CN212163792U

CN212163792U - Recyclable synchronous rectification absorption circuit

Info

Publication number: CN212163792U
Application number: CN202020472035.6U
Authority: CN
Inventors: 朱兴成; 廖光裕
Original assignee: Hangzhou Zhongxinli Technology Co ltd
Current assignee: Hangzhou Zhongxinli Intelligent Equipment Co.,Ltd.
Priority date: 2020-04-03
Filing date: 2020-04-03
Publication date: 2020-12-15
Anticipated expiration: 2030-04-03

Abstract

The utility model discloses a recoverable synchronous rectification absorption circuit, which comprises a transformer leakage inductance LS, an inductance L2, 2 metal oxide semiconductor field effect transistors MOSFET, 3 capacitors, 4 diodes, 2 resistors and 1 triode; 2 drains (D poles) of 2 Metal Oxide Semiconductor Field Effect Transistors (MOSFET) are respectively connected with two ends of a leakage inductance (LS) of the transformer, and 2 sources (S poles) of the 2 MOSFET are grounded; the middle end of the transformer leakage inductor LS is grounded through an inductor L2 and an output capacitor C0, and the voltage V + is connected between the inductor L2 and the output capacitor C0; the utility model discloses peak energy recuperation improves efficiency, reduces peak voltage, promotes metal oxide semiconductor field effect transistor MOSFET's reliability, reduces EMI and disturbs.

Description

Recyclable synchronous rectification absorption circuit

Technical Field

The utility model relates to a LED drive power supply technical field specifically is a recoverable synchronous rectification absorption circuit.

Background

In low-voltage and high-current occasions, along with the continuous progress of the MOSFET technology, the high-frequency MOSFET with low on-resistance is mature continuously, and the metal oxide semiconductor MOSFET is used as a rectifier tube instead of a Schottky, which is a necessary trend; the synchronous rectification technology is developed, a metal oxide semiconductor field effect transistor MOSFET for synchronous rectification is usually driven by a special chip, the chip determines the on-off of the metal oxide semiconductor field effect transistor MOSFET by adopting the current on the metal oxide semiconductor field effect transistor MOSFET, and the other method is driven by a self-excitation method.

Especially, the leakage inductance on the main control transformer increases the peak when the synchronous rectifier tube is turned off, and at the moment, the peak is hardly absorbed by a simple RC circuit, and the peak energy is lost by the RC circuit absorption, so that the efficiency is reduced, and meanwhile, the temperature of the power supply is correspondingly increased. Therefore, a recyclable synchronous rectification absorption circuit is provided.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a recoverable synchronous rectification snubber circuit to solve the problem that proposes among the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme: a recyclable synchronous rectification absorption circuit comprises a transformer leakage inductance LS, an inductance L2, 2 metal oxide semiconductor field effect transistors MOSFET, 3 capacitors, 4 diodes, 2 resistors and 1 triode; 2 drains (D poles) of 2 Metal Oxide Semiconductor Field Effect Transistors (MOSFET) are respectively connected with two ends of a leakage inductance (LS) of the transformer, and 2 sources (S poles) of the 2 MOSFET are grounded; the middle end of the transformer leakage inductor LS is grounded through an inductor L2 and an output capacitor C0, and the voltage V + is connected between the inductor L2 and the output capacitor C0; the base electrode of the triode Q1 is connected to one end of the transformer leakage inductance LS through a resistor R1, the drain electrode (D pole) of a metal oxide semiconductor field effect transistor MOSFET close to one end of the transformer leakage inductance LS is connected with the anode of a diode D1, the cathode of the diode D1 is connected with the emitting electrode of the triode Q1, and the collector electrode of the triode Q1 is connected with a voltage V + through a resistor R2; one end of the capacitor C1 is connected with the cathode of the diode D3, the other end of the capacitor C1 is connected with the cathode of the diode D1, and the anode of the diode D3 is grounded; one end of a capacitor C2 is connected with the anode of a diode D4, the cathode of a diode D4 is connected with the emitter of a triode Q1, and the other end of a capacitor C2 is grounded; the anode of the diode D2 is connected to the cathode of the diode D3, and the cathode of the diode D2 is connected to the anode of the diode D4.

Preferably, when the energy release voltages V _ C1 and V _ C2 on the capacitor C1 and the capacitor C2 are equal to the output voltage V +, the current does not flow.

Preferably, when the voltage of the MOSFET is higher than the sum of the voltages at the capacitor C1 and the capacitor C2, the current on the transformer leakage inductor LS flows from the diode D1 to the capacitor C1, and flows to the capacitor C2 through the diode D2.

Compared with the prior art, the beneficial effects of the utility model are that:

the utility model discloses peak energy recuperation improves efficiency, reduces peak voltage, promotes metal oxide semiconductor field effect transistor MOSFET's reliability, reduces EMI and disturbs.

Drawings

FIG. 1 is a schematic diagram of the synchronous rectification absorption circuit of the present invention;

