System for linearly adjusting slope compensation voltage slope

Abstract

The invention discloses a system for linearly adjusting the slope compensation voltage slope. With a duty factor detection circuit, a voltage and current conversion circuit and a slope generation circuit, a duty factor of a switch signal in a peak current control mode chip is converted into a voltage signal forming a linear relationship with the duty factor by using the duty factor detection circuit, the voltage signal is linearly converted into a first current signal by using the voltage and current conversion circuit, and a second current signal formed by superposing the first current signal and a reference current source passes through the slope generation circuit to obtain slope compensation voltage, so that the invention achieves the function of linearly adjusting the slope of the slope compensation voltage according to the duty factor of the switch signal in the peak current control mode chip, well solves the problems that the peak current control mode chip is easy to generate over compensation during low duty factor and generate under compensation during high duty factor and ensures that the chip has favorable loading capacity and load regulating capacity in the work range of all duty factors.

Description

technical field [0001] The invention relates to a slope compensation technology in a peak current control mode chip, in particular to a system for linearly adjusting the slope of the slope compensation voltage. Background technique [0002] Peak current control mode (PCM, Peak Current Model) is one of the most widely used control methods in the field of switching power supplies. Its main advantages are as follows: (1) Since the output load current is proportional to the inductor current, PCM realizes the control within each switching cycle output current, so that it has more superior load adjustment characteristics and anti-input power disturbance ability; (2) It has an instantaneous peak current current limiting function, which will not damage the switch tube due to overcurrent, and greatly reduces the protection of overload and short circuit; ( 3) The entire feedback circuit becomes a first-order circuit, so the control loop compensation network of the error amplifier is s...

AI Technical Summary

Problems solved by technology

However, the slope of the traditional slope compensation voltage is a fixed value, which is prone to over-compensation and under-compensation. If the slope of the slope compensation voltage is too large, over-compensation will easily occur at a large duty cycle, which will reduce the switching power supply system. load capacity; if the slope compensation voltage slope is too small, it is prone to undercompensation at a small duty cycle, which will reduce the stability of the switching power supply system and the load regulation capability

Images