RF sensor in stacked transistors

• US 10,250,251 B1
• Filed: 02/07/2018
• Issued: 04/02/2019
• Est. Priority Date: 02/07/2018
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Schleicher, Bernd, Bakalski, Winfried, Bauder, Ruediger, Solomko, Valentyn
• Primary Examiner(s): Skibinski, Thomas
• Application Number:
  US15/891,025
• Time in Patent Office: 419 Days
• Field of Search: 327382, 455 78, 455 73
• CPC Class Codes: H03K 17/161 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

Abstract

An RF switch includes series-coupled RF switch cells coupled between an RF input and ground, a transistor including a first current node coupled to a first load resistor, a second current node coupled to ground, and a control node coupled to an internal switch node, and a filter having an input coupled to the first current node of the first transistor and an output for providing a DC voltage corresponding to the RF power present at the internal switch node.

Claims

1. An RF switch comprising:

a plurality of series-coupled RF switch cells coupled between an RF input and ground;

a first transistor comprising a first current node coupled to a first load resistor, a second current node coupled to ground, and a control node coupled to a first internal switch node associated with one of the plurality of series-coupled RF switch cells; and

a first filter having an input coupled to the first current node of the first transistor and an output configured for providing a DC voltage corresponding to the RF power present at the first internal switch node.

2. The RF switch of claim 1, further comprising:

a second transistor comprising a first current node coupled to a second load resistor, a second current node coupled to ground, and a control node coupled to a second internal switch node;

a second filter having an input coupled to the first current node of the second transistor and an output configured for providing a DC voltage corresponding to the RF power present at the second internal switch node.

3. The RF switch of claim 1, wherein each of the RF switch cells comprises a transistor.

4. The RF switch of claim 3, wherein each of the RF switch cells further comprises a first resistor across the transistor.

5. The RF switch of claim 3, wherein each of the RF switch cells further comprises a second resistor coupled between an input signal source and a control node of the transistor.

6. The RF switch of claim 1, further comprising:

a reference branch; and

an operational amplifier having a first input coupled to the output of the first filter, a second input coupled to the reference branch, and an output configured for providing an amplified DC voltage corresponding to the RF power present at the first internal switch node.

7. The switch of claim 6, wherein the reference branch comprises:

a transistor having a first current node coupled to a load resistor, a second current node coupled to ground, and a control node coupled to ground through an input resistor; and

a filter having an input coupled to the first current node of the reference transistor and an output coupled to the second input of the operational amplifier.

8. A method of operating an RF switch comprising a plurality of serially coupled RF switch cells, the method comprising:

sensing a voltage at a first internal switch node associated with one of the plurality of serially coupled RF switch cells;

half-wave rectifying the sensed voltage; and

filtering the rectified voltage.

9. The method of claim 8, wherein filtering the rectified voltage further comprises providing a DC voltage corresponding to the RF power present at the first internal switch node.

10. The method of claim 8, further comprising:

sensing a voltage at a second internal switch node;

half-wave rectifying the sensed voltage; and

filtering the rectified voltage.

11. The method of claim 8, wherein filtering the rectified voltage further comprises providing a DC voltage corresponding to the RF power present at the second internal switch node.

12. The method of claim 8, further comprising:

sensing a plurality of voltages at a plurality of internal switch nodes;

half-wave rectifying the sensed voltages; and

filtering the rectified voltages.

13. The method of claim 8, wherein filtering the rectified voltages further comprises providing a linearity indication of the RF switch.