LED driving circuit and driving device

Abstract

The present invention discloses an LED driving circuit and a driving device. The LED driving circuit comprises an LED light-emitting module, a thyristor regulator 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. The first constant current source module is used to provide driving current for the LED light-emitting module; the second constant current source module is used to provide a discharge current and a holding current for maintaining the conduction of the thyristor regulating module when the line voltage is less than the conduction voltage of the LED light-emitting module; the energy storage module is used to supply power to the LED light-emitting module when the line voltage is less than the conduction voltage of the LED light-emitting module; the third constant current source module is used to adjust the output current of the LED light-emitting module; and the protection module is used to protect the second constant current source module. The present invention can effectively improve the surge resistance and ensure the safety of the operation of the LED driving circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of LEDs, and in particular to an LED driving circuit and a driving device. Background Art

[0002] like Figure 1 As shown, in the existing LED driving circuit using thyristor dimming, a discharge current is required when the thyristor dimmer is cut in phase, otherwise it will cause abnormal operation. When the online voltage of the LED lamp is lower than the lighting voltage of the LED lamp, no current flows through the LED lamp, so the LED driving circuit compatible with the thyristor dimmer will add an additional discharge circuit. However, since the discharge current does not flow through the lamp string, but only flows through the resistor Rb and the first constant current source SC1, when a high-voltage surge occurs in the power supply line network, the surge high voltage is borne by the resistor Rb and the first constant current source SC1, which can easily cause damage to the resistor Rb and the first constant current source SC1, resulting in abnormal operation of the LED driving circuit.

[0003] Therefore the prior art still needs to be improved and enhanced. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide an LED driving circuit and a driving device, which can effectively improve the surge resistance and ensure the safety of the LED driving circuit.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An LED driving circuit comprises an LED light-emitting module and a thyristor regulator for adjusting the brightness of the LED light-emitting module, and further comprises 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 to provide a driving current for the LED light-emitting module; the second constant current source module is used to provide a discharge current and a holding current for maintaining the conduction of the thyristor regulating module when the line voltage is less than the conduction voltage of the LED light-emitting module; the energy storage module is used to supply power to the LED light-emitting module when the line voltage is less than the conduction voltage of the LED light-emitting module; the third constant current source module is used to adjust the output current of the LED light-emitting module; and the protection module is used to protect the second constant current source module.

[0007] In the LED driving circuit, the second constant current source module includes a constant current source unit and an enabling unit. The constant current source unit is used to provide a discharge current and a holding current for maintaining the conduction of the thyristor adjustment module when the line voltage is less than the conduction voltage of the LED light-emitting module; the enabling unit is used to control the constant current source unit to be turned off when the line voltage is greater than the conduction voltage of the LED light-emitting module.

[0008] In the LED driving circuit, the third constant current source module includes a voltage stabilizing unit, a switch unit, an adjustment unit and an energy storage unit. The voltage stabilizing unit is used to charge the energy storage unit when the switch unit is turned off; when the charging voltage of the energy storage unit increases to a threshold voltage, the switch unit is controlled to be turned on; and the adjustment unit is used to control the switch unit to be turned off after it is turned on, so as to adjust the output current of the LED light-emitting module.

[0009] In the LED driving circuit, the enabling unit includes 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.

[0010] In the LED driving circuit, the voltage stabilizing unit includes a voltage stabilizing diode, the positive electrode of the voltage stabilizing diode is connected to the energy storage unit and the switch unit, and the negative electrode of the voltage stabilizing diode is connected to the switch unit and the LED light-emitting module.

[0011] In the LED driving circuit, the energy storage unit includes a first capacitor, one end of the first capacitor is connected to the voltage stabilizing unit and the switch 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 adjustment unit.

[0012] In the LED driving circuit, the switch unit includes a first MOS tube, the drain of the first MOS tube is connected to the voltage stabilizing unit and the LED light-emitting module, the gate of the first MOS tube is connected to the energy storage unit and the voltage stabilizing unit, and the source of the first MOS tube is connected to the regulating unit.

[0013] In the LED driving circuit, the regulating unit includes a second resistor, one end of the second resistor is connected to the source of the first MOS tube, 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.

[0014] In the LED driving circuit, the protection module includes a first diode, the 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 the cathode of the first diode is grounded.

[0015] An LED driving device comprises a housing, wherein a PCB board is arranged inside the housing, and is characterized in that the PCB board is provided with the LED driving circuit as described above.

