CN110933798A

CN110933798A - LED drive circuit and drive device

Info

Publication number: CN110933798A
Application number: CN201910672739.XA
Authority: CN
Inventors: 麦炎全; 陈博; 邓迅升
Original assignee: Shenzhen Sendis Semiconductor Co Ltd
Current assignee: Shenzhen Sendis Semiconductor Co Ltd
Priority date: 2019-07-24
Filing date: 2019-07-24
Publication date: 2020-03-27

Abstract

The invention discloses an LED driving circuit and a driving device, wherein the LED driving circuit comprises an LED light-emitting module, a Silicon Controlled Rectifier (SCR) regulator for regulating the brightness of the LED light-emitting module, a first constant current source module, a second constant current source module, a third constant current source module, an energy storage module and a protection module, wherein the first constant current source module is used for providing driving current for the LED light-emitting module; the second constant current source module is used for providing a discharge current and a maintaining current for maintaining the conduction of the silicon controlled rectifier regulating module when the line voltage is less than the conduction voltage of the LED light-emitting module; the energy storage module is used for supplying power to the LED light-emitting module when the online voltage is less than the breakover voltage of the LED light-emitting module; the third constant current source module is used for adjusting the output current of the LED light-emitting module; the protection module is used for protecting the second constant current source module, and the anti-surge capacity can be effectively improved, so that the working safety of the LED driving circuit is ensured.

Description

LED drive circuit and drive device

Technical Field

The invention relates to the technical field of LEDs, in particular to an LED driving circuit and a driving device.

Background

As shown in fig. 1, in the conventional LED driving circuit using scr dimming, a leakage current is required when the scr dimmer is cut in phase, otherwise, the operation is abnormal. When the line voltage of the LED lamp is lower than the lighting voltage of the LED lamp, no current passes through the LED lamp, so that a bleeder circuit is additionally added to the LED driving circuit compatible with the silicon controlled rectifier dimmer. However, since the leakage current does not flow through the string lights, but only flows through the resistor Rb and the first constant current source SC1, when a high voltage surge occurs in the power supply network, the surge high voltage is borne by the resistor Rb and the first constant current source SC1, which easily causes the resistor Rb and the first constant current source SC1 to be damaged, and causes the LED driving circuit to operate abnormally.

Thus, the prior art has yet to be improved and enhanced.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide an LED driving circuit and a driving device, which can effectively improve the anti-surge capability and ensure the safety of the operation of the LED driving circuit.

In order to achieve the purpose, the invention adopts the following technical scheme:

an LED driving circuit comprises an LED light-emitting module, a Silicon Controlled Rectifier (SCR) for adjusting the brightness of the LED light-emitting module, a first constant current source module, a second constant current source module, a third constant current source module, an energy storage module and a protection module, wherein the first constant current source module is used for providing driving current for the LED light-emitting module; the second constant current source module is used for providing a discharge current and a maintaining current for maintaining the conduction of the silicon controlled rectifier regulating module when the line voltage is less than the conduction voltage of the LED light-emitting module; the energy storage module is used for supplying power to the LED light-emitting module when the online voltage is smaller than the breakover voltage of the LED light-emitting module; the third constant current source module is used for adjusting the output current of the LED light-emitting module; the protection module is used for protecting the second constant current source module.

In the LED driving circuit, the second constant current source module includes a constant current source unit and an enabling unit, and the constant current source unit is configured to provide a bleed current and a holding current for holding conduction of the thyristor regulation module when the line voltage is less than the conduction voltage of the LED lighting module; the enabling unit is used for controlling the constant current source unit to be closed when the line voltage is greater than the conduction voltage of the LED light-emitting module.

In the LED driving circuit, the third constant current source module comprises a voltage stabilizing unit, a switch unit, a regulating unit and an energy storage unit, wherein the voltage stabilizing unit is used for charging the energy storage unit when the switch unit is turned off; when the charging voltage of the energy storage unit is increased to a threshold voltage, controlling the switch unit to be conducted; the adjusting unit is used for controlling the switch-off of the switch unit after the switch unit is switched on so as to adjust the output current of the LED light-emitting module.

In the LED driving circuit, the enabling unit comprises a first resistor, one end of the first resistor is connected with the constant current source unit, the protection module, the third constant current source module and the energy storage module, and the other end of the first resistor is grounded.

