Spread spectrum operating circuit with function of reducing peak noise

Abstract

The invention provides a spread spectrum operating circuit with a function of reducing peak noise, and belongs to the field of power management. The spread spectrum operating circuit comprises a circuit for generating a pseudo random sequence, 4-16 decoder circuits, a current reference for generating variable current, and an oscillator. The pseudo random sequence generating circuit generates the pseudo random sequence via a nonlinear feedback shift register, the outputs of four D triggers are connected to 4-16 decoders, and 16 outputs are respectively connected to the gates of 16 MOS (Metal Oxide Semiconductor) transistors of the current reference to control on and off of the MOS transistors; the MOS transistors are turned on to short-circuit resistors connected with the sources and drains of the MOS transistors, thus, the magnitude of resistance is changed, and the magnitude of current is influenced; the current reference adopts a secondary operational amplifier, which is not excessively introduced herein, and the generated current flows into the oscillator; and the frequency of the oscillator is changed along with the change of the magnitude of current, then the internal oscillator generates a clock pulse having a random cycle in one-by-one switching cycles, and the switching noise is spread within a wide frequency range, so that the peak noise is remarkably reduced.

Description

technical field [0001] The invention relates to the field of power management, in particular to a spread spectrum operation circuit for reducing peak noise. Background technique [0002] With the popularization of portable electronic products, the power management system is more and more important, and the quality of the power management part determines the performance of the whole system to a large extent. Switching regulators can be particularly troublesome where electromagnetic interference (EMI) is a concern. Switching regulators are cycled to deliver power to an output. In most cases, the operating frequency is a fixed value or a constant. This conversion method produces a large noise component at the operating frequency (fundamental frequency) and its multiples (harmonics). The frequency of the traditional oscillator remains unchanged, which will cause the noise at the output to superimpose at the same frequency, resulting in high peaks. [0003] In order to reduce...

AI Technical Summary

Problems solved by technology

The frequency of the traditional oscillator remains unchanged, which will cause the noise at the output to superimpose at the same frequency, resulting in high peaks

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