Isolated Power Supply Control Circuit for Feedback Fault Overvoltage
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Solution Overview
Problem
Existing power supply modules with isolated feedback loops face issues of overvoltage when the isolation barrier fails, leading to open-loop control states, and current solutions require additional components or strict topology restrictions.
Innovation Solution
A control circuit that outputs an open-loop control signal when feedback is absent and stops it based on preset conditions, such as duration or duty cycle, to prevent overvoltage without additional components, applicable to various circuit topologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional components are added to protect against feedback faults, then reliability is improved, but device complexity increases
Solution Approach 1:
The control circuit monitors its own feedback signal status and automatically switches between open-loop and closed-loop control modes. The system uses its existing resources (control circuit, feedback circuit, isolation circuit) to detect faults and adjust operation, eliminating the need for separate protection components.
2Reliability
If strict topology requirements are imposed, then reliability is improved, but adaptability deteriorates
Solution Approach 1:
The control method is designed to be topology-agnostic, working with any power supply module topology that has a feedback circuit and isolation circuit. The protection mechanism relies on universal control concepts (open-loop vs. closed-loop) rather than topology-specific features, enabling broad applicability across different circuit architectures.
3Ease of operation
If open-loop control is maintained for long duration, then ease of operation is improved, but harmful factors increase
Solution Approach 1:
The control circuit proactively monitors the feedback signal status and prepares to switch control modes before overvoltage can occur. By detecting the absence of feedback signals early and transitioning to open-loop control with appropriate safeguards, the system prevents harmful overvoltage conditions before they develop.
Solution Approach 2:
The system uses the presence or absence of feedback signals as a control parameter to determine operating mode. When feedback signals are absent, the control circuit identifies this as a fault condition and adjusts operation accordingly, using the feedback signal status itself as the control input for mode switching.
Data Source
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AI summary
This application provides a control circuit and a control method for a power supply module, a power supply module, and an electronic device. The power supply module includes a voltage conversion circuit, a secondary-side feedback circuit, and an isolation circuit. The voltage conversion circuit is configured to convert a direct current input voltage into a direct current output voltage. The secondary-side feedback circuit is configured to obtain the direct current output voltage and output a sampling voltage based on the direct current output voltage. The isolation circuit is configured to output a feedback signal in response to the sampling voltage. The control circuit is configured to: in response to not receiving the feedback signal, output an open-loop control signal to the voltage conversion circuit; and in response to open-loop pule generation information meeting a preset condition, stop outputting the open-loop control signal. The open-loop pule generation information includes open-loop pule generation duration or an open-loop pule generation duty cycle, the open-loop pule generation duration is a time period for the control circuit to output the open-loop control signal, and the open-loop pule generation duty cycle is a duty cycle of the open-loop control signal.