CN114828332A - Constant current drive circuit, constant current drive device and lamp - Google Patents
Constant current drive circuit, constant current drive device and lamp Download PDFInfo
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- CN114828332A CN114828332A CN202110120693.8A CN202110120693A CN114828332A CN 114828332 A CN114828332 A CN 114828332A CN 202110120693 A CN202110120693 A CN 202110120693A CN 114828332 A CN114828332 A CN 114828332A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/345—Current stabilisation; Maintaining constant current
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/36—Circuits for reducing or suppressing harmonics, ripples or electromagnetic interferences [EMI]
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/37—Converter circuits
- H05B45/3725—Switched mode power supply [SMPS]
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
- H05B45/59—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits for reducing or suppressing flicker or glow effects
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Abstract
The utility model belongs to the technical field of drive, a constant current drive circuit, constant current drive arrangement and lamps and lanterns are provided, insert the alternating current through rectifier module to carry out rectification processing to the alternating current and generate direct current voltage signal, set up electrolytic capacitor at rectifier module's output, with promotion circuit efficiency, and eliminate stroboscopic phenomenon among the direct current voltage signal, drive module generates the constant current drive signal according to direct current voltage signal under the discontinuous conduction mode, and according to the constant current drive signal adjusts output duty cycle, in order to maintain the constancy of constant current drive signal's electric current, and by the filtering of electromagnetic suppression module clutter interference signal among the direct current voltage signal, with the electromagnetic properties of improvement circuit, solved in the circuit additionally increase and go the stroboscopic circuit, the drive cost that leads to is higher, the great problem of drive space size.
Description
Technical Field
The application belongs to the technical field of driving, and particularly relates to a constant current driving circuit, a constant current driving device and a lamp.
Background
Buck/Boost converter: the buck-boost converter is a single-tube non-isolated direct current converter with output voltage lower or higher than input voltage, but the polarity of the output voltage is opposite to that of the input voltage. The Buck/Boost converter can be regarded as a series connection of the Buck converter and the Boost converter, and a switching tube is combined.
However, the current Boost circuit usually uses a thin film capacitor for filtering after rectification, and its output will generate stroboflash, so that a stroboflash removing circuit needs to be added, resulting in the problems of high driving cost and large driving space size.
Disclosure of Invention
An object of the application is to provide a constant current drive circuit, constant current drive device and lamps and lanterns, aim at solving current boost circuit and need increase and remove the stroboscopic circuit, lead to the higher, great problem of drive space size of drive cost.
A first aspect of an embodiment of the present application provides a constant current driving circuit, including:
the rectification module is used for accessing alternating current and rectifying the alternating current to generate a direct current voltage signal;
the electrolytic capacitor is connected with the rectifying module and used for improving the circuit efficiency and eliminating the stroboscopic phenomenon in the direct-current voltage signal;
the driving module is connected with the rectifying module and used for generating a constant current driving signal according to a direct current voltage signal in an intermittent conduction mode and adjusting an output duty ratio according to the constant current driving signal so as to maintain the constant current of the constant current driving signal; and
and the electromagnetic suppression module is connected with the driving module and used for filtering clutter interference signals in the direct-current voltage signals so as to improve the electromagnetic performance of the circuit.
Optionally, the driving module is specifically configured to perform current sampling on the constant current driving signal, and adjust a switching duty ratio of the driving module according to a sampling result.
Optionally, the driving module controls the duty ratio of the switch according to a preset on-off time relation, where the preset on-off time relation is:
t_off＝(V_in-1)/(V_o+1)*t_on；
wherein t _ off is an off time, t _ on is an on time, V _ in is an input voltage, and V _ o is an output voltage.
Optionally, the constant current driving circuit further includes:
and the filtering module is connected with the driving module and is used for filtering the constant current driving signal.
Optionally, the electromagnetic suppression module includes: the first capacitor, the first diode and the first resistor;
the first end of the first capacitor and the anode of the first diode are connected to the rectifying module in a sharing mode, the second end of the first capacitor is connected to the first end of the first resistor, and the second end of the first resistor and the cathode of the first diode are connected to the output end of the driving module in a sharing mode.
Optionally, the filtering module includes at least one electrolytic capacitor, a first end of the at least one electrolytic capacitor is connected to the driving module, and a second end of the at least one electrolytic capacitor is grounded.
