A high-power LED electrodeless dimming driving circuit

Abstract

The application provides a high-power LED electrodeless dimming driving circuit, and belongs to the technical field of constant current driving and dimming of LEDs. The circuit comprises an anti-reverse slow start filter unit, a pulse width modulation unit and a constant current driving unit. The anti-reverse slow start filter unit is used for preventing reverse connection of the circuit and filtering the input power. The pulse width modulation unit is used for outputting a PWM waveform with a variable pulse width by adjusting the input voltage. The constant current driving unit outputs a variable current by receiving the PWM waveform with a variable pulse width output by the pulse width modulation unit. The circuit solves the problems of additional interface quantity, low dimming efficiency and poor electromagnetic compatibility in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of constant current driving and dimming technology of LEDs, and specifically relates to a high-power LED stepless dimming driving circuit. Background Technology

[0002] Currently, LED lights with dimming capabilities are widely used. Common LED dimming driving methods mainly include voltage dimming, current dimming, and PWM dimming. Voltage dimming adjusts brightness by changing the voltage across the LED. Its dimming range is small, and the current increases as the LED heats up, reducing LED reliability and lifespan. Therefore, it is suitable for low-power, low-heat-generating lamps. Current dimming adjusts brightness by changing the LED's driving current, allowing for a wide brightness adjustment range of 1% to 100%. It is suitable for high-power dimming, but only suitable for lamps with built-in dimming switches or those requiring an additional dimming interface to receive external dimming signals. PWM dimming adjusts brightness by controlling the on / off ratio of a constant current LED. It offers high dimming precision. There are generally two types of PWM dimming: one does not increase the number of interfaces, requiring the host computer to process the PWM signal into a drive signal to directly drive the LED. However, this method uses a linear constant current drive circuit, which is inefficient and suitable for low-power dimming. The other type requires increasing the number of interfaces, requiring the host computer to provide a separate PWM dimming signal. This method uses a DC / DC constant current drive circuit, which is efficient and suitable for high-power dimming. However, the increased number of interfaces makes it less compatible with electromagnetic incompatibility. Summary of the Invention

[0003] The purpose of this invention is to solve the problems of existing technologies, such as the need to increase the number of interfaces, low dimming efficiency, and poor electromagnetic compatibility, in order to solve the problems of high-power LED dimming.

[0004] To achieve the above objectives, the present invention provides an LED constant current driving circuit that is highly efficient, has few interfaces, high reliability, and a wide dimming range. The circuit includes an anti-reverse soft-start filter unit, a pulse width modulation unit, and a constant current driving unit. The anti-reverse soft start filter unit is used to prevent circuit reversal and filter the power supply. The pulse width modulation unit is used to output a PWM waveform with varying pulse width by adjusting the input voltage; The constant current drive unit outputs a changing current by receiving the PWM waveform with varying pulse width output from the pulse width modulation unit.

[0005] The high-power LED stepless dimming drive circuit provided by this invention also has the following technical features: the pulse width modulation unit includes a switching power supply controller that converts the received changing voltage into a PWM waveform with varying pulse width, and a linear voltage regulator that provides a stable 5V output voltage.

[0006] The high-power LED stepless dimming drive circuit provided by this invention also has the following technical features: the switching power supply controller is a pulse width modulator U2; and the linear voltage regulator is a three-terminal regulator U1.

[0007] The high-power LED stepless dimming drive circuit provided by this invention also has the following technical feature: the pulse width modulation unit further includes an input terminal Vi, a capacitor C1, a rectifier diode D1, a resistor R1, a capacitor C2, a resistor R3, a resistor R4, a resistor R5, a capacitor C4, a capacitor C3, a resistor R6, a resistor R7, and an output terminal PWM. The input terminal Vi is connected to one end of capacitor C1, the input terminal of the three-terminal regulator U1, and the anode of rectifier diode D1. The cathode of rectifier diode D1 is connected to one end of resistor R1. The output terminal of the three-terminal regulator U1 is connected to one end of capacitor C2, one end of resistor R3, one end of resistor R4, and pin 15 of pulse width modulator U2. The other end of resistor R3 is connected to pin 13 of pulse width modulator U2. The other end of resistor R4 is connected to pin 2 of pulse width modulator U2 and one end of resistor R5. The other end of resistor R1 is connected to pin 9 of pulse width modulator U2. One end of capacitor C4 and one end of resistor R7 are connected. One end of capacitor C3 is connected to pin 5 of pulse width modulator U2. One end of resistor R6 is connected to pin 6 of pulse width modulator U2. Pins 11 and 14 of pulse width modulator U2 are both connected to the output terminal PWM. The other end of capacitor C1, the negative terminal of three-terminal regulator U1, the other end of capacitor C2, pin 8 of pulse width modulator U2, pin 1 of pulse width modulator U2, the other end of capacitor C3, the other end of resistor R6, the other end of resistor R5, the other end of capacitor C4, and the other end of resistor R5 are all connected to GND.

