Predictive Synchronous Rectification Controller Dead Time Control
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Solution Overview
Problem
Conventional predictive secondary-side synchronous rectification controllers have complex circuit designs that increase fabrication costs and reduce power converting efficiency, necessitating a simpler control method to manage dead time effectively.
Innovation Solution
A predictive synchronous rectification controller comprising a ramp generator, peak sampling unit, and output control unit generates a ramp signal and reference voltage signal to compare and control the conducting state of the synchronous rectification switch, simplifying the control process and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional digital controlling method with multiple counters and finite state machines is used to calculate dead time, then the dead time can be controlled, but the circuit complexity increases and fabrication cost rises
Solution Approach 1:
The patent extracts only the essential function needed for dead time control from the complex digital system. By using a simple RC circuit to generate the ramp signal and a comparator to generate the control signal, it removes unnecessary components like multiple counters, oscillators, and finite state machines while retaining the core dead time control capability.
Solution Approach 2:
The patent replaces expensive and complex digital controlling components with inexpensive analog components. The RC circuit and comparator approach uses basic, readily available components that are much cheaper than digital counters and finite state machines, achieving the same control function at a lower cost and complexity level.
2Loss of energy
If the synchronous rectification switch is controlled to turn on and off precisely, then power converting efficiency is improved, but the control circuit becomes more complex
Solution Approach 1:
The patent replaces complex digital control systems with a simpler analog control system. By using an RC circuit to generate a ramp signal and a comparator to generate the control signal based on voltage thresholds, it achieves precise switch control with much simpler circuitry, reducing complexity while maintaining or improving power converting efficiency.
3Ease of manufacture
If a simple control circuit is used, then fabrication cost is reduced, but precise dead time control becomes difficult
Solution Approach 1:
The patent introduces a ramp signal generated by an RC circuit as an intermediary element. This ramp signal serves as a time reference that allows the simple comparator circuit to achieve precise dead time control. The ramp signal acts as a mediator between the simple control circuit and the precise timing requirement, enabling accurate control without complex circuitry.
Data Source
AI summary
A predictive synchronous rectification controller for controlling at least one synchronous rectification switch is provided. The synchronous rectification controller has a ramp generator, a peak sampling unit, and an output control unit. The ramp generator receives a synchronous signal and generates a ramp signal accordingly. The peak sampling unit generates a predicted reference voltage signal by retrieving a peak voltage of the ramp signal. The output control unit compares the ramp signal with the predicted reference voltage signal to generate a synchronous rectification control signal to control a conducting state of the switch.