CN204518177U - A kind of LED drive power circuit - Google Patents

Abstract

The utility model discloses an LED driving power supply circuit, which comprises a fuse FU, a capacitor C1, a resistor R1, a transformer T1, a rectifier bridge Q, a chip U1 and a MOS tube VT1. The utility model adopts the single-stage flyback conversion technology controlled by the primary side, which is suitable for TRIAC dimming and is compatible with the LED driver. The current will follow the input voltage to obtain a high power factor, making the LED driver compatible with the TRIAC dimmer; in addition, using the primary side control, the output current signal and the TRIAC dimming signal are obtained on the primary side of the transformer T2, which greatly simplifies The circuit structure is improved, the output current is changed by the change of the TRIAC conduction angle, and a nearly linear dimming curve is obtained, and the efficiency is very high.

Description

A kind of LED driving power supply circuit

technical field

The utility model relates to a driving circuit, in particular to an LED driving power supply circuit.

Background technique

Due to its high brightness, energy saving and long life, LED has become the fourth generation of lighting sources. Energy-saving LED dimming is one of the hot spots in current application and research. At present, the main dimming methods of LED lighting are: analog dimming, pulse width modulation (PWM) dimming, silicon controlled rectifier (TRIAC) dimming, and silicon controlled rectifier (TRIAC) dimming, and silicon controlled rectifier dimming is a kind of dimming method widely used at present because it does not need to change the original circuit, and is suitable for non-isolated LED drivers for TRIAC dimming , is to add a capacitor network to the circuit to increase the maintenance current to ensure that the TRIAC works in a linear cycle, thereby avoiding the flicker problem. However, this method is only applicable to the half-bridge structure, and an external circuit is required to detect the dimming angle of the TRIAC, and the TRIAC and TRIAC For LED compatibility issues, the solutions in most industries are very inefficient (firing angle detection and TRIAC maintain current require dummy loads), and the cost of complex isolated feedback structures or two-stage conversion is also high.

Utility model content

The purpose of the present utility model is to provide a low-cost LED driving power supply circuit suitable for TRIAC dimming and compatible with LED drivers, so as to solve the problems raised in the above-mentioned background technology.

In order to achieve the above object, the utility model provides the following technical solutions:

