CN111031633B

CN111031633B - Flash lamp driving circuit

Info

Publication number: CN111031633B
Application number: CN202010023830.1A
Authority: CN
Inventors: 贾玉虎
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2020-01-09
Filing date: 2020-01-09
Publication date: 2021-09-24
Anticipated expiration: 2040-01-09
Also published as: WO2021139653A1; CN111031633A

Abstract

An exemplary embodiment of the present application discloses a flash driving circuit, which at least includes: flash light, driver chip and power, wherein: the driving chip is connected with the flash lamp and used for starting a booster circuit in the driving chip when a photographing instruction is received; the booster circuit is used for providing voltage for the flash lamp when the forward voltage of the flash lamp is higher than the power supply voltage so as to enable the flash lamp to flash.

Description

Flash lamp driving circuit

Technical Field

The present application relates to the field of flash drive technology, and relates to, but is not limited to, a flash drive circuit.

Background

In the related technology, on a mobile phone and a mobile power supply, a Metal Oxide Semiconductor (MOS) tube is additionally arranged on a path of a charging circuit integrated chip (charge) of an input power supply and a switching power supply to connect a power supply and ground, when a high-temperature event of the charging path is detected, the additionally arranged MOS tube is opened, a short-time large current is generated on the charging path, overcurrent protection of an external adapter for supplying power to the switching power supply is triggered, and the external adapter is turned off to output, so that equipment on the path is prevented from being heated and burnt due to long-time short-circuit current; however, due to the additional arrangement of the MOS transistor, the material cost is increased, the circuit area is increased, and the precious space of the electronic product is occupied.

Disclosure of Invention

In view of the above, an exemplary embodiment of the present application provides a flash driving circuit to solve at least one problem in the related art.

The technical scheme of an exemplary embodiment of the present application is realized as follows:

an exemplary embodiment of the present application provides a flash driving circuit, including:

the flash drive circuit includes at least: flash light, driver chip and power, wherein:

the driving chip is connected with the flash lamp and used for starting a booster circuit in the driving chip when a photographing instruction is received;

the booster circuit is used for providing voltage for the flash lamp when the forward voltage of the flash lamp is higher than the power supply voltage so as to enable the flash lamp to flash.

In the above circuit, the driving chip further includes:

the interface and control module is used for adjusting the current working mode to a direct-connection mode when the forward voltage of the flash lamp is lower than the power supply voltage, disconnecting the booster circuit and sending a control instruction to a high-power light-emitting diode driving module in the driving chip;

the high-power light-emitting diode driving module is used for responding to a received control instruction and adjusting the current of the flash lamp so as to enable the current of the flash lamp to be smaller than a preset current threshold value.

In the above circuit, the driving chip further includes:

the short-circuit protection module is connected with the voltage output end of the flash lamp and used for monitoring the output voltage of the flash lamp, controlling a fault register position when the output voltage is smaller than a short-circuit protection threshold value, disconnecting a channel of the flash lamp and clearing the fault register position;

and the overvoltage protection module is connected with the voltage output end of the flash lamp and used for monitoring the output voltage of the flash lamp and disconnecting the passage of the flash lamp when the output voltage is greater than or equal to an overvoltage protection threshold value.

In the above circuit, the overvoltage protection module is further configured to adjust a voltage of a modulation controller in the flash lamp driving circuit to increase the output voltage of the flash lamp when the output voltage is smaller than the overvoltage protection threshold.

In the above circuit, the booster circuit further includes:

and the inductive current protection module is used for clamping the inductive current and setting the fault register when the inductive peak current of the inductive current monitored by the booster circuit is greater than the inductive current threshold value.

In the circuit, the booster circuit is respectively connected with the first capacitor, the inductor and the second capacitor, so that the current of the output end of the booster circuit is constant current; the output end of the boosted current is connected with the flash lamp, and a battery power supply is adopted to supply power to the boosted circuit; the first capacitor is an input capacitor, and the second capacitor is an output capacitor.

In the above circuit, the driving chip further includes:

and the input/output port is used for being connected with an external controller, and in the flash process of the flash lamp, if the external controller is detected to be in a working state, the flash current of the flash lamp is reduced.

