WM8352 datasheet(165/336 Pages) WOLFSON

165 / 336 page

Production Data

WM8352

PD, February 2011, Rev 4.4

165

17.7.7

BATTERY FAULT CONDITIONS

The WM8352 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.

Battery Temperature Monitoring

The WM8352 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

oC and

45oC safe battery charging conditions. The WM8352 indicates a cold battery temperature condition is

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.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R168 (A8h)

Battery

Charger

Control 1

CHG_NTC_M

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.

CHG_BATT_H

OT_MON

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.

CHG_BATT_C

OLD_MON

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.

Note: Some batteries may not require battery temperature monitoring. Disable with caution.

Table 110 Battery Temperature Monitoring

WM8352 Datasheet(PDF) 165 Page - Wolfson Microelectronics plc

WM8352 Datasheet(HTML) 165 Page - Wolfson Microelectronics plc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL