GaN Output Transistor Degradation Detection by Off-State Current Integration
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Solution Overview
Problem
Existing technologies lack an effective method to readily detect the degradation state of GaN transistors used in power source circuits, which is crucial for reducing power consumption and preventing increased on-resistance.
Innovation Solution
A degradation detection device and method that integrate the output current of GaN transistors over a predetermined period when they transition from an on-state to an off-state, comparing this integral value with a predetermined threshold to determine the degradation state based on the on-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If GaN transistor is used as output transistor in power source circuit, then power consumption is reduced and withstanding voltage is increased, but degradation detection becomes difficult
Solution Approach 1:
The patent introduces a detection circuit as an intermediary component that measures the drain charge of the GaN transistor indirectly through integration of drain current. This mediator enables degradation detection without directly interfering with the transistor's primary function, resolving the contradiction between maintaining low power consumption and enabling effective degradation monitoring.
2Reliability
If on-resistance of output transistor increases, then degradation is indicated, but power consumption increases
Solution Approach 1:
The patent implements preliminary detection of degradation by continuously monitoring the drain charge and comparing it against threshold values before significant on-resistance increase occurs. This preliminary action allows for early intervention and replacement of transistors before they enter high-power consumption states, thus maintaining reliability while preventing excessive power consumption.
3Reliability
If degradation detection method is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the degradation detection function with the existing drive circuit by integrating the drain charge measurement and comparison logic into the same circuit block. This consolidation enables degradation detection without adding separate independent circuits, thus improving reliability while minimizing the increase in overall device complexity.
Data Source
AI summary
According to one embodiment, a degradation detection device includes a driving circuit that supplies a driving signal that controls on/off of an output transistor to the output transistor and an output circuit that compares a value of integral of an output current that is output by the output transistor in an off-state thereof over a predetermined period of time with a predetermined threshold when the output transistor is turned from an on-state thereof to an off-state thereof and outputs a signal that indicates a degradation state of the output transistor depending on a result of such comparison.