Self-isolation NMOS-DMOS technology for automotive low-side switches

A self-isolation NMOS-DMOS technology has been developed and successfully applied to an automotive intelligent power MOSFET low-side switch. Though self-isolation technology provides a cost-effective approach for intelligent power switches (IPSs), there are strict limitations for usable device structures and device connections. The limitations are tightest in the case of low-side IPSs. To overcome these limitations, an over-temperature detection circuit, a current limiting circuit, a dynamic clamping circuit, and an electrostatic surge protection method have been developed for self-isolation low-side IPSs. The principles of these circuits and experimental results are presented together with an outline of self-isolation NMOS-DMOS technology. The applicability of self-isolation NMOS-DMOS technology to high voltage and/or IGBT (insulated-gate bipolar transistor) type IPSs is also demonstrated