Optionally, the driving module includes: a first inductor, a second capacitor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a second diode and a constant current driving chip, the first end of the first inductor is connected with the rectifying module, the second end of the first inductor, the first end of the second capacitor and the anode of the second diode are connected with the output pin of the constant current driving chip, the second end of the second capacitor is connected with the first end of the second resistor in common, the cathode of the second diode and the second end of the second resistor are connected with the input pin of the constant current driving chip in common, a current detection pin of the constant current driving chip, a first end of the third resistor and a first end of the fourth resistor are connected in common, an overvoltage protection pin of the constant current driving chip is connected with a first end of the fifth resistor, and a second end of the third resistor, a second end of the fourth resistor and a second end of the fifth resistor are connected to an output end of a load in common.
Optionally, the constant current driving chip includes: the device comprises a reference voltage signal source, a first switch tube, a second switch tube, an under-voltage locking unit, a locking restarting unit, an overvoltage protection unit, a current detection unit, a current control unit, a conduction time control unit and a driving unit; wherein, the first input end of the overvoltage protection unit forms an overvoltage protection pin of the constant current driving chip, the first end of the first switch tube and the first input end of the overvoltage protection unit are connected together to form an input pin of the constant current driving chip, the second end of the first switch tube is connected with the undervoltage locking unit, the control end of the first switch tube is connected with the substrate thereof, the input end of the current detection unit forms a current detection pin of the constant current driving chip, the first input end of the locking restart unit is connected with the undervoltage locking unit, the second input end of the locking restart unit is connected with the overvoltage protection unit, the input end of the current detection unit forms a current detection pin of the constant current driving chip, the first input end of the current control unit is connected with a reference voltage signal source, and the second input end of the current control unit is connected with the current detection unit, the input end of the conduction time control unit is connected with the current control unit, the first input end of the driving unit is connected with the conduction time control unit, the second input end of the driving unit is connected with the locking restarting unit, the first end of the second switch tube is connected with the output pin of the constant current driving chip, and the second end of the second switch tube is connected with the current detection pin of the constant current driving chip.
Optionally, the overvoltage protection unit is configured to sample an output current of the load to generate a reference overvoltage signal, and generate an overvoltage protection signal when a voltage of the constant current driving signal is greater than the reference overvoltage signal;
the undervoltage locking unit is used for detecting the voltage of an input constant current driving signal and generating an undervoltage protection signal when the voltage of the constant current driving signal is lower than a preset undervoltage threshold value;
and the locking and restarting unit is used for locking or restarting the driving unit according to the overvoltage protection signal and the undervoltage protection signal.
Optionally, the current detection unit is configured to detect a current of the constant current driving signal and generate a current detection signal;
the current control unit is used for comparing the current detection signal with a reference voltage signal provided by the reference voltage signal source and generating a current control signal according to a comparison result so as to control the current of the constant current driving signal.
Optionally, the on-time control unit is configured to set a switching duty ratio according to the current control signal, and generate a driving control signal based on the switching duty ratio to control a current magnitude of the constant current driving signal.
Optionally, the driving unit is configured to control the second switching tube to be turned on and off according to the driving control signal.
Optionally, when the constant current driving chip operates in an intermittent conduction mode, when the second switching tube is turned on, the inductive current output by the driving module increases, when the second switching tube is turned off, the inductive current output by the driving module decreases, and when the turn-off time t _ off is (V _ in-1)/(V _ o +1) × t _ on, the second switching tube is turned on again; wherein t _ off is an off time, t _ on is an on time, V _ in is an input voltage, and V _ o is an output voltage.
A second aspect of embodiments of the present application provides a constant current driving device including the constant current driving circuit according to any one of the above aspects.
A third aspect of the embodiments of the present application provides a luminaire, including: a light source module; and the constant current driving circuit is connected with the light source module.
The embodiment of the application provides a constant current drive circuit, constant current drive arrangement and lamps and lanterns inserts the alternating current through rectifier module to carry out rectification processing to the alternating current and generate direct current voltage signal, set up electrolytic capacitor at rectifier module's output, cooperation constant current drive circuit has promoted circuit efficiency, and eliminate stroboscopic phenomenon among the direct current voltage signal, drive module generates the constant current drive signal according to direct current voltage signal under the discontinuous conduction mode, and according to the constant current drive signal adjusts the output duty cycle, in order to maintain the constancy of constant current drive signal's electric current, and by the filtering of electromagnetism suppression module clutter interference signal among the direct current voltage signal to improve the electromagnetic properties of circuit, solved in the circuit and additionally increased and removed the stroboscopic circuit, the drive cost that leads to is higher, the great problem of drive space size.
