such as the sixth driving device, the first bypass unit SH1 in any one of the driving devices, such as the third driving device 100, IS required to adaptively adjust the self current so as to ensure that the respective input currents flowing into the different driving devices are equal. For example, if the third driving device 100 sets a driving current IS lower than the driving currents IS of other driving devices, such as the sixth driving device, the so-called first bypass unit SH1 in the third driving device should increase the current to equalize the input currents of the third and sixth driving devices. As compared with the drive current IS set by the third drive device 100, which IS slightly higher than the drive current IS set by another drive device such as the sixth drive device, the so-called first bypass unit SH1 in the third drive device should reduce the current so that the input currents of the third and sixth drive devices are equal to each other and equal to the cascade current ISE.

Referring to fig. 3, the mismatch mechanism includes that the multi-stage driving devices receive respective communication data asynchronously: when the previous frame of communication data sent to the cascade-connected multi-stage driving devices is refreshed to the next frame of communication data, the first type data of one part of the driving devices are updated according to the next frame of communication data, and the first type data of the other part of the driving devices are still determined by the previous frame of communication data. So that in the multi-stage driving device under the series structure, there is a mismatch between the driving current set by one part of the driving devices and the driving current set by another part of the driving devices. The earlier the cascade position is, the earlier the time point of receiving the communication data is, and the later the cascade position is, the later the time point of receiving the communication data is. The mechanism for making the difference between the drive current set by any one of the drive devices and the drive current set by the other drive device includes: the multiple drives are unsynchronized in their receipt of their respective communication data, and this discrepancy is substantially similar in principle to the mismatch described above.

Referring to fig. 7, in an alternative example, a second bypass unit SH2 is connected between the power supply input terminal VCC and the potential reference terminal GND as shown. The effect of the so-called second bypass unit SH2 is set on the premise that the multistage drive 100 is connected in series (fig. 3): when the voltage drop between the power input terminal VCC of the driving device and the potential reference terminal GND exceeds the second threshold voltage or the critical voltage set by the second bypass unit SH2, the second bypass unit SH2 is turned on to perform the functions of voltage stabilization and current division, thereby preventing the driving device from being damaged. The second bypass unit SH2 acts as an optional, rather than a required, item so as to allow in some embodiments the second bypass unit SH2 to be discarded directly.

Referring to fig. 3, in an alternative example, the cascade current flowing through each column driver is ISE. When there IS a mismatch between the driving current IS set by any one of the driving devices and the driving currents IS set by the remaining driving devices, the so-called first bypass unit SH1 in any one of the driving devices adaptively adjusts its current, thereby ensuring that the input currents respectively flowing into the different driving devices are equal and are all the cascade currents ISE. When the driving current IS set by any one of the driving devices IS lower than the driving currents IS set by the remaining other driving devices, the first bypass unit SH1 turns up the current, and when the driving current IS set by the corresponding one of the driving devices IS higher than the driving currents IS set by the other driving devices, the first bypass unit SH1 turns down the current flowing through itself. The current of the first bypass unit SH1 of any one of the driving devices may be continuously dynamically changed so as to automatically adapt to the aforementioned mismatch with respect to the driving current existing in any one of the driving devices. The method for the driving device to adjust the self current means that the driving device adjusts the input current or the output current and makes the input current or the output current equal to or follow the cascade current ISE.

Referring to fig. 8, in an alternative example, the input current or the output current of an optional one of the driving devices 100 of fig. 2-3 can be approximately represented by a curve 108 shown in the figure. A voltage drop level between the power supply input VCC and the potential reference GND of the drive means is represented approximately by the abscissa in the coordinate system, and a current level representing an input current flowing into the drive means or an output current flowing out is represented approximately by the ordinate in the coordinate system. The input current of the driver, which is equal to its output current and which is also equal to the cascade current ISE flowing through the series-connected multi-stage drivers, flows from the supply input VCC and the output current flows from the potential reference GND. If the aforementioned first type of data, i.e., the current adjustment data, IS additionally used to fine-tune the value of the driving current IS, for example, the criterion of adjusting the value of the driving current to a relatively small water level can be approximately represented by the curve 208 shown in the figure. The value of the drive current represented by curve 208 is significantly smaller than the value of the drive current represented by curve 108. The mismatch problem of the driving current IS discussed in the following text with the curve 108 as the object of study, and it IS noted that if the driving current IS burned in advance, it IS not necessary to edit and modify the driving current online through communication data, and the curve 208 in the figure can be omitted.

Referring to fig. 8, in an alternative example, fig. 3 is incorporated. In a series multi-stage drive: when the driving current IS set by any one driving device IS lower than the input current of the driving device in the cascade connection, the first bypass unit SH1 in the driving device adaptively increases the current. Thereby ensuring that the input current of any one of the drive devices can still be maintained at a level equal to the cascade current ISE. If the drive current IS set to 12mA for the first drive device of the train and the cascade current ISE IS toggled by the drive currents IS set for the remaining other drive devices, the input current of the first drive device of the train has a tendency to be lower than the cascade current ISE, provided that the drive currents IS of the other drive devices are around 15mA, then the first bypass unit SH1 in the first drive device of the train should adaptively increase the current to overcome the aforementioned negative tendency. To the right of the turning point N1 on the curve 108 representing the input current of the driving device, the first bypass unit SH1 starts to conduct, so that the input current of the driving device will slightly change to overcome the negative effect caused by the difference of the driving currents IS. Since the driving current IS of other driving devices IS set to be about 15mA, the first bypass unit SH1 of other driving devices may also adaptively reduce the current according to the rule of the present application, ensuring that the input currents of different driving devices are equal.