[0008] The high-power LED stepless dimming drive circuit provided by this invention also has the following technical features: the constant current drive unit is a DC / DC switching power supply topology, and the input voltage range of the constant current drive unit is 10VDC~32VDC.

[0009] The high-power LED stepless dimming drive circuit provided by this invention also has the following technical features: the constant current drive unit includes an input terminal Vi, an input terminal PWM, an output terminal Vo+, an output terminal Vo-, capacitors C5 and C6, a constant current drive chip U3, a resistor R8, a Schottky rectifier diode D2, capacitors C7, C8, and C9, a MOSFET Q1, resistors R9, R10, and R11, and an inductor L1. The input terminal Vi is connected to one end of capacitor C5, one end of capacitor C6, pin 1 of constant current driver chip U3, one end of resistor R8, the cathode of Schottky rectifier diode D2, and one end of capacitor C8. The other end of resistor R8 is connected to pin 2 of constant current driver chip U3. The anode of Schottky rectifier diode D2 is connected to the drain of MOSFET Q1, one end of resistor R11, one end of capacitor C9, and one end of inductor L1. The other end of capacitor C8 is connected to the other end of resistor R11. Pin 5 of constant current driver chip U3 is connected to one end of resistor R9. The other end of resistor R9... One end of capacitor C7 is connected to one end of resistor R10 and the gate of MOSFET Q1. One end of capacitor C7 is connected to pin 6 of constant current driver chip U3. The other ends of capacitors C5, C6, and C7, pin 4 of constant current driver chip U3, the other end of resistor R10, the source of MOSFET Q1, and the other end of capacitor C9 are all connected to GND. Pin 3 of constant current driver chip U3 is connected to the input terminal PWM. The other end of resistor R8 and pin 2 of constant current driver chip U3 are both connected to the output terminal Vo+. The other end of inductor L1 is connected to the output terminal Vo-. The output terminal Vo+ is connected to the positive terminal of the load LED, and the output terminal Vo- is connected to the negative terminal of the load LED.

[0010] Beneficial effects: The high-power LED stepless dimming drive circuit provided in this application solves the problems of existing technologies, such as the need to increase the number of interfaces, low dimming efficiency, and poor electromagnetic compatibility. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a block diagram illustrating the working principle of an embodiment of the present invention; Figure 2 This is a circuit diagram of the pulse width modulation unit disclosed in an embodiment of the present invention; Figure 3 This is a circuit diagram of the constant current driving unit disclosed in an embodiment of the present invention; Figure 4 This is a flowchart illustrating the entire circuit disclosed in an embodiment of the present invention. Detailed Implementation

[0013] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent changes or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the protection scope of the present invention.

[0014] In the description of the embodiments of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention.

[0015] Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0016] The terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of these terms in this invention based on the specific circumstances.

[0017] like Figure 1-4 As shown, this embodiment of the invention provides a high-power LED stepless dimming drive circuit, which includes an anti-reverse soft-start filter unit 1, a pulse width modulation unit 2, and a constant current drive unit 3. The anti-reverse soft start filter unit 1 is used to prevent circuit reversal and filter the power supply. The pulse width modulation unit 2 is used to output a PWM waveform with varying pulse width by adjusting the input voltage; The constant current drive unit 3 outputs a changing current by receiving the PWM waveform with varying pulse width output by the pulse width modulation unit 2.

[0018] The circuit outputs a constant current within the input voltage range. When a PWM (Pulse Width Modulation) signal with varying pulse width is input, the output current changes accordingly, converting the PWM signal into a varying current. The stepless dimming drive circuit has an input voltage range of 10VDC to 32VDC for stepless dimming.

[0019] In some embodiments, the pulse width modulation unit 2 includes a switching power supply controller that converts the received changing voltage into a PWM waveform with varying pulse width, and a linear voltage regulator that provides a stable 5V output voltage.

