Output voltage controlling circuit and power supply provided with same

Abstract

The present invention discloses an output voltage controlling circuit and a power supply provided with the same. The output voltage controlling circuit comprises an error elimination circuit, a comparator, a control logic circuit, a conduction timer and a drive circuit, wherein the two input ends of the error elimination circuit are respectively connected with a feedback voltage signal and a reference voltage signal and the two output ends of the error elimination circuit are respectively connected with the two positive input ends of the comparator; the two negative input ends of the comparator are respectively connected with the feedback voltage signal and the reference voltage signal, and the output end of the comparator is connected with the first input end of the control logic circuit; the output end of the control logic circuit is connected with the input end of the drive circuit, and the drive circuit outputs a switch tube controlling signal; and one end of the conduction timer is connected with the second input end of the control logic circuit, and the other end of the conduction timer is connected with the switch tube controlling signal. According to the output voltage controlling circuit and the power supply disclosed by the present invention, a feedback voltage average value and a reference voltage error are detected by the error elimination circuit, and reference voltage is dynamically regulated, so that the purposes of reducing the error and improving the accuracy of outputting the voltage in a mode of constant conduction time control are achieved.

Description

Technical field [0001] The present invention relates to the technical field of power electronics, in particular to an output voltage control circuit and a power supply with the circuit. Background technique [0002] With the continuous development of electronic products, the requirements for power chips are getting higher and higher. Not only are they required to provide a stable power supply voltage and provide high conversion efficiency within the full load range, but also to the response speed and application Diversity also has higher and higher requirements. In order to extend battery life and improve the performance of electronic products, it is necessary to design a power management chip with high conversion efficiency and diverse working modes. Among them, the use of constant on-time control mode (constant on-time, referred to as COT) combined with pulse frequency modulation mode (Pulse Frequency Modulation, referred to as PFM) and skip cycle modulation mode (Pulse Skip M...

AI Technical Summary

Problems solved by technology

[0005] The output voltage control circuit of the existing DC-to-DC power supply adopts the COT control method, and the output voltage accuracy is not high

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