Transformer Input Voltage Detection Circuit Using Auxiliary Winding
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Solution Overview
Problem
Existing power converter control circuits require additional feedback input terminals to detect input voltage, increasing complexity and potentially reducing efficiency due to the need for multiple terminals.
Innovation Solution
A detection circuit that utilizes a current source circuit, current-to-voltage circuit, sample-and-hold circuit, and pulse generator to correlate the output voltage with the input voltage of a transformer, eliminating the need for additional feedback input terminals by directly sensing the transformer's input voltage through its auxiliary winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate flyback input terminal is used for voltage detection, then voltage detection accuracy is improved, but device complexity increases
Solution Approach 1:
The voltage-detection terminal is designed to serve dual functions: detecting the reflected voltage for regulation purposes and sensing the input voltage of the transformer. By making the terminal universal, the patent eliminates the need for a separate flyback input terminal, thereby reducing device complexity while maintaining voltage detection accuracy through the existing terminal's dual-role operation
2Measurement precision
If a separate flyback input terminal is used for voltage detection, then voltage detection capability is improved, but quantity of components increases
Solution Approach 1:
The patent merges the voltage detection function with the existing voltage-detection terminal that is already part of the control circuit for regulation purposes. By combining these functions into a single terminal rather than adding a separate flyback input terminal, the quantity of components is reduced while the voltage detection capability is maintained through the integrated approach
3Device complexity
If the voltage-detection terminal is used to sense input voltage, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent introduces a current source circuit as an intermediary element that generates a current proportional to the input voltage, which is then converted to a voltage signal by the current-to-voltage circuit. This intermediary approach allows the existing voltage-detection terminal to accurately sense the input voltage through the proportional relationship, maintaining measurement precision while reducing device complexity by avoiding a separate flyback terminal
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
Simplifies the control circuitry by directly sensing the transformer's input voltage, enhancing efficiency and reducing the complexity of feedback mechanisms, thereby improving the regulation of power converters.
Implementation Method 1
A current-to-voltage circuit is coupled to the current source circuit to generate a first voltage in response to the current outputted from the current source circuit
Implementation Method 2
A sample-and-hold circuit generates an output voltage by sampling the first voltage
Implementation Method 3
The operating of the sample-and-hold circuit provides low pass filtering to the output voltage
Implementation Method 4
The transformer is coupled to an input voltage
Data Source
AI summary
A circuit for detecting an input voltage of a transformer is provided. The circuit includes a current source circuit coupled to a winding of a transformer. A current-to-voltage circuit is coupled to the current source circuit to generate a first voltage in response to a current outputted from the current source circuit. A sample-and-hold circuit generates an output voltage by sampling the first voltage. The transformer is coupled to the input voltage, and the output voltage is correlated to the input voltage of the transformer.