Switching Converter Output Voltage Control During Overcurrent
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Solution Overview
Problem
Converters, such as DC-DC converters, face issues with output voltage overshoot due to duty cycle limiting during overcurrent conditions, leading to adverse impacts on the converter's operation after the overcurrent condition ends.
Innovation Solution
A control circuit comprising a voltage control stage, an overcurrent control stage, and a reference voltage control stage that detects overcurrent conditions, limits the duty cycle, and enables the reference voltage to track the feedback voltage, mitigating output voltage overshoot by adjusting the control signal and reference voltage accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the duty cycle is limited during overcurrent conditions, then the converter output voltage stability is improved, but the reference voltage mismatch causes output voltage overshoot after the overcurrent condition ends
Solution Approach 1:
The patent applies preliminary action by adjusting the reference voltage to track the feedback voltage during the overcurrent condition before it ends. This proactive adjustment ensures that when the duty cycle limit is removed, there is no reference voltage mismatch to cause overshoot, thus preventing the harmful effect before it can occur.
Solution Approach 2:
The patent implements feedback by continuously monitoring the feedback voltage and dynamically adjusting the reference voltage to match it during overcurrent conditions. This closed-loop feedback mechanism ensures that the reference voltage accurately reflects the actual output voltage state, eliminating the mismatch that would otherwise cause overshoot when overcurrent protection is removed.
2Power
If the duty cycle is increased to maintain output voltage, then the power delivery capability is improved, but the converter may enter overcurrent condition causing voltage drop
Solution Approach 1:
The patent applies dynamics by making the reference voltage adjustable and adaptive rather than fixed. During overcurrent conditions, the reference voltage dynamically tracks the feedback voltage, allowing the system to maintain power delivery capability while adapting to current limitations, thus preventing voltage drops and maintaining output voltage stability.
Solution Approach 2:
The patent implements parameter changes by modifying the reference voltage parameter in response to overcurrent conditions. By changing the reference voltage to match the feedback voltage during overcurrent, the system can operate at reduced power levels without causing voltage instability, thus maintaining reliability while adapting power delivery to actual conditions.
Data Source
AI summary
A method and apparatus for controlling a converter are provided. In the method and apparatus, a converter is operated in accordance with a duty cycle and based on a difference between a feedback signal representing an output voltage of the converter and a reference signal. An overcurrent condition is detected in the converter. In response to detecting the overcurrent condition, the duty cycle used to operate the converter is limited and the reference signal is made to track the feedback signal to mitigate an output voltage overshoot at an end of the overcurrent condition.