Drawings
Fig. 1 is a schematic circuit structure diagram of a constant current driving circuit according to an embodiment of the present disclosure;
fig. 2 is a schematic circuit structure diagram of another constant current driving circuit provided in the embodiment of the present application;
fig. 3 is a schematic circuit structure diagram of another constant current driving circuit according to an embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of a constant current driving chip provided in an embodiment of the present application.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, refer to an orientation or positional relationship illustrated in the drawings for convenience in describing the present application and to simplify description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present application.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
The embodiment of the present application provides a constant current driving circuit, which is used to solve the problems of stroboflash and low efficiency in the existing driving circuit, and as shown in fig. 1, the constant current driving circuit in the embodiment includes: the electromagnetic suppression device comprises a rectification module 10, an electrolytic capacitor C3, a driving module 20 and an electromagnetic suppression module 30, wherein the rectification module 10 is used for accessing alternating current and rectifying the alternating current to generate a direct current voltage signal; the electrolytic capacitor C3 is connected with the rectifier module 10 and used for improving the circuit efficiency and eliminating the stroboscopic phenomenon in the direct-current voltage signal; the driving module 20 is connected to the rectifying module 10, and configured to generate a constant current driving signal according to the dc voltage signal in the discontinuous conduction mode, and adjust an output duty ratio according to the constant current driving signal to maintain a constant current of the constant current driving signal; the electromagnetic suppression module 30 is connected to the driving module 20 and configured to filter noise interference signals in the dc voltage signal to improve the electromagnetic performance of the circuit.
In this embodiment, the alternating current is accessed through the rectifier module 10, and the alternating current is rectified to generate a direct current voltage signal, the electrolytic capacitor C3 is arranged at the output end of the rectifier module 10 to improve the circuit efficiency and eliminate the stroboscopic phenomenon in the direct current voltage signal, the driving module 20 generates a constant current driving signal according to the direct current voltage signal in the discontinuous conduction mode, and adjusts the output duty ratio according to the constant current driving signal to maintain the constant current of the constant current driving signal, and the electromagnetic suppression module 30 filters the clutter interference signal in the direct current voltage signal to improve the electromagnetic performance of the circuit, thereby solving the problems of high driving cost and large driving space size caused by additionally adding a stroboscopic removing circuit in the circuit.
Specifically, in the present embodiment, the rectifier module 10 converts the ac power into the pulsating dc power, and a larger-capacity electrolytic capacitor C3 is connected after the rectifier circuit, so as to improve the circuit efficiency by replacing the conventional small-capacity film capacitor with the electrolytic capacitor C3, and further, the rectified pulsating dc voltage is changed into a relatively stable dc voltage by using the charging and discharging characteristics of the electrolytic capacitor C3.
In a practical embodiment, in order to prevent the supply voltage of each part of the circuit from varying due to the variation of the load 00, an electrolytic capacitor with a capacitance of several tens to several hundreds microfarads (for example, 10-500uF) is generally connected to the output terminal of the rectifier module 10 and the power input terminal of the load 00. since the electrolytic capacitor with a large capacitance generally has a certain inductance effect and cannot effectively filter out high-frequency and pulse interference signals, a capacitor with a capacitance of 0.001-0.lpF is connected in parallel to the two ends of the electrolytic capacitor to filter out high-frequency and pulse interference.
In one embodiment, the driving module 20 is specifically configured to perform current sampling on the constant current driving signal, and adjust a switching duty ratio of the driving module 20 according to a sampling result.
In the present embodiment, the driving module 20 determines whether the magnitude of the output current is within a constant preset range based on the current sampling result of the constant current driving signal output by the driving module, and thus controls the switching duty ratio therein, so as to maintain the output current constant.
For example, the driving module 20 detects the current flowing from the load 00 through a current sampling pin thereof to obtain a current detection signal, compares the current detection signal with a reference voltage signal provided by the reference voltage signal source 21, and controls the duty ratio of the on-time and the off-time of the driving module 20 in the Discontinuous Conduction Mode (DCM) according to the current detection threshold corresponding to the average current calculated according to the reference voltage, so as to maintain the output current of the driving module 20 constant.
