Distributed Series Feedback Amplifiers for Voltage Regulator Transient Response
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Solution Overview
Problem
Conventional voltage regulator circuits suffer from narrow bandwidth and slow transient response due to high-gain error amplifiers, leading to voltage overshoot or undershoot, which affects the accuracy of signal detection and overall performance.
Innovation Solution
A feedback type voltage regulator circuit with distributed series feedback amplifiers, comprising cascaded amplifiers with varying gains and bandwidths, and a two-stage error amplifier with Miller-compensation and high-frequency compensation, to extend bandwidth and improve transient response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-gain error amplifier is used in the voltage regulator circuit, then the output voltage accuracy is improved, but the bandwidth is narrowed and transient response becomes slow
Solution Approach 1:
The error amplifier is divided into multiple cascaded stages with different gain and bandwidth characteristics. The first stage provides high gain for accuracy, while subsequent stages provide wider bandwidth for fast transient response, resolving the contradiction between precision and speed.
Solution Approach 2:
The amplifier stages are designed with dynamic characteristics where earlier stages operate with high gain for steady-state accuracy, while later stages provide wider bandwidth for dynamic transient response, allowing the system to adapt to different operating conditions.
2Speed
If the bandwidth of the error amplifier is increased to improve transient response, then the response to load current changes is faster, but the output voltage accuracy deteriorates
Solution Approach 1:
The amplifier is segmented into stages where early stages provide high gain for accuracy and later stages provide wide bandwidth for speed, allowing both requirements to be met simultaneously through cascaded architecture.
3Device complexity
If a single-stage error amplifier is used, then the circuit complexity is reduced, but the bandwidth is limited and transient response is slow
Solution Approach 1:
The amplifier is divided into multiple stages, each with moderate complexity, that together provide the required wide bandwidth and fast transient response, overcoming the limitations of a single-stage design.
4Speed
If the gain of the error amplifier is reduced to widen the bandwidth, then the transient response is improved, but the output voltage regulation accuracy deteriorates
Solution Approach 1:
The amplifier stages are configured with decreasing gain from early to late stages, where early stages provide high gain for regulation accuracy and later stages provide wide bandwidth for transient response, resolving the accuracy-speed tradeoff.
Data Source
AI summary
The present invention discloses a feedback type voltage regulator, including a voltage reference circuit for providing a reference voltage, distributed series feedback amplifiers electrically coupled to the voltage reference circuit and a power transistor which gate is electrically connected to the distributed series feedback amplifiers. The distributed series feedback amplifiers comprises three set of amplifiers serially connected with each other, wherein the relation of the gain of the first amplifier (A1), the second amplifier (A2), and the third amplifier (A3) is A1>A2>A3, wherein the relation of the bandwidth of the first amplifier (B1), the second amplifier (B2), and the third amplifier (B3) is B1<B2<B3.