| 摘要 |
PURPOSE:To remove static charges intruding to a circuit from outisde efficiently, impedance between power supply lines thereof is high, and to prevent the breakdown of an element by connecting a protective circuit shortening a section between the power supply lines when potential difference between the power supply lines is larger than the operating voltage. CONSTITUTION:A P channel transistor 12 and an N channel transistor 13 are arranged in series, and an output 15 is lead out of a section between the transistors 12 and 13. In such an inverter 11, the voltage of VCC and VSS is each represented by 5V and 0V under the normal state of operation. A resistor R3 disposed between VCC and the inverter 11 prevents the sudden impact of the intrusion of static charges to the intrusion. When positive static charges are applied to a VCC pad, a transistor 16 is turned ON when voltage applied to the transistor 16 having approximately 10V threshold voltage is 10V or higher, and currents flow in the direction of the arrow and are absorbed to VSS. When positive static charges are applied to a VSS terminal, a transistor 17 having approximately 10V threshold voltage is turned ON when -V is 10V or higher, and currents flow in the direction of the arrow, and are absorbed to VCC. |
