Radio frequency switch device with source-follower

• US 9,203,396 B1
• Filed: 02/22/2013
• Issued: 12/01/2015
• Est. Priority Date: 02/22/2013
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: TriQuint Semiconductor Incorporated (Qorvo, Inc.)
• Inventors: Clausen, William J., Furino, James P. Jr.
• Primary Examiner(s): LE, THANH C
• Application Number:
  US13/774,928
• Time in Patent Office: 1,012 Days
• Field of Search: 455/78, 455/80, 455/82, 455/83, 455/550.1, 455/575.1, 333/103, 333/104, 327/537, 327/427, 327/434, 327/436
• US Class Current: 1/1
• CPC Class Codes: H03K 17/161 in field-effect transistor switches

Abstract

Embodiments provide a switching device including one or more cells. In embodiments, a cell may include a switch field-effect transistor (FET) and a source-follower FET, coupled between a gate and a body of the switch FET. Other embodiments may be described and claimed.

Claims

1. A circuit configured to switch a radio-frequency (“

RF”

) signal, the circuit comprising;

a switch field-effect transistor (“

FET”

) including a source terminal, a gate terminal, a drain terminal, and a body terminal; and

a source-follower FET coupled with and between the gate terminal and the body terminal, the source-follower FET configured to provide a negative bias voltage to the body terminal when the switch FET is off.

2. The circuit of claim 1, wherein the source-follower FET includes:

a source terminal coupled with the body terminal of the switch FET;

a gate terminal coupled with the gate terminal of the switch FET; and

a drain terminal coupled with a voltage source.

3. The circuit of claim 2, wherein the drain terminal of the source-follower FET is coupled with the voltage source through a first resistor.

4. The circuit of claim 3, wherein the gate terminals of the switch FET and the source-follower FET are further coupled with the voltage source through a second resistor.

5. The circuit of claim 1, wherein the source-follower FET is further configured to allow the body terminal to forward bias limit when the switch FET is on.

6. The circuit of claim 1, wherein the source-follower FET is configured to provide a low impedance when the switch FET is off to provide the negative bias voltage to the body terminal.

7. The circuit of claim 1, wherein the source-follower FET is configured to provide a high impedance to the body terminal when the switch FET is on.

8. The circuit of claim 1, further comprising:

a plurality of FETs, including the switch FET, coupled in series with one another.

9. The circuit of claim 1, wherein the switch FET is an n-channel FET and the source-follower FET is a p-channel FET.

10. The circuit of claim 1, wherein the circuit comprises a silicon-on-insulator (“

SOI”

) circuit.

11. 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 radio frequency front-end including a silicon-on-insulator switch device that has;

a decoder configured to set individual switch field-effect transistors (“

FETs”

) in an off state or an on state; and

a cell with a switch field-effect transistor (“

FET”

) of the plurality of switch FETs and a source-follower FET, wherein the source-follower FET is coupled with and between a gate and a body of the switch FET of the cell and is configured to provide a negative body bias voltage to the body when the switch FET of the cell is in an off-state.

12. The wireless communication device of claim 11, wherein the source-follower FET includes:

a source coupled with the body of the switch FET;

a gate coupled with the gate of the switch FET; and

a drain coupled with the decoder.

13. The wireless communication device of claim 12, wherein the drain of the source-follower FET is coupled with the decoder through a first resistor.

14. The wireless communication device of claim 13, wherein the gates of the switch FET and the source-follower FET are further coupled with the decoder through a second resistor.

15. The wireless communication device of claim 11, wherein the switch FET is an n-channel FET and the source-follower FET is a p-channel FET.

16. The wireless communication device of claim 11, wherein switching device comprises a silicon-on-insulator (“

SOI”

) circuit.

17. A method comprising:

controlling, with a decoder circuit, a switch field-effect transistor (“

FET”

) to be in an off state; and

providing, with a source-follower FET coupled between a gate and body of the switch FET, a negative bias voltage to the body while the switch FET is in the off state.

18. The method of claim 17, wherein the source-follower FET is a p-channel FET and the switch FET is an n-channel FET.

19. The method of claim 17, further comprising:

controlling, with the decoder circuit, the switch FET to be in an on state by providing a positive voltage at the gate of the switch FET; and

limiting forward biasing, with the source-follower FET, the body of the switch FET while the switch FET is in the on state.