In the circuit, in the layout of the circuit board to which the driving chip belongs, the distances between the battery power supply, the first capacitor and the second capacitor and the interface and the control module are set to be smaller than a distance threshold value;

in the layout of the circuit board, the surface layers of the first capacitor and the second capacitor are connected in common and connected to a main ground through a through hole.

In the circuit, the area of the metal ground in the preset range of each component in the layout of the circuit board is larger than the preset area; and the metal ground in the preset range is connected to the ground plane through a plurality of through holes.

In the circuit, in the layout of the circuit board, a connecting wire with a preset width is adopted to connect the battery power supply and the inductor to the booster circuit;

in the circuit board layout, the area of a metal ground of a bonding pad belonging to each flash lamp in a preset range is set to be larger than a preset area threshold value, and a preset number of radiating holes are drilled in the metal ground of the bonding pad in the preset range.

An exemplary embodiment of the present application provides a flash driving circuit, wherein the flash driving circuit at least includes: flash light, driver chip and power, wherein: the driving chip is connected with the flash lamp and used for starting a booster circuit in the driving chip when a photographing instruction is received; the booster circuit is used for providing voltage for the flash lamp to enable the flash lamp to flash when the forward voltage of the flash lamp is higher than the power supply voltage; therefore, when the flash function needs to be started, the voltage is provided for the flash lamp by starting the booster circuit in the driving chip, so that the flash lamp flashes, and therefore the driving chip is used for controlling the flash of the flash lamp, and the control precision and the conversion efficiency are improved.

Drawings

Fig. 1 is a schematic diagram illustrating a structure of a flash driving circuit according to an exemplary embodiment of the present disclosure;

FIG. 2A is a schematic diagram of another exemplary flash driver circuit according to the present application;

FIG. 2B is a schematic diagram of another exemplary flash driver circuit according to the present application;

FIG. 3 is a functional block diagram of a driver chip according to an exemplary embodiment of the present application;

FIG. 4 is a schematic diagram of a flash drive according to an exemplary embodiment of the present disclosure;

fig. 5 is a PCB layout diagram of a driving circuit of a flash according to an exemplary embodiment of the present application.

Detailed Description

The technical solution in an exemplary embodiment of the present application will be clearly and completely described below with reference to the accompanying drawings in an exemplary embodiment of the present application.

An exemplary embodiment of the present application provides a flash lamp driving circuit, which is applied to an electronic device with a photographing function, such as a mobile phone, a tablet computer, a mobile power supply, and the like; fig. 1 is a schematic diagram of a structure of a flash driving circuit according to an exemplary embodiment of the present application, and as shown in fig. 1, the flash driving circuit 10 at least includes: flash 101, driver chip 102 and power supply 103, wherein:

the driver chip 102 is connected to the flash 101, and is configured to start the voltage boost circuit 121 in the driver chip 102 when receiving a photographing instruction.

Here, the driving chip 102 is in soft start, and the driving chip 102 further includes a short-circuit protection module, an overvoltage protection module, an inductive current protection module, and the like; and when the interface and control module in the driver chip 102 receives the photographing instruction, the voltage of the boost circuit in the chip is adjusted according to the voltage fed back by the amplifier in the chip. The booster circuit 121 is configured to make the output voltage higher than the input voltage. The flash 101 may be comprised of any type of photodiode, such as an LED flash. The driver chip 102 has a soft start function, the maximum soft start time is 1200 microseconds (us), the switching frequency is 100 megahertz (MHz), and the operating frequency can be set to 50MHz by software.

The voltage boost circuit 121 is configured to provide a voltage to the flash lamp to flash the flash lamp when the forward voltage of the flash lamp 101 is higher than the power supply voltage.

Here, the boost circuit 121 at least includes an inductor, a capacitor, a MOS transistor, and the like, and when the forward voltage of the flash lamp 101 is higher than the power supply voltage, the driver chip 102 activates the boost circuit to make the boost circuit in an operating state, so as to provide the flash lamp with the forward voltage according to the requirement of the internal current source. Therefore, when the flash function needs to be started, the voltage is provided for the flash lamp by starting the booster circuit in the driving chip, so that the flash lamp flashes, the driving chip is used for controlling the flash of the flash lamp, and the control precision and the conversion efficiency are improved.