In one embodiment, the driving module 20 controls the switching duty ratio according to a preset on-off time relation, where the preset on-off time relation is: t _ off ═ V _ in-1)/(V _ o +1) × t _ on; wherein t _ off is an off time, t _ on is an on time, V _ in is an input voltage, and V _ o is an output voltage.
In this embodiment, the driving module 20 adjusts the output current thereof by controlling the ratio of the on time and the off time of the internal switching tube (e.g., MOSFET) thereof, specifically, when the driving module 20 operates in the discontinuous conduction mode, the internal inductor current thereof increases when the internal switching tube is turned on, and when the switching tube is turned off, the internal inductor current of the driving module 20 decreases until t _ off is (V _ in-1)/(V _ o +1) × t _ on, and the switching tube is turned on again.
In one embodiment, referring to fig. 2, the constant current driving circuit further includes a filtering module 40, and the filtering module 40 is connected to the driving module 20 and is configured to filter the constant current driving signal.
In one embodiment, referring to fig. 3, the electromagnetic suppression module 30 includes: a first capacitor C1, a first diode D1, and a first resistor R1; a first end of the first capacitor C1 and an anode of the first diode D1 are commonly connected to the rectifier module 10, a second end of the first capacitor C1 is connected to a first end of the first resistor R1, and a second end of the first resistor R1 and a cathode of the first diode D1 are commonly connected to an output end of the driver module 20.
In the present embodiment, the first capacitor C1, the first diode D1 and the first resistor R1 form a primary EMI circuit for eliminating noise interference in the dc voltage signal to improve the electromagnetic performance of the circuit.
In one embodiment, referring to FIG. 3, the rectifier module 10 is a rectifier bridge.
In the present embodiment, the rectifier bridge converts the input 50/60HZ voltage of sine wave into 100/120HZ voltage waveform without negative half cycle, thereby achieving the effect of full-wave rectification.
In one embodiment, the filtering module 40 includes at least one electrolytic capacitor, a first terminal of the at least one electrolytic capacitor is connected to the driving module 20, and a second terminal of the at least one electrolytic capacitor is grounded.
In a specific application embodiment, referring to fig. 3, the filtering module 40 includes a fourth capacitor C4, a first terminal of the fourth capacitor C4 is connected to the output terminal of the driving module 20, and a second terminal of the fourth capacitor C4 is connected to ground, wherein the fourth capacitor C4 is an electrolytic capacitor.
In certain applications, such as in a switching power supply, the filter module 40 may also be used as an output capacitor to store energy to maintain a constant voltage. The capacitor of the Boost circuit is selected mainly to control the output ripple within the range specified by the index. For Boost circuits, the impedance of the capacitor and the output current determine the magnitude of the output voltage ripple. The impedance of the capacitor consists of three components, namely, equivalent series inductance (ESL), Equivalent Series Resistance (ESR), and capacitance (C). In the inductor current continuous mode, the size of the capacitor depends on the output current, the switching frequency and the desired output ripple. When the switch tube inside the driving module 20 is turned on, the output filter capacitor provides the entire load 00 current.
In one embodiment, the driving module 20 includes: a first inductor L1, a second capacitor C2, a second resistor R2, a third resistor R3 and a fourth resistor R4, a fifth resistor R5, a second diode D2, and a constant current driving chip U1, wherein a first end of the first inductor L1 is connected to the rectifier module 10, a second end of the first inductor L1, a first end of the second capacitor C2, and an anode of the second diode D2 are commonly connected to an output pin Drain of the constant current driving chip U1, a second end of the second capacitor C2 is commonly connected to a first end of the second resistor R2, a cathode of the second diode D2 and a second end of the second resistor R2 are commonly connected to an input pin Vin of the constant current driving chip U1, a current detection pin ISP of the constant current driving chip U1, a first end of the third resistor R3, and a first end of the fourth resistor R4 are commonly connected, an overvoltage protection pin OVP of the constant current driving chip U1 is connected to a first end of the fifth resistor R5, and a second end of the third resistor R3, a second end of the fourth resistor R4, and a second end of the fifth resistor R5 are commonly connected to a load output terminal of the load output terminal U3600.
