Structure of 600 V IC and a new voltage sensing device

A novel high-voltage isolation structure which has a 600-V breakdown voltage has been developed. This structure realizes improved stability of the breakdown voltage by combining reduced surface field (RESURF) technology with a multiple floating field plate (MFFP) and an n ⁺/n^- buried layer. A high-voltage n-ch MOSFET was realized by combining a lateral DMOS structure with the high-voltage isolation structure. A high-voltage p-ch MOSFET was realized by combining the offset gate using the polysilicon layer of the MFFP. A novel voltage sensing device was constructed by the addition of a p-type floating layer to the high-voltage isolation structure. Its output voltage is automatically restricted within the logic power supply level