In some embodiments, in order to improve the control accuracy of the driving chip on the voltage and current of the flash lamp, the driving chip 102 further includes an interface and control module and a high-power led driving module:

and the interface and control module is used for adjusting the current working mode to a direct-through mode when the forward voltage of the flash lamp is lower than the power supply voltage, disconnecting the booster circuit and sending a control instruction to the high-power light-emitting diode driving module in the driving chip.

Here, when the forward voltage of the flash lamp is lower than the Power voltage, the boost circuit does not operate, the interface and control module operates in a Pass-through (Pass-through) mode, and the flash lamp current is adjusted by an internal High Power Light Emitting Diode (HPLED DRIVER).

The high-power light-emitting diode driving module is used for responding to a received control instruction and adjusting the current of the flash lamp so as to enable the current of the flash lamp to be larger than or equal to a preset current threshold value.

Here, the high power led driving module can adjust the current of the flash lamp to make the current of the flash lamp smaller, and the preset current threshold is the current when the flash lamp normally operates. The current of the flash lamp is adjusted by adopting the high-power light-emitting diode driving module, so that the flash lamp can work normally.

In some embodiments, in order to improve the conversion efficiency of the input voltage and the output voltage, the driving chip 102 further includes a short-circuit protection module 201 and an overvoltage protection module 202, as shown in fig. 2A, fig. 2A is a schematic diagram of another constituent structure of a flash driving circuit according to an exemplary embodiment of the present application, and the following description is made with reference to fig. 1:

and the short-circuit protection module 201 is connected with the voltage output end of the flash lamp and is used for monitoring the output voltage of the flash lamp, controlling the position of the fault register 203 to be set, disconnecting the access of the flash lamp and clearing the position of the fault register when the output voltage is smaller than the short-circuit protection threshold value.

Here, the driver chip has a plurality of safety protection functions, such as short-circuit protection, overvoltage protection, inductive current protection, etc., wherein the short-circuit protection module 201 monitors the output voltage (LED _ OUT voltage) of the flash lamp, the LED _ OUT pin level is pulled low when the flash lamp is short-circuited, when the voltage of the flash lamp is detected to be lower than a short-circuit protection threshold (e.g., 1.2V (maximum 1.3V)), it is determined that the flash lamp is short-circuited, the corresponding fault register 203 bit is set, and a path is opened until the register bit is cleared; therefore, a control mechanism of software is added, and whether the circuit is short-circuited can be more sensitively monitored.

And the overvoltage protection module 202 is connected with the voltage output end of the flash lamp and is used for monitoring the output voltage of the flash lamp and disconnecting the passage of the flash lamp when the output voltage is greater than or equal to an overvoltage protection threshold value.

Here, the overvoltage protection module 202 monitors the output voltage of the flash lamp, and when the output voltage is greater than an overvoltage protection threshold (e.g., greater than 5.5V), the flash lamp is disconnected, so that the flash lamp circuit is protected.

In some possible implementations, the overvoltage protection module 202 is further configured to adjust a voltage of a modulation controller in the flash lamp driving circuit to increase the output voltage of the flash lamp when the output voltage is less than the overvoltage protection threshold; thereby increasing the current control range.

For example, when the driving circuit is turned on, the constant current source inside the circuit adjusts the modulation controller to continuously boost, the overvoltage protection module monitors the voltage of the output end, and when the voltage of the output end reaches 5.5V, the overvoltage protection module judges that the voltage is overvoltage, and the path is cut off.

In some embodiments, the driving chip further includes:

Here, the (General-purpose input/output2, GPIO2) signal at the input/output port is usually used as a transmit mask (TxMask) function, and can be connected to an enable signal of an external controller, and if the external controller works during a flash process, the signal is triggered to turn on the TxMask function, so as to reduce a flash current and prevent excessive voltage from pulling a power supply to affect normal operation of the system. If the port is not used, suspending the pin of the port; thus, the current control range is increased.

In an exemplary embodiment of the present application, the driving chip 102 further has an inductor current protection function, and an inductor current protection module is further disposed in the boost circuit, as shown in fig. 2B, fig. 2B is a schematic diagram of another composition structure of the flash lamp driving circuit according to an exemplary embodiment of the present application, and the following description is made with reference to fig. 2A:

and the inductive current protection module 221 is configured to clamp the inductive current and set the fault register when an inductive peak current of the inductive current monitored by the boost circuit is greater than an inductive current threshold.

