CN201114903Y - High power LED dimming drive circuit - Google Patents

Abstract

The utility model discloses a large power LED light adjustment drive circuit which comprises a rectification module, a PWM module, a voltage adjusting module and a voltage-stabilizing module. An output end of the rectification module is connected with a voltage input end of the PWM module; a switch power output end of the PWM module is connected with the voltage-stabilizing module; one end of the voltage adjusting module is connected with a VCC end of the PWM module while one end of the voltage adjusting module is connected with a feedback end of the PWM module and the other end of the voltage adjusting module is grounded. An output end of the voltage adjusting module of the large power LED light adjustment drive circuit of the utility model is connected with the cathode of loaded LED while an output end of the voltage-stabilizing module is connected with the anode of the loaded LED; the output current can be set in an appropriate range according to different requirements and ensured to regulate the brightness of the loaded LED to realize output with stable brightness or to satisfy different brightness requirements of the LED lighting under various circumstances.

Description

High power LED dimming drive circuit

【Technical field】

The utility model relates to a circuit, in particular to a circuit with adjustable current output.

【Background technique】

At present, high-power LED lighting products cannot realize the dimming function, and cannot adjust the brightness to adapt to various environments; and the uneven brightness of the LED itself is a major defect of the LED, even if the LED chips produced in the same batch have very high brightness. Unevenness, generally divided into 3-4 levels according to different brightness; therefore, the brightness of products produced by LED lamp manufacturers varies greatly.

【Content of invention】

The main purpose of the utility model is to design a driving circuit with adjustable constant current output, which is used for adjusting the brightness of LEDs.

In order to achieve the above object, the utility model proposes a high-power LED dimming drive circuit, including a rectification module, a PWM module, a voltage stabilization module, and a voltage regulation module; the output terminal of the rectification module is connected to the voltage input terminal of the PWM module, The switching power supply output end of the PWM module is connected to the voltage stabilizing module; one end of the voltage regulation module is connected to the reference voltage end of the PWM module, one end is connected to the feedback end of the PWM module, and the other end is grounded.

The above-mentioned high-power LED dimming driving circuit further includes a filter module connected between the output terminal of the rectification module and the voltage input terminal of the PWM module.

In the above-mentioned high-power LED dimming drive circuit, the voltage regulation module includes a first resistor, an adjustable resistor, and a second resistor; the first resistor is connected between the reference voltage terminal and the feedback terminal of the PWM module; the One end of the adjustable resistor is connected to the feedback end of the PWM module, and the other end is connected to one end of the second resistor; the other end of the second resistor is grounded. The voltage regulating module further includes a third resistor and a fourth resistor, the fourth resistor is connected between the adjustable resistor and the second resistor, and the third resistor is connected in parallel with the adjustable resistor.

In the above-mentioned high-power LED dimming drive circuit, the voltage stabilizing module includes a filter inductor, a filter capacitor and a freewheeling diode, one end of the filter inductor is connected to the output end of the switching power supply of the PWM module, and the other end is connected to the filter capacitor; The other end of the filter capacitor is grounded, one end of the freewheeling diode is connected to the output end of the switching power supply of the PWM module, and the other end is grounded.

The above-mentioned high-power LED dimming driving circuit further includes a decoupling capacitor connected between the VCC terminal of the PWM module and the ground.

Due to the adoption of the above scheme, the utility model connects the output terminal of the voltage stabilizing module to the negative pole of the load LED, and the output terminal of the voltage stabilizing module is connected to the positive pole of the load LED, and the output current can be set in a suitable range according to different needs; The brightness of LED can be adjusted to achieve stable brightness output; or to adapt to the brightness requirements of LED lighting in various environments.

The utility model has small volume and large driving current. When the space is large enough, the driving current can reach up to 3A; the internal PWM control output, wide input voltage, universal AC and DC, the maximum input voltage can reach DC26V, and the circuit start-up voltage can be determined according to the load. , the maximum output voltage value can reach 90% of the input voltage value, the circuit efficiency is high, the maximum efficiency can reach 91%; the circuit itself generates less heat and saves electricity.

【Description of drawings】

Fig. 1 is the block diagram of circuit principle of the utility model.

Fig. 2 is a schematic circuit diagram of the utility model embodiment.

【Detailed ways】

The present invention will be described in further detail below through specific embodiments and in conjunction with the accompanying drawings.

Please refer to the circuit diagrams shown in Figure 1 and Figure 2, the rectifier module, filter module, PWM module, voltage regulator module, and voltage regulator module; the output terminal of the rectifier module is connected to the input terminal of the filter module, and the output terminal of the filter module is connected to the PWM module. The voltage input terminal VIN and the switching power supply output terminal LX of the PWM module are connected to the voltage stabilizing module; one end of the voltage regulating module is connected to the reference voltage terminal VCC of the PWM module, one end is connected to the feedback terminal FB of the PWM module, and one end is grounded. The output terminal of the voltage regulating module is used to connect the negative pole of the high-power LED terminal, and the output terminal of the voltage stabilizing module is used to connect the positive pole of the high-power LED. By adjusting the voltage of the second resistor R2 of the voltage regulating module, the driving current of the high-power LED can be adjusted. , so as to achieve the adjustment of its brightness to achieve a stable brightness output.

