Method and application of reference voltage correcting circuit for controlling buck converter

Abstract

The invention relates to the technical field of power sources and correcting circuits, in particular to a method and application of a reference voltage correcting circuit for controlling a buck converter. According to the circuit, the output end of a comparator EA is connected with one end of a capacitor C and a grid electrode G of a field-effect tube, a source electrode S of the field-effect tube is connected with a constant current source 2I input signal line, one end of a constant current source 2I output signal line is connected with the other end of the capacitor C, a tapping line of the constant current source 2I output signal line is connected to the ground, a drain electrode D of the field-effect tube is the VREF output voltage point C of a comparator and is connected with one end of a resistor R and one end of a constant current source I output signal line, the other end of a constant current source I input signal line is connected with a power source VDD, the other end of the resistor R is connected with the reverse input end of the comparator EA, a voltage VREF is arranged at the reverse input end of the comparator EA, a voltage FB is arranged at the same-phase input end of the comparator EA, and the circuit output voltage point C is controlled by the voltage VREF and the voltage FB. Compared with the prior art, input offset voltages are small, the output voltage errors caused by a COT structure can be removed, and the output voltage precision is improved.

Description

[technical field] [0001] The invention relates to the technical field of power supplies and correction circuits, in particular to a method and application for controlling a reference voltage correction circuit of a step-down converter. [Background technique] [0002] As we all know, modern circuit systems have an accurate output voltage as the reference for circuit work, and the output voltage is offset by the loss of the circuit and components. The traditional COT-controlled DC-DC directly uses a high-speed comparator (COMP) to control the output voltage, the loop response is very fast, and the output voltage has an extremely fast response to the transient changes of the input voltage and load current. However, because COT controls the ripple valley of the output voltage, and when the input voltage changes, the duty cycle will change, and the ripple amplitude will also change accordingly, so when the input conditions are different, the output voltage will change accordingly...

AI Technical Summary

Problems solved by technology

However, because COT controls the ripple valley of the output voltage, and when the input voltage changes, the duty cycle will change, and the ripple amplitude will also change accordingly, so when the input conditions are different, the output voltage will change accordingly. Changes, showing relatively poor linear adjustment rate (line regulation) indicators, for this reason, the existing COT-controlled DC-DC must be transformed and innovated

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