fig. 2 is a schematic diagram of the prior art synchronous rectification circuit of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Referring to fig. 1, the present invention provides a technical solution: a recyclable synchronous rectification absorption circuit comprises a transformer leakage inductance LS, an inductance L2, 2 metal oxide semiconductor field effect transistors MOSFET, 3 capacitors, 4 diodes, 2 resistors and 1 triode; 2 drains (D poles) of 2 Metal Oxide Semiconductor Field Effect Transistors (MOSFET) are respectively connected with two ends of a leakage inductance (LS) of the transformer, and 2 sources (S poles) of the 2 MOSFET are grounded; the middle end of the transformer leakage inductor LS is grounded through an inductor L2 and an output capacitor C0, and the voltage V + is connected between the inductor L2 and the output capacitor C0; the base electrode of the triode Q1 is connected to one end of the transformer leakage inductance LS through a resistor R1, the drain electrode (D pole) of a metal oxide semiconductor field effect transistor MOSFET close to one end of the transformer leakage inductance LS is connected with the anode of a diode D1, the cathode of the diode D1 is connected with the emitting electrode of the triode Q1, and the collector electrode of the triode Q1 is connected with a voltage V + through a resistor R2; one end of the capacitor C1 is connected with the cathode of the diode D3, the other end of the capacitor C1 is connected with the cathode of the diode D1, and the anode of the diode D3 is grounded; one end of a capacitor C2 is connected with the anode of a diode D4, the cathode of a diode D4 is connected with the emitter of a triode Q1, and the other end of a capacitor C2 is grounded; the anode of the diode D2 is connected to the cathode of the diode D3, and the cathode of the diode D2 is connected to the anode of the diode D4.

Referring to fig. 2, in a low-voltage and high-current situation, due to the existence of the leakage inductance of the transformer, when the MOSFET is turned off, the leakage inductance energy may cause large spikes to be generated at the D pole and S pole of the MOSFET, and the spikes are too high to cause the breakdown and damage of the MOSFET voltage, and the conduction radiation may also cause an influence.

As shown in fig. 1, when the voltage of the MOSFET is turned off and the voltages of the D pole and the S pole are increased, and when the voltage is greater than the sum of the voltages of the capacitor C1 and the capacitor C2, the current on the leakage inductance LS of the transformer flows from the diode D1 into the capacitor C1, through the diode D2 to the capacitor C2, the currents on the capacitor C1 and the capacitor C2 can go hundreds of nfs, which is enough to store the peak energy, but the voltages on the capacitor C1 and the capacitor C2 are too high, so the peak voltage on the D pole of the MOSFET is also limited.

After the MOSFET is switched on, the D is at a low level, the E of the triode Q1 is at a high level, the triode Q1 is switched on at the moment, the capacitor C1, the diode D3 and the triode Q1 form a discharge loop, the diode D4, the capacitor C2 and the triode Q1 form a discharge loop, and energy on the capacitor C1 and the capacitor C2 flows to the output capacitor C0.

When the energy release voltages V _ C1 and V _ C2 on the capacitors C1 and C2 are equal to the output voltage V +, current does not flow, so the voltages on the capacitors C1 and C2 are maintained equal to the output capacitor C0, and after the absorption peak, the voltages on the capacitors C1 and C2 are slightly higher than the voltage on the output capacitor C0, and when the MOSFET is turned on, the higher energy is released to the output capacitor C0.

Therefore, the novel absorption circuit of this experiment can retrieve the peak energy to output capacitance, raises the efficiency, reduces metal oxide semiconductor field effect transistor MOSFET peak, improves metal oxide semiconductor field effect transistor MOSFET's reliability, reduces EMI and disturbs.

The leakage inductance of the transformer Is Ls, the output capacitance of the MOSFET Is C0, the energy on the leakage inductance Ls Is assumed to be Ls Is/2, the energy of the leakage inductor Ls Is partially charged to the output equivalent capacitor C0, partially charged to the capacitor C1 and the capacitor C2 of the absorption circuit, Ls Is/2-C0 Vo/2 ═ (V _ jf-Vo) × C1/4, the switching frequency of the MOSFET Is Fs, the duty ratio Is D, the on time Is D/Fs, the current I1 (V _ jf-Vo) C1/2/(D/Fs) discharged from the capacitor C1 and the capacitor C2 to the output capacitor C0, the value of the resistor R1, (Vo/R1). beta.i 1, R1. beta/I1, and the resistance R1 needs to be smaller than the above formula value to meet the requirement that the energy Is discharged to the output capacitor C0 every week.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A recoverable synchronous rectification absorption circuit is characterized in that: the circuit comprises a transformer leakage inductor L1, an inductor L2, 2 Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), 3 capacitors, 4 diodes, 2 resistors and 1 triode; 2 drains of 2 Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) are respectively connected with two ends of a transformer leakage inductance L1, and 2 sources (S poles) of the 2 MOSFETs are grounded; the middle end of the transformer leakage inductor L1 is grounded through an inductor L2 and a capacitor C3, and the voltage V + is connected between the inductor L2 and the capacitor C3; the base of the triode Q1 is connected to one end of the transformer leakage inductance L1 through a resistor R1, the drain of the MOSFET close to one end of the transformer leakage inductance L1 is connected with the anode of a diode D1, the cathode of the diode D1 is connected with the emitter of the triode Q1, and the collector of the triode Q1 is connected with the voltage V + through a resistor R2; one end of the capacitor C1 is connected with the cathode of the diode D3, the other end of the capacitor C1 is connected with the cathode of the diode D1, and the anode of the diode D3 is grounded; one end of a capacitor C2 is connected with the anode of a diode D4, the cathode of a diode D4 is connected with the emitter of a triode Q1, and the other end of a capacitor C2 is grounded; the anode of the diode D2 is connected to the cathode of the diode D3, and the cathode of the diode D2 is connected to the anode of the diode D4.

2. A recyclable synchronous rectification absorber circuit as claimed in claim 1, wherein: when the energy release voltages V _ C1 and V _ C2 on the capacitor C1 and the capacitor C2 are equal to the output voltage V +, current does not flow.

3. A recyclable synchronous rectification absorber circuit as claimed in claim 1, wherein: when the voltage is greater than the sum of the voltage of the capacitor C1 and the voltage of the capacitor C2, the current on the leakage inductance LS of the transformer flows into the capacitor C1 from the diode D1 and flows into the capacitor C2 through the diode D2.