Multi-Phase Switching Converter Adaptive On-Time Control
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Solution Overview
Problem
Multi-phase switching converters are limited by a maximum duty cycle of (100/N) %, which restricts their use in applications requiring higher duty cycles, as they cannot turn on subsequent switching circuits immediately after the off-time of the current circuit reaches a minimum off-time threshold.
Innovation Solution
The controller of the multi-phase switching converter can turn on the next switching circuit based on a comparison signal only after the current switching circuit's on-time reaches a first time threshold or its off-time reaches a second time threshold, allowing for partial overlap of on-times and increasing the maximum duty cycle, and includes a control circuit with a comparing circuit and a control circuit that generates control signals to manage the switching of multiple circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control circuit waits for the off-time of the current switching circuit to reach a minimum off-time threshold before turning on the next switching circuit, then the switching circuits can be turned on successively with proper timing, but the maximum duty cycle is limited to (100/N)%
Solution Approach 1:
The patent applies dynamics by making the turn-on timing of subsequent switching circuits adaptive rather than fixed. The control circuit dynamically adjusts when to turn on subsequent switching circuits based on whether the current switching circuit's on-time has reached a first time threshold or its off-time has reached a second time threshold. This dynamic timing mechanism allows the duty cycle to exceed the traditional (100/N)% limit while maintaining reliable switching control.
2Reliability
If the multi-phase switching converter uses traditional minimum off-time control, then the switching circuits operate safely with proper reset time, but the converter cannot be used in applications with duty cycle larger than (100/N)%
Solution Approach 1:
The patent changes the timing parameters by introducing two different thresholds: a first time threshold for on-time and a second time threshold for off-time. This parameter change allows the system to maintain safe operating conditions (reliability) while enabling duty cycles larger than (100/N)% (application range). The control circuit monitors both on-time and off-time against their respective thresholds, providing flexible timing control that expands application versatility without compromising safety.
3Speed
If the control circuit turns on the following switching circuit immediately when the comparison signal is high, then the response speed is improved, but the on-times of switching circuits overlap causing loss of control
Solution Approach 1:
The patent implements feedback by continuously monitoring the on-time and off-time of the current switching circuit against predetermined thresholds. The control circuit uses this feedback information to determine the appropriate moment to turn on subsequent switching circuits. This feedback mechanism ensures that switching circuits are turned on quickly (improved speed) only when it is safe to do so (maintained control stability), preventing overlapping on-times that would cause loss of control.
Data Source
AI summary
A multi-phase switching converter comprising a plurality of switching circuits, a comparing circuit and a control circuit. The comparing circuit generates a comparison signal based on a reference signal and the output voltage of the multi-phase switching converter. The control circuit can turn on the following switching circuit based on the comparison signal only after the time from the current switching circuit being turned on reaches a first time threshold or the off-time of the current switching circuit reaches a second time threshold, wherein the first time threshold is longer than the second time threshold.