Referring to fig. 8, in an alternative example, fig. 3 is incorporated. In a series multi-stage drive: when the driving current IS set by any one driving device so that the input current of the any one driving device tends to be higher than the aforesaid cascade current ISE flowing through the cascade of the multi-stage driving devices connected in series, the first bypass unit SH1 in the any one driving device adaptively reduces the current. Thereby ensuring that the input current of any one of the drive devices can still be maintained at a level equal to the cascade current ISE. If the drive current IS set to 14mA for the first drive device of the train and the cascade current ISE IS toggled by the drive currents IS set for the remaining other drive devices, the input current of the first drive device of the train has a tendency to be higher than the cascade current ISE, provided that the drive currents IS of the other drive devices are around 10mA, then the first bypass unit SH1 in the first drive device of the train should be adapted to reduce the current to overcome the aforementioned negative tendency. To the left of the turning point N1 on the curve 108 representing the input current of the drive device is the first bypass unit SH1 which starts to turn off. Since the driving current IS of other driving devices IS set to be about 10mA, the first bypass unit SH1 of other driving devices may also adaptively increase the current according to the rule of the present application, ensuring that the input currents of different driving devices are equal.

Referring to fig. 8, in an alternative example, fig. 3 is incorporated. There is usually a reduction in the voltage drop between the supply input VCC of the drive means and the so-called potential reference GND. The voltage drop of the driving device is induced by various factors such as the voltage drop of the power supply. For example, if the voltage drop of one part of the series-connected multi-stage driving devices occupies a large voltage share of the external power supply, and the voltage drop of the other part of the series-connected multi-stage driving devices occupies a small voltage share of the external power supply, i.e., the voltage distribution is not uniform, the voltage drop of the driving device occupying a small voltage share of the external power supply will naturally tend to be reduced. The voltage drop is reduced, which is accompanied by the input and output currents of the driving device tending to be reduced, and the voltage drop is observed to be reduced on the left side of the turning point N1 on the curve 108, so that the charging behavior of the capacitor CZ connected between the power input terminal and the potential reference terminal of the driving device can avoid the voltage drop from being reduced too much. The solution that the reduction of voltage drop causes the abnormal operation of the driving device and may not be operated normally is as follows: if the constant current unit CS1 is turned off and the first bypass unit SH1 is turned off, the capacitor CZ is forced to be charged, the charging means that the voltage drop will rise and the driving apparatus may recover to the turning point N1, but the driving apparatus is in an under-voltage state after all, the rise of the voltage drop will be interrupted quickly and fall to the left side of the turning point N1 and the input/output current tends to decrease, and it is necessary to turn off the constant current unit CS1 and turn off the first bypass unit SH1 to charge the capacitor CZ according to the design rules, and so on.

Referring to fig. 8, in an alternative example, fig. 7 is incorporated. The voltage drop between the power input end of the driving device and the potential reference end exceeds a second threshold voltage or a critical voltage set by the second bypass unit SH2, and the second bypass unit SH2 is conducted to play the roles of voltage stabilization and shunt. To the right of the transition point N2 on the curve 108 representing the input current of the driving device, it can be seen that the input current rises sharply, and to the right of the transition point N2, it indicates that the voltage drop of the driving device is at a high level and sufficient to trigger the second bypass unit SH2 to be turned on, and to the left of the transition point N2, the second bypass unit SH2 is turned off. In an alternative example, the second bypass unit SH2 includes a conventional voltage regulator circuit, which has a second threshold voltage and is turned on when the voltage drop exceeds the second threshold voltage set by the second bypass unit SH 2.

Referring to fig. 8, in an alternative example, fig. 3 is incorporated. When the driving current IS set by any one driving device IS different from the driving currents IS set by the rest of the driving devices, the first bypass unit SH1 in the driving device adaptively increases or decreases the current, thereby ensuring that the input currents flowing into the different driving devices connected in series are equal. In a preferred embodiment, the current of the first bypass unit of any one of the driving devices is allowed to be automatically and dynamically adjusted up or down continuously, so that any one of the driving devices automatically adapts to the existing mismatch. For example, any one of the actuators operates between the illustrated transition point N1 and the illustrated transition point N2: the continuous automatic dynamic adjustment of the current of the first bypass unit SH1 means that the requirement that the input current of the driving device follows the cascade current ISE is met, and in fact, this current self-regulation is also the process of each driving device in finding its proper voltage operating point.

Referring to fig. 9, a three-way led load is illustrated for ease of explanation. The specific number of loads is not limiting and is for reference only. Referring to fig. 10, when the data transmission module COM decodes multiple sets of second-type data in the communication data, the first PWM module MOD1 forms the first PWM signal PWM1 corresponding to the first led, i.e., R, according to the second-type data distributed to the first led, i.e., R, and according to the same principle, the second PWM module MOD2 forms the second PWM signal PWM2 corresponding to the second led, i.e., G, according to the second-type data distributed to the second led, i.e., G. And for the same reason, it can be known that the third PWM module MOD3 forms the third PWM signal PWM3 corresponding to the third led, i.e., B, according to the second type data distributed to the third led, i.e., B. Therefore, each pulse width modulation module in the driving device forms a corresponding pulse width modulation signal according to the second type data matched with the corresponding or paired light emitting diode. Specifically, each pulse width modulation module forms a pulse width modulation signal corresponding to each light emitting diode according to the second type data distributed to each light emitting diode. In addition, the multi-path light emitting diode can also comprise a white light emitting diode besides the three primary color light sources of red, green and blue, or comprise two green and red and blue, and the like. If the lighting display scene needs more LED light sources, the three LEDs can be increased to more LEDs, and if the lighting display scene needs less LED light sources, the three LEDs can be reduced to one to two LEDs. The second type of data may include, for example, data including duty cycle information or gray scale data and the first type of data may include current regulation data. Representative of the first through third pwm modules described above is the illustrated pwm module MOD 1-3.

