Gas Gauge Device

• US 20130204560A1
• Filed: 02/02/2012
• Published: 08/08/2013
• Est. Priority Date: 02/02/2012
• Status: Abandoned Application

• Current Assignee: Energy Pass Incorporation
• Original Assignee: Energy Pass Incorporation
• Inventors: Lo, Ying-Che, Lee, Ming-Hsien
• Application Number:
  US13/364,343
• Publication Number:
  US 20130204560A1
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 19/2509 Details concerning sampling, digitizing or waveform capturing
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3828 using current integration

Abstract

The present invention discloses a gas gauge device for measuring a state of charge of a battery. The gas gauge device comprises a first programmable gain amplifier (PGA), for amplifying a battery current of the battery with a first adjustable gain, to generate an amplified battery current; a first analog to digital (ADC) converter, for converting the amplified battery current into a digital amplified battery current with a first adjustable sampling rate; and a micro controller, for adjusting the first adjustable gain and the first adjustable sampling rate to measure the battery current.

Claims

1. A gas gauge device for determining a state of charge of a battery, comprising:

a first programmable gain amplifier (PGA), for amplifying a battery current of the battery with a first adjustable gain, to generate an amplified battery current;

a first analog to digital (ADC) converter, for converting the amplified battery current into a digital amplified battery current with a first adjustable sampling rate; and

a micro controller, for adjusting the first adjustable gain and the first adjustable sampling rate to measure the battery current.

2. The gas gauge device of claim 1, wherein the micro controller adjusts the first adjustable sampling rate according to a variation of the battery current.

3. The gas gauge device of claim 1, wherein the micro controller adjusts the first adjustable gain according to whether the amplified battery current is in a measurable range of the first ADC converter.

4. The gas gauge device of claim 1, wherein the micro controller operates in a normal operation mode if the battery current is greater than a predefined minimum current.

5. The gas gauge device of claim 1 further comprising a memory, for storing a current integration calibration table, and the micro controller determines the state of charge according to the battery current, a corresponding charge/discharge cycle of the battery and the current integration calibration table in a normal operation mode.

6. The gas gauge device of claim 5, wherein the current integration calibration table is established according to battery currents of other batteries in a same batch as the battery with different charge rates, temperatures and charge/discharge cycles.

7. The gas gauge device of claim 1 further comprising a second ADC converter, for converting a battery voltage and a battery temperature into a digital battery voltage and a digital battery temperature with a second adjustable sampling rate, and the micro controller adjusts the second sampling rate to measure the battery voltage and the battery temperature.

8. The gas gauge device of claim 6 further comprising a second PGA, for amplifying the battery voltage with a second adjustable gain for the second ADC converter, and the micro controller adjusts the adjustable gain to measure the battery voltage.

9. The gas gauge device of claim 7, wherein the micro controller operates in a sleep mode if the battery current is less than a predefined minimum current.

10. The gas gauge device of claim 7 further comprising a memory, for storing an open circuit voltage (OCV) calibration table, and the micro controller determines the state of charge according to the battery voltage, a corresponding charge/discharge cycle of the battery and the OCV calibration table if the battery current is less than a predefined minimum current, the battery voltage is less than a predefined minimum voltage and the micro controller is in a sleep mode longer than a predefined period.

11. The gas gauge device of claim 9, wherein the OCV calibration table is established according to OCVs of batteries in a same batch as the battery with different charge/discharge cycles and state of charges.

12. The gas gauge device of claim 7 further comprising an oscillator for generating a system clock, wherein the micro controller controls the oscillator to adjust the system clock according to the digital battery temperature.

13. A state of charge determination method for a battery, comprising:

amplifying a battery current of the battery with a first adjustable gain, to generate an amplified battery current;

converting the amplified battery current into a digital amplified battery current with a first adjustable sampling rate; and

adjusting the first adjustable gain and the first adjustable sampling rate to measure the battery current.

14. The state of charge determination method of claim 13, wherein the step of adjusting the first adjustable gain and the first adjustable sampling rate to measure the battery current comprises:

adjusting the first adjustable sampling rate according to a variation of the battery current.

15. The state of charge determination method of claim 13, wherein the step of adjusting the first adjustable gain and the first adjustable sampling rate to measure the battery current comprises:

adjusting the first adjustable gain according to whether the amplified battery current is in a measurable range.

16. The state of charge determination method of claim 13 further comprising:

operating in a normal operation mode if the battery current is greater than a predefined minimum current.

17. The state of charge determination method of claim 13 further comprising:

storing a current integration calibration table; and

determining the state of charge according to the battery current, a corresponding charge/discharge cycle of the battery and the current integration calibration table in a normal operation mode.

18. The state of charge determination method of claim 17, wherein the current integration calibration table is established according to battery currents of other batteries in a same batch as the battery with different charge rates, temperatures and charge/discharge cycles.

19. The state of charge determination method of claim 13 further comprising:

converting a battery voltage and a battery temperature into a digital battery voltage and a digital battery temperature with a second adjustable sampling rate; and

adjusting the second sampling rate to measure the battery voltage and the battery temperature.

20. The state of charge determination method of claim 18 further comprising:

amplifying the battery voltage with a second adjustable gain for the second ADC converter; and

adjusting the adjustable gain to measure the battery voltage.

21. The state of charge determination method of claim 19 further comprising:

operating in a sleep mode if the battery current is less than a predefined minimum current.

22. The state of charge determination method of claim 19 further comprising:

storing an open circuit voltage (OCV) calibration table; and

determining the state of charge according to the battery voltage, a corresponding charge/discharge cycle of the battery and the OCV calibration table if the battery current is less than a predefined minimum current, the battery voltage is less than a predefined minimum voltage and the micro controller is in a sleep mode longer than a predefined period.

23. The state of charge determination method of claim 21 further comprising:

establishing the OCV calibration table according to OCVs of batteries in a same batch as the battery with different charge/discharge cycles and state of charges.

24. The state of charge determination method of claim 19 further comprising:

adjusting a system clock according to the digital battery temperature.