Wireless communications circuitry with temperature compensation

• US 8,831,529 B2
• Filed: 04/30/2012
• Issued: 09/09/2014
• Est. Priority Date: 04/30/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Toh, Yuping, Luong, Anh
• Primary Examiner(s): Wendell, Andrew
• Assistant Examiner(s): TRANDAI, CINDY HUYEN
• Application Number:
  US13/460,718
• Publication Number:
  US 20130288610A1
• Time in Patent Office: 862 Days
• Field of Search: 455/67.11, 32475001-75009
• US Class Current: 455/67.11
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03G 3/3042 in modulators, frequency-changers, transmitters or power amplifiers transmission power control in bidirectional transmission systems H04W52/04

Abstract

A test system for calibrating wireless electronic devices is provided. The test system may include a test host, a radio communication tester, and a temperature chamber in which an electronic device under test (DUT) may be tested. The DUT may include a temperature sensor for monitoring an internal temperature of the DUT and may include power amplifier circuitry for outputting radio-frequency test signals. The tester may be used to measure output power levels of the radio-frequency test signals when the DUT is operating at a given reference temperature and when the DUT is operating at target operating temperature levels other than the given reference temperature. Power amplifier output level offset compensation values may be computed by comparing output power levels measured at each of the target operating temperatures to output power levels measured at the given reference temperature and may be stored in the DUT prior to normal operation.

Claims

1. A method of using a test system to calibrate an electronic device, wherein the test system includes a radio communication tester and a test chamber in which the electronic device is placed during calibration, the method comprising:

while the test chamber is set to provide a first a first internal chamber temperature, obtaining baseline measurement data from the electronic device with the radio communication tester;

while the test chamber is set to provide a second internal chamber temperature that is different than the first internal chamber temperature, obtaining additional measurement data from the electronic device with the radio communication tester, wherein the electronic device includes wireless communications circuitry configured to generate radio-frequency test signals during calibration, and wherein obtaining the baseline measurement data and the additional measurement data comprises obtaining radio-frequency output power measurements associated with the radio-frequency test signals using the radio communication tester; and

computing calibration data for the electronic device by comparing the additional measurement data to the baseline measurement data.

2. The method defined in claim 1, wherein comparing the additional measurement data to the baseline measurement data comprises computing differences between the additional measurement data and the baseline measurement data.

3. The method defined in claim 1, further comprising:

storing the calibration data in the electronic device, wherein the electronic device is configured to operate in normal user operation using settings based on the stored calibration data.

4. The method defined in claim 1, wherein the electronic device includes power amplifier circuitry, and wherein the test system further includes a test host, the method further comprising:

with the test host, configuring the power amplifier circuitry in the electronic device to output radio-frequency test signals using a plurality of radio-frequency gain settings at desired frequencies.

5. The method defined in claim 1, wherein the test system further includes a power supply unit, the method further comprising:

with the power supply unit, proving power to the electronic device during calibration; and

with the power supply unit, monitoring power consumption levels for the electronic device during calibration.

6. The method defined in claim 1, wherein the second internal chamber temperature comprises a target temperature level in a list of predetermined target temperatures levels to be calibrated, the method further comprising:

calibrating the electronic device while setting the test chamber to each target temperature level in the list of predetermined target temperature levels; and

computing calibration data for each target temperature level in the list of predetermined target temperature levels.

7. The method defined in claim 1, wherein the electronic device includes power amplifier circuitry, wherein computing the calibration data for the electronic device comprises computing output power offset compensation values for the power amplifier circuitry, and wherein the output power offset compensation values configure the power amplifier circuitry to output radio-frequency signals at satisfactory levels across different device operating temperatures.

8. The method defined in claim 1, wherein the electronic device includes power amplifier circuitry, antenna structures, and a transmission line path interposed between the power amplifier circuitry and the antenna structures, and the method further comprising:

coupling the radio communication tester to the transmission line path using a radio-frequency test probe, wherein the antenna structures are electrically decoupled from the power amplifier circuitry when the radio-frequency test probe is coupled to the transmission line path.

