Patent ID: 9646965
Date: 2017-05-09
CPC Classifications: H01L,H02M,Y02B

Claim:
1. An integrated semiconductor transistor chip for use in a buck converter, comprising: a high side transistor formed on the integrated semiconductor transistor chip and comprising a laterally diffused metal oxide semiconductor (LDMOS) transistor; a low side transistor formed on the integrated semiconductor transistor chip and comprising a source down metal oxide semiconductor field effect transistor (MOSFET); a substrate of the integrated semiconductor transistor chip for use as a source for the low side transistor; and an n-doped well for isolation of the high side transistor from the source of the low side transistor and a p-doped well formed within the n-doped well for further isolation, the n-doped well being kept at a switch node potential; and a p-doped well that is formed between the n-doped well and a high side drain LDD region for disrupting a parasitic p-n-p transistor that would otherwise be formed between the substrate (p), n-well (n), and a high side body region (p); further comprising a metal layer formed in the integrated semiconductor transistor chip to electrically connect a drain of the low side transistor to the source of the high side transistor.