A LED driving power supply circuit, including a fuse FU, a capacitor C1, a resistor R1, a transformer T1, a rectifier bridge Q, a chip U1 and a MOS tube VT1, one end of the fuse FU is connected to 220V AC, and the other end of the fuse FU is connected to a capacitor C3 and inductor L9, the other end of capacitor C3 is connected to the other end of 220V AC and inductor L10, the other end of inductor L10 is connected to capacitor C2 and transformer T1 coil L2, the other end of capacitor C2 is respectively connected to the other end of inductor L9 and transformer T1 coil L1, transformer The other end of T1 coil L1 is respectively connected to resistor R1 and rectifier bridge Q pin 3, the other end of transformer T1 coil L2 is respectively connected to capacitor C1 and rectifier bridge Q pin 2, the other end of capacitor C1 is connected to resistor R1, rectifier bridge Q pin 4 respectively Connect the resistor R3, the capacitor C4 and the S pole of the MOS tube VT1, the other end of the capacitor C4 is respectively connected to the resistor R2, the positive pole of the diode D1 and the G pole of the MOS tube VT1, and the other end of the resistor R2 is respectively connected to the negative pole of the diode D1 and the D pole of the MOS tube VT1 , the other end of resistor R3 and inductor L11 are grounded, the other end of inductor L11 is connected to inductor L6, resistor R4, resistor R5, inductor L7, resistor R6, capacitor C8 and transformer T2 coil L3, and the other end of inductor L6 is connected to the rectifier bridge Q pin 1. The other end of the coil L3 of the transformer T2 is respectively connected to the anode of the diode D4 and the D pole of the MOS transistor VT2, the S pole of the MOS transistor VT2 is respectively connected to the resistor R11 and the resistor R12, and the G pole of the MOS transistor VT2 is connected to the lead of the chip U1 through the resistor R10. Pin 6, pin 5 of chip U1 is connected to the other end of resistor R11, pin 7 of chip U1 is connected to capacitor C8, the other end of capacitor C8 is respectively connected to the positive pole of diode D3, coil L5 of transformer T2 and resistor R14, and the negative pole of diode D3 is connected to the other end of resistor R5 and chip U1 pin 8, the other end of the inductor L7 is respectively connected to the other end of the resistor R6, the other end of the capacitor C8 and the cathode of the diode D4, the other end of the resistor R4 is respectively connected to the cathode of the diode D2 and the resistor R15, and the other end of the resistor R15 is respectively connected to Capacitor C5 and chip U1 pin 1, the other end of capacitor C5 is connected to the positive pole of diode D2, resistor R13, capacitor C6, capacitor C7, chip U1 pin 4 and the other end of resistor R12 and grounded, and the other end of resistor R13 is connected to capacitor C6 and the other One end, pin 2 of the chip U1 and the other end of the resistor R14, the other end of the capacitor C7 is connected to the pin 3 of the chip U1, the other end of the coil L5 of the transformer T2 is grounded, and one end of the coil L4 of the transformer T2 is respectively connected to the anode of the diode D5 and the capacitor C9, The other end of capacitor C9 is respectively connected to the cathode of diode D5, capacitor C10, resistor R7 and inductor L9, the other end of inductor L8 is connected to resistor R8, capacitor C11 and LED-, and the other end of capacitor C11 is connected to LED+, capacitor R9, the positive electrode of diode D6, capacitor The other end of C10 is connected to the other end of transformer T2 coil L4, and the cathode of diode D6 is respectively connected to the other end of resistor R7 and capacitor C1 2. The other end of the capacitor C12 is connected to the other end of the resistor R8 and the other end of the resistor R9 respectively.

As a further solution of the present invention: the model of the chip U1 is FL7730.

Compared with the prior art, the beneficial effect of the utility model is that the utility model adopts the single-stage flyback conversion technology controlled by the primary side, is suitable for TRIAC dimming and is compatible with the LED driver, and the output current is detected by the primary side of the transformer T2 The signal is accurately calculated and controlled. When the chip U1 is operated in DCM mode, the input current will follow the input voltage to obtain a high power factor, which makes the LED driver compatible with the TRIAC dimmer; in addition, the use of primary side control makes the output current signal and The TRIAC dimming signal is obtained on the primary side of the transformer T2, which greatly simplifies the circuit structure. The output current is changed by the change of the TRIAC conduction angle, and a nearly linear dimming curve is obtained, with very high efficiency.

Description of drawings

Figure 1 is a circuit diagram of the LED drive power supply circuit.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. example. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

