Secondary Controller for Power Converter Voltage Detection
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Solution Overview
Problem
Existing power converter control methods using primary and secondary controllers are inefficient due to indirect voltage detection by the primary controller and reliance on costly optical couplers and programmable shunt regulators, leading to higher costs and slower dynamic responses to output voltage variations.
Innovation Solution
A secondary controller with a control signal generation circuit, voltage detection signal generation circuit, and gate control signal generation circuit utilizes a short winding switch to control the power converter, eliminating the need for optical couplers and programmable shunt regulators by generating gate pulse signals in response to output voltage variations, ensuring accurate and efficient turning-on and turning-off of the primary side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a primary controller utilizes an auxiliary winding to detect output voltage indirectly, then the controller can be applied to the primary side, but the control accuracy is reduced and the dynamic response is slower
Solution Approach 1:
The secondary controller directly detects the output voltage on the secondary side and generates control signals autonomously, eliminating the need for indirect detection through auxiliary windings. The system serves itself by using the secondary side detection to control the primary side switching, achieving both high accuracy and simplicity.
2Reliability
If a secondary controller uses a feedback path with an optical coupler and programmable shunt regulator, then the output voltage can be controlled, but the cost increases and the dynamic response becomes slower
Solution Approach 1:
The patent extracts and eliminates the optical coupler and programmable shunt regulator from the feedback path. Instead of using these complex components, the secondary controller directly generates control signals based on secondary side voltage detection, maintaining control stability while significantly reducing component complexity and cost.
Solution Approach 2:
The patent introduces a new intermediary mechanism where the secondary controller directly couples the detection circuit with the primary side control through electrical isolation, replacing the traditional optical coupler intermediary. This direct coupling approach maintains isolation while improving response speed and reducing cost.
3Reliability
If a feedback path includes an optical coupler and programmable shunt regulator, then voltage feedback can be achieved, but the cost of the power converter increases
Solution Approach 1:
The patent replaces expensive components (optical coupler and programmable shunt regulator) with simpler, cheaper alternatives. The secondary controller uses basic voltage detection circuits and direct control signal generation, eliminating the need for costly components while maintaining feedback reliability through direct electrical coupling with isolation.
Data Source
AI summary
A secondary controller applied to a secondary side of a power converter includes a control signal generation circuit, a voltage detection signal generation circuit, and a gate control signal generation circuit. The control signal generation circuit generates a short-circuited control signal to a short winding switch after a gate control signal to make the short winding switch be turned on. When an output voltage of the power converter is less than a predetermined voltage, the voltage detection signal generation circuit generates a first detection signal to the control signal generation circuit. The control signal generation circuit further generates a gate pulse control signal according to the first detection signal. The gate control signal generation circuit generates a gate pulse signal according to the gate pulse control signal, wherein the gate pulse signal is used for making a primary side of the power converter be turned on.