Low-Battery Handling - Intermec CK30 Service Manual

Low-Battery Handling

Low-Battery Thresholds
State Temp (ºC)
Software 2/3
< 0°C
capacity threshold
10°C
20°C
30°C
40°C
50°C
Software 1/3
< 0°C
capacity threshold
10°C
20°C
30°C
40°C
50°C
Software low-
< 0°C
battery threshold
10°C
20°C
30°C
40°C
50°C
Critically low
< 0°C
battery
10°C
20°C
30°C
40°C
50°C
* These temperature ranges are approximate because the Vbat temperature compensation is not calibrated at
manufacture. Also, because the battery level is averaged over 10 samples at 3-second intervals, it may take up to
30 seconds for a threshold crossing to take effect.
** These temperature ranges are approximate because the Vbat temperature compensation is done in hardware.
CK30 Handheld Computer Service Manual
Power management software on the PXA255 uses the battery voltage and
temperature data for temperature-compensated fuel gauging and low-
battery detection. Three levels of battery status are indicated through an
icon in the status bar:
Percentage of Charge Remaining
67% to 100% charge remaining
34% to 67% charge remaining
1% to 33% charge remaining
0% charge remaining
The first three battery status thresholds are defined in software; the final
critically low battery threshold is based on hardware comparator U36.
Threshold to
Enter State
<= 7.73V*
<= 7.78V
<= 7.83V
<= 7.87V
<= 7.92V
<= 7.97V
<= 7.07V*
<= 7.16V
<= 7.25V
<= 7.35V
<= 7.44V
<= 7.53V
<= 6.4V*
<= 6.54V
<= 6.68V
<= 6.82V
<= 6.96V
<= 7.10V
<= 5.82V**
<= 5.96V
<= 6.15V
<= 6.31V
<= 6.45V
<= 6.55V
Chapter 4 — Theory of Operation
Icon Displayed
(No icon displays)
Threshold to Exit
State Action
>= 7.83V* Battery at approximately 67%
>= 7.88V capacity; "2/3" battery status
>= 7.93V icon is displayed.
>= 7.97V
>= 8.02V
>= 8.07V
>= 7.17V* Battery at approximately 33%
>= 7.26V capacity; "1/3" battery status
>= 7.35V icon is displayed.
>= 7.45V
>= 7.54V
>= 7.63V
>= 6.5V* Battery at 0%; "Empty"
>= 6.64V battery status icon is displayed,
>= 6.78V and the red LED turns on.
>= 6.92V
>= 7.06V
>= 7.20V
>= 6.41V** Critically low battery. U36
>= 6.55V asserts interrupt
>= 6.69V BATT_FAULT_IRQ to start
>= 6.80V a Suspend. This state must be
>= 6.88V exited before the CK30 is
>= 6.94V allowed to resume.
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