Switching device with negative bias circuit
View Patent ↗Embodiments provide a switching device including one or more field-effect transistors (FETs). In embodiments, a negative bias circuit is configured to generate a negative voltage signal based on a radio frequency (RF) signal applied to the circuit. When the FET is in an off state, the negative voltage signal is provided to a gate terminal of the FET.
1. A switching device comprising:
a field-effect transistor (FET) including a gate terminal;
a negative bias circuit configured to generate a negative voltage signal at an output terminal of the negative bias circuit based on a radio frequency (RF) signal applied to the switching device; and
a decoder circuit coupled with the output terminal of the negative bias circuit and the gate terminal, the decoder circuit configured to couple the output terminal of the negative bias circuit with the gate terminal when the FET is in an off state.
2. The switching device of claim 1 , wherein the FET is an n-type FET.
3. The switching device of claim 1 , wherein the negative bias circuit includes an input terminal configured to receive the RF signal applied to the switching device and a rectifier circuit coupled between the input terminal and the output terminal.
4. The switching device of claim 3 , wherein the rectifier circuit includes a first half-wave rectifier branch and a second half-wave rectifier branch, the first and second half-wave rectifier branches having opposite polarities.
5. The switching device of claim 4 , wherein the first half-wave rectifier branch includes a diode-connected FET.
6. The switching device of claim 5 , wherein the second half-wave rectifier branch includes a plurality of diode-connected FETs.
7. The switching device of claim 5 , wherein the first half-wave rectifier branch includes a resistor coupled between the input terminal and the diode-connected FET.
8. The switching device of claim 4 , wherein the negative bias circuit includes a capacitor coupled between the input terminal and the first half-wave rectifier branch.
9. The switching device of claim 1 , wherein the FET includes a body terminal and the output terminal of the negative bias circuit is coupled to the body terminal when the FET is in an off state.
10. The switching device of claim 1 , wherein the FET is a first FET including a source terminal and the switching device further comprises:
a second FET including a gate terminal and a drain terminal, the drain terminal of the second FET coupled with the source terminal of the first FET;
wherein the output terminal of the negative bias circuit is coupled with the gate terminal of the second FET when the first FET is in an off state.
11. The switching device of claim 1 , wherein the FET is a first FET including a source terminal and the switching device further comprises:
a second FET including a source terminal, a gate terminal, and a drain terminal, wherein the drain terminal of the second FET is coupled with the source terminal of the first FET, the source terminal of the second FET is coupled with ground, and the output terminal of the negative bias circuit is not coupled with the gate terminal of the second FET when the first FET is in an off state.
12. The switching device of claim 1 , wherein the FET is a first FET including a drain terminal and the switching device further comprises:
a second FET including a gate terminal and a drain terminal, the drain terminal of the second FET is coupled with the drain terminal of the first FET;
wherein the output terminal of the negative bias circuit is not coupled with the gate terminal of the second FET when the first FET is in an off state.
13. The switching device of claim 1 , wherein the switching device comprises a silicon-on-insulator (SOI) circuit.
14. A wireless communication device comprising:
a transceiver;
an antenna; and
a radio frequency (RF) front-end coupled with the transceiver and the antenna and configured to communicate signals between the transceiver and the antenna, the RF front-end including a silicon-on-insulator (SOI) switching device that has:
a field-effect transistor (FET) including a gate terminal;
a negative bias circuit configured to generate a negative voltage signal at an output terminal based on a radio frequency (RF) signal applied to the switching device; and
a decoder circuit coupled with the output terminal of the negative bias circuit and the gate terminal, the decoder circuit configured to couple the output terminal of the negative bias circuit with the gate terminal when the FET is in an off state.
15. The wireless communication device of claim 14 , wherein the negative bias circuit includes an input terminal configured to receive the RF signal applied to the switching device and a rectifier circuit coupled between the input terminal and the output terminal.
16. The wireless communication device of claim 15 , wherein the rectifier circuit includes a first half-wave rectifier branch and a second half-wave rectifier branch, the first and second half-wave rectifier branches having opposite polarities.
17. The wireless communication device of claim 16 , wherein the first half-wave rectifier branch includes a plurality of diode-connected FETs.
18. The wireless communication device of claim 14 , wherein the FET includes a body terminal and the output terminal of the negative bias circuit is coupled to the body terminal when the FET is in an off state.
19. A method comprising:
generating, with a negative bias circuit, a negative voltage signal at an output terminal of the negative bias circuit based on a radio frequency (RF) signal applied to a switching device including a field-effect transistor (FET);
receiving, at a decoder circuit, a control signal indicating that the FET is to be in an off state; and
coupling, by the decoder circuit, the output terminal of the negative bias circuit with a gate terminal of the FET to provide the negative voltage signal to the gate terminal.
20. The method of claim 19 , further comprising:
providing the negative voltage signal to a body terminal of the FET when the FET is to be in the off state.
21. The method of claim 19 , further comprising:
receiving, at the decoder circuit, a control signal indicating that the FET is to be in an on state; and
in response to receiving the control signal indicating that the FET is to be in the on state, decoupling, with the decoder circuit, the output terminal of the negative bias circuit from the gate terminal of the FET.
22. The method of claim 21 , further comprising:
in response to receiving the control signal indicating that the FET is to be in the on state, coupling, by the decoder circuit, the output terminal of the negative bias circuit with a gate terminal of a shunt FET to provide the negative voltage signal to the gate terminal of the shunt FET;
wherein a drain terminal of the shunt FET is coupled with a source terminal of the FET, and a source terminal of the shunt FET is coupled with ground.