CN205430668U - LED drive circuit and lighting apparatus - Google Patents

Abstract

The utility model discloses a LED drive circuit, including commercial power, rectification filter circuit, drive circuit, output circuit and feedback circuit, wherein be provided with the regulating circuit between commercial power and the rectification filter circuit, rectification filter circuit and drive circuit are connected, and the drive circuit other end is connected with output circuit and feedback circuit. The utility model discloses an increase the regulating circuit between rectification filter circuit and drive circuit for output voltage and current stabilization, thus the stroboscopic that causes eliminated when LED drives.

Description

A kind of LED driving circuit and lighting equipment

technical field

The utility model relates to the technical field of lighting, in particular to an LED driving circuit and lighting equipment.

Background technique

With the development of science and technology, LED, as a new type of light source, has the advantages of small size, low power consumption, high light efficiency, long life, environmental protection, etc., and is widely used in the field of lighting, and various LEDs have appeared Driving circuit, in practical applications, the use of different LED driving circuits will have an impact on luminous efficiency and life.

At present, among many ways of driving LEDs, some use rectification and filtering circuits to directly connect with LED driving circuits to achieve efficient driving of LEDs. However, there are defects such as LED load flickering, easy damage, and strong high-frequency interference. caused inconvenience. In the application, the LED driving circuit needs to eliminate the stroboscopic problem caused by LED driving as much as possible.

Utility model content

Purpose of the utility model: In order to overcome the deficiencies in the prior art, the utility model provides an LED drive circuit that can eliminate the stroboscopic problem caused by LED drive.

Technical solution: In order to achieve the above purpose, the utility model provides an LED driving circuit, including mains power, rectification and filtering circuit, driving circuit, output circuit and feedback circuit, wherein a regulating circuit is arranged between the mains power and the rectification and filtering circuit, rectifying and filtering The filtering circuit is connected with the driving circuit, and the other end of the driving circuit is connected with the output circuit and the feedback circuit.

Further, the rectification filter circuit includes a piezoresistor R1, an inductor L1, an inductor L2, a resistor R2, a resistor R3, a capacitor C1 and a rectifier circuit, one end of the inductor L1 is connected to the live line L of the mains, and one end of the inductor L2 is connected to the mains The neutral line N of the electricity is connected, the other end of the inductor L1 and the inductor L2 are connected to the input end of the rectifier circuit, the two ends of the resistor R2 are respectively connected to the two ends of the inductor L1, and the two ends of the resistor R3 are respectively connected to the two ends of the inductor L2.

Further, the rectification circuit in the rectification and filtering circuit is a full-bridge rectification circuit.

Further, the drive circuit includes an inductor L3, a diode D2, a Zener diode D3, a diode D4, a Zener diode D5, a diode D6, a diode D7, a transformer T, a transistor Q3, a MOS transistor Q4 and a driver chip U1, wherein the inductor L3 One end of the inductance L3 is connected to the positive output end of the rectifier circuit, the other end of the inductance L3 is connected to the voltage input end VCC of the driver chip U1 after passing through the diode D4 and the resistor R14, and the other end of the inductance L3 is connected to the voltage input end VCC of the driver chip U1 through the primary winding of the transformer T and the diode D7. The output terminal DRV of the driver chip U1 is connected, the resistor R8 and the resistor R9 are connected in series, and one end is connected to the inductor L3, and the other end is connected to the collector of the transistor Q3, and the collector of the transistor Q3 is connected to the negative output terminal of the rectification filter circuit after being adjusted by the circuit. The connection point of the resistor R8 and the resistor R9 is connected to the anode of the diode D2 and the base of the transistor Q3, and the other end of the diode D2 is respectively connected to the emitter of the transistor Q3, one end of the capacitor C2 and one end of the resistor R10, and the other end of the capacitor C2 It is connected to the collector of the transistor Q3, the other end of the resistor R10 is connected to the gate of the MOS transistor Q4, the source of the MOS transistor Q4 is connected to the collector of the transistor Q3, and the drain of the MOS transistor Q4 is connected to the gate of the transistor Q3 after passing through the resistor R11. The collector is connected, the anode of the Zener diode D5 is connected to the other end of the inductor L3, the cathode of the Zener diode D5 is connected to the cathode of the diode D6, and the anode of the diode D6 is connected to the output terminal DRV of the driver chip U1 after passing through the diode D7.

Further, the driving chip U1 includes a field effect transistor, wherein the drain of the field effect transistor is used as the output of the driving chip U1, and the source of the field effect transistor is connected to the drain of the MOS transistor Q4.

