WM8351CGEB/RV WOLFSON [Wolfson Microelectronics plc], WM8351CGEB/RV Datasheet - Page 164

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

WM8351
w
Charger current set to zero
Trickle charging
Fast charging
Table 109 Battery Charger Status via CH_IND
The WM8351 continuously monitors battery temperature, chip temperature and battery voltage. In
case of a fault condition, it autonomously takes appropriate action, and alerts the host processor via
the applicable interrupt flags.
The WM8351 can monitor the battery temperature via the NTC (negative temperature coefficient)
resistor which is incorporated into suitable battery packs. The NTC resistor must be connected to the
AUX1 pin as shown in Section 17.7.1. Typical NTC resistor values vary over a range of temperature
(source of information is Vishay Dale’s “R-T Curve 2”).
The NTC monitoring circuit is designed to detect temperature conditions outside the typical 0
45
indicated by setting the CHG_BATT_COLD_EINT interrupt. A hot battery temperature is indicated by
setting the CHG_BATT_HOT_EINT interrupt. Battery charging is suspended when either of these
conditions is set. (Note that trickle charging will resume once the battery temperature has returned to
within normal levels.)
It is possible to disable the NTC detection circuit and associated flags. This option is protected by a
security key. The associated register bits are described in Table 110.
Safety warning - The battery temperature sensor is a safety mechanism and it is strongly
recommended that it be used, as directed, in all applications requiring Charger functionality. Disabling
this feature by any means, intentional or otherwise, could result in incorrect behaviour of the battery
charger function.
17.7.7
Battery Temperature Monitoring
o
C safe battery charging conditions. The WM8351 indicates a cold battery temperature condition is
CHARGER STATUS
BATTERY FAULT CONDITIONS
LED off
LED blinks slowly (0.5Hz)
LED blink s quickly (1Hz)
CH_IND ACTION
PD, April 2012, Rev 4.5
Production Data
o
C and
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