Please refer to Fig. 1, in the embodiment of the utility model, a kind of LED driving power supply circuit includes fuse FU, capacitor C1, resistor R1, transformer T1, rectifier bridge Q, chip U1 and MOS tube VT1, and one end of fuse FU is connected to 220V AC power, the other end of the fuse FU is connected to capacitor C3 and inductor L9, the other end of capacitor C3 is connected to the other end of 220V AC and inductor L10, the other end of inductor L10 is connected to capacitor C2 and transformer T1 coil L2, and the other end of capacitor C2 is connected to inductor The other end of L9 is connected to transformer T1 coil L1, the other end of transformer T1 coil L1 is connected to resistor R1 and rectifier bridge Q pin 3 respectively, the other end of transformer T1 coil L2 is respectively connected to capacitor C1 and rectifier bridge Q pin 2, and the other end of capacitor C1 is connected to Resistor R1, rectifier bridge Q pin 4 are respectively connected to resistor R3, capacitor C4 and S pole of MOS tube VT1, the other end of capacitor C4 is respectively connected to resistor R2, the positive pole of diode D1 and G pole of MOS tube VT1, and the other end of resistor R2 is respectively connected to The negative pole of diode D1, the D pole of MOS transistor VT1, the other end of resistor R3 and inductor L11 are grounded, and the other end of inductor L11 is connected to inductor L6, resistor R4, resistor R5, inductor L7, resistor R6, capacitor C8 and transformer T2 coil L3 respectively. The other end of the inductor L6 is connected to the Q pin 1 of the rectifier bridge, the other end of the transformer T2 coil L3 is respectively connected to the positive pole of the diode D4 and the D pole of the MOS tube VT2, the S pole of the MOS tube VT2 is respectively connected to the resistor R11 and the resistor R12, and the G pole of the MOS tube VT2 The pole is connected to the pin 6 of the chip U1 through the resistor R10, the pin 5 of the chip U1 is connected to the other end of the resistor R11, the pin 7 of the chip U1 is connected to the capacitor C8, and the other end of the capacitor C8 is respectively connected to the positive pole of the diode D3, the coil L5 of the transformer T2, and the resistor R14. The negative pole of D3 is respectively connected to the other end of resistor R5 and pin 8 of chip U1, the other end of inductor L7 is respectively connected to the other end of resistor R6, the other end of capacitor C8 and the negative pole of diode D4, and the other end of resistor R4 is respectively connected to the negative pole of diode D2 and resistor R15, resistor R15 The other end is respectively connected to capacitor C5 and pin 1 of chip U1. The other end of capacitor C5 is respectively connected to the anode of diode D2, resistor R13, capacitor C6, capacitor C7, chip U1 pin 4 and the other end of resistor R12 and grounded. The other end of resistor R13 is respectively Connect the other end of capacitor C6, pin 2 of chip U1 and the other end of resistor R14, the other end of capacitor C7 is connected to pin 3 of chip U1, the other end of transformer T2 coil L5 is grounded, and one end of transformer T2 coil L4 is respectively connected to the anode of diode D5 and capacitor C9. The other end of capacitor C9 is respectively connected to the cathode of diode D5, capacitor C10, resistor R7 and inductor L9, the other end of inductor L8 is connected to resistor R8, capacitor C11 and LED-, and the other end of capacitor C11 is connected to LED+, capacitor R9, the positive electrode of diode D6, capacitor The other end of C10 is connected to the other end of transformer T2 coil L4, and the cathode of diode D6 is respectively connected to the other end of resistor R7 and The capacitor C12, the other end of the capacitor C12 is connected to the other end of the resistor R8 and the other end of the resistor R9 respectively.

The chip U1 model is FL7730.

The working principle of the utility model is: the circuit of the utility model aims at the problem of peak current and LED light flickering in TRIAC dimming, and designs a passive discharge circuit and an active damping circuit in the circuit, and the main power topology adopts a single-stage flyback The conversion circuit works in the current discontinuous mode.

The circuit mainly includes: passive discharge circuit, active damping circuit, control circuit and single-stage flyback conversion circuit, in which the control circuit uses the control chip FL7730, FL7730 is an active power factor correction suitable for single-stage flyback topology The controller adopts the analog detection method, which is compatible with the traditional TRIAC dimming and realizes dimming control. The circuit of the utility model adopts the primary side control to simplify the circuit and reduce the cost. At the same time, the efficiency reaches above 0.8, the dimming process is stable and the LED light does not flicker , to better achieve linear frequency control.

The passive bleeder circuit provides the holding current and latching current for the TRIAC to avoid flickering and false triggering of the LED. Please refer to Figure 1. Inductor L6 is the input filter inductance. The size of capacitor C1 determines the size of the discharge current for TRIAC conduction. In dimming, the larger the discharge current, the higher the stability of dimming. Resistor R1 plays a role in the circuit. The damping function suppresses the peak current caused by the rapid charging of capacitor C1 when the dimmer is triggered.

The active damping circuit includes resistors R2, R3, capacitor C3, diode D1 and MOS tube VT1, which are used to suppress the peak voltage. When the dimmer is triggered, it is easy to cause a large current peak, and quickly charge the capacitor C1 through the power line. , if there is no resistive damping, the current spike will cause the power supply current to oscillate, and the large current will cause false triggering of the dimmer and destroy the TRIAC dimmer.