[0020] In some embodiments, the switching power supply controller is a pulse width modulator U2; the linear voltage regulator is a three-terminal regulator U1.

[0021] In some embodiments, the pulse width modulation unit 2 further includes an input terminal Vi, a capacitor C1, a rectifier diode D1, a resistor R1, a capacitor C2, a resistor R3, a resistor R4, a resistor R5, a capacitor C4, a capacitor C3, a resistor R6, a resistor R7, and an output terminal PWM. The input terminal Vi is connected to one end of capacitor C1, the input terminal of the three-terminal regulator U1, and the anode of rectifier diode D1. The cathode of rectifier diode D1 is connected to one end of resistor R1. The output terminal of the three-terminal regulator U1 is connected to one end of capacitor C2, one end of resistor R3, one end of resistor R4, and pin 15 of pulse width modulator U2. The other end of resistor R3 is connected to pin 13 of pulse width modulator U2. The other end of resistor R4 is connected to pin 2 of pulse width modulator U2 and one end of resistor R5. The other end of resistor R1 is connected to pin 9 of pulse width modulator U2. One end of capacitor C4 and one end of resistor R7 are connected. One end of capacitor C3 is connected to pin 5 of pulse width modulator U2. One end of resistor R6 is connected to pin 6 of pulse width modulator U2. Pins 11 and 14 of pulse width modulator U2 are both connected to the output terminal PWM. The other end of capacitor C1, the negative terminal of three-terminal regulator U1, the other end of capacitor C2, pin 8 of pulse width modulator U2, pin 1 of pulse width modulator U2, the other end of capacitor C3, the other end of resistor R6, the other end of resistor R5, the other end of capacitor C4, and the other end of resistor R5 are all connected to GND.

[0022] When pins 11 and 14 of pulse width modulator U2 are connected, the duty cycle range is doubled. A voltage difference between resistors R1 and R7 is used to obtain a changing voltage Vs. Pin 9 of pulse width modulator U2 receives the changing voltage and converts it into a PWM waveform with a variable pulse width.

[0023] In some embodiments, the constant current drive unit 3 is a DC / DC switching power supply topology, and the input voltage range of the constant current drive unit 3 is 10VDC to 32VDC.

[0024] In some embodiments, the constant current driving unit 3 includes an input terminal Vi, an input terminal PWM, an output terminal Vo+, an output terminal Vo-, capacitors C5 and C6, a constant current driving chip U3, a resistor R8, a Schottky rectifier diode D2, capacitors C7, C8, and C9, a MOSFET Q1, resistors R9, R10, and R11, and an inductor L1. The input terminal Vi is connected to one end of capacitor C5, one end of capacitor C6, pin 1 of constant current driver chip U3, one end of resistor R8, the cathode of Schottky rectifier diode D2, and one end of capacitor C8. The other end of resistor R8 is connected to pin 2 of constant current driver chip U3. The anode of Schottky rectifier diode D2 is connected to the drain of MOSFET Q1, one end of resistor R11, one end of capacitor C9, and one end of inductor L1. The other end of capacitor C8 is connected to the other end of resistor R11. Pin 5 of constant current driver chip U3 is connected to one end of resistor R9. The other end of resistor R9... One end of capacitor C7 is connected to one end of resistor R10 and the gate of MOSFET Q1. One end of capacitor C7 is connected to pin 6 of constant current driver chip U3. The other ends of capacitors C5, C6, and C7, pin 4 of constant current driver chip U3, the other end of resistor R10, the source of MOSFET Q1, and the other end of capacitor C9 are all connected to GND. Pin 3 of constant current driver chip U3 is connected to the input terminal PWM. The other end of resistor R8 and pin 2 of constant current driver chip U3 are both connected to the output terminal Vo+. The other end of inductor L1 is connected to the output terminal Vo-. The output terminal Vo+ is connected to the positive terminal of the load LED, and the output terminal Vo- is connected to the negative terminal of the load LED.

[0025] The constant current drive unit 3 receives the PWM signal from the output of the pulse width modulation unit 2 at its input PWM terminal, and outputs a changing current by changing the PWM pulse width.

[0026] like Figure 4 As shown, the high-power LED stepless dimming circuit provided in any of the above embodiments can adjust the current on the load LED by adjusting the input voltage. When the input voltage is constant, the output current is constant. The working process of the entire circuit is "changing voltage" → "PWM with varying pulse width" → "changing current".

