Fast LIGBT switching due to plasma confinement through pulse width control

The authors have examined the initial turn-on dynamics of the LIGBT (lateral insulated gate bipolar transistor) and shown through data and simulations that the LIGBT achieves effective conductivity modulation within approximately 200 ns of turn-on. At this time, the parasitic vertical PNP is saturated and the on-voltage has virtually reached a minimum. Beyond 200 ns, it is shown that only a marginal improvement in the on-voltage is obtained and at substantial cost in terms of switching speed. This observation was exploited by implementing a constant on-time PWM up-converter operating with 94% efficiency at 200 kHz. This demonstrated viable LIGBT operation at a frequency well above the range that conventional wisdom suggests.<
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