Utilizing computed battery resistance as a battery-life indicator in a mobile terminal

• US 7,956,615 B1
• Filed: 02/27/2007
• Issued: 06/07/2011
• Est. Priority Date: 02/27/2007
• Status: Active Grant

• Current Assignee: Qorvo US, Inc. (Qorvo, Inc.)
• Original Assignee: RF Micro Devices Incorporated (Qorvo, Inc.)
• Inventors: Jaoude, Fares, Arkiszewski, Roman Zbigniew, Hietala, Alexander Wayne
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): Diao; M'Baye
• Application Number:
  US11/679,199
• Time in Patent Office: 1,561 Days
• Field of Search: 320/132, 320/139, 320/141, 320/145, 324/427, 324/429, 324/430, 324/432, 324/436, 455/91, 455/104, 455109-113, 455/118
• US Class Current: 324/430
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health

Abstract

An over-voltage detection and correction system for a transmitter of a mobile terminal that accounts for battery droop during a transmit burst is provided. In general, prior to ramp-up for a first transmit burst, a voltage of the battery of the mobile terminal at a no-load condition is measured. After ramp-up for the transmit burst, the voltage of the battery is measured at full-load, and a current provided to a power amplifier of the transmitter at full-load is detected. Based on the measured voltage of the battery at no-load, the measured voltage of the battery at full-load, and the detected current provided to the power amplifier at full-load, a resistance of the battery is determined. The battery resistance is thereafter updated as desired and used as an indicator of remaining battery-life or power of the battery of the mobile terminal.

Claims

1. A method comprising:

measuring a battery voltage of a battery of a mobile terminal at a no-load condition prior to ramp-up for a first transmit burst to provide a no-load battery voltage;

measuring the battery voltage of the battery at a full-load condition during the first transmit burst to provide a full-load battery voltage;

measuring a current provided from the battery to power amplifier circuitry in a transmit chain of the mobile terminal at a full-load condition during the first transmit burst to provide a full-load current;

determining a battery resistance based on the no-load battery voltage, the full-load battery voltage, and the full-load current; and

providing the battery resistance as an indicator of remaining battery-life for the battery of the mobile terminal.

2. The method of claim 1 further comprising comparing the battery resistance to at least one resistance threshold to provide an indication of remaining battery-life for the battery of the mobile terminal.

3. The method of claim 1 further comprising comparing the battery resistance to at least one of a series of resistance thresholds to provide an indication of remaining battery-life for the battery of the mobile terminal, wherein the series of resistance thresholds corresponds to a series of remaining battery-life levels.

4. The method of claim 1 wherein determining the battery resistance comprises determining the battery resistance based on the equation:

8. The method of claim 1 further comprising:

measuring the battery voltage of the battery of the mobile terminal at a no-load condition prior to ramp-up for a subsequent transmit burst to provide a no-load battery voltage for the subsequent transmit burst;

measuring the battery voltage of the battery at a full-load condition during the subsequent transmit burst to provide a full-load battery voltage for the subsequent transmit burst;

measuring a current provided from the battery to the power amplifier circuitry in the transmit chain of the mobile terminal at a full-load condition during the subsequent transmit burst to provide a full-load current for the subsequent transmit burst;

updating the battery resistance based on the no-load battery voltage, the full-load battery voltage, and the full-load current for the subsequent transmit burst; and

providing the updated battery resistance as the indicator of remaining battery-life for the battery of the mobile terminal.

9. The method of claim 8 wherein updating the battery resistance comprises updating the battery resistance if a difference between the no-load battery voltage and the full-load battery voltage for the subsequent transmit burst exceeds a predetermined threshold.

10. The method of claim 1 wherein the battery resistance is a resistance of the battery plus a resistance of any elements connected between the battery and the power amplifier circuitry.

5. A method comprising:

measuring a battery voltage of a battery of a mobile terminal at a no-load condition to provide a no-load battery voltage, wherein measuring the battery voltage at a no-load condition comprises measuring the battery voltage prior to ramp-up for the first transmit burst;

measuring the battery voltage of the battery at a full-load condition after ramp-up for a first transmit burst and during the first transmit burst to provide a full-load battery voltage;

measuring a current provided from the battery to power amplifier circuitry in a transmit chain of the mobile terminal at the full-load condition during the first transmit burst to provide a full-load current;

determining a battery resistance based on the no-load battery voltage, the full-load battery voltage, and the full-load current; and

providing the battery resistance as an indicator of remaining battery-life for the battery of the mobile terminal.

6. The method of claim 5 wherein the mobile terminal operates according to a modulation scheme having an amplitude modulation component, and measuring the battery voltage at a full-load condition comprises measuring the battery voltage during a constant envelope period occurring immediately prior to ramp-down for the first transmit burst.

7. The method of claim 5 wherein the mobile terminal operates according to an 8-Level Phase Shift Keying (8PSK) modulation scheme of the Enhanced Data Rates for GSM Evolution (EDGE) standard, and measuring the battery voltage at a full-load condition comprises measuring the battery voltage during a constant envelope period beginning at 2.5 symbol periods after a center of a last data symbol of the first transmit burst and ending at a start of ramp-down for the first transmit burst.