Dual-Regulator Power Supply With Feedback-Stabilized Voltage Ratio
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Solution Overview
Problem
Existing power supply circuits using two regulators struggle to maintain a constant voltage ratio between two DC voltages due to errors in reference voltages and manufacturing errors in resistors, leading to instability in the voltage supply.
Innovation Solution
A power supply circuit is designed with two regulators and an error amplifying circuit, where the differential amplifier circuit adjusts the output voltage of the first regulator based on the difference between the output voltage of the second regulator and a voltage obtained through a resistance division, ensuring a stable voltage ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two regulators are used to supply two DC voltages, then the power supply can provide multiple voltage levels, but the voltage ratio between the two DC voltages becomes unstable due to reference voltage errors and resistor manufacturing errors
Solution Approach 1:
The patent implements a feedback mechanism where the output voltage of the second regulator is fed back to the adjustment terminal of the first regulator through a differential amplifier circuit. The differential amplifier compares the second regulator's output voltage with a reference voltage (obtained through resistance division from the first regulator's output) and adjusts the first regulator's output accordingly. This closed-loop feedback system continuously corrects voltage ratio deviations caused by reference voltage errors and resistor manufacturing tolerances, maintaining stable voltage ratio while providing multiple voltage levels.
2Ease of manufacture
If reference voltages and resistors are used in the regulator circuit, then the circuit can function properly, but manufacturing errors in these components cause voltage ratio instability
Solution Approach 1:
The patent converts the harmful effect of component errors into a beneficial feedback signal. The differential amplifier circuit is designed to detect the voltage ratio error caused by reference voltage and resistor manufacturing variations, and this error signal is used to automatically adjust the regulators. By transforming the error into a corrective feedback signal, the system compensates for manufacturing imperfections and achieves high voltage ratio accuracy despite using standard commercial components with typical tolerances.
Data Source
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AI summary
A power supply circuit includes a first regulator that includes a first input terminal to which a first voltage is input, a first output terminal from which a second voltage is output, and a first adjustment terminal, and adjusts the second voltage based on a voltage of the first adjustment terminal, a second regulator that includes a second input terminal to which the first voltage is input and a second output terminal from which a third voltage is output, and a differential amplifier circuit that outputs, to the first adjustment terminal, a signal corresponding to a difference between the third voltage and a fourth voltage at a first node between a plurality of first resistors connected in series between the first output terminal and a reference potential lower than the second voltage.