Power and impedance measurement circuits for a wireless communication device

• US 8,963,611 B2
• Filed: 10/16/2009
• Issued: 02/24/2015
• Est. Priority Date: 06/19/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: See, Puay Hoe, Ballantyne, Gary J., Sahota, Gurkanwal Singh, Hadjichristos, Aristotele, Cicalini, Alberto
• Primary Examiner(s): Wells, Kenneth B.
• Application Number:
  US12/580,988
• Publication Number:
  US 20100321086A1
• Time in Patent Office: 1,957 Days
• Field of Search: 327/359, 324/709, 333 32- 33, 333/17.3, 375/36, 375/257, 379/398, 379/36, 379/340, 379402-404, 379/394, 455/123, 455/125, 455/129, 455/289
• US Class Current: 327/359
• CPC Class Codes: G01R 21/01 in circuits having distributed constants G01R21/04, G01R21/07, G01R21/09, G01R21/12 take precedence
• CPC Class Codes: G01R 27/04 in circuits having distributed constants , e.g. having very long conductors or involving high frequencies
• CPC Class Codes: H03H 7/40 Automatic matching of load impedance to source impedance
• CPC Class Codes: H04B 1/0458 Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages matching circuits in general H03H

Abstract

Exemplary embodiments disclosed are directed to power and impedance measurement circuits that may be used to measure power and/or impedance are described. A measurement circuit may include a sensor and a computation unit. The sensor may sense (i) a first voltage signal across a series circuit coupled to a load to obtain a first sensed signal and (ii) a second voltage signal at a designated end of the series circuit to obtain a second sensed signal. The sensor may mix (i) a first version of the first sensed signal with a first version of the second sensed signal to obtain a first sensor output and (ii) a second version of the first sensed signal with a second version of the second sensed signal to obtain a second sensor output. The computation unit may determine the impedance and/or delivered power at the designated end of the series circuit based on the sensor outputs.

Claims

1. An apparatus comprising:

a sensor coupled to each of first and second ends of a circuit coupled to a load and configured to measure a voltage drop across the circuit to obtain a first sensed signal, to sense a second voltage signal at the second end of the circuit to obtain a second sensed signal, and to provide a sensor output generated based at least in part on multiplying the first and second sensed signals; and

a computation unit coupled to the sensor and to compute power observed at the load based on the sensor output.

2. The apparatus of claim 1, the sensor comprising

an amplifier to receive first and second input signals obtained from the first and second ends, respectively, of the circuit and provide the first sensed signal, and

a multiplier coupled to the amplifier and to multiply the first sensed signal with a version of the second sensed signal and provide a multiplier output.

3. The apparatus of claim 2, the sensor further comprising

a buffer to receive the second input signal and provide the second sensed signal, and

a phase shifter coupled to the buffer and to provide a phase-shifted version of the second sensed signal to the multiplier.

4. The apparatus of claim 2, the sensor further comprising

a lowpass filter coupled to the multiplier and to filter the multiplier output and provide the sensor output.

5. The apparatus of claim 2, the sensor further comprising

a first programmable attenuator coupled to the first end of the circuit and to provide the first input signal, and

a second programmable attenuator coupled to the second end of the circuit and to provide the second input signal.

6. The apparatus of claim 1, the sensor comprising

an amplifier to receive first and second input signals obtained from the first and second ends, respectively, of the circuit and provide the first sensed signal,

a buffer to receive the second input signal and provide the second sensed signal,

a phase shifter coupled to the buffer and to provide a phase-shifted signal,

a multiplier coupled to the amplifier and the phase shifter and to multiply the first sensed signal with the phase-shifted signal and provide a multiplier output, and

a lowpass filter coupled to the multiplier and to filter the multiplier output and provide the sensor output.

7. The apparatus of claim 1, the computation unit to scale the sensor output based on impedance of the circuit and provide the power delivered to the load.

8. The apparatus of claim 1, the circuit comprising an inductor coupled between the first and second ends of the circuit.

9. The apparatus of claim 1, further comprising:

a tunable matching circuit comprising the circuit; and

a power amplifier coupled to the tunable matching circuit, the tunable matching circuit being adjusted based on the power delivered to the load.

10. A method comprising:

measuring a voltage drop across first and second ends of a circuit coupled to a load to obtain a first sensed signal;

sensing a second voltage signal at the second end of the circuit to obtain a second sensed signal;

generating a sensor output based at least in part on multiplying the first and second sensed signals; and

computing power observed at the load based on the sensor output.

11. The method of claim 10, further comprising:

adjusting a matching circuit comprising the circuit based on the power delivered to the load.

12. An apparatus comprising:

means for measuring a voltage drop across first and second ends of a circuit coupled to a load to obtain a first sensed signal;

means for sensing a second voltage signal at the second end of the circuit to obtain a second sensed signal;

means for generating a sensor output based at least in part on multiplying the first and second sensed signals; and

means for computing power observed at the load based on the sensor output.

13. A wireless device comprising:

a first power amplifier to amplify a first input radio frequency (RF) signal and provide a first amplified RF signal;

a first tunable matching circuit coupled to the first power amplifier and to provide output impedance matching for the first power amplifier, to receive the first amplified RF signal, and to provide a first output RF signal; and

a computation circuit coupled in parallel to the first tunable matching circuit and to compute first impedance or observed power at output of the first tunable matching circuit, the first tunable matching circuit being adjusted based on the measured first impedance or observed power.