High voltage recoverable input protection circuit and protection device

摘要

An input protection device for protecting an input including a first transistor of a first conductivity type having a pair of controlled electrodes serially connected between a first reference voltage and the input and a controlling electrode connected to the input. A second transistor of a second conductivity type has its controlled electrodes serially connected between a second reference voltage and the input. The controlling electrode of the second transistor is connected to a second reference voltage. A third transistor of the first conductivity type has its controlled electrodes serially connected between the first reference voltage and the input and its controlling electrode connected to the first reference voltage. Optionally, a resistor connects the second of the pair of controlled electrodes of the second transistor and the second of the pair of controlled electrodes of the third transistor to the input. A device for use in input protection is also provided where the gate electrode of the device is formed on a insulator film which is formed on a gate oxide layer. The gate oxide layer is formed in an active layer with regions of doped semiconductor material.