In the LED driving circuit, the voltage stabilizing unit comprises a voltage stabilizing diode, the anode of the voltage stabilizing diode is connected with the energy storage unit and the switch unit, and the cathode of the voltage stabilizing diode is connected with the switch unit and the LED light-emitting module.

In the LED driving circuit, the energy storage unit comprises a first capacitor, one end of the first capacitor is connected with the voltage stabilizing unit and the switch unit, and the other end of the first capacitor is connected with the protection module, the second constant current source module, the energy storage module and the adjusting unit.

In the LED driving circuit, the switch unit comprises a first MOS tube, the drain electrode of the first MOS tube is connected with the voltage stabilizing unit and the LED light-emitting module, the grid electrode of the first MOS tube is connected with the energy storage unit and the voltage stabilizing unit, and the source electrode of the first MOS tube is connected with the adjusting unit.

In the LED driving circuit, the adjusting unit comprises a second resistor, one end of the second resistor is connected with the source electrode of the first MOS tube, and the other end of the second resistor is connected with the protection module, the second constant current source module and the energy storage module.

In the LED driving circuit, the protection module comprises a first diode, the anode of the first diode is connected with the second constant current source module, the third constant current source module and the energy storage module, and the cathode of the first diode is grounded.

The LED driving device comprises a shell, wherein a PCB is arranged in the shell, and the LED driving device is characterized in that the PCB is provided with the LED driving circuit.

Compared with the prior art, the LED driving circuit and the driving device provided by the invention have the advantages that the LED driving circuit comprises an LED light-emitting module, a Silicon Controlled Rectifier (SCR) regulator for regulating the brightness of the LED light-emitting module, a first constant current source module, a second constant current source module, a third constant current source module, an energy storage module and a protection module, wherein the first constant current source module is used for providing driving current for the LED light-emitting module; the second constant current source module is used for providing a discharge current and a maintaining current for maintaining the conduction of the silicon controlled rectifier regulating module when the line voltage is less than the conduction voltage of the LED light-emitting module; the energy storage module is used for supplying power to the LED light-emitting module when the online voltage is less than the breakover voltage of the LED light-emitting module; the third constant current source module is used for adjusting the output current of the LED light-emitting module; the protection module is used for protecting the second constant current source module, and the anti-surge capacity can be effectively improved, so that the working safety of the LED driving circuit is ensured.

Drawings

Fig. 1 is a schematic circuit diagram of a conventional LED driving circuit.

Fig. 2 is a block diagram of an LED driving circuit according to the present invention.

Fig. 3 and fig. 4 are schematic circuit diagrams of a first preferred embodiment of the LED driving circuit according to the present invention.

Fig. 5 is a waveform diagram of an ac input voltage, a scr input voltage, and a scr output voltage in the LED driving circuit according to the present invention.

Fig. 6 is a schematic circuit diagram of a second preferred embodiment of the LED driving circuit according to the present invention.

Detailed Description

The invention aims to provide an LED driving circuit and a driving device, which can effectively improve the anti-surge capacity and ensure the working safety of the LED driving circuit.

In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 2, the LED driving circuit provided by the present invention includes a rectifying module 100, an LED light emitting module 200, a thyristor regulator 300 for regulating the brightness of the LED light emitting module 200, a first constant current source module 400, a second constant current source module 500, a third constant current source module 600, an energy storage module 700, and a protection module 800, wherein the rectifying module 100 is externally connected to an ac power supply 10 through the thyristor regulator 300, the first constant current source module 400 is respectively connected to the rectifying module 100, the second constant current source module 500, the LED light emitting module 200, and the energy storage module 700, the energy storage module 700 is further connected to the third constant current source module 600, the protection module 800, the LED light emitting module 200, and the second constant current source module 500 is further connected to the protection module 800.

