Load-Adaptive FFNC Circuit for Regulator PSR Improvement
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Solution Overview
Problem
Conventional feed-forward mechanisms for power supply noise rejection in voltage regulators lack dynamic adjustment, leading to over- or under-compensation under varying load conditions and process-temperature variations, and fail to provide the needed accuracy and adaptability.
Innovation Solution
A load current sensor is used to regulate the feed-forward supply noise cancellation gain, adjusting it based on load current changes and process-voltage-temperature variations, enhancing power supply noise rejection performance across different conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional feed-forward mechanisms are used with fixed gain, then the circuit complexity is low, but the power supply noise rejection performance deteriorates under varying load conditions
Solution Approach 1:
The patent applies dynamics by making the feed-forward gain adjustable rather than fixed. A load current sensor detects changes in load current and dynamically adjusts the feed-forward gain accordingly. This allows the noise cancellation mechanism to adapt to varying load conditions, process variations, and temperature changes, resolving the contradiction between maintaining simple circuitry and achieving reliable noise rejection across different operating conditions.
2Adaptability or versatility
If fixed feed-forward gain is used, then the device complexity is low, but the adaptability to load changes deteriorates
Solution Approach 1:
The patent implements feedback by using a load current sensor to detect load current changes and using this information to adjust the feed-forward gain. This closed-loop feedback mechanism enables the system to automatically adapt to load changes, process variations, and temperature effects without requiring complex manual configuration or multiple fixed-gain circuits, thus resolving the contradiction between adaptability and device complexity.
3Reliability
If dynamic adjustment of feed-forward gain is implemented, then the power supply noise rejection improves, but the device complexity increases
Solution Approach 1:
The patent applies parameter changes by adjusting the feed-forward gain parameter based on detected load current changes. Instead of using a complex adaptive algorithm or multiple switching circuits, the invention changes the gain parameter dynamically in response to load conditions. This approach maintains consistent high-performance noise rejection across varying conditions while keeping the control mechanism relatively simple, resolving the contradiction between noise rejection consistency and control complexity.
Data Source
AI summary
A regulator for a load voltage includes a pass transistor for a load current, a gate voltage sensor coupled to a gate of the pass transistor, and a feed-forward supply noise cancellation circuit configured to amplify a gain of a supply noise cancelling signal at increments of the gate voltage.