Multi-phase Converter Transient Detection via Comparison Signal Period
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Solution Overview
Problem
Multi-phase converters face a challenge in responding promptly to instantaneous rises in load current due to time delays in load current sensing, leading to significant undershoots in output voltage during phase-cut mode.
Innovation Solution
A control method for multi-phase converters that compares a feedback signal with a reference signal to generate a comparison signal, detects the period of this signal, and determines if a transient rise in load current has occurred by comparing it with a time threshold, triggering all switching circuits to power operation if a transient is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If phase-cut mode is used to optimize efficiency by reducing the number of switching circuits in operation, then energy efficiency is improved, but the system's response time to load current changes deteriorates due to ripple filtering delays
Solution Approach 1:
The patent introduces an intermediary detection mechanism that monitors the period of the comparison signal (generated from feedback voltage) rather than directly monitoring load current. This intermediary approach allows the system to detect load transients quickly without being constrained by the slow ripple filtering process, enabling fast response while maintaining phase-cut efficiency.
Solution Approach 2:
The system uses feedback from the output voltage (through the comparison signal period) to indirectly detect load current changes. By monitoring how the comparison signal period changes in response to load variations, the system achieves fast transient detection without directly measuring current, thus maintaining both efficiency and responsiveness.
2Stability of the object's composition
If ripple filtering is applied to load current sensing to smooth measurements, then measurement stability is improved, but the detection speed of instantaneous load current changes deteriorates
Solution Approach 1:
Instead of directly sensing and filtering load current, the patent uses an intermediary approach by monitoring the period of the comparison signal generated from output voltage feedback. This intermediary measurement reflects load changes instantaneously without requiring current filtering, eliminating the trade-off between stability and detection speed.
3Loss of energy
If the number of switching circuits is reduced in phase-cut mode to match small load current, then energy efficiency is improved, but the system's ability to handle instantaneous load current rises deteriorates
Solution Approach 1:
The system performs preliminary detection of load transients by monitoring the comparison signal period before the actual load current change becomes apparent through current sensing. When a transient is detected early, the control unit proactively activates additional switching circuits in advance, ensuring the system is prepared to handle the load rise without voltage undershoot while maintaining efficiency during normal operation.
Data Source
AI summary
A control method of multi-phase converters, wherein the multi-phase converter includes a plurality of switching circuits coupled in parallel between an input voltage and a load. The control method includes: comparing a feedback signal with a reference signal to generate a comparison signal, wherein the feedback signal is indicative of an output voltage provided to the load; determining the number of switching circuits for power operation based on the load current; detecting a period of the comparison signal; comparing the detected period of the comparison signal with a time threshold to determine whether a transient rise of load current has occurred; and getting all the switching circuits into power operation if a transient rise of load current is detected.