Referring to fig. 10, the light emitting diodes are connected in series with a common constant current unit. The first light emitting diode, i.e., R, is connected in series with the common constant current unit CS1 through the corresponding first switch S1, the second light emitting diode, i.e., G, is connected in series with the common constant current unit CS1 through the corresponding second switch S2, and the third light emitting diode, i.e., B, is connected in series with the common constant current unit CS1 through the corresponding third switch S3. When the pulse width modulation signal corresponding to any one of the light emitting diodes has an effective logic level, the common constant current unit CS1 is enabled and any one of the light emitting diodes is switched to be connected in series with the common constant current unit CS1 to be turned on. When the first pwm signal has an active logic level, for example, a high level, the first switch S1 is turned on, so that the common constant current unit CS1 is enabled and the first light emitting diode, i.e., R, is switched to be connected in series with the common constant current unit CS1 to light up. When the second pwm signal has a high logic value, the second switch S2 is turned on to further enable the common constant current unit CS1 and the second light emitting diode, i.e., G, is switched to be connected in series with the common constant current unit CS1 to be turned on. When the third pwm signal is asserted, the third switch S3 is turned on to further enable the constant current unit CS1 and the third led, B, is switched to be connected in series with the common constant current unit CS1 to be turned on. The effective logic levels of the first path to the third path of pulse width modulation signals are set to be non-overlapping, namely, the three paths of light emitting diodes are not lighted simultaneously. Such load combinations as the three-way leds described above may constitute basic pixel sites and fig. 9 may now be used in the display field.

Referring to fig. 10, when the first to third pulse width modulation signals PWM1-PWM3 are used, a single period of the pulse width modulation signals is divided into three sub-periods, and the effective logic level of each pulse width modulation signal is distributed in a corresponding one of the sub-periods. The result of the NOR operation performed by the first through third PWM signals PWM1-PWM3 is taken as the control signal DX of the bypass module, and the occurrence of the active logic level such as high level in the control signal DX triggers the parallel branches to conduct, for example, the conventional resistor W of the parallel branches to conduct. The input terminals of the nor gate 300 respectively input the first to third pulse width modulation signals PWM1-PWM3, etc., and the control signal DX output by the nor gate 300 is used to control whether the parallel branches are turned on. The conventional resistor W of the parallel branch is connected in series with the common constant current unit CS1 through the fourth switch S4 corresponding thereto. For the same reason, when the control signal DX is asserted, e.g., high, the fourth switch S4 is turned on to further enable the common constant current cell CS1 and the conventional resistor W is switched to be energized in series with the constant current cell CS 1. Substitutes for the conventional resistor W, such as light emitting diodes or non-light emitting conventional diodes, even active loads such as MOS transistors in diode connection, are permissible forms of loads.

Referring to fig. 10, in an alternative example, a driving device for driving the first to third light emitting diodes is taken as an example to explain the scheme of the present example. The result of the NOR operation performed by the PWM signals PWM1-PWM3, etc. is considered as the control signal DX of the parallel branch. The low level period of the first PWM signal 1 for the first sub-period of a single cycle makes the control signal DX high, the low level period of the second PWM signal 2 for the second sub-period makes the control signal DX high, and the low level period of the third PWM signal PWM3 for the third sub-period makes the control signal DX high. In this example, if the drive device drives only three light-emitting diodes, the total time length of the cycle period is the total duration of the sum of the three sub-periods, i.e., the single cycle period time is divided into three sub-periods and the active logic level of each pulse-width modulation signal is allocated in a corresponding one of the sub-periods. It is further noted that the parallel branch is turned on during the time period when the control signal DX is high.

Referring to fig. 11, in an alternative example, the first bypass unit SH1 includes a zener diode SR and a resistor RL connected in series between the power supply input terminal VCC and a so-called potential reference terminal GND. The cathode or anode of the zener diode SR is coupled to the supply input VCC via a resistor RL, the anode or anode of the zener diode SR is coupled to the so-called potential reference GND, and the positions of both the zener diode SR and the resistor RL can be reversed. The zener diode SR can be coupled directly between the supply input VCC and the potential reference GND if the resistor RL is omitted. The first bypass unit SH1 is turned on when the voltage drop of the driving device is not lower than a threshold voltage that makes the zener diode SR turn on by reverse breakdown, otherwise the first bypass unit SH1 is turned off. Namely: when the voltage drop is not lower than the critical voltage to cause the reverse breakdown of the Zener diode SR, the first bypass unit SH1 is switched on; when the voltage drop is lower than the critical voltage, the zener diode SR is turned off, and the first bypass unit SH1 is turned off. The second bypass unit SH2 comprises in an alternative example a zener diode ZR, the cathode or anode of which is coupled to the supply input VCC and the anode or cathode of which is correspondingly coupled to the potential reference GND. It is defined that the threshold voltage for reverse breakdown of the zener diode SR is a first threshold voltage, the threshold voltage for reverse breakdown of the zener diode ZR is a second threshold voltage, and the second threshold voltage is much larger than the first threshold voltage according to the curve 108 of the input current of the driving apparatus.

