Multi-Output DC-DC Converter Clock Synchronization
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Solution Overview
Problem
Implementing constant on time (COT) control in multi-output DC-DC converters is challenging due to varying switching frequencies, making it difficult to achieve time division multiplexing of input voltage signals across sub-switching converters.
Innovation Solution
A multi-output DC-DC converter design incorporating N switching circuits, a clock generator producing clock signals with the same frequency and predetermined phase shifts, and N COT controllers that synchronize control signals with clock signals to stabilize switching frequencies across each converter channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If COT control is used in multi-output DC-DC converter, then dynamic response speed is improved, but switching frequency varies making time division multiplexing difficult
Solution Approach 1:
The patent changes the parameter of switching frequency from variable (in traditional COT control) to fixed by introducing a clock signal with predetermined frequency. The COT controller synchronizes the on-time of switches with this fixed-frequency clock signal, allowing multiple output channels to operate at consistent frequencies that enable time division multiplexing while preserving the fast dynamic response characteristics of COT control.
2Ease of operation
If peak current control is used in multi-output DC-DC converter, then time division multiplexing is easier to implement, but dynamic response speed is reduced
Solution Approach 1:
The patent segments the control function into two independent parts: a clock signal generator that provides fixed-frequency timing signals for time division multiplexing, and a COT controller that manages the on-time of switches based on output feedback. This segmentation allows the system to achieve both fixed switching frequencies (for easy time division multiplexing) and fast dynamic response (through COT control mechanisms).
Data Source
AI summary
A multi-output DC-DC converter with constant on time control. The multi-output DC-DC converter has N clock signals, and N switching circuits converting an input voltage signal to N output voltage signals respectively. The N clock signals have the same frequency and a predetermined phase shift between every two successive clock signals of the N clock signals. When the N switching circuits are operated in a steady state, each of the N switching circuits is synchronized with a corresponding one of the N clock signals.