Tsutomu Matsushita

A surge-free intelligent power device specific to automotive high side switches

A novel type of intelligent power device (IPD), which is suitable for automotive monolithic high side switch with high current capability, is presented. An integration of a vertical-power DMOSFET and planar MOS IC devices is performed by the newly developed junction-isolation technique using only one epitaxial growth. The isolation voltage of 80 V has been obtained, which is large enough for automotive IPDs if they are protected against high voltage transients on the battery line. A rugged vertical DMOSFET (VDMOS) has also been developed for this IPD. It has a cellular Zener diode between its source and drain, which prevents the secondary breakdown of parasitic bipolar transistor, and the resulting avalanche capability enhancement is more than an order of magnitude. This VDMOS is used for both output power device and protection device for low-voltage MOS circuitry, which makes the IPD free from any transients in the automobile without the need for external protection. >