Bias circuit and method for a high-voltage RF switch

• US 10,680,605 B2
• Filed: 02/28/2018
• Issued: 06/09/2020
• Est. Priority Date: 02/28/2018
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Schleicher, Bernd, Bauder, Ruediger, Kehrer, Daniel, Solomko, Valentyn
• Primary Examiner(s): Shiue, Dong-Chang
• Application Number:
  US15/908,087
• Publication Number:
  US 20190267990A1
• Time in Patent Office: 832 Days
• CPC Class Codes: H01P 1/15 by semiconductor devices
• CPC Class Codes: H03K 17/102 in field-effect transistor switches
• CPC Class Codes: H03K 17/6871 the output circuit comprising more than one controlled field-effect transistor
• CPC Class Codes: H03K 17/693 Switching arrangements with several input- or output-terminals, e.g. multiplexers, distributors logic circuits H03K19/00; code converters H03M5/00, H03M7/00
• CPC Class Codes: H04B 1/40 Circuits

Abstract

An RF switch includes series-coupled RF switch cells coupled between an RF input and ground, each RF switch cell having an input, and a biasing network having outputs for individually biasing each of the RF switch cell inputs to a distinct bias voltage based upon a rank number of the RF switch cell.

Claims

1. An RF switch comprising:

a plurality of series-coupled RF switch cells coupled between an RF input and ground, each RF switch cell having an input; and

a biasing network having a plurality of outputs configured for individually biasing each of the RF switch cell inputs to a distinct bias voltage based upon a rank number of the RF switch cell,

wherein each RF switch cell comprises a first current node and a second current node, wherein the first current node of a first RF switch cell is coupled to the RF input, and wherein the second current node of a last RF switch is coupled to ground, and

wherein the biasing network further comprises a switch configured for biasing the RF switch cell inputs to the distinct negative bias voltages based upon the rank number of the RF switch cell in an off mode of operation of the plurality of series-coupled RF switch cells, and for biasing the RF switch cell inputs to an equal positive bias voltage in an on mode of operation of the plurality of series-coupled RF switch cells, and wherein the distinct negative bias voltages comprise a plurality of different voltage values in the off mode and the equal positive bias voltage comprises a single voltage value in the on mode.

2. The RF switch of claim 1, wherein the distinct bias voltages range from a first voltage associated with a first RF switch cell of the plurality of series-coupled RF switch cells to a second voltage associated with a last RF switch cell of the plurality of series-coupled RF switch cells and different from the first voltage.

3. The RF switch of claim 2, wherein the distinct bias voltages range linearly from the first voltage to the second voltage.

4. The RF switch of claim 1, wherein each RF switch cell of the plurality of series-coupled RF switch cells comprises a transistor having a control node forming the input of the RF switch cell.

5. The RF switch of claim 4, wherein each RF switch cell of the plurality of series-coupled RF switch cells further comprises a resistor and a capacitor coupled across the first and second current nodes of the transistor.

6. The RF switch of claim 1, further comprising a power detector configured for adjusting the distinct bias voltages.

7. An RF switch comprising:

a plurality of series-coupled RF switch cells coupled between a first RF input and a second RF input, each RF switch cell having an input; and

a biasing network having a plurality of outputs configured for individually biasing each of the RF switch cell inputs to a distinct bias voltage based upon a rank number of the RF switch cell,

wherein each RF switch cell comprises a first current node and a second current node, wherein the first current node of a first RF switch cell is coupled to the first RF input, and wherein the second current node of a last RF switch is coupled to the second RF input, and

wherein the biasing network further comprises a switch configured for biasing the RF switch cell inputs to the distinct negative bias voltages based upon the rank number of the RF switch cell in an off mode of operation of the plurality of series-coupled RF switch cells, and for biasing the RF switch cell inputs to an equal positive bias voltage in an on mode of operation of the plurality of series-coupled RF switch cells, and wherein the distinct negative bias voltages comprise a plurality of different voltage values in the off mode and the equal positive bias voltage comprises a single voltage value in the on mode.

8. The RF switch of claim 7, wherein the distinct bias voltages range from a first voltage associated with a first RF switch cell of the plurality of series-coupled RF switch cells to a second voltage associated with an intermediate RF switch cell of the plurality of series-coupled RF switch cells and different from the first voltage, and from a third voltage associated with a last RF switch cell of the plurality of series-coupled RF switch cells and different from the second voltage to the second voltage associated with the intermediate RF switch cell.

9. The RF switch of claim 8, wherein the distinct bias voltages range linearly from the first voltage to the second voltage, and from the third voltage to the second voltage.

10. The RF switch of claim 7, wherein each RF switch cell of the plurality of series-coupled RF switch cells comprises a transistor having a control node forming the input of the RF switch cell.

11. The RF switch of claim 10, wherein each RF switch cell of the plurality of series-coupled RF switch cells further comprises a resistor and a capacitor coupled across the first and second current nodes of the transistor.

12. The RF switch of claim 7, further comprising a power detector configured for adjusting the distinct bias voltages.

13. A method of operating an RF switch comprising a plurality of serially coupled RF switch cells, wherein each RF switch comprises first and second current nodes and an input node, wherein the first current node of a first RF switch is coupled to a first RF input, and wherein the second current node of a second RF switch is coupled to a second RF input or ground, the method comprising individually biasing each input node of the RF switch cells to a distinct negative bias voltage based upon a rank number of the RF switch cell in an off mode of operation of the plurality of serially coupled RF switch cells, and biasing each input node of the RF switch cells to an equal positive bias voltage in an on mode of operation of the plurality of serially coupled RF switch cells, such that each RF switch cell has a unique and different bias voltage value in the off mode of operation, and each RF switch has a same bias voltage value in the on mode of operation.

14. The method of claim 13, wherein the distinct bias voltages vary between a first voltage and a second voltage in at least a portion of the RF switch.

15. The method of claim 14, wherein the distinct bias voltages vary linearly between the first voltage and the second voltage.

16. The method of claim 13, further comprising monitoring an internal node of the RF switch to provide a monitored output voltage.

17. The method of claim 16, further comprising adjusting the distinct bias voltages in response to the monitored output voltage.

18. An RF switch comprising:

a plurality of series-coupled RF switch cells coupled between an RF input and ground, each RF switch cell having an input; and

a biasing network having a plurality of outputs configured for individually biasing each of the RF switch cell inputs to a distinct bias voltage based upon a rank number of the RF switch cell,

wherein the biasing network further comprises a switch configured for biasing the RF switch cell inputs to the distinct negative bias voltages based upon the rank number of the RF switch cell in an off mode of operation of the plurality of series-coupled RF switch cells, and for biasing the RF switch cell inputs to an equal positive bias voltage in an on mode of operation of the plurality of series-coupled RF switch cells, and wherein the distinct negative bias voltages comprise a plurality of different voltage values in the off mode and the equal positive bias voltage comprises a single voltage value in the on mode.