Further, the output circuit includes a Zener diode D8, a capacitor C6 and a resistor R19, the anode of the Zener diode D8 is connected to the positive end of the secondary winding of the transformer T, and the cathode of the Zener diode D8 is connected in series via a plurality of LEDs. The connected LED light strings are then connected to the negative terminal of the secondary winding of the transformer T.

Further, the feedback circuit includes a diode D9, a diode D10, a Zener diode D11 and a triode Q5, wherein the anode of the diode D9 is connected to the positive end of the auxiliary winding of the transformer T through a resistor R18, and the cathode of the diode D9 is connected to the triode Q5 through a resistor R15. The collector of Q5 is connected to the feedback terminal FB of the driver chip U1, the anode of the diode D10 is connected to the positive terminal of the auxiliary winding of the transformer T, the cathode of the diode D10 is connected to the cathode of the Zener diode D11 and one end of the capacitor C9, and the other end of the capacitor C9 One end is connected to the emitter of the transistor Q5, and the anode of the Zener diode D11 is connected to the base of the transistor Q5.

Further, the regulating circuit includes a MOS transistor Q1, a resistor R4, a resistor R5, a resistor R6 and a transistor Q2, wherein the drain of the MOS transistor Q1 is connected to the positive output terminal of the rectifier circuit, and the source of the MOS transistor Q1 passes through the resistor R4 It is connected to the negative output terminal of the rectifier circuit, one end of the resistor R5 is connected to the positive output terminal of the rectifier circuit, the other end of the resistor R5 is connected to the gate of the MOS transistor Q1 and the collector of the transistor Q2, and the emitter stage of the transistor Q2 is connected to the rectifier circuit The base of the transistor Q2 is connected to the negative output terminal of the rectifier circuit after passing through resistors R6 and R7, and one end of the voltage regulator tube D1 is connected to the gate of the MOS transistor Q1, and the other end is connected to the negative output terminal of the rectifier circuit , the connection point of the resistor R6 and the resistor R7 is connected to the collector of the triode Q3 in the drive circuit.

An illuminating device includes the above-mentioned LED driving circuit.

Compared with the prior art, the utility model has the advantages that: the utility model adds a regulating circuit between the rectification filter circuit and the driving circuit, so that the output voltage and current are stable, thereby eliminating the flicker caused by LED driving.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is a circuit structure diagram of the LED driving circuit of the present invention.

detailed description

Below in conjunction with accompanying drawing and specific embodiment, further illustrate the utility model.

This embodiment provides a kind of LED drive circuit, as shown in Figure 1, mains 1, rectification and filter circuit 2, drive circuit 3, output circuit 4 and feedback circuit 5, it is characterized in that it also includes regulation circuit 6, and it is connected to rectifier Between the filter circuit 2 and the drive circuit 3 .

Fig. 2 shows the LED control circuit 3 structure of the utility model LED driving circuit, specifically:

The rectification filter circuit 2 includes a piezoresistor R1, an inductor L1, an inductor L2, a resistor R2, a resistor R3, a capacitor C1, and a rectifier circuit. One end of the inductor L1 and one end of the inductor L2 are respectively connected to the live line L and the neutral line N of the mains 1, The other end of the inductance L1 and the other end of the inductance L2 are connected to the input end of the rectification circuit, and the resistors R2 and R3 are respectively connected in parallel to the two ends of the inductance L1 and the inductance L2. The rectification circuit is a full-bridge rectification circuit.

The regulating circuit 6 includes a MOS transistor Q1, a resistor R4, a resistor R5, a resistor R6, and a triode Q2, wherein the drain of the MOS transistor Q1 is connected to the positive output terminal of the rectifier circuit, and the source of the MOS transistor Q1 is connected to the positive output terminal of the rectifier circuit after passing through the resistor R4. The negative output terminal of the output terminal, one terminal of the resistor R5 is connected to the positive output terminal of the rectifier circuit, the other terminal of the resistor R5 is connected to the gate of the MOS transistor Q1 and the collector of the transistor Q2, and the emitter of the transistor Q2 is connected to the negative output terminal of the rectifier circuit, The base of the transistor Q2 is connected to the negative output terminal of the rectifier circuit through the resistor R6 and the resistor R7, and the regulator D1 is connected between the gate of the MOS transistor Q1 and the negative output terminal of the rectifier circuit, and the connection point of the resistor R6 and the resistor R7 It is connected with the collector of the triode Q3 in the driving circuit 3 .

