| 摘要 |
PURPOSE:To prevent the adverse influence to a protecting device when negatively excessive noise voltage is applied to an input terminnal by connecting the isolation region of the diffused resistor of the device to a low voltage source via the resistor. CONSTITUTION:A diffused resistor 12 is connected between an input terminal IN and a C-MOS inverter 10, and a diode is connected between the input terminal of the inverter 10 and high and low voltage sources VCC, VSS. Further, a resistor 45 is connected between the isolation region of the resistor 12 and the low voltage source VSS. When the resistor 45 is thus provided, even if negatively excessive noise voltage is applied to the input terminal, the current flowing through the source VSS, resistor 12 and input terminal IN is limited. Accordingly, the burnout due to overcurrent can be prevented. |