Here, the inductor current protection module in the boost circuit monitors the inductor current, and when the inductor peak current reaches the inductor current threshold set by the driver chip, the current is limited to the threshold and will not be further increased, and meanwhile the corresponding fault register is set.

In some embodiments, the driver chip further includes a thermal sensor for monitoring a temperature in the circuit, and when the temperature in the circuit is monitored to be too high, for example, higher than a specific temperature threshold, the circuit is turned off, and components of the circuit are protected in time.

In some embodiments, in order to more accurately adjust the output voltage and current of the flash lamp, the boost circuit is respectively connected with the first capacitor, the inductor and the second capacitor, so that the current at the output end of the boost circuit is a constant current; the output end of the boosted current is connected with the flash lamp, and a battery power supply is adopted to supply power for the boosted circuit.

Here, pins VIN, SW and VOUT of the boost circuit are respectively connected to a first capacitor, an inductor and a second capacitor, the first capacitor is an input capacitor, and the second capacitor is an output capacitor, so as to ensure that the current at the output terminal of the boost circuit is a constant current.

The booster circuit is powered by battery voltage, the output end (LED _ OUT) of the booster circuit is in constant current output, and the output end is connected with the flash lamp, so that the voltage provided for the flash lamp is guaranteed to be constant voltage.

In some embodiments, in a layout of a Printed Circuit Board (PCB) of the driver chip, distances from the battery power supply, the first capacitor, and the second capacitor to the interface and the control module are set to be smaller than a distance threshold value.

Here, the driving chip is a boost circuit, and according to the requirement of a Direct current-Direct current converter (DC/DC), the inductor, the first capacitor and the second capacitor are all placed as close as possible to the interface and the control module, and the wiring is as short as possible, so that the antenna effect caused by too long wiring when the elements work at a high switching frequency is avoided; the wiring makes the drive chip have short wiring, easy layout, simple wiring and high interference resistance.

In the layout of the PCB, the surface layers of the first capacitor and the second capacitor are connected in common and connected to a main ground through a through hole.

Here, the input and output capacitors are connected in common and individually connected through the vias to the main ground, reducing DC/DC loops and interference with other circuits.

In some possible implementations, an area of the metal ground within a preset range of each component in the layout of the PCB is larger than a preset area.

Here, the metal ground in the preset range is connected to the ground plane through a plurality of through holes, and the preset range can be understood as the range around the component, so that the area of the metal ground around the component is enlarged to help heat dissipation; and the periphery of the element is connected to the ground plane through a plurality of through holes, so that noise interference on sensitive circuits is reduced.

In some possible implementations, in the layout of the PCB, the battery power source and the inductor are connected to the boost circuit by using a connection line having a width greater than a preset width.

Here, the battery power supply and the inductor are connected to the booster circuit by using wider connecting wires, and can bear larger current flowing through the switch node line of the inductor; for example, at the moment of flashing at a lower efficiency, the current may reach around 1.4 amps (a).

In the PCB layout, the area of a metal ground of a bonding pad belonging to each flash lamp in a preset range is set to be larger than a preset area threshold value, and a preset number of radiating holes are drilled in the metal ground of the bonding pad in the preset range.

Here, the lamp efficiency of the flash lamp is reduced when the temperature of the flash lamp rises, and the flash lamp is damaged when the temperature of the flash lamp exceeds the junction temperature, so that the heat dissipation area of the LED is increased in the PCB layout, for example, the heat dissipation area of a single lamp is 70-80 square millimeters, the metal area around each bonding pad is increased as much as possible, and a plurality of heat dissipation holes are broken. In order to ensure the lamp effect, the distance between the flash lamps and the camera is not more than 13mm, and if two lamps are used, the distance between the flash lamps is ensured to be within 4-10 mm (for example, the effect is better when the distance is close to 4 mm). Therefore, the wiring in the driving chip is short, the anti-interference capability is strong, the luminous efficiency is improved, the temperature rise is reduced, and the performance is reliable.

