Low-Noise Multi-Output Power Supply Frequency Control
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Solution Overview
Problem
Conventional multi-output switch mode power supply circuits face challenges in minimizing electromagnetic compatibility (EMC) input filters due to beat frequencies, which result in increased circuit size and production costs, while fixed frequency control leads to inefficiencies and poor dynamic response during light-load or dynamic states.
Innovation Solution
A method and circuit configuration that detect operation states of switch mode power supplies to generate frequency modulation signals, controlling operating frequencies to match a main frequency in heavy-load steady states and become independent in light-load or dynamic states, using detection and frequency modulation circuits to minimize beat frequencies and optimize efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fixed frequency control is used in multi-output switch mode power supply circuits, then electromagnetic compatibility input filters can be minimized, but efficiency and dynamic response deteriorate during light-load or dynamic states
Solution Approach 1:
The patent implements dynamic frequency control where the operating frequency of each switch mode power supply is adjusted based on its load state. Detection circuits monitor the operation state of each power supply, and frequency modulation circuits adjust the frequency accordingly - maintaining synchronized main frequency during heavy-load steady states to minimize input ripple, and allowing independent frequency adjustment during light-load or dynamic states to optimize efficiency and response time.
Data Source
AI summary
Disclosed herein are low-noise multi-output power supply circuits and methods. In one embodiment, a method of controlling a low-noise multi-output power supply circuit, can include: (i) detecting operation states of each of a plurality of switch mode power supplies; (ii) generating a frequency modulation signal to control an operating frequency of a switch mode power supply to be substantially equal to a main frequency signal when the switch mode power supply is detected to operate in a heavy-load steady state; and (iii) controlling the operating frequency of the switch mode power supply to be independent of the main frequency signal when the switch mode power supply is detected to operate in a light-load or a dynamic state.