Patent ID: 7084694
Filing Date: 2006-08-01
Classification: H03K

Abstract:
1. A switching circuit for controllably switching a high-bitrate bipolar input signal from an input to an output, said circuit comprising: a constant current source comprising a first metal oxide semiconductor field effect transistor; first and second emitter-coupled bipolar transistors transferring the input signal from said input to said output, emitters of said first and second transistors being coupled to a drain of said first metal oxide semiconductor field effect transistor of said constant current source; at least a second metal oxide semiconductor field effect transistor for activating or deactivating said constant current source under the control of at least one control signal; and a resistor voltage divider circuit coupled to collectors of said first and second bipolar transistors, the constant current source being accurately controlled by a voltage difference between a potential drop at the resistor voltage divider circuit and a constant reference voltage, whereby the resistor voltage divider circuit defines a potential of logical levels in the output signal.