CN204721677U - A kind of LED drive power circuit - Google Patents

Abstract

This invention provides an LED driver power supply circuit that effectively solves the problems of severe current waveform distortion and low power factor (PF) value in existing flyback power supply circuits by adding a single-stage PFC module and separating the energy storage capacitor in the input rectifier circuit module from the bridge rectifier module. It has the advantages of high PF value and simple circuit structure, and can also effectively solve the problem of LED light source flicker.

Description

A kind of LED driving power supply circuit

technical field

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

Background technique

At present, as a semiconductor component that can convert electrical energy into light energy, LED has the advantages of small size, low power consumption, long service life, environmental protection and durability, etc. It is widely used in lighting fixtures, display screens, traffic lights and other fields . Since LED is a semiconductor device with sensitive characteristics and has negative temperature characteristics, it needs to be driven in a steady state during the application process, thus requiring a dedicated LED driving power supply. For LED drive power supply, there are higher requirements for PF (power factor), such as 25W LED drive power supply, its power factor must be greater than 0.9. The existing LED drive power supply has a low PF value, which is difficult to meet the requirements of relevant standards, and there are problems such as a relatively complicated circuit structure.

Utility model content

In order to overcome the deficiencies and existing problems of the prior art, the utility model provides an LED drive power supply circuit, which has the advantages of high PF value, simple circuit structure and high cost performance.

The utility model is realized through the following technical solutions: an LED driving power supply circuit, the circuit includes an input terminal rectification circuit module, a flyback transformer module, an output terminal rectification filter module, a PWM control module, a single-stage PFC module, a sampling and an optocoupler feedback module and a switch tube; the input rectifier circuit module, the flyback transformer module, and the output rectifier filter module are sequentially connected, and the primary end of the flyback transformer module is connected to the PWM control module through a switch tube One end of the sampling and optocoupler feedback module is connected to the node between the secondary end of the flyback transformer module and the output rectification and filtering module, and the other end of the sampling and optocoupler feedback module is connected to the The PWM control module is connected, and the input rectifier circuit module includes an EMI common mode inductance module, a bridge rectifier module, an EMI differential mode inductance module and an energy storage capacitor connected in sequence, and one end of the single-stage PFC module is connected to the EMI The node between the differential mode inductance module and the energy storage capacitor, the other end of the single-stage PFC module is connected to the node between the primary end of the flyback transformer module and the switch tube, the single-stage PFC module It includes a first diode, a second diode, a third diode and a PFC inductor, the first diode is connected in series between the EMI differential mode inductor module and the energy storage capacitor, and the PFC inductor One end of the PFC inductor is connected to the positive pole of the first diode, the other end of the PFC inductor passes through the positive pole of the second diode in turn, the negative pole of the second diode is connected to the switch tube, and the third two The cathode of the pole tube is connected to the anode of the second diode, and the anode of the third diode is grounded.

Preferably, the model of the PWM control chip in the PWM control module is OB5269B; the switch tube is a MOS tube.

The LED driving power supply circuit provided by the utility model solves the problems in the existing flyback power supply circuit well by adding a single-stage PFC module and because the energy storage capacitor in the rectification circuit module at the input end is independent from the bridge rectification module. The current waveform is seriously distorted and the PF value is low. It has the advantages of high PF value and simple circuit structure, and can also solve the problem of flickering in LED light sources.

Description of drawings

Fig. 1 is a schematic block diagram of the circuit structure of the LED driving power supply circuit in the embodiment of the utility model;

Fig. 2 is a schematic diagram of the specific circuit structure of the LED driving power supply circuit in the embodiment of the present invention in practical application.

