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

• US 8,035,397 B1
• Filed: 09/01/2010
• Issued: 10/11/2011
• Est. Priority Date: 02/27/2007
• Status: Expired due to Fees

• 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): Diao; M'Baye
• Application Number:
  US12/873,968
• Time in Patent Office: 405 Days
• Field of Search: 324/430
• 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 mobile terminal comprising:

a system adapted to;

i) measure a battery voltage of a battery of the mobile terminal at a no-load condition to provide a no-load battery voltage;

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

iii) measure 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;

iv) determine a battery resistance based on the no-load battery voltage, the full-load battery voltage, and the full-load current; and

v) provide the battery resistance as an indicator of remaining battery-life for the battery of the mobile terminal, wherein the system is further adapted to measure the battery voltage prior to ramp-up for the first transmit burst to measure the battery voltage at a no-load condition.

2. The mobile terminal of claim 1 wherein the battery resistance is compared to at least one resistance threshold to provide an indication of remaining battery-life for the battery of the mobile terminal.

3. The mobile terminal of claim 1 wherein the battery resistance is compared 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, the series of resistance thresholds corresponding to a series of remaining battery-life levels.

4. The mobile terminal of claim 1 wherein the system is further adapted to determine the battery resistance based on the equation:

5. The mobile terminal of claim 1 wherein the system is further adapted to measure the battery voltage after ramp-up for the first transmit burst to measure the battery voltage at a full-load condition.

6. The mobile terminal of claim 1 wherein the mobile terminal operates according to a modulation scheme having an amplitude modulation component, and the system is further adapted to measure the battery voltage during a constant envelope period occurring immediately prior to ramp-down for the first transmit burst in order to measure the battery voltage at a full-load condition.

7. The mobile terminal of claim 1 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 the system is further adapted to measure 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 in order to measure the battery voltage at a full-load condition.

8. The mobile terminal 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.