Dual-Regulator Power Supply Using Feedback for Stable 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 supplied voltages.
Innovation Solution
A power supply circuit is designed with two regulators and an error amplifying circuit, where the differential amplifier circuit adjusts the output voltages based on the difference between the output voltage of one regulator and a divided version of the output voltage of the other regulator, using highly accurate resistors to maintain 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 circuit can provide multiple voltage outputs, 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 one regulator is fed back to the adjustment terminal of the other regulator through a differential amplifier circuit. This feedback loop continuously monitors and adjusts the voltage outputs to maintain a stable voltage ratio, compensating for reference voltage errors and resistor manufacturing variations.
Solution Approach 2:
The patent introduces a differential amplifier circuit as an intermediary component between the two regulators. This intermediary circuit processes the voltage signals, compares them against the desired ratio, and generates correction signals to maintain accurate voltage proportioning despite component tolerances.
2Ease of manufacture
If standard resistors are used in the voltage division circuit, then the circuit is easy to manufacture, but manufacturing errors in resistors cause errors in the voltage ratio
Solution Approach 1:
The feedback mechanism compensates for resistor manufacturing errors by continuously adjusting the regulator outputs based on actual voltage measurements. Even with standard tolerance resistors, the feedback loop ensures accurate voltage ratio by detecting deviations and correcting them in real-time.
Solution Approach 2:
The patent converts the inherent manufacturing errors in standard resistors into manageable variations through the feedback mechanism. Rather than requiring precision resistors, the system uses ordinary resistors with the feedback loop compensating for their tolerances, thereby maintaining accuracy while simplifying manufacturing.
3Ease of manufacture
If reference voltage errors are present in the regulators, then the regulators can operate with standard components, but the voltage ratio between outputs becomes inaccurate
Solution Approach 1:
The feedback mechanism directly addresses reference voltage errors by measuring the actual output voltages and adjusting them to maintain the correct ratio. The differential amplifier compares the voltages and generates correction signals that compensate for reference voltage drift and errors in real-time.
Solution Approach 2:
The system performs preliminary voltage adjustment through the feedback mechanism before the voltages are used by downstream circuits. The differential amplifier proactively corrects voltage ratio deviations caused by reference errors, ensuring accurate voltages are delivered to the load.
Data Source
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.