| 摘要 |
PURPOSE:To prevent a substrate potential from floating and transistor(TR) characteristics from varying owing to an increase in substrate current by connecting a TR in series of an output TR and connecting its gate to the source through another TR. CONSTITUTION:An enhancement TR 3 is connected in series to the power source side of output TRs 1 and 2. The TRs 1-3 are off at the time of writing, so an output terminal is in a high impedance state. At this time, if the potential at an output terminal Dout drops below the ground potential owing to an external noise and its value is larger than a threshold voltage, the TR 2 turns on and the potential at a contact A drops down to the same potential with the Dont. A TR 4 turns on earlier than the TR 3 because its threshold voltage is lower and its gate voltage is lowered according to the potential at the contact A, so the TR 3 is still off and no current flows from a power source. |
