| 摘要 |
PURPOSE:To fix a voltage to be applied to an input stage when an IC is to be constituted by connecting a signal input terminal to a circuit consisting of two transistors constituting the input stage and an inverter by a method wherein a voltage setting circuit using transistors is provided in parallel between the input terminal and a gate of the transistor on one side. CONSTITUTION:The depletion type MOS transistor 1 and the enhancement type MOS transistor 2 are connected in series between a high potential electric power source VC and a low potential electric power source VS to constitute the input stage, and the inverter 3 is connected to the node between a gate of the transistor 1 and the transistor 2. Then the signal input terminal 4 is connected to a gate of the transistor 2 through a protective resistor 5 to constitute the IC. At this constitution, the depletion type element 9, the enhancement type element 17 connected through a capacitor 10, and the voltage setting circuit 16 containing enhancement type elements 11-15 are connected in parallel to those nodes, and even when an abnormal voltage is applied to the terminal 4, the input stage is held at a fixed voltage. |
