High-efficiency and low-loss AC/DC (Alternating Current/Direct Current) power supply circuit and control method thereof

Abstract

Disclosed herein are high efficiency, low loss AC-DC power supply circuits, and associated control methods. In one embodiment, an AC-DC power supply circuit can include: (i) a rectifier configured to rectify an AC power supply to generate a DC input voltage; (ii) a first stage voltage converter configured to convert the DC input voltage to a first output voltage, and to convert a first control signal to a feedback signal that represents the first output voltage; and (iii) a second stage voltage converter configured to convert the first output voltage to a constant DC output signal, where the first control signal represents a duty cycle of the second stage voltage converter.

Description

technical field [0001] The invention relates to the field of switching power supplies, more specifically, to a high-efficiency, low-loss AC-DC power supply circuit and a control method thereof. Background technique [0002] The schematic block diagram of the traditional AC and DC power supply circuit is as follows: figure 1 As shown, the DC input voltage V obtained after the AC power supply is processed by the rectifier bridge and the filter capacitor g It is converted into a DC voltage output through a step-up circuit and a flyback converter in turn. Wherein the boost circuit has a power factor correction function, and its power factor correction control circuit receives the input voltage V g and the bus voltage V obtained by voltage sampling BUS To obtain the current reference, the current loop control circuit controls the switch tube Q according to the current reference and the sampled input current 1 The switching action to convert the DC input voltage to the bus vol...

AI Technical Summary

Problems solved by technology

[0005] In view of this, the object of the present invention is to provide a high-efficiency, low-loss AC-DC power supply circuit and its control method to solve the problems in the prior art that the loss of the sampling resistor is too large under the high-voltage bus and the switching loss is difficult to reduce under light load. Small enough to cause unnecessary waste of electric energy

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