A dimming type LED driving circuit and lighting equipment

Abstract

The present invention discloses a dimming type LED driving circuit and lighting equipment. In the dimming type driving circuit, a main power conversion module is used to convert a constant input voltage into a constant current and output it to an LED lamp, thereby driving the LED lamp to emit light, and the current of the LED lamp is sampled to obtain a sampling signal, and the dimming signal is output through the dimming module, so that the operational square amplifier U1 of the average current control module compares the sampling signal and the dimming signal to output a reference signal, and then the comparator U2 of the peak current detection module compares the reference signal and the sampling signal to output a driving signal, thereby enabling the main power conversion module to convert the constant input voltage into a constant current and output it under the control of the driving signal. The above method can realize the dimming of the LED lamp, and the structure is simple, which is conducive to reducing costs.

Description

Technical Field

[0001] The present invention relates to the technical field of LED driving, and in particular to a dimming type LED driving circuit and lighting equipment. Background Art

[0002] LED lights have the advantages of high efficiency, energy saving, long life, and environmental protection, and are widely used in lighting, display light sources, stage lighting and other scenes. In practical applications, people often hope to adjust the light intensity according to actual needs to meet relevant requirements. Existing dimming circuits are mostly implemented using relatively complex integrated circuits, which are often expensive and not conducive to cost reduction. Summary of the invention

[0003] The purpose of the present invention is to address the deficiencies in the prior art and provide a dimming LED driving circuit and lighting device that can achieve dimming while reducing costs.

[0004] To achieve this object, in a first aspect, the present invention provides a dimming LED driving circuit, comprising an LED lamp, a constant voltage power supply module, a main power conversion module, a dimming module, an average current control module and a peak current control module; wherein the average current control module comprises an operational amplifier U1, and the peak current control module comprises a comparator U2;

[0005] The constant voltage power supply module is connected to the main power conversion module and is used to provide a constant input voltage;

[0006] The main power conversion module is connected to the LED lamp, and is used to convert the constant input voltage into a constant current and output it to the LED lamp, and is used to sample the current flowing through the LED lamp to obtain a sampling signal, and output the sampling signal to the average current control module and the peak current control module;

[0007] The dimming module is used to output a dimming signal to the average current control module; the operational amplifier U1 of the average current control module is used to compare the sampling signal with the dimming signal, so as to output a reference signal to the peak current control module according to the comparison result; the comparator U2 of the peak current detection module is used to compare the reference signal with the sampling signal, so as to output a driving signal to the main power supply module according to the comparison result, and the main power conversion module converts the constant input voltage into a constant current under the control of the driving signal and outputs it.

[0008] Furthermore, the mainstream power conversion module includes an input filter capacitor Cin, a switch tube Q1, a drive circuit, an inductor L1, a freewheeling diode D1, an output filter capacitor Cout and a sampling resistor R0;

[0009] The first end of the input filter capacitor Cin is connected to the positive terminal of the constant voltage power supply module and the first end of the switch tube Q1, and the second end of the input filter capacitor Cin and the negative terminal of the constant voltage power supply module are both grounded; the second end of the switch tube Q1 is connected to the negative electrode of the freewheeling diode D1 and the first end of the inductor L1, the positive electrode of the freewheeling diode D1 and the first end of the sampling resistor R0 are both grounded, the second end of the inductor L1 is connected to the first end of the output filter capacitor Cout and the positive electrode of the LED lamp, the second end of the output filter capacitor Cout is connected to the negative electrode of the LED lamp and the second end of the sampling resistor R0, the second end of the sampling resistor R0 is used to output the sampling signal, the output end of the drive circuit is connected to the control end of the switch tube Q1 to control the switch tube Q1 to be turned on or off, and the signal input end of the drive circuit is connected to the peak current control module for inputting the drive signal.