[0016] Compared with the prior art, the LED driving circuit and driving device provided by the present invention include an LED light-emitting module, a thyristor regulator 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. The first constant current source module is used to provide driving current for the LED light-emitting module; the second constant current source module is used to provide a discharge current and a holding current for maintaining the conduction of the thyristor regulating module when the line voltage is less than the conduction voltage of the LED light-emitting module; the energy storage module is used to supply power to the LED light-emitting module when the line voltage is less than the conduction voltage of the LED light-emitting module; the third constant current source module is used to adjust the output current of the LED light-emitting module; the protection module is used to protect the second constant current source module. The present invention can effectively improve the surge resistance and ensure the safety of the operation of the LED driving circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a circuit schematic diagram of an existing LED driving circuit.

[0018] Figure 2 This is a structural block diagram of the LED driving circuit provided by the present invention.

[0019] Figure 3 and Figure 4 This is a circuit schematic diagram of a first preferred embodiment of the LED driving circuit provided by the present invention.

[0020] Figure 5 The waveform diagram is of the AC input voltage, the thyristor regulator input voltage and the thyristor regulator output voltage in the LED driving circuit provided by the present invention.

[0021] Figure 6 This is a circuit schematic diagram of a second preferred embodiment of the LED driving circuit provided by the present invention. DETAILED DESCRIPTION

[0022] The object of the present invention is to provide an LED driving circuit and a driving device, which can effectively improve the surge resistance and ensure the safety of the LED driving circuit.

[0023] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] See also Figure 2The LED driving circuit provided by the present invention includes a rectifier module 100, an LED light-emitting module 200, a thyristor regulator 300 for adjusting 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 rectifier 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 rectifier 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 also 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, and the second constant current source module 500 is also connected to the protection module 800.

[0025] 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 a prior art and can be implemented using an existing mature circuit, and its structure and connection relationship are not described in detail here. The first constant current source module 400 is used to provide driving current for the LED light-emitting module 200, that is, the first constant current source module 400 controls the maximum current of the LED driving circuit; the second constant current source module 500 is used to provide a discharge current and a maintenance current for maintaining the conduction of the thyristor regulation module when the line voltage Vrec is less than the conduction voltage of the LED light-emitting module 200. When the line voltage Vrec is less than the conduction voltage of the LED light-emitting module 200, the current Iac of the AC power supply 10 will flow from the first constant current source module 400 to the ground through the second constant current source module 500, and will not flow through the energy storage module 700 and the LED light-emitting module 200. Correspondingly, the LED light-emitting module 200 does not emit light without current passing therethrough, that is, the second constant current source module 500 provides the thyristor regulator 300 with a discharge current and a working circuit to maintain its operation, so that the thyristor regulator 300 can operate stably.

[0026] Furthermore, the energy storage module 700 is used to supply power to the LED light emitting module 200 when the line voltage Vrec is less than the conduction 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 conduction voltage of the LED light emitting module 200, the current Iac of the AC power supply 10 in the LED driving circuit is at a maximum value, the energy storage module 700 enters a charging state, and correspondingly, the second constant current source module 500 is turned off; and the third constant current source module 600 is used to adjust the output current of the LED light emitting module 200, that is, relative to the traditional LED driving circuit, when the line voltage Vrec is greater than the conduction voltage of the LED light emitting module 200, the current Iac of the AC power supply 10 in the LED driving circuit is at a maximum value, the energy storage module 700 enters a charging state, and correspondingly, the second constant current source module 500 is turned off; and the third constant current source module 600 is used to adjust the output current of the LED light emitting module 200, that is, relative to the traditional LED driving circuit, when the line voltage V When rec is less than the on-voltage of the LED light-emitting module 200, the LED light-emitting module 200 does not emit light. Therefore, each sinusoidal wave cycle will cause the LED light-emitting module 200 to change from on to off, resulting in a flickering phenomenon. In the present application, the output current of the LED light-emitting module 200 is controlled by combining the energy storage module 700 with the third constant current source module 600, so that the current flowing through the LED light-emitting module 200 does not change or changes very little, thereby ensuring that the LED light-emitting module 200 does not experience a flickering phenomenon; the protection module 800 is used 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 can ensure that the second constant current source module 500 is not damaged by the surge high voltage, thereby improving the safety of the LED drive circuit.

