Undershoot Reduction Circuit for Low-Current Voltage Regulators
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Solution Overview
Problem
Voltage regulators experience undershoot transients, particularly during transitions from high to low voltage states, which can cause logic errors due to the regulator's narrow loop bandwidth and are not effectively addressed by existing technologies.
Innovation Solution
An undershoot reduction circuit is introduced, which generates a short current pulse in response to an indication of potential undershoot, using a pulse generator and voltage-controlled current source to compensate for the undershoot without relying on feedback from the output, thereby maintaining a positive current and increasing transconductance and bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the voltage regulator uses a narrow loop bandwidth design, then power consumption is reduced, but output undershoot transients occur during voltage transitions
Solution Approach 1:
The undershoot reduction circuit detects the transition from high to low voltage state and proactively generates a current pulse before the undershoot can fully develop. This preliminary action prevents the harmful transient by anticipating the problem based on the detected voltage state transition.
Solution Approach 2:
The circuit applies a counteracting current pulse that opposes the developing undershoot transient. By generating current in the opposite direction of the transient current flow, the circuit neutralizes the harmful effect before it can cause logic errors or voltage instability.
2Reliability
If closed-loop feedback schemes are used to address undershoot, then output voltage stability is improved, but response time increases due to feedback delay
Solution Approach 1:
Instead of waiting for the undershoot to occur and then responding through feedback, the circuit detects the voltage state transition and generates the compensating current pulse in advance. This eliminates the feedback delay by acting before the transient fully develops.
Solution Approach 2:
The undershoot reduction circuit acts as an intermediary between the voltage regulator and the load, providing direct current compensation without relying on the feedback loop. This intermediary circuit bypasses the feedback delay by directly sensing the voltage state and applying immediate correction.
3Use of energy by moving object
If the regulator transitions from high to low voltage state, then power efficiency is improved, but undershoot transients occur causing logic errors
Solution Approach 1:
The circuit converts the potentially harmful voltage transition that causes undershoot into a useful trigger signal. The same transition that would normally cause problems is detected and used to initiate the compensating current pulse, turning the harmful event into the activation signal for the solution.
Solution Approach 2:
By detecting the high-to-low voltage transition, the circuit prepares and applies the counteracting current pulse before the undershoot can cause logic errors. This preliminary anti-action prevents the harmful effects while allowing the efficient low-voltage state to be achieved.
Data Source
AI summary
An electronic circuit includes a voltage regulator and an undershoot reduction circuit. The undershoot reduction circuit is configured to receive an indication of an event that potentially causes an undershoot in an output of the voltage regulator, and, in response to the indication, to generate and couple to the output of the voltage regulator a pulse that reduces the undershoot.