Output Feedback Circuit Using Dual Amplifiers and Remote Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional output feedback control circuits face challenges in achieving high speed and enhanced accuracy simultaneously.
Innovation Solution
An output feedback control circuit is designed with a first amplifier generating a first error signal based on the difference between the output voltage and a reference voltage, a second faster amplifier generating a second error signal, and a calculator superimposing a remote sense signal on the reference voltage, with a capacitor connected between the error signal and remote sense signal terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single amplifier is used for output feedback control, then the circuit structure is simple, but it is difficult to achieve high speed and enhanced accuracy simultaneously
Solution Approach 1:
The error amplifier is divided into two separate amplifiers: a first amplifier configured to generate a first error signal with high accuracy, and a second amplifier configured to generate a second error signal with high speed. This segmentation allows each amplifier to be optimized for its specific function, resolving the contradiction between accuracy and speed while maintaining overall system reliability.
2Speed
If a faster amplifier is used for high speed response, then the response time is reduced, but the accuracy may be compromised
Solution Approach 1:
The system separates the accuracy-critical function (comparing output voltage to reference voltage) from the speed-critical function (rapid error signal generation). The first amplifier handles accuracy with proper biasing and configuration, while the second amplifier handles speed with optimized transistor sizing and compensation, eliminating the trade-off between these two parameters.
3Measurement precision
If remote sense signal is superimposed on reference voltage without proper filtering, then the control accuracy is improved, but high frequency noise may be introduced
Solution Approach 1:
A capacitor is introduced as an intermediary element between the remote sense signal input and the reference voltage superposition point. This capacitor acts as a low-pass filter that blocks high-frequency noise while allowing the DC remote sense voltage to pass through, thereby maintaining accuracy without introducing harmful high-frequency components into the feedback loop.
Data Source
AI summary
An output feedback control circuit includes, for example, a first amplifier configured to generate a first error signal commensurate with a difference between an output voltage, which is fed to a load, or a feedback voltage commensurate therewith and a reference voltage, a second amplifier configured to be faster than the first amplifier and to generate a second error signal commensurate with a difference between the output voltage or the feedback voltage and the first error signal (or the reference voltage), a calculator configured to superimpose a remote sense signal, which is derived from a grounded terminal of the load, on the reference voltage, which is fed to the first amplifier, and a capacitor connected between an application terminal for the first error signal and an application terminal for the remote sense signal.