After the LED driving circuit is powered on, the rectifier module 100 rectifies the electric energy provided by the ac power supply 10 and outputs the line voltage Vrec to the first constant current source module 400, it should be noted that the rectifier module 100 is in the prior art and can be implemented by using a mature circuit, and the structure and connection relationship thereof are not described herein. The first constant current source module 400 is configured to provide a driving current for the LED lighting module 200, that is, the first constant current source module 400 controls the magnitude of the maximum current of the LED driving circuit; the second constant current source module 500 is configured to provide a bleed current and a sustain current for maintaining conduction of the thyristor regulation module when the line voltage Vrec is smaller than the conduction voltage of the LED light emitting module 200, and when the line voltage Vrec is smaller than the conduction voltage of the LED light emitting module 200, the current Iac of the ac power supply 10 is sent from the first constant current source module 400 to the ground via the second constant current source module 500 and does not flow through the energy storage module 700 and the LED light emitting module 200, and correspondingly, no current passes through the LED light emitting module 200 and does not emit light, that is, the second constant current source module 500 provides a bleed current and a working circuit for maintaining working of the thyristor regulator 300, so that the thyristor regulator 300 stably works.

Further, the energy storage module 700 is configured to supply power to the LED light emitting module 200 when the line voltage Vrec is smaller than the on-state voltage of the LED light emitting module 200, that is, when no current flows through the LED light emitting module 200, the energy storage module 700 discharges the LED light emitting module 200; when the line voltage Vrec is greater than the on-state voltage of the LED lighting module 200, at this time, the current Iac of the ac power supply 10 in the LED driving circuit is the maximum value, the energy storage module 700 enters a charging state, and correspondingly, the second constant current source module 500 is turned off; the third constant current source module 600 is configured to adjust an output current of the LED light emitting module 200, that is, when the line voltage Vrec is smaller than the conduction voltage of the LED light emitting module 200, the LED light emitting module 200 does not emit light, so that the LED light emitting module 200 may change on and off in each sine wave period, and a flash frequency phenomenon occurs, in this application, the energy storage module 700 is combined with the third constant current source module 600 to control the output current of the LED light emitting module 200, so that the current flowing through the LED light emitting module 200 is always unchanged or slightly changed, and the LED light emitting module 200 is ensured not to have the flash frequency phenomenon; the protection module 800 is configured to protect the second constant current source module 500, that is, when there is a surge high voltage, the existence of the protection module 800 may ensure that the second constant current source module 500 is not damaged by the surge high voltage, and may improve the safety of the LED driving circuit.

Further, referring to fig. 3 and fig. 4, the second constant current source module 500 includes a constant current source unit 520 and an enabling unit 510, the constant current source unit 520 is respectively connected to the first constant current source module 400, the enabling unit 510 and the protection module 800, and the enabling unit 510 is further connected to the protection module 800; the constant current source unit 520 is configured to provide a bleed current and a holding current for holding conduction of the thyristor regulation module when the line voltage Vrec is smaller than the conduction voltage of the LED light emitting module 200; the enabling unit 510 is configured to control the constant current source unit 520 to turn off when the line voltage Vrec is greater than the turn-on voltage of the LED lighting module 200, and when the line voltage Vrec is greater than the turn-on voltage of the LED lighting module 200, the current Iac of the ac power supply 10 is a maximum value Imax, and the maximum current value Imax flows through the enabling unit 510, and the voltage R1 across the enabling unit 510 is increased to be greater than the reference voltage Vref2 of the constant current source unit 520, so that the constant current source unit 520 is turned off; when the line voltage Vrec is smaller than the conduction voltage of the LED light emitting module 200, the constant current source unit 520 provides a leakage current to the scr regulator 300 and maintains a working circuit thereof, so that the scr regulator 300 stably works.

In this embodiment, the second constant current source module 500 further includes a sampling resistor Rb1, one end of the sampling voltage is connected to the first constant current source module 400, the other end of the sampling resistor Rb1 is connected to the constant current source unit 520, that is, the sampling resistor Rb1 is connected in series with the constant current source unit 520, when there is a surge high voltage, the energy storage module 700 can share a part through the protection module 800, and the remaining part can be shared by the first constant current source module 400, the sampling voltage and constant current source unit 520, compared with the existing LED driving circuit, two branches of the invention can share the high voltage surge, each part can bear a certain high voltage surge, and then make the surge high pressure that each part bore reduce, and then guaranteed that each part can not damaged, and then improved the anti surge ability of circuit, improved the security of circuit work.

Further, with continuing reference to fig. 3 and fig. 4, the third constant current source module 600 includes a voltage stabilizing unit 610, a switching unit 630, a regulating unit 640, and an energy storage unit 620, where the voltage stabilizing unit 610 is configured to charge the energy storage unit 620 when the switching unit 630 is turned off; when the charging voltage VC of the energy storage unit 620 increases to a threshold voltage, controlling the switch unit 630 to be turned on; the adjusting unit 640 is used for controlling the switching unit 630 to be turned off after being turned on, so as to adjust the output current of the LED lighting module 200.

