Self-adaptive secondary slope compensation circuit for BUCK converter

Abstract

The invention belongs to the field of electronic technology, and particularly relates to a self-adaptive secondary slope compensation circuit for a peak current mode BUCK converter. The circuit in the invention includes a self-adaptive current generating circuit and a secondary voltage signal generating circuit. A first input end of the self-adaptive current generating circuit is connected with a duty cycle signal of a BUCK converter. A second input end of the self-adaptive current generating circuit is connected with reference voltage. An output end of the self-adaptive current generating circuit is connected with a first input end of the secondary voltage signal generating circuit. A second input end of the secondary voltage signal generating circuit is connected with a pulse switch signal. An output end of the secondary voltage signal generating circuit outputs a self-adaptive secondary voltage signal. The invention has the beneficial effects of having the advantage of secondary slope compensation and meanwhile being suitable for a current mode Buck converter with a variable switching frequency.

Description

Technical field [0001] The invention belongs to the field of electronic technology, and specifically relates to an adaptive secondary slope compensation circuit for a peak current mode BUCK converter. Background technique [0002] Most of the increasingly powerful electronic systems use point-of-load power supplies. The requirements for this type of power supply are high reliability, high efficiency, and high power density. Even some battery-powered devices require point-of-load power supplies to be able to operate at very low input voltages. normal work. These high requirements undoubtedly bring new challenges to the design of voltage converters. Current-mode switching power supply chips are widely used as point-of-load power supplies due to their advantages of simple compensation loop and good dynamic performance. However, current mode control is susceptible to some factors, such as improper slope compensation, which can cause sub-harmonic oscillation or poor loop response. ...

AI Technical Summary

Problems solved by technology

[0004] The structure of the fixed slope compensation circuit is simple, but the constant compensation slope leads to overcompensation or undercompensation under certain application conditions, which affects the load capacity, response speed and stability of the system; the compensation slope of the piecewise linear slope compensation is in the whole Several different values ​​can be taken within the range of the duty ratio, which avoids the overcompensation of the fixed slope compensation in the case of a small duty ratio to a certain extent, but it does not realize that the slope compensation is the most optimal under all duty ratios. Excellent value; the quadratic slope compensation solves the correspondence between the optimal compensation slope and the duty cycle well, and achieves good stability and response speed of the system under all duty cycles

However, in order to adapt to more occasions, the current current-mode Buck converter adopts a switching frequency that can be adjusted externally, because different switching frequencies correspond to different inductance values, and the slope of the compensation is related to the inductance value. Slope compensation presents a difficult problem, and none of the above three solutions are applicable anymore

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