Detailed ways

In order to facilitate the understanding of those skilled in the art, the utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in accompanying drawings 1 and 2, a kind of LED drive power supply circuit, described circuit comprises input end rectification circuit module, flyback type transformer module 20, output end rectification filter module 30, PWM control module 40, single-stage PFC module 50 , a sampling and optocoupler feedback module 60 and a switch tube Q1; the input rectifier circuit module, the flyback transformer module 20, and the output rectifier filter module 30 are connected in sequence, and the primary end of the flyback transformer module 20 is connected through a switch Tube Q1 is connected to the PWM control module 40, one end of the sampling and optocoupler feedback module 60 is connected to the node between the secondary end of the flyback transformer module 20 and the output end rectification and filtering module 30, the The other end of sampling and optocoupler feedback module 60 is connected with described PWM control module 40, and described input terminal rectification circuit module comprises the EMI common-mode inductance module 11, bridge rectification module 12, EMI differential-mode inductance module 13 and Energy storage capacitor C1, one end of the single-stage PFC module 50 is connected to the node between the EMI differential mode inductance module 13 and the energy storage capacitor C1 (the energy storage capacitor C1 is an electrolytic capacitor), the single-stage PFC module The other end of 50 is connected to the node between the primary end of the flyback transformer module 20 and the switching tube Q1, and the single-stage PFC module 50 includes a first diode D1, a second diode D2, The third diode and the PFC inductor L2, the first diode D1 is connected in series between the EMI differential mode inductor module 13 and the energy storage capacitor C1, one end of the PFC inductor L2 is connected to the first two The anode of the pole tube D1 is connected, the other end of the PFC inductor L2 passes through the anode of the second diode D2 in turn, the cathode of the second diode D2 is connected to the switching tube Q1, and the third diode The cathode is connected to the anode of the second diode D2, and the anode of the third diode D3 is grounded. For those that have not been described about the connection relationship of relevant functional modules or electronic devices, please refer to accompanying drawings 1 and 2 for details, and no further details will be given here.

In this embodiment, the model of the PWM control chip in the PWM control module 40 is preferably OB5269B; the switch tube Q1 is a MOS tube.

The following briefly describes the working principle or process of the LED driving power supply circuit in this embodiment: when the switch tube Q1 is turned on, the input voltage is applied to the FPC inductor, and the current of the PFC inductor L2 rises linearly to store energy, and at the same time, the energy storage capacitor C1 provides feedback. The primary coil of the transformer in the excited transformer module 20 stores energy, and the transformer current rises linearly to complete the work of the first half cycle; when the switch tube Q1 is disconnected, the PFC inductor L2 and the transformer begin to release energy, the current drops linearly, and the PFC inductor L2 The released energy is loaded to the primary coil, part of the energy is charged to the energy storage capacitor C1, and the other part of the energy is supplied to the secondary coil through the transformer, and the transformer energy releases energy to the secondary coil according to the turn ratio according to the working principle of the flyback transformer. Complete the work of the second half cycle. Wherein, the switching on and off of the switching tube Q1 is controlled by the PWM control chip in the PWM control module 40 .

The LED drive power supply circuit provided in this embodiment has a simple circuit structure and high cost performance. By adding a single-stage PFC module 50, the energy storage capacitor C1 in the rectification circuit module at the input end is independently arranged outside the bridge rectification module 12. , which solves the serious distortion of the current waveform and the low PF value in the existing flyback power supply circuit. Small, well solved the problem of stroboscopic LED light source.

The above embodiment is a preferred implementation of the utility model, not a limitation of the utility model, any obvious replacement is within the protection scope of the utility model without departing from the inventive concept of the utility model.

Claims (3)

1. A kind of LED driving power supply circuit, described circuit comprises input end rectification circuit module, flyback transformer module (20), output end rectification filter module (30), PWM control module (40), single-stage PFC module (50) ), a sampling and optocoupler feedback module (60) and a switch tube (Q1); the input rectifier circuit module, the flyback transformer module, and the output rectifier filter module are connected in sequence, and the primary end of the flyback transformer module The switching tube is connected to the PWM control module, one end of the sampling and optocoupler feedback module is connected to the node between the secondary end of the flyback transformer module and the output end rectification and filtering module, the sampling and optocoupler feedback module The other end of the coupling feedback module is connected with the PWM control module, and it is characterized in that: the input terminal rectification circuit module includes an EMI common mode inductor module (11), a bridge rectifier module (12), and an EMI differential mode inductor connected in sequence module (13) and energy storage capacitor (C1), one end of the single-stage PFC module is connected to the node between the EMI differential mode inductance module and the energy storage capacitor, and the other end of the single-stage PFC module is connected to the The node between the primary end of the flyback transformer module and the switch tube, the single-stage PFC module includes a first diode (D1), a second diode (D2), a third diode ( D3) and the PFC inductor (L2), the first diode (D1) is connected in series between the EMI differential mode inductor module (13) and the energy storage capacitor (C1), the PFC inductor (L2) One end is connected to the anode of the first diode (D1), the other end of the PFC inductor passes through the anode of the second diode in turn, and the cathode of the second diode is connected to the switch tube, the first The cathodes of the three diodes are connected to the anodes of the second diodes, and the anodes of the third diodes are grounded. 2. The LED driving power supply circuit according to claim 1, characterized in that: the model of the PWM control chip in the PWM control module (40) is OB5269B. 3. The LED driving power supply circuit according to claim 1 or 2, characterized in that: the switching tube (Q1) is a MOS tube.