[0027] Please also refer to Figure 3 and Figure 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 also connected to the protection module 800; the constant current source unit 520 is used to provide a discharge current and a holding current for maintaining the conduction of the thyristor adjustment module when the line voltage Vrec is less than the conduction voltage of the LED light-emitting module 200; the enabling unit 510 is used to control the constant current source unit 520 to be turned off when the line voltage Vrec is greater than the conduction voltage of the LED light-emitting module 200, When the line voltage Vrec is greater than the on-voltage of the LED light-emitting module 200, the current Iac of the AC power supply 10 is at the maximum value Imax, and the maximum current value Imax will flow through the enabling unit 510, and the voltage R1 across the enabling unit 510 increases 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; and when the line voltage Vrec is less than the on-voltage of the LED light-emitting module 200, the constant current source unit 520 provides the thyristor regulator 300 with a discharge current and a working circuit to maintain its operation, so that the thyristor regulator 300 operates stably.

[0028] In this embodiment, the second constant current source module 500 further includes a sampling resistor Rb1, and one end of the sampling resistor is connected to the first constant current source module 400, and 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 of it through the protection module 800, and the remaining part can be shared by the first constant current source module 400, the sampling resistor and the constant current source unit 520. Compared with the existing LED drive circuit, the present invention has two branches that can share the surge high voltage, and each part can withstand a certain surge high voltage, thereby reducing the surge high voltage borne by each part, thereby ensuring that each part will not be damaged, thereby improving the circuit's surge resistance and improving the safety of the circuit operation.

[0029] For further information, please refer to Figure 3 and Figure 4The third constant current source module 600 includes a voltage stabilizing unit 610, a switch unit 630, an adjusting unit 640 and an energy storage unit 620. The voltage stabilizing unit 610 is used to charge the energy storage unit 620 when the switch unit 630 is turned off; when the charging voltage VC of the energy storage unit 620 increases to a threshold voltage, the switch unit 630 is controlled to be turned on; the adjusting unit 640 is used to control the switch unit 630 to be turned off after being turned on, so as to adjust the output current of the LED light-emitting module 200.

[0030] After power-on, the voltage stabilizing unit 610 in the third constant current source module 600 charges the energy storage unit 620. When the charging voltage of the energy storage unit 620 increases to a threshold voltage, i.e., the on-voltage of the switch unit 630, the switch unit 630 is turned on, so that the voltage stabilizing unit 610 and the energy storage unit 620 are short-circuited and charging stops, and then the voltage of the regulating unit 640 rises, and conversely, the voltage of the switch unit 630 decreases and is cut off, and the energy storage unit 620 continues to enter the charging state, and finally reaches a dynamic balance, so as to adjust the current flowing through the LED light-emitting module 200, i.e., the output current of the LED light-emitting module 200.

[0031] In a specific implementation, the enabling unit 510 includes a first resistor R1, one end of which 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, and the other end of the first resistor R1 is grounded. When the line voltage Vrec is greater than the turn-on voltage of the LED light-emitting module 200, the charging current of the energy storage module 700 and the output current of the LED light-emitting module 200 both flow through the first resistor R1, so that the voltage across the first resistor R1 increases to a value greater than the reference voltage Vref2 of the constant current source unit 520, so that the constant current source unit 520 is turned off, that is, the enabling unit 510 can realize the switching of the constant current source unit 520, that is, the second constant current source module 500.

[0032] Furthermore, the voltage stabilizing unit 610 includes a voltage stabilizing diode ZD1, the energy storage unit 620 includes a first capacitor C1, the positive electrode of the voltage stabilizing diode ZD1 is connected to one end of the first capacitor C1 and the switch unit 630, the negative electrode of the voltage stabilizing diode ZD1 is connected to the switch unit 630 and the LED light-emitting 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 adjustment unit 640 and the energy storage module 700; when power is turned on, the power supply charges the first capacitor C1 through the voltage stabilizing 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 then the voltage stabilizing diode ZD1 and the first capacitor C1 are short-circuited and charging stops, so as to facilitate the subsequent adjustment of the output voltage of the LED light-emitting module 200.