Please refer to Figure 2, the working principle of the circuit is: the AC and DC voltage input is rectified by the rectifier module D1 and then filtered by the electrolytic capacitor of the filter module, which is used for the voltage input terminal VIN of the PWM module U1, and the VCC pin of the PWM module U1, By connecting a 1uF decoupling capacitor to GND, the decoupling function is achieved; the voltage regulating module includes the first resistor R1, the second resistor R2, the adjustable resistor VR, the third resistor R3, and the fourth resistor R4; the voltage stabilizing module includes a filter inductor L1, filter capacitor C6 and freewheeling diode D2, one end of the filter inductor L1 is connected to the output terminal of the PWM module switching power supply, the other end is connected to the filter capacitor C6; the other end of the filter capacitor C6 is grounded, and one end of the freewheeling diode D2 is connected to the output terminal of the PWM module switching power supply. The other end is grounded.

The second resistor R2 has a resistance value of 0.3Ω, the third resistor R3 has a resistance value of 6.2KΩ, and the fourth resistor R4 has a resistance value of 1.2KΩ; the VCC pin has a 4.2V reference voltage, which is the voltage at point A, and the VCC pin passes a 39K first The resistor R1 is connected to the feedback terminal FB of U1, and the voltage of this feedback terminal is 0.8V, so the current flowing through R1 is:

I _R1 = (V _A -V _B )/R1 = (4.2-0.8)/39K = 0.000087A

V _C ＝V _B -I _R1 *(R3+VR//1.2K)＝0.8-0.000087*(6.2K+VR//1.2K)

I _LED = V _C /R2 = [0.8-0.000087*(6.2K+VR//1.2K)]/0.3.

Therefore, the LED current can be adjusted through an adjustable resistor. For example, if VR is a 2K adjustable resistor, when VR is adjusted to the maximum:

I _LED min=[0.8-0.000087*(6.2K+0.75K)]/0.3=652mA

When VR is adjusted to the minimum, the maximum I _LED = 868mA, where R4 is the VR protection resistor, when VR is open, the LED current is 520mA, change the fourth resistor R4, adjustable resistor VR, third resistor R3, second resistor R2 It is very convenient to adjust the LED current in the appropriate range. In this way, the brightness adjustment of LED lighting fixtures can be realized to ensure the consistency of products; the brightness can also be adjusted according to requirements.

The above content is a further detailed description of the utility model in combination with specific preferred embodiments, and it cannot be assumed that the specific implementation of the utility model is only limited to these descriptions. For those of ordinary skill in the technical field to which the utility model belongs, on the premise of not departing from the concept of the utility model, some simple deduction or replacement can also be made, which should be regarded as belonging to the protection scope of the utility model.

Claims (6)

1. A high-power LED dimming drive circuit is characterized in that: it comprises a rectification module, a PWM module, a voltage regulating module, and a voltage stabilizing module; the output end of the rectification module is connected with the voltage input end of the PWM module, and the PWM module The output end of the module switching power supply is connected to the voltage stabilizing module; one end of the voltage regulating module is connected to the VCC end of the PWM module, one end is connected to the feedback end of the PWM module, and the other end is grounded. 2. The high-power LED dimming drive circuit according to claim 1, further comprising a filter module connected between the output terminal of the rectification module and the voltage input terminal of the PWM module. 3. The high-power LED dimming drive circuit according to claim 1 or 2, characterized in that: the voltage regulation module includes a first resistor (R1), an adjustable resistor (VR), and a second resistor (R2); The first resistor (R1) is connected between the VCC terminal and the feedback terminal of the PWM module; one end of the adjustable resistor (VR) is connected to the feedback terminal of the PWM module, and the other end is connected to the second resistor (R2) one end; the other end of the second resistor (R2) is grounded. 4. The high-power LED dimming drive circuit according to claim 3, characterized in that: the voltage regulating module further includes a third resistor (R3), a fourth resistor (R4), and the third resistor (R3) Connected between the adjustable resistor (VR) and the second resistor (R2), the fourth resistor (R4) is connected in parallel with the adjustable resistor (VR). 5. The high-power LED dimming drive circuit according to claim 3, characterized in that: the voltage stabilizing module includes a filter inductor (L1), a filter capacitor (C6) and a freewheeling diode (D2), and the filter inductor One end of (L1) is connected to the output terminal of the switching power supply of the PWM module, and the other end is connected to the filter capacitor (C6); the other end of the filter capacitor (C6) is grounded, and one end of the freewheeling diode (D2) is connected to the switching power supply of the PWM module output, and the other end is grounded. 6. The high-power LED dimming driving circuit according to claim 3, further comprising a decoupling capacitor (C4) connected between the VCC terminal of the PWM module and the ground.

Images