Flyback Power Converter Multi-Function Pin Detection Circuit
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Solution Overview
Problem
Existing power conversion apparatuses with PWM control chips require multiple isolated detection pins for over voltage and over current protection, increasing production costs due to the need for separate pins for each function.
Innovation Solution
A flyback-based power conversion apparatus with a control chip and detection auxiliary circuit that utilizes a multi-function detection pin to perform over current, valley voltage, and over voltage/under voltage detection, allowing for various control and protection functions through a single pin, thereby reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple isolated detection pins are used for over voltage and over current protection, then detection accuracy and protection reliability are improved, but device complexity and production cost increase
Solution Approach 1:
The patent implements a multi-function detection pin that can perform both over-current detection and over-voltage detection functions. The detection auxiliary circuit switches between different detection modes based on the PWM signal state (enabling period for over-current detection via first detection voltage, disabling period for over-voltage detection via second detection voltage), allowing a single pin to replace multiple isolated detection pins while maintaining protection reliability
Solution Approach 2:
The patent merges over-current detection and over-voltage detection functions into a single detection pin. The detection auxiliary circuit combines multiple detection pathways (first detection voltage for over-current, second detection voltage for over-voltage) and routes them through one shared pin interface, reducing the number of pins required while preserving both detection capabilities
2Measurement precision
If multiple isolated detection pins are used for over voltage and over current protection, then detection accuracy is improved, but production cost increases
Solution Approach 1:
The detection pin is designed with multi-functionality to perform both over-current and over-voltage detection. The control chip configured with this multi-function pin requires fewer total pins, simplifying the chip design and reducing manufacturing complexity, which directly lowers production costs while maintaining detection accuracy through dedicated detection circuits for each function
Solution Approach 2:
The patent combines multiple detection functions into a single pin implementation. By merging over-current and over-voltage detection pathways through one pin, the chip requires fewer I/O pins, reducing pin count-related manufacturing costs and simplifying the overall chip fabrication process while preserving detection precision
Data Source
AI summary
A power conversion apparatus including a flyback power conversion circuit, a control chip and a detection auxiliary circuit is provided. The flyback power conversion circuit converts an input voltage into a direct current (DC) output voltage. The control chip generates a pulse width modulation (PWM) signal for controlling operations of the flyback power conversion circuit. The detection auxiliary circuit assists the control chip in obtaining a first detection voltage via a multi-function detection pin of the control chip within an enabling period of the PWM signal, so as to execute an over current detection according to the first detection voltage. Besides, the detection auxiliary circuit assists the control chip in obtaining a second detection voltage via the multi-function detection pin within a disabling period of the PWM signal, so as to execute a valley voltage detection according to the second detection voltage.