The active damping circuit and linear frequency control circuit in the circuit of the utility model can effectively suppress the peak voltage and solve problems such as flickering. The design of the primary side control makes the structure of the LED driving circuit simple, and has good compatibility with the existing lighting system and high efficiency. , low cost, well meet the practical application requirements of indoor LED drivers.

Claims (2)

1. a LED drive power circuit, comprise fuse FU, electric capacity C1, resistance R1, transformer T1, rectifier bridge Q, chip U1 and metal-oxide-semiconductor VT1, it is characterized in that, described fuse FU one end connects 220V alternating current, the fuse FU other end connects electric capacity C3 and inductance L 9 respectively, the electric capacity C3 other end connects the 220V alternating current other end and inductance L 10 respectively, inductance L 10 other end connects electric capacity C2 and transformer T1 coil L2 respectively, the electric capacity C2 other end connects inductance L 9 other end and transformer T1 coil L1 respectively, the transformer T1 coil L1 other end is contact resistance R1 and rectifier bridge Q pin 3 respectively, the transformer T1 coil L2 other end connects electric capacity C1 and rectifier bridge Q pin 2 respectively, electric capacity C1 other end contact resistance R1, rectifier bridge Q pin 4 is contact resistance R3 respectively, the S pole of electric capacity C4 and metal-oxide-semiconductor VT1, the electric capacity C4 other end is contact resistance R2 respectively, the G pole of diode D1 positive pole and metal-oxide-semiconductor VT1, the resistance R2 other end connects diode D1 negative pole respectively, the D pole of metal-oxide-semiconductor VT1, the resistance R3 other end and inductance L 11 also ground connection, inductance L 11 other end connects inductance L 6 respectively, resistance R4, resistance R5, inductance L 7, resistance R6, electric capacity C8 and transformer T2 coil L3, inductance L 6 other end connects rectifier bridge Q pin 1, the described transformer T2 coil L3 other end connects the D pole of diode D4 positive pole and metal-oxide-semiconductor VT2 respectively, the S pole contact resistance R11 and resistance R12 respectively of metal-oxide-semiconductor VT2, the G pole of metal-oxide-semiconductor VT2 connects chip U1 pin 6 by resistance R10, the chip U1 pin 5 contact resistance R11 other end, chip U1 pin 7 connects electric capacity C8, the electric capacity C8 other end connects diode D3 positive pole respectively, transformer T2 coil L5 and resistance R14, diode D3 negative pole is the contact resistance R5 other end and chip U1 pin 8 respectively, described inductance L 7 other end is the contact resistance R6 other end respectively, the electric capacity C8 other end and diode D4 negative pole, the described resistance R4 other end connects diode D2 negative pole and resistance R15 respectively, the resistance R15 other end connects electric capacity C5 and chip U1 pin 1 respectively, the electric capacity C5 other end connects diode D2 positive pole respectively, resistance R13, electric capacity C6, electric capacity C7, chip U1 pin 4 and the resistance R12 other end ground connection, the resistance R13 other end connects the electric capacity C6 other end respectively, chip U1 pin 2 and the resistance R14 other end, the described electric capacity C7 other end connects chip U1 pin 3, described transformer T2 coil L5 other end ground connection, transformer T2 coil L4 one end connects diode D5 positive pole and electric capacity C9 respectively, the electric capacity C9 other end connects diode D5 negative pole respectively, electric capacity C10, resistance R7 and inductance L 9, inductance L 8 other end is contact resistance R8 respectively, electric capacity C11 and LED-, the electric capacity C11 other end connects LED+ respectively, electric capacity R9, diode D6 positive pole, the electric capacity C10 other end and the transformer T2 coil L4 other end, diode D6 negative pole is the contact resistance R7 other end and electric capacity C12 respectively, the electric capacity C12 other end is the contact resistance R8 other end and the resistance R9 other end respectively.

2. LED drive power circuit according to claim 1, is characterized in that, described chip U1 model is FL7730.