Programmable stabilization network

• US 9,160,376 B1
• Filed: 09/15/2014
• Issued: 10/13/2015
• Est. Priority Date: 09/15/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Scuderi, Antonino
• Primary Examiner(s): NEFF, MICHAEL R
• Application Number:
  US14/487,000
• Time in Patent Office: 393 Days
• Field of Search: 375/297, 375/296, 375/295
• US Class Current: 1/1
• CPC Class Codes: H03F 1/0222 by using a signal derived from the input signal
• CPC Class Codes: H03F 1/34 Negative-feedback-circuit arrangements with or without positive feedback H03F1/02 - H03F1/30, H03F1/38 - H03F1/50, H03F3/50 take precedence ; for rejection of common mode signals H03F3/45479
• CPC Class Codes: H03F 1/342 in field-effect transistor amplifiers
• CPC Class Codes: H03F 1/56 Modifications of input or output impedances, not otherwise provided for
• CPC Class Codes: H03F 2200/102 A non-specified detector of a signal envelope being used in an amplifying circuit
• CPC Class Codes: H03F 2200/144 the feedback circuit of the amplifier stage comprising a passive resistor and passive capacitor
• CPC Class Codes: H03F 2200/15 the supply or bias voltage or current at the drain side of a FET being continuously controlled by a controlling signal
• CPC Class Codes: H03F 2200/153 Feedback used to stabilise the amplifier
• CPC Class Codes: H03F 2200/156 One or more switches are realised in the feedback circuit of the amplifier stage
• CPC Class Codes: H03F 2200/222 A circuit being added at the input of an amplifier to adapt the input impedance of the amplifier
• CPC Class Codes: H03F 2200/387 A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier
• CPC Class Codes: H03F 2200/405 the output amplifying stage of an amplifier comprising more than three power stages
• CPC Class Codes: H03F 3/195 in integrated circuits
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 2001/0433 with linearisation using feedback

Abstract

The present disclosure includes programmable stabilization circuits and methods. In one embodiment, a power amplifier in a wireless transmitter includes a transistor comprising a gate, a source, and a drain. Feedback from the drain to the gate is modified dynamically to stabilize the amplifier under changing operating conditions. In one embodiment, a series RC circuit is configured between the drain the gate and the RC circuit value is adjusted based on different power supply voltage modes.

Claims

1. A wireless transmitter comprising:

a transistor comprising a source, a gate, and a drain, wherein the gate is coupled to an input signal to be transmitted, and wherein the drain is coupled to a power supply voltage and to an antenna, wherein the transistor is configured to amplify the input signal and produce an output signal;

a programmable feedback circuit having an input terminal coupled to the drain, an output terminal coupled to the gate, and a control input, wherein the programmable feedback circuit adjusts a series resistor and capacitor (RC) circuit between the gate and the drain of the transistor based on a control signal received on the control input,

wherein the programmable feedback circuit is configured to produce a first RC circuit value when the wireless transmitter is configured to produce a first power supply voltage to the drain of the transistor, and wherein the programmable feedback circuit is configured to produce a second RC circuit value to change a negative feedback from the drain to the gate when the wireless transmitter is configured to produce a second power supply voltage to the drain of the transistor.

2. The wireless transmitter of claim 1 wherein the first RC circuit value is produced when the wireless transmitter is configured to produce a variable power supply voltage corresponding to an envelope of the input signal, and wherein the second RC circuit value is produced when the wireless transmitter is configured to produce a constant power supply voltage to the drain of the transistor, and wherein the second RC circuit value is less than the first RC circuit value to increase negative feedback from the drain to the gate.

3. The wireless transmitter of claim 1 wherein the control signal is a logic signal.

4. The wireless transmitter of claim 1 wherein the control signal is a continuous signal.

5. The wireless transmitter of claim 1 wherein the control signal is the power supply voltage.

6. The wireless transmitter of claim 5 wherein the programmable feedback circuit comprises a voltage shaping circuit having an input coupled to receive the power supply voltage and an output producing a feedback resistance having a functional relation to the power supply voltage.

