Leakage Compensation Circuit With Feedback-Clamped Output Stage
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Solution Overview
Problem
MOS transistors experience significant leakage current due to PN junctions, particularly in high drive and high voltage output stages, leading to excessive leakage current flow from the output terminal, which current handling methods have not fundamentally addressed.
Innovation Solution
A leakage compensation circuit that samples leakage current from the output stage and returns it to the stage using operational amplifier circuits and sampling circuits to compensate for the leakage, effectively clamping voltages at specific nodes to prevent current flow from the output terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the MOS transistor size is increased for high drive and high voltage output stages, then the drive capability is improved, but the leakage current increases
Solution Approach 1:
The patent implements a feedback mechanism where the leakage current from the output stage is sampled and fed back through the operational amplifier to the gate of the output transistor. This feedback loop dynamically compensates for the leakage current by adjusting the gate voltage, thereby maintaining the transistor in a properly biased state while canceling out the leakage effects.
Solution Approach 2:
The patent changes the electrical parameters (voltage and current) at the gate terminal of the MOS transistor through the operational amplifier circuit. By dynamically adjusting the gate-source voltage based on the sampled leakage current, the system modifies the transistor's operating parameters to compensate for leakage without changing the physical transistor size.
2Loss of energy
If process optimization is applied to reduce leakage current, then the leakage current is partially reduced, but the problem is not fundamentally solved
Solution Approach 1:
The patent implements a feedback mechanism where the leakage current from the output stage is sampled and fed back through the operational amplifier to the gate of the output transistor. This feedback loop dynamically compensates for the leakage current by adjusting the gate voltage, thereby maintaining the transistor in a properly biased state while canceling out the leakage effects.
Solution Approach 2:
The patent converts the harmful leakage current into a useful signal by sampling it and using it as feedback to adjust the transistor's operating state. The leakage current that was previously wasted energy is now utilized to control the gate voltage, effectively turning the harmful effect into a beneficial self-regulating mechanism.
3Loss of energy
If a leakage compensation circuit is added, then the leakage current is compensated, but the circuit complexity increases
Solution Approach 1:
The operational amplifier in the patent serves multiple functions: it amplifies the sampled leakage current signal, acts as a voltage controller for the output transistor, and provides the compensation mechanism. By using a single multi-functional component, the circuit achieves leakage compensation without adding excessive complexity.
Solution Approach 2:
The patent merges the leakage sensing function, signal amplification function, and transistor control function into a single integrated operational amplifier circuit. This consolidation reduces the overall circuit complexity compared to having separate dedicated circuits for each function.
Data Source
AI summary
A leakage compensation circuit, a chip, and an electronic device are provided. The leakage compensation circuit includes an output stage circuit, a first sampling circuit, an operational amplifier circuit, and a second sampling circuit. The operational amplifier circuit includes an operational amplifier output stage circuit and an operational amplifier first stage circuit. The first sampling circuit samples a leakage current of the output stage circuit to obtain a first sampling current, and provides it to the operational amplifier output stage circuit via a first node. The second sampling circuit samples a current of the operational amplifier output stage circuit to obtain a second sampling current, and provides it to the output stage circuit via a second node, to compensate for the leakage current of the output stage circuit. The operational amplifier first stage circuit clamps voltages at the first node and the second node.