External adjustable overpower compensation circuit of switching power supply

Abstract

The invention discloses an external adjustable overpower compensation circuit of a switching power supply. The external adjustable overpower compensation circuit comprises a voltage-current conversion circuit, a current multiplying circuit, an input voltage detection circuit and a compensation circuit, wherein the voltage-current conversion circuit and the current multiplying circuit are arranged in a switching power supply controller chip; and the input voltage detection circuit and the compensation circuit are arranged outside the switching power supply controller chip. The external adjustable overpower compensation circuit of the switching power supply is applied to the switching power supply; ideal compensation voltage can be obtained by adjusting parameter values of components which are correspondingly arranged outside the switching power supply controller chip; and the condition that overpower output points of the switching power supply are kept consistent under the conditions of high input voltage and low input voltage is achieved, so that the problems that secondary development and manufacturing are carried out again due to excessive or insufficient compensation found when system testing is carried out after chip manufacturing is ended are solved; the cost is effectively reduced; and the application flexibility of the switching power supply controller chip is greatly improved.

Description

technical field [0001] The invention relates to the technical field of electronic circuits, in particular to an external adjustable overpower compensation circuit of a switching power supply. Background technique [0002] In the design of the switching power supply system, it is often required that the overpower point of the system be consistent to facilitate the subsequent application. However, due to the time delay from the action of the overcurrent protection module of the switching power supply system to the shutdown of the output control power MOS tube, the current of the power MOS tube will continue to rise after reaching the internally set threshold. At the same time, in the case of high input voltage and low input voltage, the rising rate of the inductor current of the switching power supply is different. When the input voltage is high, the current of the power switching tube rises faster, resulting in the phase of the output overpower point of the switching power su...

AI Technical Summary

Problems solved by technology

However, since the over-power compensation circuit is set inside the chip, if the over-compensation or under-compensation is found when the chip is manufactured and the system test is completed, no external adjustment can be performed.

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