
Analog Integrated Circuit Device Data
Freescale Semiconductor
44
PC34708
Functional Block Requirements and Behaviors
Battery Management Block Description and Application Information
The charger will turn off the CHRGLEDR LED and illuminate the CHRGLEDG LED when the battery charging is complete. The
red charge LED CHRGLEDR will be on as long as the charger is charging. During a battery over-temperature, the CHRGLEDR
LED will continue to stay on. In the following fault conditions, USBOVP, AUXOVP, BATTOVP, CHRTIMEXP, WKVBUSDET, and
WKAUXDET, the CHRGLEDR LED will blink at the 1.0 Hz rate. Software can take control over the CHRGLEDs by setting the
CHRGOVRD bit.
During the constant current/constant voltage charge mode, the charge timer is running (CHRTMR). If the CHRTMR expires
before the CHRITERM limit is reached, the charging will be stopped and the CHRTIMEEXP interrupt generated. The charge timer
is programmable by the CHRTMR[3:0] SPI bits. It defaults to 12 hours on power up.
The detection of the transistor MBATT placed versus MBATT not placed is reflected through the CHRGSSS MBATTSNS bit. A logic
1 indicates MBATT is detected. If MBATT not placed, the GBAT pin must be left grounded.
The charging circuit will stop charging if the die temperature of the IC exceeds the thermal protection shutdown threshold. To re-
enable the charger, a turn on event is required.
7.1.4.3
Factory Mode
In factory mode, power is provided to the application with no battery present. This is only available on the USB charge path. It is
not a situation which should occur in the field. The factory mode is differentiated from a USB Host by and in addition to USBDET,
a UID being pulled to ground via a 64.9 k resistor, see
USB Interface.
With MBATT present, the application will be powered with the buck charger input current limit set to a typical 950 ma, and the
constant current charge setting to 950 mA. If the ILIM_1P5 SPI bit is set, the constant current charger current setting will be set
to 1500 mA, as will the input current limit. The transistor MBATT is opened (non conducting) to separate BP from BATT, and the
internal trickle charge current source is not enabled. All the charger timers are disabled.
Table 39. Charge Termination Current Settings
CHRITERM[2:0]
Charger Termination Current (mA)
000
50
001
100
010
150
011
200
100
250
101
300
110
350
111
400
Table 40. Charger Timer Settings
CHRGTMR [3:0]
Charge Time
(Hrs)
CHRGTMR [3:0]
Charge Time
(Hrs)
0000(default)
1
1000
9
0001
2
1001
10
0010
3
1010
11
0011
4
1011
12
0100
5
1100
13
0101
6
1101
14
0110
7
1110
15
0111
8
1111
16