[0010] Furthermore, the average current control module further includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1 and a second capacitor C2;

[0011] The first end of the first resistor R1 is connected to the second end of the sampling resistor R0, the second end of the first resistor R1 is connected to the first end of the second resistor R2 and the first input end of the operational amplifier U1, and the second input end of the operational amplifier U1 is connected to the output end of the dimming module for inputting the dimming signal; the second end of the second resistor R2 is connected to the first end of the first capacitor C1, the second end of the first capacitor C1 is connected to the output end of the operational amplifier U1 and the first end of the third resistor R3, the second end of the third resistor R3 is connected to the first end of the fourth resistor R4, the first end of the second capacitor C2 and the peak current control module to output a reference signal to the peak current control module, and the second end of the fourth resistor R4 and the second end of the second capacitor C2 are both grounded.

[0012] Furthermore, the peak current control module further includes a fifth resistor R5, a sixth resistor R6 and a third capacitor C3;

[0013] The first end of the fifth resistor R5 is connected to the second end of the third resistor R3, the second end of the fifth resistor R5 and the first end of the third capacitor C3 are both connected to the non-inverting input terminal of the comparator U2, the second end of the third capacitor C3 and the first end of the sixth resistor R6 are both connected to the inverting input terminal of the comparator U2, the second end of the sixth resistor R6 is connected to the second end of the sampling resistor R0, and the output terminal of the comparator U2 is connected to the signal input terminal of the drive circuit.

[0014] Furthermore, it also includes an auxiliary power supply module, the input end of the auxiliary power supply module is connected to the positive end of the constant voltage power supply module, the first output end of the auxiliary power supply module is connected to the driving circuit, and the second output end of the auxiliary power supply module is connected to the voltage input end of the operational amplifier, the voltage input end of the comparator, and the voltage input end of the dimming module.

[0015] Furthermore, the driving circuit is a PWM control circuit.

[0016] Furthermore, the first switch tube is a MOS tube.

[0017] In a second aspect, an embodiment of the present invention provides a lighting device, comprising any one of the dimming LED driving circuits described above.

[0018] Beneficial effects of the present invention: In the dimming type LED driving circuit of the present invention, the constant input voltage is converted into a constant current by using the main power conversion module and outputted to the LED lamp, thereby driving the LED lamp to emit light, and the current of the LED lamp is sampled to obtain a sampling signal, and the dimming signal is outputted through the dimming module, so that the operational amplifier U1 of the average current control module compares the sampling signal with the dimming signal, so as to output a reference signal to the peak current control module according to the comparison result, and then the comparator U2 of the peak current detection module compares the reference signal with the sampling signal, so as to output a driving signal to the main power supply module according to the comparison result, thereby making the main power conversion module convert the constant input voltage into a constant current and output it under the control of the driving signal, and the constant current driving of the LED lamp can be realized by the above method, and different dimming signals can be outputted through the dimming module, and then the peak current detection module can output different driving signals, so that the main power conversion module outputs different constant currents under the control of different driving signals, so as to achieve the purpose of dimming, and in addition, the control of the main power conversion module is realized by the operational amplifier U1 and the comparator U2 in the present invention, and the structure is simple, which is conducive to reducing the cost compared with the integrated circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a structural schematic diagram of a dimming LED driving circuit provided by an embodiment of the present invention;

[0020] Figure 2 4 is a circuit schematic diagram of a dimming LED driving circuit provided in an embodiment of the present invention.

[0021] Reference numerals:

[0022] 100 dimming type LED driving circuit, 10 constant voltage power supply module, 20 main power conversion module, 30 dimming module, 40 average current control module, 50 peak current control module, and 60 auxiliary power supply module. DETAILED DESCRIPTION

[0023] The present invention will be described in detail below with reference to specific embodiments.

[0024] See also Figure 1 An embodiment of the present invention provides a dimming LED driving circuit 100, including an LED lamp, a constant voltage power supply module 10, a main power conversion module 20, a dimming module 30, an average current control module 40 and a peak current control module 50; wherein the average current control module 40 includes an operational amplifier U1, and the peak current control module 50 includes a comparator U2.

[0025] Furthermore, the constant voltage power supply module 10 is connected to the main power conversion module 20 to provide a constant input voltage. The main power conversion module 20 is connected to the LED lamp to convert the constant input voltage into a constant current and output it to the LED lamp, and to sample the current flowing through the LED lamp to obtain a sampling signal, and output the sampling signal to the average current control module 40 and the peak current control module 50.