[0027] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A high-power LED stepless dimming drive circuit, characterized in that, The circuit includes an anti-reverse soft-start filter unit, a pulse width modulation unit, and a constant current drive unit. The anti-reverse soft start filter unit is used to prevent circuit reversal and filter the power supply. The pulse width modulation unit is used to output a PWM waveform with varying pulse width by adjusting the input voltage; The constant current drive unit outputs a changing current by receiving the PWM waveform with varying pulse width output from the pulse width modulation unit.

2. The high-power LED stepless dimming drive circuit according to claim 1, characterized in that, The pulse width modulation unit includes a switching power supply controller that converts the received changing voltage into a PWM waveform with varying pulse width, and a linear voltage regulator that provides a stable 5V output voltage.

3. The high-power LED stepless dimming drive circuit according to claim 2, characterized in that, The switching power supply controller is a pulse width modulator U2; the linear voltage regulator is a three-terminal regulator U1.

4. The high-power LED stepless dimming drive circuit according to claim 3, characterized in that, The pulse width modulation unit also includes an input terminal Vi, a capacitor C1, a rectifier diode D1, a resistor R1, a capacitor C2, a resistor R3, a resistor R4, a resistor R5, a capacitor C4, a capacitor C3, a resistor R6, a resistor R7, and an output terminal PWM. The input terminal Vi is connected to one end of capacitor C1, the input terminal of the three-terminal regulator U1, and the anode of rectifier diode D1. The cathode of rectifier diode D1 is connected to one end of resistor R1. The output terminal of the three-terminal regulator U1 is connected to one end of capacitor C2, one end of resistor R3, one end of resistor R4, and pin 15 of pulse width modulator U2. The other end of resistor R3 is connected to pin 13 of pulse width modulator U2. The other end of resistor R4 is connected to pin 2 of pulse width modulator U2 and one end of resistor R5. The other end of resistor R1 is connected to pin 9 of pulse width modulator U2. One end of capacitor C4 and one end of resistor R7 are connected. One end of capacitor C3 is connected to pin 5 of pulse width modulator U2. One end of resistor R6 is connected to pin 6 of pulse width modulator U2. Pins 11 and 14 of pulse width modulator U2 are both connected to the output terminal PWM. The other end of capacitor C1, the negative terminal of three-terminal regulator U1, the other end of capacitor C2, pin 8 of pulse width modulator U2, pin 1 of pulse width modulator U2, the other end of capacitor C3, the other end of resistor R6, the other end of resistor R5, the other end of capacitor C4, and the other end of resistor R5 are all connected to GND.

5. The high-power LED stepless dimming drive circuit according to claim 1, characterized in that, The constant current drive unit is a DC / DC switching power supply topology, and the input voltage range of the constant current drive unit is 10VDC to 32VDC.

6. The high-power LED stepless dimming drive circuit according to claim 5, characterized in that, The constant current drive unit includes an input terminal Vi, an input terminal PWM, an output terminal Vo+, an output terminal Vo-, capacitors C5 and C6, a constant current drive chip U3, a resistor R8, a Schottky rectifier diode D2, capacitors C7, C8, and C9, a MOSFET Q1, resistors R9, R10, and R11, and an inductor L1. The input terminal Vi is connected to one end of capacitor C5, one end of capacitor C6, pin 1 of constant current driver chip U3, one end of resistor R8, the cathode of Schottky rectifier diode D2, and one end of capacitor C8. The other end of resistor R8 is connected to pin 2 of constant current driver chip U3. The anode of Schottky rectifier diode D2 is connected to the drain of MOSFET Q1, one end of resistor R11, one end of capacitor C9, and one end of inductor L1. The other end of capacitor C8 is connected to the other end of resistor R11. Pin 5 of constant current driver chip U3 is connected to one end of resistor R9. The other end of resistor R9... One end of capacitor C7 is connected to one end of resistor R10 and the gate of MOSFET Q1. One end of capacitor C7 is connected to pin 6 of constant current driver chip U3. The other ends of capacitors C5, C6, and C7, pin 4 of constant current driver chip U3, the other end of resistor R10, the source of MOSFET Q1, and the other end of capacitor C9 are all connected to GND. Pin 3 of constant current driver chip U3 is connected to the input terminal PWM. The other end of resistor R8 and pin 2 of constant current driver chip U3 are both connected to the output terminal Vo+. The other end of inductor L1 is connected to the output terminal Vo-. The output terminal Vo+ is connected to the positive terminal of the load LED, and the output terminal Vo- is connected to the negative terminal of the load LED.

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