Active Clamp Converter Voltage Sensing Using Same Polarity Auxiliary Winding
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Solution Overview
Problem
Existing active clamp switching power converter circuits face challenges in controlling switching timing for efficient power operation without relying on complex external circuits or high voltage components.
Innovation Solution
A switching power converter circuit with a transformer, a sensing circuit using an auxiliary winding, and a controller that regulates the power switch and active clamp switch to achieve zero voltage switching by detecting a sensed voltage proportional to the input voltage, allowing for efficient recycling of leakage energy and precise timing control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional voltage sensing methods are used with opposite polarity windings, then voltage regulation is achieved, but circuit complexity and component requirements increase
Solution Approach 1:
The patent inverts the traditional sensing approach by using an auxiliary winding with the same polarity as the primary winding, rather than the conventional opposite polarity. This inversion allows the sensing circuit to directly detect voltage without requiring complex polarity management, external circuits, or high voltage components, thereby reducing device complexity while maintaining reliable voltage regulation
2Manufacturing precision
If complex external circuits are used for timing control, then switching timing precision is improved, but device complexity and component count increase
Solution Approach 1:
The auxiliary winding with same polarity enables the circuit to self-detect voltage conditions and automatically determine optimal switching timing without requiring complex external timing circuits. The sensing circuit directly provides timing information to the controller, allowing the system to self-regulate switching operations and achieve precise timing control while minimizing external component requirements
3Measurement precision
If high voltage components are used for sensing, then voltage detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The auxiliary winding with same polarity acts as an intermediary that transforms high voltage detection into a manageable sensing problem. By coupling the auxiliary winding to the same polarity as the primary, it provides a scaled-down voltage signal that accurately represents the primary voltage condition without requiring high voltage components in the sensing circuit, thereby achieving accurate voltage detection with standard low-voltage components
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient power operation by recycling leakage energy and optimizing switching timing, reducing power loss and dependency on complex external circuits or high voltage components.
Implementation Method 1
an auxiliary winding around the core of the transformer having a same polarity as the primary winding. The sensing circuit generates a sensed voltage based on an auxiliary winding voltage across the auxiliary winding
Data Source
AI summary
An active clamp switching power converter circuit includes a primary-side sensing circuit that generates a sensed voltage based on an auxiliary winding voltage of an auxiliary winding around the core having a same polarity as the primary winding. Based on the sensed voltage, a controller controls switching of a power switch coupled to the primary winding to control current through the primary winding and controls switching of an active clamp switch to control leakage current when the power switch is turned off. The controller regulates timing of the switching to turn on the power switch based on timing of a zero voltage switching condition for power efficient operation.