MOS Switch Leakage Compensation for Precision High-Voltage Testing
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Solution Overview
Problem
Solid state switch devices, particularly those using metal-oxide-semiconductor field-effect transistors (MOSFETs), experience current leakage due to non-idealities, which affects power efficiency and measurement accuracy in precision measurement apparatuses and high voltage automated test equipment.
Innovation Solution
A solid state switch device is designed with a compensation circuit that includes a sense device and a current amplifier. The sense device generates a leakage current correlated with the switch component's leakage current, and the current amplifier produces an estimated leakage current to be injected back into the switch component, effectively compensating for the leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid state switch device is used, then switching functionality is provided, but current leakage occurs due to non-idealities
Solution Approach 1:
The patent uses a sense device to measure the leakage current generated by the switch component, then feeds back a compensating current through a current amplifier to cancel out the harmful leakage effect, converting the harmful leakage into a measurable and compensatable parameter
Solution Approach 2:
The patent implements a feedback mechanism where the sense device continuously monitors the leakage current, and the current amplifier adjusts the compensating current based on the measured leakage, creating a closed-loop system that dynamically compensates for leakage variations
2Measurement precision
If leakage compensation is implemented, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent creates a simplified copy of the switch component's leakage characteristics using a sense device that replicates the leakage behavior, allowing the leakage to be measured and compensated without directly modifying the main switch component
Solution Approach 2:
The sense device acts as an intermediary between the switch component and the compensation mechanism, measuring the leakage current and enabling the current amplifier to generate the appropriate compensating current without direct interaction between the switch and compensation elements
3Object-generated harmful factors
If a sense device and current amplifier are added, then leakage compensation is achieved, but area efficiency is reduced
Solution Approach 1:
The patent scales the sense device parameters (size, capacitance, etc.) to match the switch component's characteristics, allowing the sense device to be smaller than the full switch while still accurately representing its leakage behavior, thus reducing the area overhead of the compensation circuit
Data Source
AI summary
A new MOS based switch for use in/with high voltage precision instruments is provided. The switch can enable leakage compensation. The switch can comprise a MOS device and a compensation circuit coupled to the MOS device to replicate and compensate for the MOS device leakage, such that the switch appears not to leak current. The compensation circuit may comprise a sense device which acts as a scaled replica of the MOS device being compensated. The sense device's leakage current can then be measured, reproduced at the scale factor, and injected back to the drain terminal of the MOS device.