Predictive LDO Regulator Control for Undershoot and Overshoot
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Solution Overview
Problem
Existing semiconductor devices face challenges in accurately monitoring and stabilizing internal voltages, leading to issues with undershoot and overshoot, which can affect their normal operation.
Innovation Solution
A low-dropout regulator is designed with a comparator, internal voltage generator, and controller that compares feedback voltage with a reference voltage, generates a comparison signal, and monitors load current to suppress undershoot and overshoot by adjusting the voltage level based on specific threshold conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low-dropout regulator generates internal voltage based on comparison signal, then the internal voltage can be regulated, but undershoot and overshoot occur during load current transitions
Solution Approach 1:
The controller predicts load current transitions by monitoring the comparison signal and takes preliminary action by adjusting the voltage level of the comparison signal before the actual load change occurs. This predictive control prevents undershoot and overshoot by proactively compensating for upcoming load variations, thereby maintaining internal voltage stability during dynamic conditions.
2Reliability
If the regulator monitors load current to suppress voltage fluctuations, then voltage stability improves, but the device complexity increases
Solution Approach 1:
The controller performs multiple functions using a single integrated circuit: it monitors load current, generates comparison signals, predicts load transitions, and adjusts voltage levels to suppress undershoot and overshoot. By combining these functions into one multi-functional controller, the patent achieves improved voltage stability without proportionally increasing device complexity.
Data Source
AI summary
A low-dropout regulator includes a comparator for comparing a feedback voltage with a reference voltage to output a comparison signal, which corresponds to a comparison result, to a control node; an internal voltage generator coupled to the control node, and for generating the feedback voltage and an internal voltage based on the comparison signal; and a controller coupled to the control node, and for monitoring the internal voltage based on the comparison signal, and controlling a voltage level of the comparison signal according to a monitoring result.