[0026] The dimming module 30 is used to output a dimming signal to the average current control module 40; the operational amplifier U1 of the average current control module 40 is used to compare the sampling signal with the dimming signal, so as to output a reference signal to the peak current control module 50 according to the comparison result; the comparator U2 of the peak current detection module 50 is used to compare the reference signal with the sampling signal, so as to output a driving signal to the main power supply module 20 according to the comparison result, and the main power conversion module 20 converts the constant input voltage into a constant current under the control of the driving signal and outputs it.

[0027] Therefore, through the above method, constant current driving of the LED lamp can be achieved, and different dimming signals can be output through the dimming module 30, so that the peak current detection module 50 can output different driving signals, so that the main power conversion module 20 outputs different constant currents under the control of different driving signals, thereby achieving the purpose of dimming. In addition, in the embodiment of the present invention, the control of the main power conversion module 20 is achieved through the operational amplifier U1 and the comparator U2, which has a simple structure and is conducive to reducing costs compared with integrated circuits.

[0028] See also Figure 2 , Figure 2FIG. 1 is a circuit diagram of a dimming LED driving circuit provided by an embodiment of the present invention. Figure 2 As shown, the mainstream power conversion module 20 includes an input filter capacitor Cin, a switch tube Q1, a drive circuit, an inductor L1, a freewheeling diode D1, an output filter capacitor Cout and a sampling resistor R0.

[0029] The constant voltage power supply module 10 can be implemented by an isolated or non-isolated AC-DC constant voltage circuit, and can support a wider constant voltage input range according to actual output parameters. The drive circuit can be, for example, a PWM control circuit, that is, a circuit that outputs a PWM control signal.

[0030] The first end of the input filter capacitor Cin is connected to the positive terminal of the constant voltage power supply module 10 and the first end of the switch tube Q1, and the second end of the input filter capacitor Cin and the negative terminal of the constant voltage power supply module 10 are both grounded; the second end of the switch tube Q1 is connected to the negative electrode of the freewheeling diode D1 and the first end of the inductor L1, the positive electrode of the freewheeling diode D1 and the first end of the sampling resistor R0 are both grounded, the second end of the inductor L1 is connected to the first end of the output filter capacitor Cout and the positive electrode of the LED lamp, the second end of the output filter capacitor Cout is connected to the negative electrode of the LED lamp and the second end of the sampling resistor R0, and the second end of the sampling resistor R0 is used to output the sampling signal U R The output end of the driving circuit is connected to the control end of the switch tube Q1 to control the switch tube Q1 to be turned on or off, and the input end of the driving circuit is connected to the peak current control module 50 to input the driving signal Drive.

[0031] When the switch tube Q1 is turned on, the current of the inductor L1 increases and reaches I H When the control switch Q1 is turned off, the current of the inductor L1 decreases to I L , when the switch tube Q1 is turned on again, the cycle repeats. After the filtering effect of the output filter capacitor C2, the constant current can be output as:

[0032] I O =(I H +I L ) / 2

[0033] The switch tube Q1 may be a MOS tube, for example, an NMOS tube, wherein the first end of the switch tube Q1 is the drain of the NMOS tube, the second end of the switch tube Q1 is the source of the NMOS tube, and the control end of the switch tube Q1 is the gate of the NMOS tube. Of course, in other embodiments, the switch tube Q1 may also be implemented by a triode or other switch tubes.

[0034] Furthermore, in the embodiment of the present invention, the average current control module 40 further includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1 and a second capacitor C2.

[0035] The first end of the first resistor R1 is connected to the second end of the sampling resistor R0, the second end of the first resistor R1 is connected to the first end of the second resistor R2 and the first input end of the operational amplifier U1, the second input end of the operational amplifier U1 is connected to the output end of the dimming module 30, and is used to input the dimming signal DIM; the second end of the second resistor R2 is connected to the first end of the first capacitor C1, the second end of the first capacitor C1 is connected to the output end of the operational amplifier U1 and the first end of the third resistor R3, the second end of the third resistor R3 is connected to the first end of the fourth resistor R4, the first end of the second capacitor C2 and the peak current control module 50, so as to output a reference signal Vref to the peak current control module 50, and the second end of the fourth resistor R4 and the second end of the second capacitor C2 are both grounded.