The drive circuit 3 includes an inductor L3, a diode D2, a voltage regulator diode D3, a diode D4, a voltage regulator diode D5, a diode D6, a diode D7, a transformer T, a triode Q3, a MOS transistor Q4, and a driver chip U1, wherein one end of the inductor L3 is connected to a rectifier The positive output terminal of the circuit, the other end is connected to the voltage input terminal VCC of the driver chip U1 after the diode D4 and the resistor R4, the other end of the inductor L3 is connected to the output terminal DRV of the driver chip U1 after the primary winding of the transformer T, the diode D7, and the resistor R8 and resistor R9 are connected in series between the other end of inductor L3 and the collector of transistor Q3. The collector of transistor Q3 is connected to the negative output terminal of rectifier and filter circuit 2 after adjusting circuit 6. The connection point of resistor R8 and resistor R9 Connect the anode of the diode D2 and the base of the transistor Q3, the other end of the diode D2 is respectively connected to the emitter of the transistor Q3, one end of the capacitor C2, one end of the resistor R10, the other end of the capacitor C2 is connected to the collector of the transistor Q3, and the resistor R10 The other end is connected to the gate of the MOS transistor Q4, the source of the MOS transistor Q4 is connected to the collector of the transistor Q3, the drain of the MOS transistor Q4 is connected to the collector of the transistor Q3 through the resistor R11, and the anode of the Zener diode D5 is connected to the inductor L3 At the other end, the cathode of the Zener diode D5 is connected to the cathode of the diode D6, and the anode of the diode D6 is connected to the output terminal DRV of the driver chip U1 after passing through the diode D7. The driver chip U1 includes a field effect transistor, wherein the drain of the field effect transistor As the output of the driving chip U1, the source of the field effect transistor is connected to the drain of the MOS transistor Q4.

The output circuit 4 includes a Zener diode D8, a capacitor C6, and a resistor R19. The anode of the Zener diode D8 is connected to the positive end of the secondary winding of the transformer T, and the cathode of the Zener diode D8 is connected in series through a plurality of LED lights. Then connect the negative end of the secondary winding of the transformer T.

The feedback circuit 5 includes a diode D9, a diode D10, a Zener diode D11, and a transistor Q5, wherein the anode of the diode D9 is connected to the positive terminal of the auxiliary winding of the transformer T through a resistor R18, and the cathode of the diode D9 is connected to the collector of the transistor Q5 through a resistor R15 and The feedback terminal FB of the driver chip U1, the anode of the diode D10 is connected to the positive terminal of the auxiliary winding of the transformer T, and its cathode is connected to the cathode of the Zener diode D11 and one end of the capacitor C9, and the other end of the capacitor C9 is connected to the emitter of the triode Q5. The anode of the diode D11 is connected to the base of the transistor Q5.

Since the adjustment circuit 6 is added between the rectification filter circuit 2 and the drive circuit 3, the adjustment circuit 6 senses the output voltage through the resistor R6, thereby controlling the turn-on and turn-off of the transistor Q2, and the turn-on and turn-off of the transistor Q2 further controls the MOS The turn-on and turn-off of the tube Q1 adjusts the output of the circuit through the turn-on and turn-off of the MOS tube, and the Zener diode R4 protects the MOS tube Q1. The addition of the regulating circuit 6 can eliminate the LED load stroboscopic problem caused when the rectifying and filtering circuit 2 is directly connected to the driving circuit 3 .

The utility model further provides a lighting device, which includes an LED lamp string and the LED driving circuit shown in Fig. 1-2, wherein the LED lamp string includes at least two LED lamps.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. For those skilled in the art, the present utility model can have various modifications and changes. Within, the modifications made should be included in the protection scope of the present utility model.

Claims (9)