An exemplary embodiment of the present application provides a flash driving circuit, and fig. 3 is a functional block diagram of a driving chip according to an exemplary embodiment of the present application, and as shown in fig. 3, the following description is made:

the driving chip 31 is a driving scheme using a synchronous BOOST (BOOST) circuit, and has a soft start function, the maximum soft start time is 1200 microseconds (us), the switching frequency is 100 megahertz (MHz), and the operating frequency can be set to 50MHz by software. When the forward voltage of the LED is higher than the battery voltage, the BOOST circuit starts to work, and the LED forward voltage is provided according to the requirement of an internal current source. If the battery voltage is higher than the forward voltage drop of the LED, the BOOST circuit is not operated, and the interface and CONTROL module (INTERFACE AND CONTROL, IC)312 operates in Pass-through mode to regulate the flash current by internal high power flash diode drive.

In the driving chip, an inductor (L1), a capacitor (C1), a Switch (SW), a MOS transistor 313 and a MOS transistor 314 constitute the booster circuit. The capacitor C1 is an input capacitor and may be set to 10 microfarads. And sets the input voltage to 2.7 volts (V) to 5V.

The driver chip 31 has a plurality of safety protection functions:

the short-circuit protection module 301 monitors the output voltage (LED _ OUT voltage) 302 of the flash lamp, the level of the LED _ OUT pin is pulled down when the LED is short-circuited, when the voltage is detected to be lower than the short-circuit protection threshold value 1.2V (maximum 1.3V), the short circuit is determined, the corresponding fault register 303 bit is set, and the path is disconnected until the AP clears the register bit; eventually, the current through the Light Emitting Diode (LED)317 is maintained between 25 milliamps and 1.54 amps.

Here, the output (VOUT)306 provides voltage for the high power led driver 315(HPLED driver) to cause current to flow through the HPLED driver 315 to the short protection module 301 and the high power led current control module 316.

The overvoltage protection module 305, when open-circuit, the internal constant current source adjusts the modulation CONTROLLER 304 (e.g., a PWM CONTROLLER) to continuously boost voltage, and the overvoltage protection module 305 monitors the voltage at the voltage output terminal (VOUT)306, and when the voltage reaches 5.5V, determines that the voltage is overvoltage, and opens the path.

Here, VOUT 306 is connected to capacitor Cout 307, and capacitor Cout 307 is grounded to ensure the output voltage is stable. The capacitance of the capacitor Cout may be set to 10 microfarads (μ F).

The inductive current protection module: the boost circuit monitors inductor (L1) current, and when the inductor peak current reaches a software set threshold, the current is limited to this threshold and does not increase further, while the corresponding register 303 is set.

Here, the inductance L1 may be set to 1 microfarad.

In the driver chip, an amplifier 311 is used as a feedback circuit to feed back a current to the IC 312, and the interface and control module adjusts the current through the modulation controller 304. The enable signal is input to the modulation controller 304 through an Enable (EN) 319 pin, and the SCL pin 320 and the SDA pin 321 are respectively a clock and data of an Inter-Integrated Circuit (I2C) protocol. STOBE 323 is a strobe input signal that can be directly connected to the interface and control module or to the host system and triggers the signal to turn on the flash function when a photograph is to be captured.

The input/output port 1(GPIO1) and the input/output port 2(GPIO2) can be connected with an enabling signal of an external controller, the signal is triggered if the external controller works in the flash process, the TxMask function is started, and the flash current is reduced to prevent the excessive voltage of a pull power supply from influencing the normal work of the system.

In the driver chip, a thermal sensor 318 is also provided to monitor the temperature in the circuit, and when the temperature is too high, the circuit is opened and the fault register 303 is set.