9. A method of using a test system to calibrate an electronic device having a temperature sensing circuit operable to provide a sensor output value, wherein the test system includes a test chamber in which the electronic device is placed during calibration, the method comprising:

while the test chamber is set to provide a first internal chamber temperature, obtaining a baseline sensor output value using the temperature sensing circuit in the electronic device; and

computing target sensor output values for each target calibration temperature level in a predetermined list of target calibration temperature levels based on the baseline sensor output value and a temperature coefficient associated with the temperature sensing circuit, wherein each of the computed target sensor output values specifies a respective value for which the sensor output value generated by the temperature sensing circuit has to match at a corresponding target calibration temperature level in the predetermined list of target calibration temperature levels.

10. The method defined in claim 9, wherein the temperature sensing circuit comprises a thermistor, and wherein the temperature coefficient associated with the thermistor is a fixed value.

11. The method defined in claim 9, further comprising:

configuring the test chamber to provide a second internal chamber temperature that is different than the first internal temperature; and

while the test chamber is configured to provide the second internal chamber temperature, obtaining a measured sensor output value using the temperature sensing circuit.

12. The method defined in claim 11, wherein the test system further includes a radio communication tester, the method further comprising:

determining whether the measured sensor output value is sufficiently close to a corresponding one of the target calibration sensor output values;

in response to determining that the measured sensor output value is sufficiently close to the corresponding target calibration sensor output value, using the radio communication tester to obtain desired radio-frequency measurements from the electronic device; and

in response to determining that the measured sensor output value is not sufficiently close to the corresponding target calibration sensor output value, reconfiguring the test chamber to provide a third internal chamber temperature that is different than the second internal chamber temperature.

13. The method defined in claim 10, wherein the test system further includes a radio communication tester, the method further comprising:

while the test chamber is set to provide the first internal chamber temperature, using the radio communication tester to obtain baseline radio-frequency measurements from the electronic device; and

while the test chamber is configured such that the sensor output value is sufficiently close to one of the target sensor output values, using the radio communication tester to obtain additional radio-frequency measurements from the electronic device.

14. The method defined in claim 13, wherein the electronic device further includes wireless communications circuitry, the method further comprising:

computing calibration data for the wireless communications circuitry by comparing the additional radio-frequency measurements to the baseline radio-frequency measurements.

15. A method of operating an electronic device that includes wireless communications circuitry and a temperature sensing circuit, the method comprising:

storing calibration settings on the electronic device;

with the temperature sensing circuit, monitoring an operating temperature for the electronic device;

in response to detecting a first operating temperature, configuring the wireless communications circuitry in a first gain mode by supplying at least a portion of the wireless communications circuitry with a first power supply voltage according to the stored calibration settings; and

in response to detecting a second operating temperature that is greater than the first operating temperature, configuring the wireless communications circuitry in a second gain mode by supplying the portion of the wireless communications circuitry with a second power supply voltage that is greater than the first power supply voltage according to the stored calibration settings.

16. The method defined in claim 15, wherein the temperature sensing circuit comprises a thermistor having a constant temperature coefficient.

17. The method defined in claim 15, wherein the wireless communications circuitry includes power amplifier circuitry having a given number of amplifier gain stages, and wherein configuring the wireless communications circuitry using the selected gain setting comprises selectively activating at least some of the amplifier gain stages.

18. The method defined in claim 17, wherein the electronic device further includes adjustable power supply circuitry, and wherein configuring the wireless communications circuitry using the selected gain setting further comprises providing an adjustable power supply voltage to the power amplifier circuitry with the adjustable power supply circuitry.

19. The method defined in claim 15, wherein the wireless communications circuitry includes power amplifier circuitry, wherein storing the calibration settings comprises storing power amplifier output power offset compensation values corresponding to different device operating temperatures, and wherein configuring the wireless communications circuitry using the selected gain setting comprises adjusting the power amplifier circuitry based on a corresponding power amplifier output power offset compensation value to ensure that the power amplifier circuitry is outputting radio-frequency signals at satisfactory signal levels.