After power-on, the energy storage unit 620 is charged by the voltage stabilization unit 610 in the third constant current source module 600, when the charging voltage of the energy storage unit 620 increases to the threshold voltage, that is, the on-state voltage of the switch unit 630, the switch unit 630 is turned on, so that the voltage stabilization unit 610 and the energy storage unit 620 are short-circuited to stop charging, and further the voltage of the adjustment unit 640 rises, otherwise the voltage of the switch unit 630 decreases to be turned off, and the energy storage unit 620 continues to enter the charging state, and finally a dynamic balance is achieved, so as to adjust the current flowing through the LED light emitting module 200, that is, the output current of the LED light emitting module 200.

In a specific implementation, the enabling unit 510 includes a first resistor R1, one end of the first resistor R1 is connected to the constant current source unit 520, the protection module 800, the third constant current source module 600 and the energy storage module 700, the other end of the first resistor R1 is grounded, when the line voltage Vrec is greater than the on voltage of the LED lighting module 200, both the charging current of the energy storage module 700 and the output current of the LED lighting module 200 flow through the first resistor R1, so that the voltage across the first resistor R1 is increased to be greater than the reference voltage Vref2 of the constant current source unit 520, and the constant current source unit 520 is turned off, that is, the enabling unit 510 can switch the constant current source unit 520, that is, the second constant current source module 500.

Further, the voltage stabilizing unit 610 includes a voltage stabilizing diode ZD1, the energy storage unit 620 includes a first capacitor C1, an anode of the voltage stabilizing diode ZD1 is connected to one end of the first capacitor C1 and the switch unit 630, a cathode of the voltage stabilizing diode ZD1 is connected to the switch unit 630 and the LED lighting module 200, and the other end of the energy storage unit 620 is connected to one end of the first resistor R1, the protection module 800, the adjusting unit 640 and the energy storage module 700; when the power is turned on, the power supply charges the first capacitor C1 through the zener diode ZD1, and when the charging voltage of the first capacitor C1 increases to be greater than the turn-on voltage of the switch unit 630, the switch unit 630 is turned on, and the zener diode ZD1 and the first capacitor C1 are short-circuited to stop charging, so that the output voltage of the LED lighting module 200 can be adjusted subsequently.

Preferably, the switching unit 630 includes a first MOS transistor M1, a drain of the first MOS transistor M1 is connected to a cathode of the zener diode ZD1 and the LED lighting module 200, a gate of the first MOS transistor M1 is connected to one end of the first capacitor C1 and an anode of the zener diode ZD1, a source of the first MOS transistor M1 is connected to the adjusting unit 640, when the charging voltage of the first capacitor C1 increases to the on-voltage of the first MOS transistor M1, the first MOS transistor M1 is turned on, the zener diode ZD1 and the first capacitor C1 are short-circuited to stop charging, the voltage of the adjusting unit 640 rises to cause the gate voltage of the first MOS transistor M1 to drop, the first MOS transistor M1 is turned off, the first capacitor C1 continues to be charged again, and finally, a dynamic balance is achieved, and adjustment of the output current of the LED lighting module 200 is achieved.

Preferably, the adjusting unit 640 includes a second resistor R2, one end of the second resistor R2 is connected to the source of the first MOS transistor M1, the other end of the second resistor R2 is connected to the protection module 800, the second constant current source module 500 and the energy storage module 700, after power-on, the power supply charges a first capacitor C1 through a zener diode ZD1, when the charging voltage of the first capacitor C1 increases to the on-state voltage of the first MOS transistor M1, the first MOS transistor M1 is turned on, the zener diode ZD1 and the first capacitor C1 are short-circuited, the voltage of the second resistor R2 increases, which causes the gate voltage of the first MOS transistor M1 to decrease and turn off, the first capacitor C1 continues to recover to the charging state, and thus a dynamic balance is finally achieved, so that the output current Iled of the LED lighting module 200 is equal to V_R2/R2, wherein V_R2Is the voltage of the second resistor R2; therefore, the output current of the LED light-emitting module 200 is adjusted, and the output current of the LED light-emitting module 200 is ensured to be unchanged or changed very little all the time, so that the LED light-emitting module 200 is ensured not to generate a flash frequency phenomenon.

