Direct current converter and control circuit and method for the direct current converter

Abstract

The invention discloses a control circuit for a direct current converter, comprising a current sampling module for providing a current sample signal based on an inductive current of the direct current converter; a slope compensation module for providing the slope compensation signal based on a clock signal and a control signal; a peak detector for detecting the amplitude value of the slope compensation signal and providing the peak detection signal; an error amplifier for providing the error amplifying signal based on a feedback signal and a reference signal; a clipper for clipping the error amplification signal based on the peak detection signal and the inductive current setting peak value; a compared logic module for providing the control signal to control the output level of the directcurrent converter based on the clock signal, the error amplifying signal, the slope compensation signal and the current sampling signal. The invention also comprises a method corresponding with the circuit. The real induction current peak value is adjusted to the required induction current peak value by adjusting the inductive current based on the inductive current limit signal RAMP and the clipping signal VCLAMP, therefore the output current of the direct current converter is limited.

Description

technical field [0001] The present invention relates to direct current to direct current (DC) converters, and more particularly, the present invention relates to peak current mode controlled DC converters. Background technique [0002] Peak current mode control is widely used in DC converters. Peak current mode control usually adopts slope compensation technology, so that the system can still achieve stable operation when the duty cycle of the DC converter exceeds 50%. The slope compensation technique superimposes a slope compensation signal and an inductor current sampling signal to set the inductor current limit. State-of-the-art peak current mode controlled DC converters such as figure 1 shown. [0003] figure 1 The DC converter 100 is controlled for a prior art peak current mode. Such as figure 1 As shown, the DC converter 100 includes an upper transistor M 1 and down tube M 2 The output stage 101 composed of an inductor L and an output capacitor C O LC filter c...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to solve the problem that the current peak value of the inductor current changes and the maximum output current is limited due to the slope compensation signal being affected by the switch duty cycle of the existing peak current mode DC converter, and to provide an improved DC converter

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