Peak current control device and method for switching power supply

Abstract

The invention discloses a peak current control device and method for a switching power supply. Input current is subjected to signal amplification treatment through a converting circuit unit; a first operation processing unit compares a signal output by the converting circuit unit with a first reference signal, and outputs a switching value to control the state of a signal switching circuit, so as to control the charge and discharge of an power storage element; a second operation processing unit compares a signal output by the power storage element with a second reference signal, and outputs a voltage change-over signal to a third operation processing unit; and the third operation processing unit changes an output peak current given value and outputs a current limiting value, so as to control the maximum output current within a set time. The peak current control device provided by the invention utilizes resources in the prior art to realize complicated current control, has the advantages of simple structure, low cost and rapid response, reduces the level signal conversion frequency, and has improved anti-interference ability and system stability and reliability.

Description

technical field [0001] The invention relates to the field of high-frequency switching power supplies, in particular to a control device and method for peak current of a switching power supply. Background technique [0002] In current-mode switching power supply control, peak current control is a commonly used control method. In practical applications, the peak current is difficult to control accurately. The commonly used control method is composed of a comparator, and the detected current signal is compared with a fixed voltage signal in the comparator; when the current signal is greater than the fixed voltage signal, the comparator From high level to low level, the power switch of the current-mode switching power supply is turned off by the driving circuit. In common control methods, the actually controlled peak current is not equal to the controlled peak current reference value, and has an error value with the peak current reference value. [0003] In the prior art, the ...

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Problems solved by technology

[0004] At present, in many existing current-mode switching power supply applications, the output current must have a constant current function. The solutions in the prior art have solved the problem of constant current application of switching power supplies.

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