Active power-factor correction circuit and related controller

Abstract

The invention provides an active power-factor correction circuit device which comprises a segment linear gain circuit, an error amplifier, a pulse width modulation controller and a pulse width modulation signal generator. The segment linear gain circuit is used for receiving feed-forward signals and generating corresponding gain signals, wherein sizes of the gain signals and sizes of the feed-forward signals are correlated in a broken line mode. The error amplifier is used for generating error signals according to output voltage of an alternating-current-to-direct-current converter. The pulse width controller is used for generating control signals according to the gain signals, the error signals, and the output voltage after being rectified of the alternating-current-to-direct-current converter. The pulse width modulation signal generator is used for generating pulse width modulation signals used for controlling a power switch of the alternating-current-to-direct-current converter according to the control signals. As a segment linear gain circuit is utilized to replace a traditional squarer, circuit complexity of an active power-factor correction circuit can be lowered, needed bias voltage sources are reduced, a circuit area is reduced, and electricity power consumption and cost are lowered.

Description

technical field [0001] The present invention relates to a power factor correction circuit, especially a control circuit for an active power factor correction circuit. Background technique [0002] Due to the increasing shortage of energy, people pay more and more attention to the power consumption efficiency of electronic devices. Most traditional AC-to-DC converters use diode rectifiers. Although this structure is simple and low-cost, due to the severe nonlinear distortion of the input current, it causes a large increase in low-frequency harmonics, resulting in a low power factor (PF) . Power factor refers to the ratio between effective power and apparent power, and is an index to measure the efficiency of power utilization. A low power factor will not only cause unnecessary waste of energy, but a large number of harmonics will also cause instability in the power system and troubles for generators, which will seriously affect the quality of power supply. [0003] A power...

AI Technical Summary

Problems solved by technology

[0004] However, the circuit design complexity of the squarer is high, the circuit area occupied is large, the manufacturing cost is high, and it is often very power-hungry, thus creating obstacles in improving the power efficiency of the power factor correction circuit and further reducing the size of the circuit chip

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