WM8351CGEB/RV WOLFSON [Wolfson Microelectronics plc], WM8351CGEB/RV Datasheet - Page 165

• Manufacturer Part Number: WM8351CGEB/RV
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

Production Data
w
R168 (A8h)
Battery Charger
Control 1
Note: Some batteries may not require battery temperature monitoring. Disable with caution.
Table 110 Battery Temperature Monitoring
The WM8351 has a built-in temperature sensor to monitor the silicon die temperature. If the chip
temperature reaches the thermal warning level, the WM8351 sets the SYS_CHIP_GT115_EINT (see
Section 25) and Battery Charger operation may be paused (this is programmable in Trickle Charge
mode). The charger operation will resume once the chip temperature has dropped below the thermal
warning level.
If the chip temperature reaches the thermal shutdown level, the WM8351 sets the
SYS_CHIP_GT140_EINT interrupt and shuts down. (Battery charging is always terminated in this
case.)
A low battery voltage is an indicator that the battery may be defective or removed.
In trickle charge mode, the battery voltage is checked after 30 minutes of charging, or after a quarter
of the charging time CHG_TIME (the larger of these two times applies). If the battery voltage is less
than the defective battery threshold (nominal value 2.85V) at this time, then the battery charging stops
and the WM8351 sets the CHG_BATT_FAIL_EINT interrupt as defined in Table 111.
The battery failure condition is cleared if the battery voltage rises above the defective battery
threshold. It is also cleared if any of the WM8351 power sources (including BATT) is removed and re-
applied, or if the host processor invokes USB Suspend mode. When the failure condition is cleared,
the charger then reverts back to its initial state, and may re-start if the conditions for charging are
fulfilled (see Section 17.7.2).
If fast charging mode is selected, and the battery voltage is less than the defective battery threshold,
then the WM8351 immediately reverts to trickle charging. If the fault persists, then trickle charging
stops as described above.
Chip Temperature Monitoring
Battery Voltage Detection / Defective Battery Detection
ADDRESS
BIT
3
2
1
CHG_NTC_M
ON
CHG_BATT_H
OT_MON
CHG_BATT_C
OLD_MON
LABEL
DEFAULT
1
1
1
Enable charger battery NTC detection
(some batteries may not need this - turn
off with caution)
0 = Charger ignores NO_NTC detection.
1 = Charger monitors NO_NTC detection.
Protected by user key, read-only in ROM
configs.
Enable charger battery temperature high
detection (some batteries may not need
this - turn off with caution)
0 = Charger ignores battery temperature
too high.
1 = Charger monitors battery temperature
too high.
Protected by user key, read-only in ROM
configs.
Enable charger battery temperature low
detection (some batteries may not need
this - turn off with caution)
0 = Charger ignores battery temperature
low.
1 = Charger monitors battery temperature
low.
Protected by user key, read-only in ROM
configs.
DESCRIPTION
PD, April 2012, Rev 4.5
WM8351
165