In this embodiment, the second capacitor C2, the second resistor R2, and the second diode D2 form a secondary EMI circuit, which filters interference noise in the constant current driving signal generated by the constant current driving chip U1, and since the input of the driving module 20 is direct current, the current in the first inductor L1 increases linearly at a certain ratio, which is related to the size of the inductor, and as the inductor current increases, some energy is stored in the inductor. When the MOS transistor in the constant current driver chip U1 is turned off, since the current flowing through the inductor remains specific, the current flowing through the inductor does not immediately become 0, but slowly changes the value of the charged circuit to 0, the original circuit is disconnected, and the inductor can only discharge through the new circuit, namely, the inductor starts to charge the capacitor, the voltage at the two ends of the capacitor rises and is higher than the input voltage, and after the voltage rise is finished, the boosting process is an energy transfer process of the inductor, the inductor absorbs energy during charging and emits energy during discharging, if the capacitance is large enough, the output end can keep a continuous current in the discharging process, the on-off process is repeated continuously, the voltage higher than the input voltage can be obtained at the two ends of the capacitance, meanwhile, the output current of the MOS tube is controlled by controlling the on-time and the off-time of the MOS tube, and the second diode D2 can prevent the filter capacitor of the later stage from discharging to the ground.
In the embodiment, the constant current driver chip U1 is powered by its output voltage, and when the voltage at its input pin Vin is higher than the start voltage, the constant current driver chip U1 starts to supply power. When the voltage of the input pin Vin is lower than the starting voltage, the chip starts under-voltage protection, locks the chip and starts again until the normal state is recovered. Further, the chip detects the current through the current detection pin ISP pin, and compares the detected current with the average current calculated by the reference voltage to maintain the output current constant. Specifically, the on-time t _ on is controlled to be constant, the off-time t _ off is changed, and the duty ratio is controlled, so that the on-loss is reduced, and the efficiency is improved.
In a specific application embodiment, the constant current driving chip U1 operates in an intermittent conduction mode, when the internal MOSFET is turned on, the inductor current in the driving module 20 rises, and when the MOSFET is turned off, the inductor current in the circuit falls, and finally returns to zero, until t _ off is (V _ in-1)/(V _ o +1) × t _ on, the MOSFET is turned on again.
In a specific application embodiment, the constant current driving chip U1 has an overvoltage protection function, and when the output voltage is higher than the OVP voltage set by the OVP connection mode of the overvoltage protection pin, the chip locks until the chip is started again after the chip returns to normal.
Specifically, in this embodiment, the fifth resistor R5 is connected to the over-voltage protection pin OVP of the constant current driver chip U1, since the load 00 outputs current, the voltage is divided by the fifth resistor R5 to provide an OVP voltage as a reference voltage, the voltage of the input pin Vin of the constant current driver chip U1 is compared with the reference voltage, so that the voltage of the input pin is prevented from being too large, and the reference voltage can vary with the output current of the load 00, thereby implementing dynamic over-voltage protection.
In an embodiment, the third resistor R3 and the fourth resistor R4 divide the voltage according to the current output by the load 00 to obtain a divided voltage signal, the divided voltage signal is input to the constant current driving chip U1 through the current detection pin ISP of the constant current driving chip U1, specifically, since the resistances of the third resistor R3 and the fourth resistor R4 are fixed, the divided voltage signal corresponds to the output current of the load, the constant current driving chip U1 compares the divided voltage signal with a reference voltage signal provided by a reference voltage signal source disposed inside the divided voltage signal, and controls the output current according to the comparison result, where the reference voltage signal source may correspond to the highest current threshold or rated power of the constant current driving chip U1, so as to avoid chip damage caused by excessive power due to the need of maintaining constant current output when the load of the constant current driving chip U1 increases.
In one embodiment, referring to fig. 4, the constant current driving chip U1 includes: the circuit comprises a reference voltage signal source 21, a first switch tube Q1, a second switch tube Q2, an under-voltage locking unit 22, a locking restart unit 23, an over-voltage protection unit 24, a current detection unit 25, a current control unit 26, an on-time control unit 27 and a driving unit 28.
