Linear Power Supply Circuit Transient Stability via Dual Feedback
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Solution Overview
Problem
Conventional linear power supply circuits face challenges in achieving stability during transient operations such as input voltage variations and load current changes due to negative feedback control issues.
Innovation Solution
The proposed linear power supply circuit incorporates a first output transistor of P-channel or pnp type, differential amplifiers, and drivers to generate control voltages, along with a second output transistor of N-channel or npn type, and additional differential amplifiers and drivers, to stabilize output voltage and improve transient characteristics by using voltage dividers and reference voltage generators to manage feedback loops effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional negative feedback control is used in linear power supply circuits, then the circuit structure remains simple, but stability during transient operations such as input voltage variation or load current variation cannot be achieved
Solution Approach 1:
The control system is segmented into multiple independent differential amplifiers (first differential amplifier for output voltage control, second differential amplifier for input voltage control) and multiple output transistors (first P-channel output transistor, second N-channel output transistor). Each amplifier-transistor pair handles specific control tasks, allowing the complex transient stability control to be divided into manageable segments that work together to improve overall circuit stability during transient operations.
2Stability of the object's composition
If multiple output transistors and differential amplifiers are added to improve transient characteristics, then transient response stability improves, but the circuit complexity increases
Solution Approach 1:
The first P-channel output transistor and second N-channel output transistor are merged in a complementary configuration to work together on output voltage control. The first differential amplifier and second differential amplifier are combined in a dual-loop feedback structure where both amplifiers operate simultaneously to provide comprehensive control. This merging allows the circuit to achieve superior transient stability through coordinated action of multiple components rather than requiring separate independent control systems.
Solution Approach 2:
The circuit implements dual feedback loops: the first differential amplifier receives feedback from the output voltage to control the first output transistor, and the second differential amplifier receives feedback from the input voltage to control the second output transistor. This multi-feedback mechanism enables the circuit to continuously monitor and adjust to transient changes in both input and output conditions, achieving stable transient response through active feedback control from multiple perspectives.
Data Source
AI summary
A linear power supply circuit includes a first output transistor of a P-channel type or pnp type which is connected between an input terminal to which an input voltage is input and an output terminal from which an output voltage is output; a first differential amplifier configured to amplify a difference between the output voltage or a feedback voltage according to the output voltage and a predetermined first reference voltage and output a first amplification voltage; a second differential amplifier configured to amplify a difference between the input voltage or a first monitor voltage according to the input voltage and the output voltage or a second monitor voltage according to the output voltage and output a second amplification voltage; and a first driver configured to generate a control voltage of the first output transistor according to the first amplification voltage and the second amplification voltage.