Switching circuits for differential amplifiers

Abstract

In a differential amplifier comprising first and second transistors of one conductivity type and having emitter electrodes commonly connected, a switching circuit is provided which includes third and fourth transistors of the opposite conductivity type. A switching signal is applied to the base electrodes of the third and fourth transistors, the emitter electrodes thereof are connected to the collector electrodes of the first and second transistors, and the collector electrodes of the third and fourth transistors are connected to the commonly connected emitter electrodes of the first and second transistors. A fifth transistor acting as a constant current source is connected to the commonly connected emitter electrodes of the first and second transistors. In a modified embodiment a sixth transistor is connected in parallel with the fifth transistor to prevent saturation of the third and fourth transistors acting as the switching transistors.

Dependencies are inferred from the claim text.