Semiconductor device

Abstract

Abstract PURPOSE:To ensure the sufficient protective effect by inserting new MOSFET between the input terminal and the MOSFET to be protected and controlling the bias voltage to be applied to the MOSFET in order to prescribe the gate voltage of the FET to be protected. CONSTITUTION:The input protective device is constituted as follows: input terminal IN2 is connected via resistance R2 to gate 15 of P-channel MOSFET element Q22 to be protected. In this case, P-channel MOSFET element Q11 is inserted newly between R2 and gate 15. Drain 12 of Q11, source 14 and gate 13 are connected to R2, gate 15 of Q22 and bias voltage VG respectively. Here, voltage VG is prescribed so that the voltage applied to gate 15 of Q22 may be under 30V in terms of the absolute value. For this purpose, the film thickness of the gate of Q11 is selected to prevent application of the abnormal voltage to gate 15 of Q22.

Inventors

• 👤 Koichiro Okumura
• 👤 Tsutomu Iima

Bibliographic Details