Dual-loop Voltage Regulator Architecture for Fast Response and High DC Accuracy
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Solution Overview
Problem
Conventional voltage regulators, particularly linear regulators, face challenges in achieving fast response times to sudden and extreme load current variations, leading to inadequate DC accuracy and high-frequency power supply rejection ratios, while bang-bang regulators struggle with DC accuracy and ripple control in distributed systems.
Innovation Solution
A dual-loop voltage regulation framework is implemented, featuring a fast inner loop with a bang-bang voltage regulator and a slower outer loop that adjusts the trip point of the bang-bang regulator, utilizing an error amplifier, charge pump circuit, and high-speed comparator to achieve nearly instantaneous response and high DC accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a linear voltage regulator is used, then DC accuracy and power supply rejection ratio are improved, but response time to load current variations deteriorates
Solution Approach 1:
The voltage regulator is divided into two independent loops: an inner loop with a bang-bang regulator for fast response and an outer loop with a linear regulator for high DC accuracy. Each loop operates autonomously to address different performance requirements, with the inner loop handling transient load changes and the outer loop maintaining precise DC voltage levels.
Solution Approach 2:
The system dynamically switches between two regulation modes by using a trip point comparator that monitors load current variations. When sudden changes are detected, the bang-bang regulator activates for instantaneous response; under normal conditions, the linear regulator maintains precise DC accuracy. This dynamic adaptation resolves the speed-accuracy tradeoff.
2Speed
If a bang-bang voltage regulator is used, then response time is improved, but DC accuracy and ripple control deteriorate
Solution Approach 1:
The regulator is segmented into two functional loops: the inner bang-bang loop provides fast response with a passgate transistor for instantaneous current adjustment, while the outer linear regulator loop provides precise DC accuracy through continuous voltage modulation. This segmentation allows each subsystem to optimize for its specific function without compromising the other.
Solution Approach 2:
The trip point comparator acts as an intermediary that monitors both the output voltage and load current conditions, dynamically determining when to activate the bang-bang regulator versus the linear regulator. This intermediary component enables seamless coordination between the two regulation modes, ensuring optimal performance across varying operating conditions.
3Stability of the object's composition
If linear voltage regulator compensation circuitry is added to improve stability, then loop stability is improved, but bandwidth and transient response deteriorate
Solution Approach 1:
The compensation requirements are segmented between the two loops: the inner bang-bang regulator requires minimal compensation due to its inherent stability from the high-speed comparator and passgate configuration, while the outer linear regulator receives full compensation circuitry. This segmentation allows the fast inner loop to maintain high bandwidth without stability compromises.
Solution Approach 2:
The system dynamically adjusts the effective bandwidth by switching between regulation modes. The bang-bang regulator provides effectively infinite bandwidth for transient response, while the linear regulator operates at lower bandwidth for steady-state accuracy. This dynamic bandwidth adjustment resolves the stability-speed tradeoff.
Data Source
AI summary
Dual-loop voltage regulator circuits and methods in which a dual-loop voltage regulation framework is implemented with a first inner loop having a bang-bang voltage regulator to achieve nearly instantaneous response time, and a second outer loop, which is slower in operating speed than the first inner loop, to controllably adjust a trip point of the bang-bang voltage regulator to achieve high DC accuracy.