Analog switch for transmitting high voltage signals without utilizing high voltage power supplies
Described herein are multiple designs for an improved analog switch for use in transmitting high voltage signals without using high voltage power supplies for the switch. The analog switches are able to pass and block input signals in the approximate range of −100 V to +100 V. The use of translinear loops and a bootstrap configuration results in a constant on-resistance of the symmetrical switches and matches the conductance of each analog switch to the transconductance of an NMOS transistor, which can be easily stabilized with a constant g m biasing scheme. In certain embodiments, a shunt termination (T-switch) configuration is used for better off-isolation, and each of the symmetrical switches has its own translinear loop and thus flexibility of on-resistance and termination voltage.
1. An analog switch, comprising:
a first circuit;
a second circuit;
the first circuit comprising a first translinear loop and one or more control nodes for receiving a control signal and an input node for receiving a high voltage input signal;
the second circuit comprising a second translinear loop and one or more control nodes for receiving the control signal and an output node for presenting the high voltage input signal when the control signal is at a first voltage and for blocking the high voltage input signal when the control signal is at a second voltage; and
a shunt circuit connected to a node shared by the first circuit and the second circuit, wherein the shunt circuit is connected to a power supply that supplies a voltage with an absolute value less than or equal to the absolute value of the voltage of the high voltage input signal.
2. The analog switch of claim 1 , wherein the high voltage input signal ranges between +100 volts and −100 volts.
3. The analog switch of claim 1 , wherein the first circuit and second circuit are symmetrical.
4. The analog switch of claim 1 , wherein the first circuit comprises a first set of transistors connected in series and the second circuit comprises a second set of transistors connected in series, the first set of transistors and the second set of transistors connected in series.
5. The analog switch of claim 4 , wherein the input node is located at one end of the first set of transistors and the output node is located at one end of the second set of transistors.