Referring to fig. 11, in an alternative example, when the voltage drop between the power input terminal VCC and the potential reference terminal GND exceeds the second threshold voltage set by the second bypass unit SH2, the second bypass unit SH2 is turned on. When the opposite voltage drop is lower than the second threshold voltage set by the second bypass unit SH2, the second bypass unit SH2 is turned off. For example, the second threshold voltage may be a threshold voltage at which the zener diode ZR breaks down in the reverse direction. The second bypass unit SH2 is turned on only when the voltage drop is not lower than the threshold voltage so that the zener diode ZR is reverse-breakdown, and the second bypass unit SH2 is turned off when the voltage drop is lower than the threshold voltage so that the zener diode ZR is turned off.

Referring to fig. 11, in an alternative example, an embodiment in which the second bypass unit SH2 replaces the zener diode ZR may use a voltage comparator, for example. The voltage comparator compares the voltage drop between the power input terminal VCC and the potential reference terminal GND with the second voltage, and a switch is connected between the power input terminal VCC and the potential reference terminal GND of the driving device and controlled by the comparator. When the voltage drop between the power input terminal VCC and the potential reference terminal GND exceeds the second voltage set by the second bypass unit SH2, the comparison result of the voltage comparator turns on the switch so that the second bypass unit SH2 is turned on. In contrast, when the voltage drop between the power input terminal VCC and the potential reference terminal GND is lower than the second voltage set by the second bypass unit SH2, the comparison result of the voltage comparator turns off the switch so that the second bypass unit SH2 turns off. The embodiment using voltage comparators is not shown in the figure. The second voltage applied by the voltage comparator may be the same voltage value as the aforementioned second threshold voltage, and the changeover switch is preferably connected in series with an element having a larger resistance value, such as a resistor, between the power supply input terminal and the potential reference terminal.

Referring to fig. 11, in an alternative example, an embodiment in which the first bypass unit SH1 replaces the zener diode SR may use a voltage comparator, for example. The voltage comparator compares the voltage drop between the power input terminal VCC and the potential reference terminal GND with the first voltage, and a switching switch is connected between the power input terminal VCC and the potential reference terminal GND and controlled by the comparator. When the voltage drop between the power input terminal VCC and the potential reference terminal GND exceeds the first voltage set by the first bypass unit SH1, the comparison result of the voltage comparator turns on the on-off switch so that the first bypass unit SH1 is turned on. Conversely, when the voltage drop between the power input terminal VCC and the potential reference terminal GND is lower than the first voltage set by the first bypass unit SH1, the comparison result of the voltage comparator turns off the on-off switch so that the first bypass unit SH1 turns off. The embodiment using voltage comparators is not shown in the figure. The first voltage applied by the voltage comparator and the first threshold voltage may be the same voltage value, and the switch is preferably connected in series with a component having a larger resistance value, such as a resistor and a zener diode, between the power input terminal and the potential reference terminal.

Referring to fig. 11, in an alternative example, the first bypass unit SH1 is replaced by: a resistor RL, a zener diode ZR, and a current source not shown in the figure are connected in series between the so-called power supply input VCC and the potential reference GND of the drive device. The voltage drop of the driving device is not lower than a critical voltage at which the zener diode SR can be reverse breakdown, but the first bypass unit SH1 is turned on, otherwise the first bypass unit SH1 is turned off. In the example shown in the figure, another current source is additionally connected in series with the resistor RL and the zener diode ZR.

Referring to fig. 11, in an alternative example, the first bypass unit SH1 is replaced by: a resistor RL, a zener diode ZR, and a junction field effect transistor not shown in the figure are connected in series between the so-called supply input VCC and the potential reference GND of the drive device. The Zener diode SR and the resistor RL are connected in series between the first end of the junction field effect transistor and the power input end VCC, the control end of the junction field effect transistor is coupled to the potential reference end GND, and the second end of the junction field effect transistor is coupled to the potential reference end GND through another clamping resistor. In the example shown, another junction field effect transistor is connected in series with the resistor RL and the zener diode ZR. The first and second terminals of the junction field effect transistor are for example the drain and the source, respectively, or the source and the drain, respectively. When the voltage drop of the driving device is not lower than the critical voltage to cause reverse breakdown of the zener diode SR, the first bypass unit SH1 is turned on; when the voltage drop is lower than the critical voltage, the zener diode SR is turned off, and the first bypass unit SH1 is turned off. In other words, the topology of the first bypass unit and the second bypass unit has many alternatives in addition to the examples shown in the figures, but the topology shown in the figures is simpler and relatively cost-effective and belongs to a preferred, but not the only, embodiment. For example, various examples of the voltage stabilizing circuit included in the second bypass unit and various examples of the first bypass unit are described above.

Referring to fig. 11, in an alternative example, the description is explained in conjunction with fig. 3. N drive devices 100 are connected in series between a positive electrode VP and a negative electrode VN of a power supply such as an external power supply. The voltage drop experienced by the first drive 100 itself is DIV1, the voltage drop experienced by the second drive 100 itself is DIV2, and so on until the voltage drop experienced by the so-called nth drive 100 itself is DIVN. If the voltage value of the external power supply is relatively stable and the characteristics of the driving devices are consistent, the voltage difference between the voltage drops DIV1, DIV2, and … … DIVN is very small, so as not to affect the normal operation of the driving device 100. However, once the voltage of the external power supply slightly increases and there is a difference between the driving devices, the voltage difference between the voltage drops DIV1, DIV2, and … … DIVN will increase and will negatively affect the normal operation of the driving device 100, and the difference is naturally present.