Fig. 4 is a schematic diagram of a flash lamp according to an exemplary embodiment of the present application, and the following description is made as shown in fig. 4:

u1001 is the driving chip shown in fig. 3, in the driving circuit, an input Voltage (VIN)401, a Switch (SW)402 and an output Voltage (VOUT)403 form a BOOST voltage BOOST circuit, a battery (VBAT)404 is used for supplying power, and the BOOST voltage BOOST circuit is respectively connected with an input capacitor (C1001), an inductor (L1001) and an output capacitor (C1002), an LED _ OUT 405 is a constant current output and is connected with a flash lamp 1001; EN 407 is an enable signal, active high, connected to the pull-down resistor of R1001(100 kilo-ohms); the I2C signal is connected to the I2C interface of the main system, namely R1002 and R1003 are respectively connected outside a clock pin SCL 408 and a data pin SDA409 of the I2C interface (R1002 and R1003 are pull-up resistors of 2.2K kilo-ohms) (the pull-up level is 1.8V, if other levels can be considered to use different resistance values, the system requirements and the I2C specification are met); STOBE 410 is a strobe input signal that can be connected directly to the sensor or to the host system that triggers the flash function to be turned on when a photograph is to be captured. Among them, EN 407 receives the input LED FLASH enable signal (LED _ FLASH _ EN)471, the clock pin SCL 408 receives the input LED FLASH clock signal (LED _ FLASH _ SCL)481, the data pin SDA409 receives the input LED FLASH data signal (LED _ FLASH _ SDA)491, and STOBE 410 receives the input LED FLASH STROBE signal (LED _ FLASH _ STROBE) 492.

The GPIO1 signal and the GPIO2 signal are commonly used as a TxMask function and can be connected with an enable signal of an external controller, the signal is triggered if the external controller works in the flash process, the TxMask function is started, and flash current is reduced to prevent the voltage of the pull-up VBAT 404 from being too much to influence the normal work of the system. If not, the pin is floating. The GPIO1 receives the input LED FLASH touch signal (LED _ FLASH _ touch) 493.

In this circuit, the flash may be implemented using an LED 1001.

Fig. 5 is a PCB layout diagram of a driving circuit of a flash according to an exemplary embodiment of the present application, and the following description is made as shown in fig. 5:

in fig. 5, an LED4501 represents a flash lamp, U2004 is a driver chip, U2006 is a chip connected to a communication network, U2002 is an integrated stream chip, and U2101, U3002, U2704, and U2702 are antenna switches of different radio frequencies, respectively; c3013, C3020, C3019, and C3027 respectively represent capacitances of different capacities; l3005, L3003, and L3004 respectively represent inductances of different capacities; CN2703, CN2704 and CN2701, which respectively represent the table corner of the camera and the connecting line of the PCB; SH3213 denotes the position of the camera in the PCB.

A BOOST booster circuit is adopted in the driving chip, according to the DC/DC requirement, an inductor, an input capacitor and an output capacitor are all placed close to an IC as much as possible, the wiring is as short as possible, the elements work under high switching frequency, and the antenna effect is possibly caused by overlong wiring; the input and output capacitors are connected in common and connected to the main ground by punching holes individually, so that the DC/DC loop and the interference to other circuits are reduced; the area of the metal ground at the periphery of the element is enlarged as much as possible to help heat dissipation; the periphery of the element is connected to the ground plane through a plurality of via holes, so that noise interference on a sensitive circuit is reduced; the current of the SW node line of VBAT passing through the inductor is large, the flash can reach about 1.4A instantly when the efficiency is low, and the wiring needs to be widened as much as possible.

The LED part mainly considers heat dissipation and lamp effect. The lamp effect of the flash lamp is reduced when the temperature of the flash lamp rises, the LED is damaged when the flash lamp works at the temperature exceeding the junction temperature, the heat dissipation area of the LED is increased as much as possible when the PCB is distributed, and the heat dissipation area of a single lamp is recommended to be 70-80 mm²The metal area around each bonding pad is enlarged as much as possible, and heat dissipation holes are formed. In order to ensure the lamp effect, the distance between the LED and the camera is not more than 13mm, and if two lamps are used, the distance between the LED is ensured to be within 4-10 mm (the effect is better when the distance is close to 4 mm).

The PCB layout in fig. 5 follows strictly the layout rules described above. As can be seen from fig. 5, the traces of the driving circuit of an exemplary embodiment of the present application are short; the driving current is controlled, the wiring is short, and the anti-interference capability is high; and the layout is easy, the routing is simplified, and the cost is lower.

The core of the chip driving performance is the efficiency conversion, for which the test data are shown in table 1.

