Patent ID: 7659755

Claim:
A circuit for switchably coupling a signal source to an amplifier comprising: a bipolar transistor configured to switchably couple the signal source to the high impedance load responsive to a driver signal applied to a base thereof; and a floating switch driver having a control input and an output terminal coupled to the base of the bipolar transistor to supply the driver signal comprising a limited forward current during a first state of the floating switch driver outputting a high logic level driver signal and during a second state of the floating switch driver outputting a low logic level driver signal having a voltage “Voff” not less than V cm −ΔV REB nor greater than V cm +ΔV BE where Vcm is a common mode voltage at an emitter of the bipolar transistor and ΔV REB and ΔV BE are a reverse breakdown voltage and a forward voltage drop respectively, across a base-emitter connection of the bipolar transistor and wherein the floating switch driver further comprises; a switchable current buffer coupled between a non-zero voltage source “Vcc” and a voltage sink having the fixed non-zero voltage “Voff”, to supply the driver signal at the output terminal by uncoupling the output terminal from the voltage sink in the first state and by coupling the output terminal to the voltage sink in the second state.