Referring to fig. 11, in an alternative example, the description is explained in conjunction with fig. 3. The sum of the voltage drops of the driving apparatus 100 is the voltage of the external power supply. The power supply voltage of the external power supply is functionally expressed, i.e., the sum of the voltage drops DIV1+ DIV2+ … … + DIVN. The supply power ripple or supply power is increased slightly and the variation of the supply power is sufficient to allow a large voltage difference between the series voltage drops DIV1, DIV2, … … DIVN. For example, voltage drop DIV2 is much larger than voltage drop DIV1, for example, voltage drop DIVN is much smaller than voltage drop DIV 1. In essence, the voltage of the power supply is not uniformly distributed to the respective driving devices 100, and there is a great randomness and unpredictability in such voltage distribution to the driving devices 100. The driving device 100 with an excessive voltage drop across the terminals is often in an overvoltage state, which causes an abnormal situation of large power consumption and high heat. The driving device 100 with too small voltage drop between the two ends may be under-voltage and fail to operate normally. In general, the service life of the drive device 100 under overvoltage will be terminated early, which may cause the entire row of drive devices 100 to enter a situation where they cannot be used. The reason for the above disadvantages is that the increased voltage, which is a slight or large change of the power supply, is always concentrated at one or a few drive devices.

Referring to fig. 11, in an alternative example, the description is explained in conjunction with fig. 3. The situation that the first bypass unit SH1 has the self-adaptive high current IS based on the situation that the driving current IS set by the driving device 100 deviates and the current IS small, the power consumption of the constant current unit IS relatively low, and the heat generation amount IS relatively small, and in this situation, the first bypass unit SH1 increases the self current, which IS equivalent to raising the voltage drop of the driving device 100 by the internal resistor. The adaptive low current condition of the first bypass unit SH1 IS based on the situation that the driving current IS set by the driving device 100 deviates and the current IS large, the power consumption of the constant current unit IS relatively high, and the heat generation IS relatively large, in this case, the first bypass unit SH1 reduces the self current, which IS equivalent to the voltage drop of the driving device 100 by pulling down the internal resistor. The driving device with low power consumption and less heat productivity can increase the power consumption of the driving device by the voltage drop increase, and the driving device with high power consumption and more heat productivity can decrease the power consumption of the driving device by the voltage drop decrease. Through the adaptive adjustment of the current and the voltage, the supply voltage of the power supply can be distributed to the various drive devices connected in series in a relatively balanced manner. The voltage added by slight or large variation of the power supply cannot naturally be gathered at one or a few driving devices, the voltage of the power supply is reasonably distributed to each driving device and the doubts that the voltage difference between the voltage drops DIV1, DIV2, … DIVN can become large are solved. It is not possible to concentrate and distribute heat to the individual drives by only a few drives becoming heat sources. The internal resistance is, for example, a resistance RL. In some cases, it is customary to consider both the zener diode and the zener diode as zener diode components, under which condition the zener diode SR may be referred to as a first zener diode and the zener diode ZR may be referred to as a second zener diode. The driving device with smaller driving current increases the current of the first bypass unit, and the driving device with larger driving current decreases the current of the first bypass unit. Or the current of the first bypass unit in the driving device with smaller driving current is larger than the current of the first bypass unit in the driving device with larger driving current. Namely, when the driving current set by any driving device is mismatched with the driving current set by other driving devices, the first bypass unit of any driving device self-adaptively adjusts the magnitude of the current flowing through itself.

Referring to fig. 8, in an alternative example, the first threshold voltage is represented by a voltage value V1 corresponding to a transition point N1 and the second threshold voltage is represented by a voltage value V2 corresponding to a transition point N2. When the voltage drop is not lower than the first threshold voltage set by the first bypass unit, the first bypass unit SH1 is turned on and the driving device enters the first operation mode, at which time the so-called constant current unit CS1 is enabled. For example, the driving device compares the voltage drop with the first threshold voltage by using a conventional voltage detector, and the so-called constant current unit CS1 is enabled when the voltage drop is not lower than the first threshold voltage. In case the voltage drop is lower than the first threshold voltage set by the first bypass unit SH1, the first bypass unit SH is turned off and the driving device enters the second operation mode, at which time the constant current unit CS1 is disabled. For example, the driving device may compare the voltage drop of the driving device with a first threshold voltage by using a conventional voltage detector, and the so-called constant current unit CS1 is not enabled when the voltage drop is lower than the first threshold voltage. The voltage value V1 is the second operating mode on the left and the first operating mode on the right.

Referring to fig. 8, in an alternative example, a solution is provided in which a voltage drop causes an abnormal driving device that may not operate properly. When the driving device enters the second working mode, the constant current unit CS1 and the first bypass unit SH1 are closed so as to force the capacitor CZ to be charged, the driving device enters the first working mode by boosting the voltage drop, but the driving device enters the second working mode again when the voltage drop rapidly falls back and is lower than the first threshold voltage, and the driving device cyclically jumps between the second working mode and the first working mode. The cycle is caused by insufficient voltage drop, and the cycle jump can be released only when the voltage drop is increased to be not lower than the first threshold voltage, for example, the voltage level of the power supply is required to be raised to release the cycle jump of the driving device, the charging of the local capacitor of the driving device cannot release the cycle, but the charging behavior of the local capacitor of the driving device can ensure that the driving device is not down and is in a low-voltage operation state.