Table 1 conversion performance test data of driver chip

As can be seen from table 1, according to the relationship between the input and the output of the driving chip provided in the exemplary embodiment of the present application, the conversion efficiency is as high as more than 90%, the light emitting efficiency is greatly improved, the temperature rise is reduced, and the performance is reliable. Therefore, the performance of the product is improved by adopting the driving chip, so that the control precision is high; the conversion efficiency is high, so that the power consumption loss is low; therefore, the design is optimized and the overall performance is improved according to the requirements of the existing mobile phone on the driving performance of the flash lamp. And a corresponding schematic diagram and a PCB rule are formulated for the driving chip, so that the method has a practical value and is low in cost.

Here, it should be noted that: for technical details not disclosed in the embodiments of the circuit of the present application, refer to the description of the embodiments of the circuit of the present application for understanding.

It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be understood that, in the various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of the processes should be determined by the functions and the inherent logic thereof, and should not constitute any limitation to the implementation process of an exemplary embodiment of the present application. The above-mentioned serial numbers of an exemplary embodiment of the present application are for description only and do not represent the merits of the embodiment.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above-described device embodiments are merely illustrative, for example, the division of the unit is only a logical functional division, and there may be other division ways in actual implementation, such as: multiple units or components may be combined, or may be integrated into another system, or some features may be omitted, or not implemented. In addition, the coupling, direct coupling or communication connection between the components shown or discussed may be through some interfaces, and the indirect coupling or communication connection between the devices or units may be electrical, mechanical or other forms.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units; can be located in one place or distributed on a plurality of network units; some or all of the units can be selected according to actual needs to achieve the purpose of the solution of an exemplary embodiment of the present application.

In addition, all functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may be separately regarded as one unit, or two or more units may be integrated into one unit; the integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.

Those of ordinary skill in the art will understand that: all or part of the steps for realizing the embodiments can be completed by hardware related to program instructions, the program can be stored in a computer readable storage medium, and the program executes the steps comprising the embodiments when executed; and the aforementioned storage medium includes: various media that can store program codes, such as a removable Memory device, a Read Only Memory (ROM), a magnetic disk, or an optical disk.

Alternatively, the integrated units described above in the present application may be stored in a computer-readable storage medium if they are implemented in the form of software functional modules and sold or used as independent products. Based on such understanding, the technical solutions of the exemplary embodiments of the present application may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a terminal to execute all or part of the circuits described in the embodiments of the present application. And the aforementioned storage medium includes: a removable storage device, a ROM, a magnetic or optical disk, or other various media that can store program code.

The above description is only for the embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A flash drive circuit, comprising: flash light, driver chip, power, interface and control module and high power emitting diode drive module, wherein:

the booster circuit is used for providing voltage for the flash lamp to enable the flash lamp to flash when the forward voltage of the flash lamp is higher than the power supply voltage;

and the high-power light-emitting diode driving module is used for responding to the received control instruction and adjusting the current of the flash lamp so as to enable the current of the flash lamp to be larger than or equal to a preset current threshold.

2. The circuit of claim 1, wherein the driver chip further comprises:

3. The circuit of claim 2, wherein the over-voltage protection module is further configured to adjust a voltage of a modulation controller in the flash driver circuit to increase the output voltage of the flash when the output voltage is less than the over-voltage protection threshold.

4. The circuit of claim 1, wherein the boost circuit further comprises:

5. The circuit according to any one of claims 1 to 4, wherein the boost circuit is connected to a first capacitor, an inductor and a second capacitor, respectively, so that the current at the output terminal of the boost circuit is a constant current; the output end of the booster circuit is connected with the flash lamp, and a battery power supply is adopted to supply power to the booster circuit; the first capacitor is an input capacitor, and the second capacitor is an output capacitor.

6. The circuit according to any one of claims 1 to 4, wherein the driving chip further comprises:

7. The circuit of claim 5, wherein in the layout of the circuit board of the driving chip, the distances from the battery power supply, the first capacitor and the second capacitor to the interface and the control module are set to be less than a distance threshold respectively;

8. The circuit of claim 7, wherein the area of the metal ground within a predetermined range of each component in the layout of the circuit board is greater than a predetermined area; and the metal ground in the preset range is connected to the ground plane through a plurality of through holes.

9. The circuit of claim 7, wherein in the layout of the circuit board, the battery power source and the inductor are connected to the boost circuit using a connection line having a width greater than a preset width;