[0036] The dimming signal DIM output by the dimming module 30 can be an analog DC level or a DC signal after RC filtering of a PWM signal. According to the control principle of the integration circuit of the operational amplifier U1, it can be obtained:

[0037] I o *R=V DIM

[0038] Among them, I o is the average current of the loop, that is, the constant current output by the main power conversion module 20, V DIM is the voltage value of the dimming signal DIM, and R is the resistance value of the sampling resistor R0.

[0039] The peak current control module 50 further includes a fifth resistor R5, a sixth resistor R6 and a third capacitor C3.

[0040] The first end of the fifth resistor R5 is connected to the second end of the third resistor R3, the second end of the fifth resistor R5 and the first end of the third capacitor C3 are both connected to the non-inverting input terminal of the comparator U2, the second end of the third capacitor C3 and the first end of the sixth resistor R6 are both connected to the inverting input terminal of the comparator U2, the second end of the sixth resistor R6 is connected to the second end of the sampling resistor R0, and the output terminal of the comparator U2 is connected to the signal input terminal of the drive circuit.

[0041] It can be understood that the reference signal Vref is a signal obtained by dividing the signal output by the operational amplifier U2 through the third resistor R3 and the fifth resistor R5. R The comparator U2 inputs the reference signal Vref and the sampling signal U R For comparison, when U R When Vref is less than Vref, a drive signal Drive is sent to the drive circuit, so that the drive circuit controls the switch tube Q1 to turn on; when U R ≥Vref, a driving signal Drive is sent to the driving circuit, so that the driving circuit controls the switch tube Q1 to be turned off.

[0042] In the embodiment of the present invention, the operational amplifier U1, the comparator U2 and the peripheral resistor and capacitor components form a double negative feedback loop, which can control the main power conversion module 20 to work stably and output a constant current I o When the dimming module 30 changes the value of the dimming signal DIM, the average current control module 40 and the peak current control module 50 will promptly process the changed signal and output the corresponding drive signal DRIVE. The frequency and duty cycle of the drive signal DRIVE will be adjusted accordingly, thereby changing the current I output by the main power conversion module 20. o , that is, the dimming function is realized.

[0043] Furthermore, the dimming LED lamp driving circuit 100 of the embodiment of the present invention may also include an auxiliary power supply module 60, the input end of the auxiliary power supply module 60 is connected to the positive terminal of the constant voltage power supply module 10, the first output end of the auxiliary power supply module 60 is connected to the driving circuit, and the second output end of the auxiliary power supply module 60 is connected to the voltage input end of the operational amplifier U1, the voltage input end of the comparator U2, and the voltage input end of the dimming module 30, so as to provide auxiliary power supply to the driving circuit, the operational amplifier U1, the comparator U2 and the dimming module 30. The auxiliary power supply module 60 may include a DC-DC circuit, which converts the output voltage of the constant voltage power supply module 10 into the power supply voltage of the driving circuit, the operational amplifier U1, the comparator U2 and the dimming module 30 through the DC-DC circuit. Of course, in other embodiments, the constant voltage power supply module 10 may also be used to provide the driving circuit, the operational amplifier U1, the comparator U2 and the dimming module 30 with the voltage required for operation.

[0044] The dimming LED driving circuit of the present invention only requires a general operational amplifier and a comparator and simple peripheral capacitor and resistor devices to realize the dimming of the LED lamp, which has low cost and is more versatile and flexible in device selection than integrated circuits, thereby greatly increasing the comprehensive competitiveness of the product.

[0045] An embodiment of the present invention further provides a lighting device, comprising the dimming LED driving circuit described in any one of the above embodiments.

[0046] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, according to the concept of the present invention, there will be changes in the specific implementation methods and application scopes. The content of this specification should not be understood as limiting the present invention.

