Dual-Loop Voltage Regulator for Fast Transient Suppression
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Solution Overview
Problem
Low power regulator circuits face challenges in addressing transient overshoot and undershoot events during startup and dynamic load changes, leading to slow settling times due to limited load current, which is exacerbated in ultra-low power applications.
Innovation Solution
Implementing a secondary circuit loop with higher bandwidth and latency than the main regulator loop to quickly correct output voltage transients, and using an open-loop low-power sub-regulator in standby modes to reduce power consumption by disabling the main regulator loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single main regulator loop is used, then the circuit structure is simple, but the transient response is slow and settling time is long in low-power applications
Solution Approach 1:
The regulator circuit is divided into two independent loops: a main regulator loop for steady-state voltage regulation and a secondary transient suppression loop for rapid transient response. The secondary loop includes a transient suppressor circuit that activates during transient events to quickly correct voltage deviations, while the main loop continues to provide overall voltage regulation. This segmentation allows each loop to be optimized for its specific function, resolving the contradiction between structural simplicity and transient response speed.
2Measurement precision
If the main regulator loop is enabled for steady-state regulation, then voltage regulation accuracy is improved, but power consumption increases in standby mode
Solution Approach 1:
The regulator circuit dynamically switches between different operational modes based on the system state. In standby mode, the main regulator loop is disabled and only the low-power transient suppressor circuit remains active, minimizing power consumption. When a transient event is detected, the suppressor circuit activates rapidly. During normal operation, the main regulator loop is enabled to provide accurate voltage regulation. This dynamic operation resolves the contradiction between regulation accuracy and power consumption by activating full regulation only when necessary.
3Speed
If higher load current is used, then recovery from transient events is faster, but power consumption increases
Solution Approach 1:
The transient suppressor circuit is designed to provide high transient response current during transient events without requiring continuous high current operation. The circuit uses energy storage elements that are charged during normal operation and discharged during transients, allowing rapid recovery without sustained high power consumption. The suppressor circuit automatically activates only when transient conditions are detected, providing fast recovery speed while maintaining low average power consumption through on-demand operation.
Data Source
AI summary
A voltage regulator circuit can include two feedback loops, such as to reduce or suppress an unwanted transient condition in an output voltage during transient conditions such as during startup or during load current demand transients. One of the two feedback loops can include a shunt device arranged to provide a temporary current pathway during the transient condition to change current provided to a load connected to an output of the voltage regulation circuit. In addition, or instead, the voltage regulator circuit can include an open-loop regulation circuit separate from a loop corresponding to the first error amplifier. The open-loop regulator circuit can operate in a lower-power mode as compared to a closed-loop regulator circuit. A portion or an entirety of the voltage regulator circuit can be implemented in an integrated circuit, such as monolithically.