[0033] Preferably, the switch unit 630 includes a first MOS tube M1, a drain of the first MOS tube M1 is connected to the cathode of the voltage zener diode ZD1 and the LED light-emitting module 200, a gate of the first MOS tube M1 is connected to one end of the first capacitor C1 and the anode of the voltage zener diode ZD1, and a source of the first MOS tube M1 is connected to the regulating unit 640. When the charging voltage of the first capacitor C1 increases to the turn-on voltage of the first MOS tube M1, the first MOS tube M1 is turned on, the voltage zener diode ZD1 and the first capacitor C1 are short-circuited and charging stops, the voltage of the regulating unit 640 rises, causing the gate voltage of the first MOS tube M1 to drop, the first MOS tube M1 is turned off, and the first capacitor C1 continues to charge, and finally reaches a dynamic balance, thereby realizing the regulation of the output current of the LED light-emitting module 200.

[0034] Preferably, the regulating unit 640 includes a second resistor R2, one end of the second resistor R2 is connected to the source of the first MOS tube M1, and 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 the first capacitor C1 through the voltage regulator diode ZD1. When the charging voltage of the first capacitor C1 increases to the turn-on voltage of the first MOS tube M1, the first MOS tube M1 is turned on, the voltage regulator diode ZD1 and the first capacitor C1 are short-circuited, and the voltage of the second resistor R2 rises, causing the gate voltage of the first MOS tube M1 to drop and be cut off, and the first capacitor C1 continues to restore the charging state, so that a dynamic balance is finally reached, so that the output current Iled of the LED light-emitting module 200 is equal to V R2 / R2, where V R2is the voltage of the second resistor R2; thereby achieving the adjustment of the output current of the LED light emitting module 200, ensuring that the output current of the LED light emitting module 200 does not change or changes very little, thereby ensuring that the LED light emitting module 200 does not flicker.

[0035] Please also refer to Figure 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 light-emitting 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 adjusts the brightness of the LED light-emitting module 200, the conduction phase angle changes, resulting in a change in the charging time Tchg of the second capacitor C2, and then the peak voltage of the second capacitor C2 will also change accordingly. When the effective phase output of the thyristor regulator 300 is larger, , the longer the charging time Tchg of the second capacitor C2 is, the higher the peak voltage of the second capacitor C2 will be, the drain voltage Vd of the first MOS tube M1 is Vd=VC-Vled, where VC is the charging voltage of the second capacitor C2, and Vled is the voltage of the LED light-emitting module 200. Since the first capacitor C1 can only discharge through its own internal resistance, Vg=Vdmax-Vdz1=VCmax-Vled-Vdz1, where Vg is the gate voltage of the first MOS tube M1, Vdmax is the maximum drain voltage of the first MOS tube M1, and Vdz1 is the voltage regulator. The voltage of the diode ZD1, VCmax is the peak voltage of the second capacitor C2, that is, the gate voltage of the first MOS tube 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 tube M1 increases, and the first capacitor C1 is charged, so that the gate voltage of the first MOS tube M1 increases and turns on, and then the voltage of the second resistor R2 increases, that is, the corresponding output current Iled of the LED light-emitting module 200 increases; when the peak voltage of the second capacitor C2 decreases, the gate voltage of the first MOS tube M1 decreases. The gate voltage of the first MOS tube M1 decreases, and the first capacitor C1 discharges through its own internal resistance, so that the gate voltage of the first MOS tube M1 decreases, and the voltage of the second resistor R2 decreases, that is, the corresponding output current Iled of the LED light-emitting module 200 decreases, that is, the output current of the LED light-emitting module 200 changes with the peak voltage of the second capacitor C2, so the third constant current source module 600 can change the current of the LED light-emitting module 200 according to the adjustment of the thyristor regulator 300 to achieve a dimming effect, and the LED light-emitting module 200 will not have a flicker phenomenon.

[0036] 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 tube M2, the non-phase input terminal of the first operational amplifier U1 is connected to the positive electrode of the first constant voltage power supply, the inverting input terminal of the first operational amplifier U1 is connected to one end of the first resistor R1, the source of the second MOS tube M2 and the positive electrode of the first diode D1, the negative electrode of the first constant voltage power supply and the negative electrode of the first diode D1 are grounded, and the output terminal of the first operational amplifier U1 is connected to the positive electrode of the first constant voltage power supply. The gate of the second MOS tube M2, the drain of the second MOS tube 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, specifically, when there is a surge high voltage, the first diode D1 clamps the voltage of the first resistor R1 within its forward conduction voltage, that is, 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 the surge high voltage, thereby improving the surge resistance of the LED drive circuit.

[0037] Furthermore, the LED driving circuit also includes a second diode D2, which 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, and the cathode of the second diode D2 is connected to the LED light-emitting module 200 and one end of the second capacitor C2. 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 operation of the LED driving circuit.

