| 摘要 |
A protection circuit is coupled between a low voltage signal processing semiconductor device subject to damage by high voltage transients, and a signal output terminal at which high voltage transients can appear. The protection circuit comprises a first transistor arranged as an emitter follower for normally conducting signals from the semiconductor device to the output terminal, and a second transistor of opposite conductivity type. The base and emitter electrodes of the first transistor are directly connected to the base and emitter electrodes of the second transistor, respectively, such that the second transistor is normally non-conductive. Transient currents associated with negative high voltage transients at the output terminal are diverted to a point of operating potential via the first transistor. The second transistor is rendered conductive in response to positive high voltage transients at the output terminal for diverting associated transient currents to a point of operating potential. |