Referring to fig. 8, in an alternative example, when the voltage drop is not lower than the second threshold voltage set by the second bypass unit SH2, such as not lower than the voltage value V2 corresponding to the turning point N2, the driving apparatus enters the third operation mode and both the first bypass unit SH1 and the second bypass unit SH2 are turned on. It is apparent that the second threshold voltage is significantly greater than the first threshold voltage. The voltage value V2 is the first operating mode on the left and the third operating mode on the right. For example, the driving device may utilize a conventional voltage detector to compare the voltage drop with the first and second threshold voltages. When the voltage drop is lower than the voltage value V1, the driving device enters the second working mode, when the voltage drop is not lower than the voltage value V1 but is lower than the voltage value V2, the driving device enters the first working mode, and when the voltage drop is not lower than the voltage value V2, the driving device directly enters the third working mode. The driving apparatus 100 mainly includes the above three operation modes. It is noted that the input current or the output current of the drive in the second operating mode does not drop substantially sharply, since the drive also has a capacitive device, such as a capacitor CZ, connected between the power input and the potential reference. When the driving device enters the second operation mode, such capacitor device will supply power to ensure that the driving device is not powered off and still can supply weak current, for example, the capacitor CZ can still supply power to the data transmission module and the pulse width modulation module of the driving device, and even other functional modules, although the constant current unit is not enabled and the first bypass unit is also turned off at this time, other functions of the driving device are not affected. The formation of current or communication breakpoints in the multi-stage drive chain is avoided, since the capacitor CZ still supplies power to the drive. It is envisaged that if a drive is powered down without current flowing and a so-called current break is formed, the entire link is switched off. The illustrated input-output current, curve 108, drops somewhat but not so much as to approach zero in the second mode of operation. The drive means may be switchable between the three modes or may be operable in only any one of the three modes. The first bypass element is therefore indispensable for the drive but the second bypass element is optionally discardable, and the first operating mode is indispensable for the drive but the second and third operating modes are discardable.

Referring to FIG. 8, in an alternative example, the interval V1-V2 is defined as the first operating mode. When the driving current IS set by any driving device IS different from the driving current IS set by other driving devices, the so-called first bypass unit SH1 of any driving device adjusts the value of the voltage drop of any driving device while adjusting the current flowing through the first bypass unit SH1, so as to ensure that the input currents flowing into different driving devices are equal, and the voltage drops of different driving devices with different driving currents are clamped at different voltage values. Any given driving device 100 may assume that there are three cases where its driving current IS different in magnitude: the first case IS when the driving current IS large, the second case IS when the driving current IS small, and the third case IS when the driving current IS small. The first bypass unit SH1 of the driving device 100 is designated to adjust its own current to be small in the first case due to a large driving current, the first bypass unit SH1 of the driving device 100 is designated to adjust its own current to be centered in the second case due to a medium driving current, and the first bypass unit SH1 of the driving device is designated to adjust its own current to be large in the third case due to a small driving current. Then in the first case the first bypass unit SH1 has a low current so that the specified drive device 100 operates at voltage VX. And the second case where the first bypass unit SH1 is current-centered specifies that the driving device 100 is operating at the voltage VY. Also in the third case the first bypass unit SH1 is so current-intensive that the drive device 100 is designated to operate at the voltage VZ. The three cases work at voltages between the voltage intervals V1-V2, VZ is greater than VY and VY is greater than VX. It is obvious that the first bypass unit SH1 satisfying the specified driving device 100 adjusts the voltage drop value of the specified driving device 100 synchronously while adjusting the current flowing through itself. The rule is as follows: however, the voltage drop of the driving device is smaller when the driving current is larger, and the voltage drop of the driving device is larger when the driving current is smaller. Or the voltage drop of the driving device with larger driving current is lower than that of the driving device with smaller driving current.

Referring to FIG. 8, in an alternative example, the interval V1-V2 is defined as the first operating mode. Then, different driving devices are selected from the multi-stage driving connected in series for comparison. For example, it can be assumed that there IS a difference in the driving currents IS of the column-head driving device 100 and of the middle driving device 100 and the column-tail driving device 100: the specific differences are represented by the largest driving current IS of the first driving device 100, the next to the driving current IS of the middle driving device 100, and the smallest driving current IS of the column of the last driving device 100. The first bypass unit SH1 of the column header driving device 100 has the smallest current and the voltage drop of the column header driving device 100 is the smallest. The first bypass unit SH1 of the middle driving device 100 is current-centered and the voltage drop of the middle driving device 100 is centered. The first bypass unit SH1 of the row tail driving device 100 has the largest current and the voltage drop of the row tail driving device 100 is the largest. Thus, the input currents flowing into the three exemplary driving devices are equal, and the voltage drops of the three driving devices are clamped at different voltage values. Note that in addition to the drive devices as examples, in a multistage drive device: if the driving current set by any driving device is different from the driving currents set by the rest driving devices, the first bypass unit of any driving device can adjust the current flowing through the first bypass unit to ensure that the input currents flowing into different driving devices are equal, and simultaneously adjust the voltage drop of any driving device so as to clamp the voltage drops of different driving devices with different driving currents at different voltage values.

