| 摘要 |
PURPOSE:To normally operate a switching circuit and to make a current across an integrated circuit become below a holding current and to enable an automatic return from a latch-up state, by detecting a drop due to the latch-up in a power voltage and interrupting supply of the power voltage to the integrated circuit for a prescribed time and forming a power voltage drop detection circuit and the switching circuit on an insulating layer of the same substrate as the integrated circuit. CONSTITUTION:Transistors 3 and 4, resistors 5 and 6, a capacitor 7, and a diode 8 in addition to a CMOS circuit 2 are formed on a silicon oxidizing film formed on a silicon substrate. When some noise causes the CMOS circuit 2 to be latched up and a large current flows across the CMOS circuit 2, a potential on a power source line 9 is lowered and the transistor 3 is turned on, so that the power voltage VCC is applied to the capacitor 7. Subsequently a potential on a gate terminal of the transistor 4 is temporarily raised to turn off the transistor 4. Thus the power source line 9 of the CMOS circuit 2 is interrupted from the power voltage VDD so that the latch-up can be avoided. |