Specifically, the overvoltage protection unit 24 is configured to sample an output current of the load to generate a reference overvoltage signal, and generate an overvoltage protection signal when a voltage of the constant current driving signal is greater than the reference overvoltage signal; a first input end of the overvoltage protection unit 24 forms an overvoltage protection pin OVP of the constant current driving chip U1, and a first end of the first switch tube Q1 and a first input end of the overvoltage protection unit 24 are connected in common to form an input pin Vin of the constant current driving chip U1; the undervoltage locking unit 22 is configured to perform voltage detection on the input constant current driving signal, and generate an undervoltage protection signal when the voltage of the constant current driving signal is lower than a preset undervoltage threshold; the second end of the first switch tube Q1 is connected to the under-voltage locking unit 22, and the control end of the first switch tube Q1 is connected to the substrate thereof; the locking and restarting unit 23 is used for locking or restarting the driving unit 28 according to the overvoltage protection signal and the undervoltage protection signal; a first input end of the lock restart unit 23 is connected with the under-voltage lock unit 22, and a second input end of the lock restart unit 23 is connected with the overvoltage protection unit 24; the current detection unit 25 is configured to detect a current of the constant current drive signal and generate a current detection signal; the input end of the current detection unit 25 forms a current detection pin ISP of the constant current driving chip U1; a current control unit 26 for comparing the current detection signal with a reference voltage signal provided by the reference voltage signal source 21 and generating a current control signal according to the comparison result; a first input end of the current control unit 26 is connected with the reference voltage signal source 21, and a second input end of the current control unit 26 is connected with the current detection unit 25; an on-time control unit 27 for setting a switching duty ratio according to the current control signal and generating a driving control signal; the input end of the on-time control unit 27 is connected with the current control unit 26; the driving unit 28 is used for controlling the on and off of the second switching tube Q2 according to the driving control signal; a first input end of the driving unit 28 is connected to the on-time control unit 27, a second input end of the driving unit 28 is connected to the lock restart unit 23, a first end of the second switching tube Q2 is connected to an output pin of the constant current driving chip U1, and a second end of the second switching tube Q2 is connected to a current detection pin of the constant current driving chip U1.
In this embodiment, the under-voltage locking unit 22 is configured to perform voltage detection on the voltage of the input pin Vin of the constant-current driving chip U1, and when the voltage of the input pin Vin is lower than a preset under-voltage threshold (i.e., a start voltage), the chip triggers an under-voltage locking function, sends an under-voltage protection signal to the locking restart unit 23 to lock and stop the driving unit 28, and restarts after the voltage of the input pin Vin is recovered.
In this embodiment, the overvoltage protection unit 24 is configured to determine an OVP voltage (i.e., a voltage of a preset reference overvoltage signal) according to a connection manner of the overvoltage protection pin OVP of the constant current driver chip U1, and meanwhile, the overvoltage protection unit 24 receives the constant current driving signal of the input pin Vin, and generates an overvoltage protection signal to be sent to the lock restart unit 23 when the voltage of the constant current driving signal is greater than the reference overvoltage signal, so as to restart the chip after the chip is locked for a preset time.
The current detection unit 25 detects the output current of the load 00 by detecting the current of the current detection pin ISP, generates a current detection signal, and sends the current detection signal to the current control unit 26, the current control unit 26 compares the feedback received current detection signal with the reference voltage signal provided by the reference voltage signal source 21, and generates a current control signal according to the comparison result to adjust the output current of the constant current driving chip U1, specifically, the on-time control unit 27 sets a switching duty ratio according to the current control signal, and generates a driving control signal to limit the on-time ton, so as to ensure that the chip operates in an intermittent on-mode, and the driving unit 28 generates a corresponding pulse width modulation signal to drive the second switching tube Q2 to alternately turn on and off, thereby maintaining the output current of the constant current driving chip U1 constant.
In one embodiment, the constant current driver chip U1 further includes a power supply unit 29 configured to supply power to other functional units in the chip, and specifically, the constant current driver chip U1 may obtain power according to its output voltage, and perform voltage conversion to generate various voltages to supply power to other functional units.
In one embodiment, the first switch transistor Q1 and the second switch transistor Q2 are both N-type MOS transistors.
In a specific application embodiment, when the constant current driving chip U1 operates in the discontinuous conduction mode, when the second switching tube Q2 is turned on, the inductor current in the driving module 20 rises, and when the second switching tube Q2 is turned off, the inductor current in the circuit falls, and finally returns to zero, until t _ off is (V _ in-1)/(V _ o +1) × t _ on, the MOSFET is turned on again.
The embodiment of the application also provides a constant current driving device, which comprises the constant current driving circuit.
An embodiment of the present application further provides a lamp, including: a light source module; and the constant current driving circuit is connected with the light source module.