Claims

1. A dimming LED driving circuit, characterized in that: It includes an LED lamp, a constant voltage power supply module, a main power conversion module, a dimming module, an average current control module and a peak current control module; wherein the average current control module includes an operational amplifier U1, and the peak current control module includes a comparator U2; The constant voltage power supply module is connected to the main power conversion module and is used to provide a constant input voltage; The main power conversion module is connected to the LED lamp, and is used to convert the constant input voltage into a constant current and output it to the LED lamp, and is used to sample the current flowing through the LED lamp to obtain a sampling signal, and output the sampling signal to the average current control module and the peak current control module; The dimming module is used to output a dimming signal to the average current control module; the operational amplifier U1 of the average current control module is used to compare the sampling signal with the dimming signal, so as to output a reference signal to the peak current control module according to the comparison result; The comparator U2 of the peak current control module is used to compare the reference signal with the sampling signal, so as to output a driving signal to the main power conversion module according to the comparison result, and the main power conversion module converts the constant input voltage into a constant current under the control of the driving signal and outputs it; The main power conversion module includes an input filter capacitor Cin, a switch tube Q1, a drive circuit, an inductor L1, a freewheeling diode D1, an output filter capacitor Cout and a sampling resistor R0; The first end of the input filter capacitor Cin is connected to the positive terminal of the constant voltage power supply module and the first end of the switch tube Q1, and the second end of the input filter capacitor Cin and the negative terminal of the constant voltage power supply module are both grounded; the second end of the switch tube Q1 is connected to the negative electrode of the freewheeling diode D1 and the first end of the inductor L1, the positive electrode of the freewheeling diode D1 and the first end of the sampling resistor R0 are both grounded, the second end of the inductor L1 is connected to the first end of the output filter capacitor Cout and the positive electrode of the LED lamp, the second end of the output filter capacitor Cout is connected to the negative electrode of the LED lamp and the second end of the sampling resistor R0, the second end of the sampling resistor R0 is used to output the sampling signal, the output end of the drive circuit is connected to the control end of the switch tube Q1 to control the switch tube Q1 to be turned on or off, and the signal input end of the drive circuit is connected to the peak current control module for inputting the drive signal; The average current control module further includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1 and a second capacitor C2; The first end of the first resistor R1 is connected to the second end of the sampling resistor R0, the second end of the first resistor R1 is connected to the first end of the second resistor R2 and the first input end of the operational amplifier U1, and the second input end of the operational amplifier U1 is connected to the output end of the dimming module for inputting the dimming signal; the second end of the second resistor R2 is connected to the first end of the first capacitor C1, the second end of the first capacitor C1 is connected to the output end of the operational amplifier U1 and the first end of the third resistor R3, the second end of the third resistor R3 is connected to the first end of the fourth resistor R4, the first end of the second capacitor C2 and the peak current control module to output a reference signal to the peak current control module, and the second end of the fourth resistor R4 and the second end of the second capacitor C2 are both grounded; The peak current control module further includes a fifth resistor R5, a sixth resistor R6 and a third capacitor C3; The first end of the fifth resistor R5 is connected to the second end of the third resistor R3, the second end of the fifth resistor R5 and the first end of the third capacitor C3 are both connected to the non-inverting input terminal of the comparator U2, the second end of the third capacitor C3 and the first end of the sixth resistor R6 are both connected to the inverting input terminal of the comparator U2, the second end of the sixth resistor R6 is connected to the second end of the sampling resistor R0, and the output terminal of the comparator U2 is connected to the signal input terminal of the drive circuit.

2. The dimming LED lamp driving circuit according to claim 1, characterized in that: It also includes an auxiliary power supply module, the input end of the auxiliary power supply module is connected to the positive end of the constant voltage power supply module, the first output end of the auxiliary power supply module is connected to the driving circuit, and the second output end of the auxiliary power supply module is connected to the voltage input end of the operational amplifier, the voltage input end of the comparator, and the voltage input end of the dimming module.

3. The dimming LED lamp driving circuit according to claim 1, characterized in that: The driving circuit is a PWM control circuit.

4. The dimming LED lamp driving circuit according to claim 1, characterized in that: The switch tube Q1 is a MOS tube.

5. A lighting device, characterized in that: The invention comprises the dimming type LED driving circuit as described in any one of claims 1 to 4.

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