Self-adaptive loop compensating method, compensating circuit and switching power supply with compensating circuit

Abstract

The invention relates to the field of electronics, and discloses a self-adaptive loop compensating method, a compensating circuit and a switching power supply with the compensating circuit. The self-adaptive loop compensating method includes the steps that current output voltages of the switching power supply are determined; bias currents are generated according to the output voltages and are in linear relation with the output voltages; the bias currents are input into a bias control end of an error amplifying circuit; the error amplifying circuit compares current output feedback voltage signals of the switching power supply with preset output feedback reference signals under the control of the bias currents to generate error compensation voltages and controls output of the switching power supply according to the error compensation voltages. According to the technical scheme, the problem that a bandwidth becomes narrower along with increasing of the output voltages can be avoided, and a stable transient response of the switching power supply can be further guaranteed.

Description

technical field [0001] The invention relates to the field of electronics, in particular to a method and circuit for adaptive loop compensation and a switching power supply with the compensation circuit. Background technique [0002] Switching power supply is a kind of power supply that uses modern power electronic technology to control the time ratio of switching on and off to maintain a stable output voltage. [0003] Adaptive loop compensation is a technology that dynamically controls the switching power supply according to the current output feedback of the switching power supply to achieve stable output. [0004] In the prior art, a certain bias current is input to the error amplifier, and the error amplifier (denoted as EA) compares the current output feedback voltage (denoted as Vfb) with the feedback reference signal (denoted as Vref1) reflecting the output voltage expected by the user , generate an error compensation current signal (denoted as Ic) at the output term...

AI Technical Summary

Problems solved by technology

[0010] Generally, in a BUCK switching power supply, when the output voltage Vout is the smallest, the loop stability of the circuit is the worst, and when the output voltage Vout is the largest, the dynamic response characteristics of the circuit are the worst

Therefore, in order to ensure that the loop is stable at all output voltages, it is necessary to ensure that the loop is stable in the worst case (when the output voltage is the smallest); but this will cause the loop bandwidth to change at the maximum output voltage. too narrow, resulting in very poor load transient response

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