Patent ID: 8593770
Filing Date: 2013-11-26
Classification: H01L

Abstract:
1. A protection circuit comprising: a first diode arranged such that an anode thereof is connected to a terminal to be protected; a first transistor configured as an N-channel MOSFET, and arranged such that one terminal of a conduction channel thereof is connected to a cathode of the first diode, and the other terminal of the conduction channel thereof, a gate thereof, and a back gate thereof, are connected to a fixed voltage terminal, and a protection resistor arranged between a ground terminal and a region of the well in which the second transistor and the second diode are formed, with the aforementioned region being closer to the second diode side than it is to the isolation region wherein the first transistor is configured as a floating MOSFET formed within an N-type well formed in a P-type semiconductor substrate, wherein the first diode is formed within the shared N-type well in which the first transistor is formed, and wherein the cathode of the first diode and the aforementioned one terminal of the conduction channel of the first transistor are connected to the N-type well; wherein the second transistor and the second diode are formed such that they are isolated from one another.