| 摘要 |
PURPOSE:To suppress the occurrence of latch up in an internal circuit, by providing an attenuating means, which positively attenuates the noise voltage of the voltage in a peripheral power source system and supplies said voltage to an internal power source system. CONSTITUTION:A positive noise voltage is applied to a Vcc terminal 1. When the noise voltage exceeds a breakdown voltage of an N-channel MOSFET7, the FET7 is broken down and the noise voltage on a peripheral power source line 2 is attenuated. The noise component on the peripheral power source line 2 is attenuated by the voltage across a resistance component 8. A filter is constituted by the capacity between the drain and the gate of an N-channel MOSFET9 and the resistance component 8. Thus, the potential fluctuation in the peripheral power source line 2 due to the noise voltage, which is applied on the power source terminal 1, is sufficiently attenuated in an internal power source line 5. The latch-up voltage at the power source terminal is well improved. |