The embodiment of the application provides a constant current drive circuit, constant current drive device and lamps and lanterns inserts the alternating current through rectifier module to carry out rectification processing to the alternating current and generate direct current voltage signal, set up electrolytic capacitor at rectifier module's output, in order to promote circuit efficiency, and eliminate stroboscopic phenomenon among the direct current voltage signal, drive module generates the constant current drive signal according to direct current voltage signal under the discontinuous conduction mode, and according to the constant current drive signal adjusts the output duty cycle, in order to maintain the constancy of constant current drive signal's electric current, and by the filtering of electromagnetic suppression module clutter interference signal among the direct current voltage signal to improve the electromagnetic properties of circuit, solved in the stroboscopic circuit additionally to increase and go the circuit, the drive cost that leads to is higher, the great problem of drive space size.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working processes of the units and modules in the system may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.
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, may be located in one place, or may be 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 the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.
Claims (15)
1. A constant current drive circuit, characterized in that the constant current drive circuit comprises:
the rectification module is used for accessing alternating current and rectifying the alternating current to generate a direct current voltage signal;
the electrolytic capacitor is connected with the rectifying module and used for improving the circuit efficiency and eliminating the stroboscopic phenomenon in the direct-current voltage signal;
the driving module is connected with the rectifying module and used for generating a constant current driving signal according to a direct current voltage signal in an intermittent conduction mode and adjusting an output duty ratio according to the constant current driving signal so as to maintain the constant current of the constant current driving signal; and
and the electromagnetic suppression module is connected with the driving module and used for filtering clutter interference signals in the direct-current voltage signals so as to improve the electromagnetic performance of the circuit.
2. The constant current driving circuit according to claim 1, wherein the driving module is specifically configured to perform current sampling on the constant current driving signal and adjust a switching duty cycle of the driving module according to a sampling result.
3. The constant current driving circuit according to claim 2, wherein the driving module controls a duty ratio of a switch according to a preset on-off time relation, and the preset on-off time relation is:
t_off＝(V_in-1)/(V_o+1)*t_on；
wherein t _ off is an off time, t _ on is an on time, V _ in is an input voltage, and V _ o is an output voltage.
4. The constant current drive circuit according to claim 1, further comprising:
and the filtering module is connected with the driving module and is used for filtering the constant current driving signal.
5. The constant current driving circuit according to claim 4, wherein the filtering module comprises at least one electrolytic capacitor, a first end of the at least one electrolytic capacitor is connected with the driving module, and a second end of the at least one electrolytic capacitor is grounded.
6. The constant current drive circuit according to claim 1, wherein the electromagnetic suppression module includes: the first capacitor, the first diode and the first resistor;
the first end of the first capacitor and the anode of the first diode are connected to the rectifying module in a sharing mode, the second end of the first capacitor is connected to the first end of the first resistor, and the second end of the first resistor and the cathode of the first diode are connected to the output end of the driving module in a sharing mode.
7. The constant current drive circuit according to claim 1, wherein the drive module includes: the constant current driving circuit comprises a first inductor, a second capacitor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a second diode and a constant current driving chip;
the first end of the first inductor, the first end of the second capacitor and the anode of the second diode are connected to an output pin of the constant current driving chip, the second end of the second capacitor and the first end of the second resistor are connected together, the cathode of the second diode and the second end of the second resistor are connected to an input pin of the constant current driving chip, a current detection pin of the constant current driving chip, the first end of the third resistor and the first end of the fourth resistor are connected together, an overvoltage protection pin of the constant current driving chip is connected to the first end of the fifth resistor, and the second end of the third resistor, the second end of the fourth resistor and the second end of the fifth resistor are connected to an output end of a load.
8. The constant current drive circuit according to claim 7, wherein the constant current drive chip includes: the device comprises a reference voltage signal source, a first switch tube, a second switch tube, an under-voltage locking unit, a locking restarting unit, an overvoltage protection unit, a current detection unit, a current control unit, a conduction time control unit and a driving unit;
wherein, the first input end of the overvoltage protection unit forms an overvoltage protection pin of the constant current driving chip, the first end of the first switch tube and the first input end of the overvoltage protection unit are connected together to form an input pin of the constant current driving chip, the second end of the first switch tube is connected with the undervoltage locking unit, the control end of the first switch tube is connected with the substrate thereof, the input end of the current detection unit forms a current detection pin of the constant current driving chip, the first input end of the locking restart unit is connected with the undervoltage locking unit, the second input end of the locking restart unit is connected with the overvoltage protection unit, the input end of the current detection unit forms a current detection pin of the constant current driving chip, the first input end of the current control unit is connected with a reference voltage signal source, and the second input end of the current control unit is connected with the current detection unit, the input end of the conduction time control unit is connected with the current control unit, the first input end of the driving unit is connected with the conduction time control unit, the second input end of the driving unit is connected with the locking restarting unit, the first end of the second switch tube is connected with the output pin of the constant current driving chip, and the second end of the second switch tube is connected with the current detection pin of the constant current driving chip.
