
Analog Integrated Circuit Device Data
Freescale Semiconductor
30
PC34708
Functional Block Requirements and Behaviors
Battery Management Block Description and Application Information
The control loop will monitor the voltage drop across the MVBUSSW and the MAUXSW to limit the input current. This current input
current limit is set automatically/manually by the input current limit, as detailed in
USB Interface. When the VBUS connection is
not in input current regulation mode, and the MANUAL S/W is 1, the USB current limit USBCHR[1:0] is set automatically by
detecting the charger connected connection and can select between 100 mA, 500 mA, and 950 mA current limits (set by the
USBCHR[1:0]). The AUX current limit can be set manually by setting the AUXILIM[2:0] bits and setting the AUXWEAKEN =0.
Changing the AUXWEAKEN=0 also disables the WKAUXDET interrupt. If AUXWEAKEN=1, then WKAUXDET interrupt will be
enabled, and the AUX input current will be configured in auto input current regulation mode. The input current limit can be set to
1.5 A on both the USB, and AUX charge path by setting the ILIM_1P5 SPI bit = 1. When it is set to a one, the USBCHR[1:0] and
AUXILIM[1:0] settings are ignored. The ILIM_1P5 bit defaults to 0 on reset. The buck input current limit does not apply to the
trickle current. The VBUS input current can be overridden by setting the MANUAL S/W =0 and setting the MUSBCHR[1:0] bits
The charge constant current is programmable by SPI through CHRCC[3:0] bits in steps of 50 mA, from 250 mA to 1550 mA. The
constant charge current is set to 550 mA by default.
010000
3.82
101001
4.32
010001
3.84
101010
4.34
010010
3.86
101011
4.36
010011
3.88
101100
4.38
010100
3.90
101101
4.40
010101
3.92
101110
4.42
010110
3.94
101111
4.44
Table 13. Buck Input Current Limit Settings
ILIM_1P5 USBCHR[1:0] AUXILIM[2:0]
Input Current Limit
(mA)
1
XX
XXX
1500
0
11
111
950
0
10
110
500
0
101
400
0
100
300
0
011
250
0
010
200
0
001
150
0
01
000
100
0
00
NA
0 (off)
Table 12. Buck Charger Constant Voltage Settings
CHRCV[5:0]
Buck Charge
Output Voltage (V)
CHRCV[5:0]
Buck Charge
Output Voltage (V)