Further, referring to fig. 5, the energy storage module 700 includes a second capacitor C2, one end of the second capacitor C2 is connected to the first constant current source module 400, one end of the sampling resistor Rb1 and the LED lighting module 200, and the other end of the second capacitor C2 is connected to the protection module 800 and the other end of the second resistor R2; when the thyristor regulator 300 regulates the brightness of the LED lighting module 200, the conduction phase angle changes, which results in a change of the charging time Tchg of the second capacitor C2, and thus a change of the peak voltage of the second capacitor C2, when the effective phase output by the thyristor regulator 300 is larger, the charging time Tchg of the second capacitor C2 is longer, the peak voltage of the second capacitor C2 is higher, the drain voltage of the first MOS transistor M1 is VC-Vled, where VC is the charging voltage of the second capacitor C2, Vled is the voltage of the LED lighting module 200, and since the first capacitor C1 can only discharge through its internal resistance, Vg is Vdmax-Vdz1 is VCmax-Vled-Vdz1, Vg is the gate voltage of the first MOS transistor M1, Vdmax is the drain voltage of the first MOS transistor M1, Vdz1 is the maximum drain voltage of the zener diode ZD 62, and Vg is the peak voltage of the second capacitor C2, that is, the gate voltage of the first MOS transistor M1 changes with the change of the peak voltage of the second capacitor C2, when the peak voltage of the second capacitor C2 increases, the drain voltage of the first MOS transistor M1 increases, and the first capacitor C1 is charged, so that the gate voltage of the first MOS transistor M1 increases and is turned on, and the voltage of the second resistor R2 increases, that is, the output current Iled of the corresponding LED lighting module 200 increases; when the peak voltage of the second capacitor C2 decreases, the gate voltage of the first MOS transistor M1 decreases, the first capacitor C1 discharges through its internal resistance, so that the gate voltage of the first MOS transistor M1 decreases, the voltage of the second resistor R2 decreases, that is, the corresponding output current Iled of the LED lighting module 200 decreases, that is, the output current of the LED lighting module 200 varies with the peak voltage of the second capacitor C2, therefore, the third constant current source module 600 may change the current of the LED lighting module 200 according to the adjustment of the scr regulator 300 to achieve the dimming effect, and the LED lighting module 200 may not generate the flash frequency phenomenon.

Further, the protection module 800 includes a first diode D1, the constant current source unit 520 includes a first operational amplifier U1, a first constant voltage power supply, and a second MOS transistor M2, a positive input terminal of the first operational amplifier U1 is connected to a positive terminal of the first constant voltage power supply, an opposite input terminal of the first operational amplifier U1 is connected to one end of the first resistor R1, a source of the second MOS transistor M2, and a positive terminal of the first diode D1, a negative terminal of the first constant voltage power supply and a negative terminal of the first diode D1 are grounded, an output terminal of the first operational amplifier U1 is connected to a gate of the second MOS transistor M2, a drain of the second MOS transistor M2 is connected to the other end of the sampling resistor Rb1, the first diode D1 is used to protect the second constant current source module 500, and particularly, when there is a high voltage surge, the first diode D1 clamps a voltage of the first clamping resistor R1 as a forward on-voltage Vf, wherein Vf > Vref2, Vref2 is the reference voltage input by the first operational amplifier U1, thereby ensuring that the constant current source unit 520 and the first resistor R1 are not damaged by surge high voltage, and improving the anti-surge capability of the LED driving circuit.

Further, the LED driving circuit further includes a second diode D2, the second diode D2 is an isolation diode, the anode of the second diode D2 is connected to one end of the sampling resistor Rb1 and the first constant current source module 400, the cathode of the second diode D2 is connected to the LED light emitting module 200 and one end of the second capacitor C2, and the isolation diode can effectively prevent the energy stored in the second capacitor C2 from flowing away from the second constant current source module 500, thereby ensuring the safety of the LED driving circuit.

Furthermore, the first constant current source module 400 includes a second operational amplifier U2, a third MOS transistor M3, a third resistor R3 and a second constant voltage power supply, a positive input terminal of the second operational amplifier U2 is connected to a positive electrode of the second constant voltage power supply, an inverted input terminal of the second operational amplifier U2 is connected to one end of the third resistor R3 and a source of the third MOS transistor M3, a gate of the third MOS transistor M3 is connected to an output terminal of the second operational amplifier U2, and a drain of the third MOS transistor M3 is connected to the rectifying module 100.