9. The constant current drive circuit according to claim 8, wherein the overvoltage protection unit is configured to sample an output current of the load to generate a reference overvoltage signal, and generate an overvoltage protection signal when a voltage of the constant current drive signal is greater than the reference overvoltage signal;
the undervoltage locking unit is used for detecting the voltage of an input constant current driving signal and generating an undervoltage protection signal when the voltage of the constant current driving signal is lower than a preset undervoltage threshold value;
and the locking and restarting unit is used for locking or restarting the driving unit according to the overvoltage protection signal and the undervoltage protection signal.
10. The constant current drive circuit according to claim 8, wherein the current detection unit is configured to detect a current of the constant current drive signal and generate a current detection signal;
the current control unit is used for comparing the current detection signal with a reference voltage signal provided by the reference voltage signal source and generating a current control signal according to a comparison result so as to control the current of the constant current driving signal.
11. The constant current drive circuit according to claim 10, wherein the on-time control unit is configured to set a switching duty ratio according to the current control signal and generate a drive control signal based on the switching duty ratio to control a current magnitude of the constant current drive signal.
12. The constant current driving circuit according to claim 11, wherein the driving unit is configured to control the second switching tube to be turned on and off according to the driving control signal.
13. The constant-current driving circuit according to claim 8, wherein when the constant-current driving chip operates in an intermittent conduction mode, when the second switching tube is turned on, the inductor current output by the driving module increases, when the second switching tube is turned off, the inductor current output by the driving module decreases, and when the second switching tube is turned off for (V _ in-1)/(V _ o +1) × t _ on), the second switching tube is turned on again; wherein t _ off is an off time, t _ on is an on time, V _ in is an input voltage, and V _ o is an output voltage.
14. A constant current driving device characterized by comprising the constant current driving circuit according to any one of claims 1 to 13.
15. A light fixture, comprising: a light source module; and the constant current driving circuit according to any one of claims 1 to 13, the constant current driving circuit being connected to the light source module.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110120693.8A CN114828332A (en) | 2021-01-28 | 2021-01-28 | Constant current drive circuit, constant current drive device and lamp |
| EP21215168.2A EP4037439A1 (en) | 2021-01-28 | 2021-12-16 | Constant-current drive circuit, constant-current drive device and lamp |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110120693.8A CN114828332A (en) | 2021-01-28 | 2021-01-28 | Constant current drive circuit, constant current drive device and lamp |
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| CN114828332A true CN114828332A (en) | 2022-07-29 |
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| CN202110120693.8A Pending CN114828332A (en) | 2021-01-28 | 2021-01-28 | Constant current drive circuit, constant current drive device and lamp |
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| Country | Link |
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| EP (1) | EP4037439A1 (en) |
| CN (1) | CN114828332A (en) |
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| CN114980422B (en) * | 2022-05-19 | 2024-04-09 | 东风柳州汽车有限公司 | Self-adaptive constant current control circuit |
| CN117147517B (en) * | 2023-10-31 | 2024-03-22 | 青岛海研电子有限公司 | Circuit for detecting dissolved oxygen |
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| CN102594155A (en) * | 2012-03-30 | 2012-07-18 | 江苏晟芯微电子有限公司 | Primary edge control type switch power supply with high-precision constant-voltage/constant-current output and high-pulse-frequency (PF) value |
| CN203435204U (en) * | 2013-09-02 | 2014-02-12 | 南京汉德森科技股份有限公司 | Miniature LED constant-current driving circuit with low electromagnetic interference |
| US10197225B2 (en) * | 2015-03-10 | 2019-02-05 | Jiaxing Super Lighting Electric Appliance Co., Ltd. | LED tube lamp |
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- 2021-01-28 CN CN202110120693.8A patent/CN114828332A/en active Pending
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