7. The wireless transmitter of claim 5 wherein the transistor is a first transistor, and wherein programmable feedback circuit comprises:

a capacitor having a first terminal coupled to the drain of the first transistor and a second terminal;

a first resistor having a first terminal coupled to the second terminal of the capacitor and a second terminal;

a second resistor having a first terminal coupled to the second terminal of the first resistor and a second terminal coupled to the gate of the first transistor; and

a second transistor having a first terminal coupled to the first terminal of the first resistor, a second terminal coupled to the second terminal of the first resistor, and a control terminal coupled to a control voltage based on the power supply voltage, wherein the control voltage turns on the second transistor as the power supply voltage increases to reduce a series resistance between the drain and the gate of the second transistor, and in accordance therewith, increase the negative feedback from the drain to the gate of the first transistor.

8. The wireless transmitter of claim 1 wherein the programmable feedback circuit comprises a plurality of resistors, a plurality of switches, and a capacitor.

9. The wireless transmitter of claim 8 wherein each one of the plurality of resistors is in series with one of the plurality of switches, and wherein the plurality of resistors are configured in parallel with each other and in series with the capacitor.

10. The wireless transmitter of claim 8, the plurality of resistors and the plurality of switches comprising:

a first resistor having a first terminal coupled to a first terminal of the capacitor and a second terminal;

a first switch having a first terminal coupled to the second terminal of the first resistor and a second terminal coupled to the first terminal of the first resistor;

a second switch having a first terminal coupled to the second terminal of the first resistor and a second terminal;

a second resistor having a first terminal coupled to the second terminal of the second switch and a second terminal coupled to the gate of the transistor,

wherein a second terminal of the capacitor is coupled to the drain of the transistor.

11. The wireless transmitter of claim 1 wherein the transistor comprises a plurality of segments each comprising a source, a gate, and a drain, wherein each segment comprises a resistor and capacitor configured in series between the drain and the gate of the segment.

12. The wireless transmitter of claim 1 wherein the drain is coupled to the antenna through one or more additional gain stages.

13. A method comprising:

receiving an input signal on a gate of a transistor, the transistor comprising a source, a gate, and a drain, wherein the drain is coupled to a power supply voltage and to an antenna, wherein the transistor is configured to amplify the input signal and produce an output signal;

dynamically coupling a portion of the output signal from the drain of the transistor to the gate of the transistor through a programmable feedback circuit having an input terminal coupled to the drain, an output terminal coupled to the gate, and a control input, wherein the programmable feedback circuit adjusts a series resistor and capacitor (RC) circuit between the gate and the drain of the transistor based on a control signal received on the control input,

wherein the programmable feedback circuit is configured to produce a first RC circuit value when the wireless transmitter is configured to produce a first power supply voltage to the drain of the transistor, and wherein the programmable feedback circuit is configured to produce a second RC circuit value to change a negative feedback from the drain to the gate when the wireless transmitter is configured to produce a second power supply voltage to the drain of the transistor.

14. The method of claim 13 wherein the first RC circuit value is produced when the wireless transmitter is configured to produce a variable power supply voltage corresponding to an envelope of the input signal, and wherein the second RC circuit value is produced when the wireless transmitter is configured to produce a constant power supply voltage to the drain of the transistor, and wherein the second RC circuit value is less than the first RC circuit value to increase negative feedback from the drain to the gate.

15. The method of claim 13 wherein the control signal is a logic signal.

16. The method of claim 13 wherein the control signal is a continuous signal.

17. The method of claim 13 wherein the control signal is the power supply voltage.

18. A wireless transmitter comprising:

a transistor comprising a source, a gate, and a drain, wherein the gate is coupled to an input signal to be transmitted, and wherein the drain is coupled to a power supply voltage and to an antenna, wherein the transistor is configured to amplify the input signal and produce an output signal on the drain;

means for adjusting negative feedback from the drain to the gate of the transistor based on a control signal,

wherein said means for adjusting negative feedback comprises a resistor and capacitor (RC) circuit and is configured to produce a first RC circuit value when the wireless transmitter is configured to produce a variable power supply voltage corresponding to an envelope of the input signal to the drain of the transistor, and wherein said means for adjusting negative feedback is configured to produce a second RC circuit value less than the first RC circuit value to increase negative feedback from the drain to the gate when the wireless transmitter is configured to produce a constant power supply voltage to the drain of the transistor.