Referring to fig. 3, the first constant current source module 400 controls the maximum current of the LED driving circuit, that is, Imax is Vref1/R3, where Vref1 is the reference voltage input by the second operational amplifier U2, R3 is the resistance of the third resistor R3, when the line voltage Vrec is smaller than the on-state voltage of the LED lighting module 200 after the LED driving circuit is powered on, the current Iac of the ac power supply 10 flows through the first constant current source module 400, the sampling resistor Rb1 and the constant current source unit 520, and does not flow through the second capacitor C2 and the LED lighting module 200, and the corresponding current Iac is Vref2/R1, at this time, the LED lighting module 200 does not light, and only the second constant current source module 500 provides the bleeder current and the holding current for the thyristor regulator 300, so that the thyristor operates stably; the second capacitor C2 discharges the LED lighting module 200, and the discharge current Idis ═ Iled at this time.

Referring to fig. 4, when the line voltage Vrec is greater than the on-state voltage of the LED lighting module 200, at this time, the current Iac of the ac power supply 10 is Imax, the charging current Ichg of the second capacitor C2 is Imax-Iled, and the third constant current source module 600 correspondingly adjusts the output current Iled of the LED lighting module 200, because the adjusting process of the third constant current source module 600 is described above, the description is omitted here; at this time, the output current Iled of the LED lighting module 200 and the charging current Ichg of the second capacitor C2 both flow through the first resistor R1, so that V1> Vref2, when the second MOS transistor M2 is turned off, Ib becomes 0, where V1 is the voltage across the first resistor R1.

Compared with the existing LED drive circuit provided with the silicon controlled regulator 300, the LED drive circuit provided by the invention can effectively solve the stroboscopic problem of the LED and improve the compatibility of the silicon controlled regulator 300; when surge high voltage exists, part of the high voltage can be absorbed by the second capacitor C2 through the first diode D1, and the rest part of the high voltage can be shared by the first constant current source module 400, the sampling resistor Rb1 and the constant current source unit 520, so that the surge high voltage borne by each part is reduced, the power supply surge resistance of the LED driving circuit is improved, and the safety of the LED driving circuit is improved.

In a second preferred embodiment of the present invention, referring to fig. 6, the voltage stabilizing unit 610 includes a fourth resistor R4, a fifth resistor R5, and a third diode D3, one end of the fourth resistor R4 and a drain of the first MOS transistor M1 are connected to the LED lighting module 200, the other end of the fourth resistor R4 and one end of the fifth resistor R5 are connected to an anode of the third diode D3, a cathode of the third diode D3 is connected to one end of the first capacitor C1 and a gate of the first MOS transistor M1, the other end of the fifth resistor R5 is connected to the other end of the first capacitor C1 and the other end of the second resistor R2, in this embodiment, after a drain voltage of the first MOS transistor M1 is divided by the fourth resistor R4 and the fifth resistor R5, the third diode D3 charges the first capacitor C1, wherein the first capacitor C1 discharges itself, the same effect as that when the zener diode ZD1 is connected can be achieved, and the adjustment effect on the output current of the LED light emitting module 200 is further achieved.

In this embodiment, the energy storage module 700 includes a fourth diode D4, a sixth resistor R6, and a third capacitor C3, the anode of the fourth diode D4 and one end of the sixth resistor R6 are both connected to one end of the third capacitor C3, the cathode of the fourth diode D4 and the other end of the sixth resistor R6 are connected to the cathode of the second diode D2, the sixth resistor R6 is a current-limiting resistor, and when there is a surge high voltage, the sixth resistor R6 can limit the charging current of the third capacitor C3, bear the excess surge voltage, and further improve the anti-surge capability of the LED driving circuit; meanwhile, the fourth diode D4 is a discharge diode, and the presence of the fourth diode D4 enables the third capacitor C3 to be free from the limitation of the sixth resistor R6 during discharging, thereby reducing power consumption.

The invention also provides an LED driving device correspondingly, which comprises a shell, wherein a PCB is arranged in the shell, and the PCB is provided with the LED driving circuit.

