Power Device Threshold Voltage Sensing Without Parasitic Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional methods for detecting threshold voltage shifts in power devices are intrusive and prone to inaccuracies, making it difficult to monitor device health and anticipate failures effectively.
Innovation Solution
A method for in situ determination of threshold voltage using calibrated currents and gate pulses to measure the voltage across power devices, allowing for precise detection of threshold voltage shifts and incipient faults by comparing against stored values, while ensuring the device is in a safe 'off' state to minimize parasitic leakage and accurately account for temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods are used to detect threshold voltage shifts across terminals when the power device is in an ON state, then threshold voltage changes can be detected, but the measurement becomes intrusive and suffers from inaccuracies due to parasitic leakage
Solution Approach 1:
The patent applies preliminary action by performing the threshold voltage measurement before the power device is activated to its normal operating state. The method measures the voltage across the device terminals while it is in an off state, before parasitic leakage currents can develop. This preliminary measurement approach eliminates the harmful effect of parasitic leakage that plagues traditional in-operando measurement methods, thereby achieving high measurement precision without accuracy degradation.
2Reliability
If traditional intrusive methods are used to monitor power device health, then threshold voltage shifts can be detected, but the monitoring process introduces measurement errors and device stress
Solution Approach 1:
The patent employs an intermediary approach by introducing a measurement current that flows through the power device in a controlled manner during the measurement process. This measurement current acts as an intermediary signal that enables voltage detection across the device terminals without requiring the device to be in its normal high-power on state. The intermediary measurement current allows for accurate threshold voltage detection while minimizing device stress and avoiding the intrusive effects of traditional monitoring methods.
3Productivity
If the power device is monitored in its normal operating state, then real-time health assessment is possible, but parasitic leakage currents cause measurement inaccuracies
Solution Approach 1:
The patent implements periodic action by performing threshold voltage measurements at scheduled intervals rather than continuously during normal operation. The system periodically interrupts the normal operation to conduct brief measurement cycles where a measurement current is applied and voltage is sampled. This periodic measurement approach enables real-time health assessment over the device lifetime while ensuring that each individual measurement is performed under controlled conditions free from parasitic leakage contamination.
Data Source
AI summary
A method for in situ threshold voltage determination of a semiconductor device includes sourcing a current to a first terminal of the semiconductor device. A gate terminal of the semiconductor device is driven with a plurality of gate levels. Each gate level includes one of a plurality of different gate voltages. A transistor voltage is measured between the first terminal and a second terminal of the semiconductor device during each gate level. The respective gate voltage is stored in response to the semiconductor device voltage transitioning past a voltage limit. A temperature dependent threshold voltage of the semiconductor device is estimated for a first measured temperature measured during the storing of the stored gate voltage from a previously stored gate voltage and a second measure temperature.