Patent ID: 9001481
Filing Date: 2015-04-07
Classification: H02H,H03K

Abstract:
1. A protection circuit for preventing application of voltage in a reverse direction to a circuit unit having a predetermined function, comprising: a power supply terminal; a ground terminal; and first to third transistors, wherein: the first transistor has one of a source and a drain connected to the power supply terminal and a gate connected to the ground terminal and has the other one of the source and drain connected to a first region including a region where a channel is to be formed in the first transistor; the second transistor has one of a source and a drain connected to a second region including a region where a channel is to be formed in the second transistor and the other one of the source and drain of the first transistor, a gate connected to the power supply terminal, the other one of the source and drain connected to the ground terminal; the third transistor has one of a source and a drain connected to the power supply terminal, a gate connected to the ground terminal, the other one of the source and drain connected to the ground terminal through the circuit unit; and the first region and the second region are integrally formed and are connected to a third region including a region where a channel is formed in the third transistor.