Method and apparatus including a driver for driving a floating bipolar switch

A switch comprising:

• an operational amplifier having a pair of inputs and an output;
• a bipolar transistor switchably coupling and uncoupling a signal source to/from one of the pair of inputs of the operational amplifier 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 Vcm−ΔVREB nor greater than Vcm+ΔVBE where Vcm is a common mode voltage at an emitter of the bipolar transistor and ΔVREB and ΔVBE 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.

A switch, comprising:

• an op amp having a pair of inputs and an output;
• a resistor coupled in a feedback loop from the output of the op amp to a selected one of the inputs of the op amp;
• a bipolar transistor coupled in series with the resistor in the feedback loop to switchably couple and uncouple the feedback loop 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 Vcm−ΔVREB nor greater than Vcm+ΔVBE where Vcm is a common mode voltage at an emitter of the bipolar transistor and ΔVREB and ΔVBE 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 “On” state and by coupling the output terminal to the voltage sink in the “Off” state.