Power Converter Controller Using Tracking Voltage for ZVS and QR
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Solution Overview
Problem
Controllers for active-clamp flyback and asymmetric half-bridge flyback power converters require additional pins and sensing resistors to detect magnetizing current states, increasing costs and package expenses.
Innovation Solution
A controller with a capacitor, adjustment signal generation circuit, and discharge circuit generates a tracking voltage using detection or compensation voltage and feedback voltage to track magnetizing current states, enabling zero-voltage switching and quasi-resonant control without additional pins or sensing resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional pins and sensing resistors are used to detect magnetizing current state, then the controller can execute zero-voltage switching control or quasi-resonant control, but the cost of the controller and package increases
Solution Approach 1:
The patent reuses existing pins (CS pin for detection voltage, COMP pin for compensation voltage, or FB pin for feedback voltage) that were originally designed for other functions, making them serve dual purposes by also detecting magnetizing current state. This multi-functionality eliminates the need for additional pins and sensing resistors, reducing controller and package costs while maintaining control precision for ZVS and QR control
Solution Approach 2:
The controller uses its own existing voltage signals (detection voltage, compensation voltage, or feedback voltage) to detect the magnetizing current state, rather than requiring external sensing components. The controller's internal circuits process these existing signals to generate the tracking voltage, enabling self-service detection that reduces external component requirements and overall system cost
2Reliability
If additional pins and sensing resistors are used to detect magnetizing current state, then the controller can execute zero-voltage switching control or quasi-resonant control, but the package cost increases
Solution Approach 1:
The patent makes existing pins serve multiple functions by using them to detect magnetizing current state in addition to their original purposes. This eliminates the need for additional pins and associated sensing resistors, directly reducing bill of materials cost and package complexity, thereby lowering manufacturing cost while maintaining control precision
Solution Approach 2:
The patent extracts the magnetizing current detection function from the traditional approach requiring external sensing components and integrates it into the controller's existing voltage signals. By taking out the detection function and implementing it through software processing of existing pins, the patent eliminates unnecessary external components, reducing package size and manufacturing cost
Data Source
AI summary
A controller applied to a power converter is installed in a primary side of the power converter. The controller includes a capacitor, an adjustment signal generation circuit, and a discharge circuit. The capacitor is used for generating a tracking voltage. The adjustment signal generation circuit is used for generating an adjustment signal according to a feedback voltage and the tracking voltage. The discharge circuit is used for discharging the capacitor according to the feedback voltage and the adjustment signal. The tracking voltage is used for tracking a state of a magnetizing current of a magnetizing inductor of the primary side of the power converter, and when the tracking voltage consists with the state of the magnetizing current, the tracking voltage is applied to at least one of zero-voltage switching (ZVS) control and quasi-resonant (QR) control of the power converter.