[0038] Furthermore, the first constant current source module 400 includes a second operational amplifier U2, a third MOS tube M3, a third resistor R3 and a second constant voltage power supply, the non-phase input terminal of the second operational amplifier U2 is connected to the positive electrode of the second constant voltage power supply, the inverting input terminal of the second operational amplifier U2 is connected to one end of the third resistor R3 and the source of the third MOS tube M3, the gate of the third MOS tube M3 is connected to the output terminal of the second operational amplifier U2, and the drain of the third MOS tube M3 is connected to the rectifier module 100.

[0039] Please continue reading Figure 3, the first constant current source module 400 controls the maximum current of the LED driving circuit, that is, Imax=Vref1 / R3, wherein Vref1 is the reference voltage of the input of the second operational amplifier U2, and R3 is the resistance value of the third resistor R3. After the LED driving circuit is powered on, when the line voltage Vrec is less than the on-voltage of the LED light-emitting module 200, 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 light-emitting module 200. The corresponding current is Iac=Ib=Vref2 / R1. At this time, the LED light-emitting module 200 does not emit light, and only the second constant current source module 500 provides the thyristor regulator 300 with a discharge current and a holding current, so that the thyristor works stably; the second capacitor C2 discharges the LED light-emitting module 200, and at this time, the discharge current Idis=Iled.

[0040] Please continue reading Figure 4 , when the line voltage Vrec is greater than the on-voltage of the LED light-emitting module 200, at this time, the current Iac of the AC power supply 10 is equal to Imax, and the charging current Ichg of the second capacitor C2 is equal to Imax-Iled. Correspondingly, the output current Iled of the LED light-emitting module 200 is adjusted by the third constant current source module 600. Since the adjustment process of the third constant current source module 600 has been described above, it will not be repeated here. At this time, the output current Iled of the LED light-emitting module 200 and the charging current Ichg of the second capacitor C2 both flow through the first resistor R1, so V1>Vref2, the second MOS tube M2 is turned off, and Ib=0, wherein V1 is the voltage across the first resistor R1.

[0041] Compared with the existing LED driving circuit provided with the thyristor regulator 300, the LED driving circuit provided by the present invention can effectively solve the flicker problem of the LED and improve the compatibility of the thyristor regulator 300; and when there is a surge high voltage, the present invention can absorb a part of it through the second capacitor C2 through the first diode D1, and the remaining part can be shared by the first constant current source module 400, the sampling resistor Rb1 and the constant current source unit 520. The three parts share the high voltage, so that the surge high voltage borne by each part is reduced, thereby improving the power supply surge resistance of the LED driving circuit and improving the safety of the LED driving circuit.

[0042] In the second preferred embodiment of the present invention, please refer to Figure 6The 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 the drain of the first MOS tube M1 are connected to the LED light-emitting module 200. The other end of the fourth resistor R4 and one end of the fifth resistor R5 are connected to the positive electrode of the third diode D3. The negative electrode of the third diode D3 is connected to one end of the first capacitor C1 and the gate of the first MOS tube 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, the drain voltage of the first MOS tube M1 can be divided by the fourth resistor R4 and the fifth resistor R5, and then the first capacitor C1 is charged by the third diode D3. The first capacitor C1 is discharged through its own internal resistance, which can also achieve the same effect as when the voltage stabilizing diode ZD1 is connected, thereby achieving the regulation of the output current of the LED light-emitting module 200.

[0043] In this embodiment, the energy storage module 700 includes a fourth diode D4, a sixth resistor R6 and a third capacitor C3, the positive electrode of the fourth diode D4 and one end of the sixth resistor R6 are connected to one end of the third capacitor C3, the negative electrode of the fourth diode D4 and the other end of the sixth resistor R6 are connected to the negative electrode of the second diode D2, the sixth resistor R6 is a current limiting resistor, when there is a surge high voltage, the sixth resistor R6 can limit the charging current of the third capacitor C3, withstand the excess surge voltage, and further improve the surge resistance of the LED drive circuit; at the same time, the fourth diode D4 is a discharge diode, the presence of the fourth diode D4 can make the third capacitor C3 not limited by the sixth resistor R6 when discharging, thereby reducing power consumption.

[0044] The present invention also provides an LED driving device, including a housing, a PCB board is arranged in the housing, and the PCB board is provided with the LED driving circuit as described above. Since the LED driving circuit has been described in detail above, it will not be described in detail here.