In summary, the LED driving circuit and the driving apparatus provided by the present invention include an LED light emitting module, a thyristor regulator for regulating the brightness of the LED light emitting module, a first constant current source module, a second constant current source module, a third constant current source module, an energy storage module, and a protection module, where the first constant current source module is used to provide a driving current for the LED light emitting module; the second constant current source module is used for providing a discharge current and a maintaining current for maintaining the conduction of the silicon controlled rectifier regulating module when the line voltage is less than the conduction voltage of the LED light-emitting module; the energy storage module is used for supplying power to the LED light-emitting module when the online voltage is less than the breakover voltage of the LED light-emitting module; the third constant current source module is used for adjusting the output current of the LED light-emitting module; the protection module is used for protecting the second constant current source module, and the anti-surge capacity can be effectively improved, so that the working safety of the LED driving circuit is ensured.

It should be understood that equivalents and modifications of the technical solution and inventive concept thereof may occur to those skilled in the art, and all such modifications and alterations should fall within the scope of the appended claims.

Claims

1. An LED driving circuit comprises an LED light-emitting module and a Silicon Controlled Rectifier (SCR) regulator for regulating the brightness of the LED light-emitting module, and is characterized by further comprising a first constant current source module, a second constant current source module, a third constant current source module, an energy storage module and a protection module, wherein the first constant current source module is used for providing driving current for the LED light-emitting module; the second constant current source module is used for providing a discharge current and a maintaining current for maintaining the conduction of the silicon controlled rectifier regulating module when the line voltage is less than the conduction voltage of the LED light-emitting module; the energy storage module is used for supplying power to the LED light-emitting module when the online voltage is smaller than the breakover voltage of the LED light-emitting module; the third constant current source module is used for adjusting the output current of the LED light-emitting module; the protection module is used for protecting the second constant current source module.

2. The LED driving circuit according to claim 1, wherein the second constant current source module comprises a constant current source unit and an enabling unit, the constant current source unit is configured to provide a drain current and a holding current for holding the thyristor regulation module in a conducting state when a line voltage is less than a conducting voltage of the LED lighting module; the enabling unit is used for controlling the constant current source unit to be closed when the line voltage is greater than the conduction voltage of the LED light-emitting module.

3. The LED driving circuit according to claim 1, wherein the third constant current source module comprises a voltage stabilizing unit, a switching unit, a regulating unit and an energy storage unit, wherein the voltage stabilizing unit is configured to charge the energy storage unit when the switching unit is turned off; when the charging voltage of the energy storage unit is increased to a threshold voltage, controlling the switch unit to be conducted; the adjusting unit is used for controlling the switch-off of the switch unit after the switch unit is switched on so as to adjust the output current of the LED light-emitting module.

4. The LED driving circuit according to claim 2, wherein the enabling unit comprises a first resistor, one end of the first resistor is connected to the constant current source unit, the protection module, the third constant current source module and the energy storage module, and the other end of the first resistor is grounded.

5. The LED driving circuit according to claim 3, wherein the voltage regulator unit comprises a voltage regulator diode, an anode of the voltage regulator diode is connected to the energy storage unit and the switch unit, and a cathode of the voltage regulator diode is connected to the switch unit and the LED light emitting module.

6. The LED driving circuit according to claim 3, wherein the energy storage unit comprises a first capacitor, one end of the first capacitor is connected to the voltage stabilizing unit and the switching unit, and the other end of the first capacitor is connected to the protection module, the second constant current source module, the energy storage module and the adjusting unit.

7. The LED driving circuit according to claim 3, wherein the switching unit comprises a first MOS transistor, a drain of the first MOS transistor is connected to the voltage stabilizing unit and the LED light emitting module, a gate of the first MOS transistor is connected to the energy storage unit and the voltage stabilizing unit, and a source of the first MOS transistor is connected to the adjusting unit.

8. The LED driving circuit according to claim 6, wherein the adjusting unit comprises a second resistor, one end of the second resistor is connected to the source of the first MOS transistor, and the other end of the second resistor is connected to the protection module, the second constant current source module and the energy storage module.

9. The LED driving circuit of claim 1, wherein the protection module comprises a first diode, an anode of the first diode is connected to the second constant current source module, the third constant current source module and the energy storage module, and a cathode of the first diode is grounded.

10. An LED driving device, comprising a housing, wherein a PCB is arranged in the housing, characterized in that the PCB is provided with the LED driving circuit as claimed in any one of claims 1 to 9.