Reverse Current Control for Isolated Power Supplies with Synchronous Rectifiers
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Solution Overview
Problem
Conventional isolated power supplies with synchronous rectifiers face challenges in protecting devices during input voltage dips, interrupts, or short-circuits, as they fail to effectively prevent reverse currents that can damage internal components, particularly when the short-circuit occurs after the input filter, and existing solutions require additional power switches and high-speed amplifiers, which may lower efficiency and increase costs.
Innovation Solution
A reverse current control module is introduced, comprising an input voltage detector, an output voltage detector, and a compare module that senses input and output voltages, generates a signal when the input voltage falls below a threshold, and transmits this signal to the synchronous rectifier control module to disable the synchronous rectifiers, thereby preventing reverse currents from flowing back into the input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If synchronous rectifiers are used to increase power density and efficiency, then power efficiency is improved, but the risk of reverse current damage increases during input voltage dips or short-circuits
Solution Approach 1:
The control module proactively disables the synchronous rectifiers when it detects an input voltage dip or short-circuit condition, before reverse current can damage the power supply components. This preventive action eliminates the need for additional protection circuitry while maintaining the efficiency benefits of synchronous rectification during normal operation.
2Reliability
If additional power switches and high-speed amplifiers are added to protect against reverse current, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The control module performs multiple functions: it controls the synchronous rectifiers during normal operation to maintain efficiency, and simultaneously provides protection against reverse current damage during fault conditions. This multi-functional approach eliminates the need for separate protection circuitry, reducing device complexity and component count.
Solution Approach 2:
The power supply system protects itself by using its existing control module to detect fault conditions and disable the synchronous rectifiers when needed. This self-protection capability eliminates the need for external protection devices or additional control circuits, simplifying the overall system design.
3Reliability
If additional power switches and high-speed amplifiers are added to protect against reverse current, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The control module performs multiple functions: it controls the synchronous rectifiers during normal operation to maintain efficiency, and simultaneously provides protection against reverse current damage during fault conditions. This multi-functional approach eliminates the need for separate protection circuitry, reducing device complexity and component count.
Data Source
AI summary
In certain example embodiments, a system is provided that includes a circuit. The system also includes a reverse current control module that provides an isolated power supply in order to protect one or more devices in a power chain during one or more testing activities having one or more requirements.