[0045] In summary, the LED driving circuit and driving device provided by the present invention include an LED light-emitting module, a thyristor regulator 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. The first constant current source module is used to provide driving current for the LED light-emitting module; the second constant current source module is used to provide a discharge current and a holding current for maintaining the conduction of the thyristor adjustment module when the line voltage is less than the conduction voltage of the LED light-emitting module; the energy storage module is used to power the LED light-emitting module when the line voltage is less than the conduction voltage of the LED light-emitting module; the third constant current source module is used to adjust the output current of the LED light-emitting module; the protection module is used to protect the second constant current source module. The present invention can effectively improve the surge resistance and ensure the safety of the operation of the LED driving circuit.

[0046] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all these changes or substitutions should fall within the protection scope of the claims attached to the present invention.

Claims

1. An LED driving circuit, comprising an LED light-emitting module and a thyristor regulator for adjusting the brightness of the LED light-emitting module, characterized in that: 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 to provide a discharge current and a holding current for maintaining the conduction of the thyristor regulator when the line voltage is less than the conduction voltage of the LED light-emitting module; the second constant current source module includes a constant current source unit and an enabling unit, the constant current source unit is used to provide a discharge current and a holding current for maintaining the conduction of the thyristor regulator when the line voltage is less than the conduction voltage of the LED light-emitting module; the enabling unit is used to control the constant current source unit to provide a discharge current and a holding current for maintaining the conduction of the thyristor regulator when the line voltage is less than the conduction voltage of the LED light-emitting module; the enabling unit is used to control the constant current source unit to provide a discharge current and a holding current for maintaining the conduction of the thyristor regulator when the line voltage is greater than the conduction voltage of the LED light-emitting module. The source unit is closed; the second constant current source module also includes a sampling resistor, and one end of the sampling resistor is connected to the first constant current source module, and the other end of the sampling resistor is connected to the constant current source unit, that is, the sampling resistor is connected in series with the constant current source unit. When there is a surge high voltage, the energy storage module can share a part through the protection module, and the remaining part can be shared by the first constant current source module, the sampling voltage and the constant current source unit; the energy storage module is used to power the LED light-emitting module when the line voltage is less than the turn-on voltage of the LED light-emitting module; the third constant current source module is used to adjust the output current of the LED light-emitting module, and the protection module is used to protect the second constant current source module from being damaged by the surge high voltage.

2. The LED driving circuit according to claim 1, characterized in that: The third constant current source module includes a voltage stabilizing unit, a switch unit, an adjustment unit and an energy storage unit. The voltage stabilizing unit is used to charge the energy storage unit when the switch unit is turned off; when the charging voltage of the energy storage unit increases to a threshold voltage, the switch unit is controlled to be turned on; and the adjustment unit is used to control the switch unit to be turned off after it is turned on, so as to adjust the output current of the LED light-emitting module.

3. The LED driving circuit according to claim 1, characterized in that: The enabling unit comprises a first resistor, one end of which 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 which is grounded.

4. The LED driving circuit according to claim 2, characterized in that: The voltage stabilizing unit comprises a voltage stabilizing diode, the anode of the voltage stabilizing diode is connected to the energy storage unit and the switch unit, and the cathode of the voltage stabilizing diode is connected to the switch unit and the LED light emitting module.

5. The LED driving circuit according to claim 2, characterized in that: The energy storage unit includes a first capacitor, one end of which is connected to the voltage stabilizing unit and the switch unit, and the other end of which is connected to the protection module, the second constant current source module, the energy storage module and the regulating unit.

6. The LED driving circuit according to claim 2, characterized in that: The switch unit includes a first MOS tube, a drain of the first MOS tube is connected to the voltage stabilizing unit and the LED light-emitting module, a gate of the first MOS tube is connected to the energy storage unit and the voltage stabilizing unit, and a source of the first MOS tube is connected to the regulating unit.

7. The LED driving circuit according to claim 6, characterized in that: The regulating unit comprises a second resistor, one end of the second resistor is connected to the source of the first MOS tube, 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.

8. The LED driving circuit according to claim 1, characterized in that: The protection module comprises a first diode, the 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 the cathode of the first diode is grounded.

9. An LED driving device, comprising a housing, wherein a PCB board is arranged in the housing, characterized in that: The PCB board is provided with the LED driving circuit as described in any one of claims 1 to 7.

Images