METHOD OF MEASURING THE BATTERY LEVEL IN A MOBILE TELEPHONE

• US 20080315838A1
• Filed: 08/14/2008
• Published: 12/25/2008
• Est. Priority Date: 02/18/2000
• Status: Active Grant

• Current Assignee: Donovan Developments Limited
• Original Assignee: Donovan Developments Limited
• Inventors: SOYER, SEBASTIAN
• Granted Patent: US 7,696,724 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm

Abstract

Measuring the voltage level of a mobile telephone battery during a charging operation involves disabling the charge temporarily so that the battery rapidly enters discharge mode. The discharge mode voltage is more representative of the true battery charge level, so that the present invention can be implemented to provide a battery charge level display that is accurate even when the telephone is being charged.

Claims

1. A method of measuring the voltage level of a mobile telephone battery during a charging operation comprising the steps of:

(a) applying current from a current source to charge the battery;

(b) temporarily causing the current from the current source to cease, to enable the battery to enter a discharge mode;

(c) measuring the voltage level of the battery when in the discharge mode;

(d) re-applying current from the current source; and

(e) repeating steps (b) and (c) until the measured voltage exceeds one or more pre-determined voltage thresholds.

2. The method of claim 1, wherein step (b) further comprises drawing a current from the battery to rapidly place the battery into the discharge mode.

3. The method of claim 2, wherein the current drawn from the battery is equivalent to operational drain.

4. The method of claim 2, wherein the current drawn from the battery is approximately 100 mA.

5. The method of claim 1, wherein a first period over which the current from the current source is caused to cease is short in comparison to a second period over which the current from the current source is applied.

6. The method of claim 5, wherein the first period is approximately one second and the second period is approximately nine seconds.

7. The method of claim 5, wherein, for approximately two-thirds of the second period, the charge is approximately 95% efficient.

8. The method of claim 1, wherein a battery level display on the telephone indicates the charge level of the battery in dependence on which the pre-determined voltage threshold or thresholds has or have been exceeded.

9. The method of claim 8, wherein the battery level display indicates four battery charge levels.

10. The method of claim 9, further comprising only determining crossover of each of the first three battery charge levels.

11. The method of claim 1, further comprising:

performing an analog to digital conversion measurement while applying the current from the current source to charge the battery; and

temporarily causing the current from the current source to cease only after the analog to digital conversion measurement is greater than approximately 95% of a typical battery voltage.