1. A LED drive circuit, comprising mains power, rectification filter circuit, drive circuit, output circuit and feedback circuit, is characterized in that: be provided with regulation circuit between mains power and rectification filter circuit, rectification filter circuit is connected with drive circuit, The other end of the driving circuit is connected with the output circuit and the feedback circuit. 2. A LED drive circuit according to claim 1, characterized in that: said rectification and filtering circuit comprises piezoresistor R1, inductor L1, inductor L2, resistor R2, resistor R3, capacitor C1 and a rectifier circuit, inductor L1 One end of the inductor L2 is connected to the live line L of the mains, one end of the inductance L2 is connected to the neutral line N of the mains, the other end of the inductor L1 and the other end of the inductor L2 are connected to the input end of the rectifier circuit, and the two ends of the resistor R2 are respectively connected to the two ends of the inductor L1 The two ends of the resistor R3 are respectively connected to the two ends of the inductor L2. 3. The LED driving circuit according to claim 2, wherein the rectification circuit in the rectification and filtering circuit is a full-bridge rectification circuit. 4. A LED drive circuit according to claim 1, characterized in that: the drive circuit includes an inductor L3, a diode D2, a Zener diode D3, a diode D4, a Zener diode D5, a diode D6, a diode D7, a transformer T, transistor Q3, MOS transistor Q4 and driver chip U1, wherein one end of the inductance L3 is connected to the positive output terminal of the rectifier circuit, and the other end of the inductance L3 is connected to the voltage input terminal VCC of the driver chip U1 after passing through the diode D4 and the resistor R14. The other end of the inductor L3 is connected to the output terminal DRV of the driver chip U1 through the primary winding of the transformer T and the diode D7, and the resistor R8 and the resistor R9 are connected in series, and one end is connected to the inductor L3, and the other end is connected to the collector of the transistor Q3. The collector is connected to the negative output terminal of the rectifier and filter circuit after the adjustment circuit, the connection point of the resistor R8 and the resistor R9 is connected to the anode of the diode D2 and the base of the transistor Q3, and the other end of the diode D2 is respectively connected to the emitter stage of the transistor Q3, One end of the capacitor C2 is connected to one end of the resistor R10, the other end of the capacitor C2 is connected to the collector of the transistor Q3, the other end of the resistor R10 is connected to the gate of the MOS transistor Q4, and the source of the MOS transistor Q4 is connected to the collector of the transistor Q3 connection, the drain of MOS transistor Q4 is connected to the collector of triode Q3 after passing through resistor R11, the anode of Zener diode D5 is connected to the other end of inductor L3, the cathode of Zener diode D5 is connected to the cathode of diode D6, and the cathode of diode D6 The anode is connected to the output terminal DRV of the driver chip U1 after passing through the diode D7. 5. A LED driving circuit according to claim 4, characterized in that: said driving chip U1 includes a field effect transistor, wherein the drain of the field effect transistor is used as the output of the driving chip U1, and the source of the field effect transistor is It is connected with the drain of MOS transistor Q4. 6. A LED drive circuit according to claim 1, characterized in that: said output circuit comprises a Zener diode D8, a capacitor C6 and a resistor R19, the anode of the Zener diode D8 is connected to the positive terminal of the secondary winding of the transformer T connected, the cathode of the Zener diode D8 is connected to the negative end of the secondary winding of the transformer T after passing through the LED light string in which multiple LED lights are connected in series. 7. The LED drive circuit according to claim 1, wherein the feedback circuit includes a diode D9, a diode D10, a Zener diode D11 and a transistor Q5, wherein the anode of the diode D9 is assisted by a transformer T through a resistor R18 The positive end of the winding is connected, the cathode of the diode D9 is connected to the collector of the triode Q5 and the feedback terminal FB of the driver chip U1 after passing through the resistor R15, the anode of the diode D10 is connected to the positive end of the auxiliary winding of the transformer T, and the cathode of the diode D10 is connected to the stabilizer The cathode of the voltage diode D11 is connected to one end of the capacitor C9, the other end of the capacitor C9 is connected to the emitter of the triode Q5, and the anode of the Zener diode D11 is connected to the base of the transistor Q5. 8. A LED driving circuit according to claim 3, characterized in that: said regulating circuit comprises MOS transistor Q1, resistor R4, resistor R5, resistor R6 and triode Q2, wherein the drain of MOS transistor Q1 is connected to the rectifier circuit The positive output terminal of the MOS transistor Q1 is connected to the negative output terminal of the rectifier circuit after passing through the resistor R4, one end of the resistor R5 is connected to the positive output terminal of the rectifier circuit, and the other end of the resistor R5 is connected to the gate of the MOS transistor Q1 It is connected to the collector of the transistor Q2, the emitter of the transistor Q2 is connected to the negative output terminal of the rectifier circuit, the base of the transistor Q2 is connected to the negative output terminal of the rectifier circuit after passing through resistors R6 and R7, and one end of the regulator tube D1 is connected to the MOS The gate of the tube Q1 is connected to the other end of the negative output terminal of the rectifier circuit, and the connection point of the resistor R6 and the resistor R7 is connected to the collector of the triode Q3 in the driving circuit. 9. A lighting device, characterized in that the lighting device comprises the LED driving circuit according to any one of claims 1-7.