Referring to fig. 7, in an alternative example, under the premise of the first operation mode, i.e., the interval V1-V2, it is assumed that the conditions that the driving device should satisfy under ideal conditions are: the driving current IS of the driving device IS the desired current value. However, in practice, various deviations occur in the drive current IS of the drive device, which IS not equal to the desired current value. In general, the drive current of the drive device is often mismatched to be smaller or larger than the desired current value. It is noted that the particular values recited above and below for the drive current or desired current value are merely illustrative examples and are not intended to be limiting, and that the drive current or desired current value may take any reasonable current value other than the particular values recited.

Referring to fig. 7, in an alternative example, the first bypass element SH1 of the first drive device 100, whose current IS the smallest, has the drive current IS the largest and whose actual value of the drive current IS has deviated from the desired current value as previously described. At the same time, for example, the driving current IS of the column tail driving device 100 IS the smallest, and the actual value of its driving current IS has deviated from the desired current value, the current of its first bypass unit SH1 IS the largest. Examples are: for example, in the chain of the driving devices, it may be assumed that the driving device 100 at the head of the column deviates from the design rule to make the driving current IS 13mA, for example, it may be assumed that the driving device 100 at the middle deviates from the design rule to make the driving current IS 12mA, and for example, it may be assumed that the driving device 100 at the tail of the column deviates from the design rule to make the driving current IS 10 mA. There IS no doubt that there IS a drive current mismatch between the drive current IS of the first-column driver 100 and the drive currents of the middle and last-column drivers 100, assuming that they should be of the same desired current value, such as 12.5 mA. The actual value of the drive current of the leading drive means is the largest and the actual value of its drive current has deviated from the desired current value, and the actual value of the drive current of the column-trailing drive means is the smallest and the actual value of its drive current has deviated from the desired current value. The current of the first bypass unit SH1 of the leading driving device is substantially the smallest and the current of the first bypass unit SH1 of the column trailing driving device is substantially the largest.

Referring to fig. 12, in an alternative example, the first bypass unit SH1 includes a three-terminal adjustable shunt reference source TL and a resistance RL connected in series between the power supply input terminal VCC and a so-called potential reference terminal GND. For example, the cathode or negative pole of the three-terminal adjustable shunt reference source TL is set to be coupled to the power supply input VCC through the resistor RL, and the anode or positive pole of the three-terminal adjustable shunt reference source TL is also set to be coupled to the so-called potential reference GND, it should also be noted that the positions of both the three-terminal adjustable shunt reference source TL and the resistor RL may be reversed. A specified voltage or a predetermined voltage can be inputted to the voltage reference terminal of the three-terminal adjustable shunt reference source TL, i.e., the REF terminal. The specified voltage or the preset voltage can be provided by a band-gap reference source arranged inside the driving device. Typically the three terminal adjustable shunt reference TL is an integrated circuit rather than a discrete device such as a zener diode, which can be nearly functionally equivalent to a zener diode that is adjustable. The terms of adjustable shunt reference voltage source or adjustable precision shunt regulator or programmable reference source circuit or three-terminal programmable shunt regulator or programmable shunt type voltage reference source are used to describe the three-terminal adjustable shunt reference source TL, but the naming rule and habit are slightly different, the cathode K and anode a and the reference terminal REF (reference) are three interface terminals of the three-terminal adjustable shunt reference source, and the reference terminal REF is also called voltage reference terminal or voltage reference terminal. The three-terminal adjustable shunt reference source can be designed into an independent device and can be integrated into a driving chip to be used as a partial sub-functional module of the driving chip.

Referring to fig. 12, in an alternative example, when the voltage drop between the power input terminal VCC and the potential reference terminal GND is not lower than the first threshold voltage set by the first bypass unit SH1, the first bypass unit SH1 is turned on. When the reverse voltage drop is lower than the first threshold voltage set by the first bypass unit SH1, the first bypass unit SH1 is turned off. The first threshold voltage may be a minimum operating voltage required for the three-terminal adjustable shunt reference source TL to conduct. When the voltage drop is not lower than the minimum working voltage to enable the three-terminal adjustable shunt reference source TL to be sufficiently conducted, the first bypass unit SH1 is turned on, and when the voltage drop is lower than the minimum working voltage, the three-terminal adjustable shunt reference source TL is turned off and the first bypass unit SH1 is turned off. In other words, the first threshold voltage is determined by the minimum working voltage required by the three-terminal adjustable shunt reference source when the three-terminal adjustable shunt reference source is conducted: the minimum working voltage is the minimum voltage value required for conducting the three-terminal adjustable shunt reference source and normally working, the voltage drop is not lower than the minimum voltage value, and then the circulating current can be formed in the first bypass unit and the three-terminal adjustable shunt reference source, and if the voltage drop is lower than the minimum voltage value, the circulating current cannot be formed in the first bypass unit and the three-terminal adjustable shunt reference source. The minimum working voltage is also called a lower limit voltage value required by the conduction and normal work of the three-terminal adjustable shunt reference source. The second bypass unit SH2 may also use a three-terminal adjustable shunt reference source as a substitute for the zener diode, for example, when the second threshold voltage set by the second bypass unit is greater than the first threshold voltage, the second threshold voltage is determined by the minimum operating voltage required when the three-terminal adjustable shunt reference source of the second bypass unit is turned on, which is an optional embodiment, and of course, the second bypass unit may still use a zener diode or a voltage comparator.

