10.8. Power to the Gates 145
10.8. Power to the Gates
Many arrangements have been used to provide the required gate drive
power. Low-voltage circuits can use a pulse transformer driven by a
fast-rising voltage with a lower voltage sustaining signal to provide
direct gate drive. The pulse transformer design must be a compromise
between pulse rise time and the sustaining current level. Alternatively,
the pulse transformer can be driven by a high-frequency pulse train,
each cycle of which has a high-level, fast-rising initial current. The
duty cycle on the pulse train should not be less than 50% for most
applications. It is difficult to provide the required rise time and sustain
current when sufficient insulation is used to operate a high-voltage
pulse transformer ...