Parallel SiC MOSFET Gate Driving for Uniform Current Sharing
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Solution Overview
Problem
Semiconductor switches, particularly wide bandgap devices like SiC power transistors, experience nonuniform current distribution when operated in parallel, leading to device overload and failure due to small disparities in turn-on resistance and threshold voltage, especially at high switching frequencies and voltage levels.
Innovation Solution
The use of multiple driver circuits with adjustable power supplies and output resistors coupled to control terminals of parallel-connected semiconductor switches, including totem-pole amplifier circuits, to ensure uniform switching and current sharing among the devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple semiconductor switches are operated in parallel to increase current carrying capacity, then the current carrying capacity is improved, but nonuniform current distribution occurs due to parameter disparities leading to device overload and failure
Solution Approach 1:
The patent applies local quality by providing individual driver circuits with independently adjustable parameters (power supply voltage, output resistance) for each semiconductor switch in the parallel configuration. This allows each switch to be locally optimized to compensate for parameter disparities, ensuring uniform current distribution while maintaining high current carrying capacity. The independent adjustment capability enables each switch to operate under tailored conditions that account for manufacturing variations.
2Speed
If wide bandgap semiconductor switches are operated at high switching frequencies and voltage levels, then switching speed and power handling are improved, but current maldistribution becomes more acute due to parameter disparities
Solution Approach 1:
The patent implements dynamics by making the driver circuit parameters adjustable and adaptable. The power supply voltage and output resistance of each driver circuit can be dynamically tuned to compensate for parameter variations in wide bandgap switches operating at high frequencies and voltage levels. This dynamic adjustment capability ensures that current distribution remains uniform even under demanding operating conditions where parameter disparities have amplified effects.
Data Source
AI summary
An apparatus includes a plurality of parallel-connected semiconductor switches (e.g., silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs) or other wide-bandgap semiconductor switches) and a plurality of driver circuits having outputs configured to be coupled to control terminals of respective ones of the plurality of semiconductor switches and configured to drive the parallel-connected semiconductor switches responsive to a common switch state control signal. The driver circuits may have respective different power supplies, which may be adjustable. Respective output resistors may couple respective ones of the driver circuits to respective ones of the semiconductor switches. The output resistors may be adjustable.