While the present invention has been described with reference to the preferred embodiments and illustrative embodiments, it is to be understood that the invention as described is not limited to the disclosed embodiments. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above description. It is therefore intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention. Any and all equivalent ranges and contents within the scope of the claims should be considered to be within the intent and scope of the present invention.

Claims

1. A drive device, comprising:

a power input terminal and a potential reference terminal;

2. The drive device according to claim 1, characterized in that:

the system also comprises a data transmission module and a pulse width modulation module;

the data transmission module is used for receiving communication data;

3. The drive device according to claim 1, characterized in that:

the data transmission module is used for forwarding communication data;

4. The drive device according to claim 1, characterized in that:

the first bypass unit of any one driving device synchronously adjusts the voltage drop between the power supply input end and the potential reference end of any one driving device while adjusting the current of the first bypass unit:

5. The drive device according to claim 1, characterized in that:

a capacitive device is connected between the power input terminal and the potential reference terminal.

6. The drive device according to claim 1, characterized in that:

the mechanisms causing the mismatch include at least:

7. The drive device according to claim 1, characterized in that:

when the voltage drop between the power supply input end and the potential reference end of the driving device is not lower than the first threshold voltage set by the first bypass unit: the first bypass unit is turned on, otherwise the first bypass unit is turned off.

8. The drive device according to claim 1, characterized in that:

the second bypass unit is connected between the power supply input end and the potential reference end;

9. The drive device according to claim 7, characterized in that:

the first bypass unit comprises a three-end adjustable shunt reference source and a resistor which are connected between a power supply input end and a potential reference end in series; the first threshold voltage is determined by the minimum working voltage required by the three-terminal adjustable shunt reference source when the three-terminal adjustable shunt reference source is conducted.

10. The drive device according to claim 8, characterized in that:

11. A method for adjusting self current of a driving device is characterized in that:

the driving device includes:

a power input terminal and a potential reference terminal;

a constant current unit which can supply a driving current to a load;

the method comprises the following steps:

connecting the multi-stage driving devices in series;

12. The method of claim 11, wherein:

a voltage drop exists between the power supply input end and the potential reference end of each driving device;

13. The method of claim 11, wherein:

14. The method of claim 11, wherein:

15. The method of claim 13, wherein:

the first bypass unit comprises a three-end adjustable shunt reference source and a resistor which are connected in series between the power supply input end and the potential reference end, and a specified voltage is input to the voltage reference end of the three-end adjustable shunt reference source;

the first threshold voltage is determined by the minimum working voltage required by the three-terminal adjustable shunt reference source when the three-terminal adjustable shunt reference source is conducted.

16. The method of claim 14, wherein:

17. The method of claim 13, wherein:

the driving device is also connected with a capacitance device between the power supply input end and the potential reference end;

18. The method of claim 11, wherein:

the data transmission module is used for receiving communication data;

19. The method of claim 11, wherein:

the data transmission module is used for forwarding communication data;

20. A drive device, comprising:

a power input terminal and a potential reference terminal;

a constant current unit which can supply a driving current to a load;

the constant current unit and the first bypass unit are in parallel connection;

21. The drive of claim 20, wherein:

and a voltage drop exists between the power supply input end and the potential reference end of the driving device, and the voltage drop of the driving device is smaller when the driving current is larger, and the voltage drop of the driving device is larger when the driving current is smaller.

22. The drive of claim 20, wherein:

when the voltage drop between the power supply input end and the potential reference end of the driving device is not lower than the first threshold voltage set by the first bypass unit: the first bypass unit is turned on, otherwise, the first bypass unit is turned off;

23. The drive of claim 22, wherein:

24. The drive of claim 20, wherein:

the data transmission module is used for receiving communication data;

25. The drive of claim 20, wherein:

the data transmission module is used for forwarding communication data;

26. A system, comprising:

each of the driving devices includes:

a power input terminal and a potential reference terminal;

a constant current unit which can supply a driving current to a load;

the data transmission module receives and forwards communication data;

in the system:

27. The system of claim 26, wherein:

28. The system of claim 26, wherein:

in each drive device:

29. The system of claim 26, wherein:

in each drive device:

the voltage drop between the power input end and the potential reference end is not lower than the critical voltage of reverse breakdown of the voltage stabilizing diode, and the second bypass unit is switched on.

30. The system of claim 26, wherein:

each drive device is further connected with a capacitive device between the power supply input terminal and the potential reference terminal.

31. The system of claim 26, wherein:

the load comprises a light emitting diode.

32. The system of claim 26, wherein:

the drive device is designed in the form of a drive chip.

33. A drive device, comprising:

a constant current unit which can supply a driving current to a load;

the multistage drive devices are connected in series:

34. The drive of claim 33, wherein:

35. The drive of claim 34, wherein:

the first bypass unit comprises a three-end adjustable shunt reference source and a resistor which are connected between a power supply input end and a potential reference end in series; the first threshold voltage is determined by the minimum working voltage required by the conduction of the three-terminal adjustable shunt reference source;

36. The drive of claim 33, wherein:

each driving device is also connected with a capacitance device between the power supply input end and the potential reference end;

37. The drive of claim 33, wherein:

each driving device also comprises a data transmission module and a pulse width modulation module;

the data transmission module is used for receiving communication data;

38. The drive of claim 33, wherein:

each driving device also comprises a data transmission module, and the data transmission module is used for transmitting communication data;

39. The drive of claim 33, wherein:

on the premise of the first operation mode, the current of the first bypass unit in the driving device with larger driving current is smaller, and the current of the first bypass unit in the driving device with smaller driving current is larger.