Driving and Sensing Design of an Enhancement-Mode-GaN Phaseleg as a Building Block

摘要

The approach of integrating a GaN phaseleg,rncurrent-boost drivers, and decoupling capacitors canrnsignificantly minimize the power loop inductance and the gaternloop inductance. However, the driving scheme and sensingrnscheme are still critical and challenging in order to survive thernhighly noisy environment due to the GaN switching. A drivingrnscheme of digital isolator plus isolated power supply is used forrnboth switches of the phaseleg. To suppress the noisernpropagated to the PWM generating board, a common-modernchoke and two Y-capacitors are used. A GaN boost converterrnproved the reduction of noise current through the PWMrncables. For the sensing circuit design, filtering is necessary forrnall the sensors. Even with the filters, it turns out that only thernDC current sensor can be placed with the phaseleg while thernDC voltage sensor and AC current sensor have to stay awayrnfrom the high dv/dt and di/dt nodes.