FAN54300 Datasheet, PDF (37/43 Pages) Fairchild Semiconductor – USB-Compliant, Dual-Power Input, Single-Cell, Li-Ion Switching Charger with USB-OTG Boost Regulator

Bit Name
2:0 VSPU
SAFE_U
7 Reserved
6:4 ISAFEU
3:0 VSAFEU
Type
R/W
R
R/W
R/W
Description
Sets the special charger control loop reference voltage when charging from VBUS. If VBUS falls
below this voltage, battery current is reduced until the input voltage is at or above VSP.
Table 19. V_SP Special Charger Reference Voltage
DEC BIN
V_SP
0
000 4.21
1
001 4.29
2
010 4.37
3
011 4.45
4
100 4.53
5
101 4.61
6
110 4.69
7
111 4.77
Reg Addr: 6
Slave Addr: D6 Default = 0100 0000
This bit returns 0.
Any attempt to write a value to ICHGU higher than the contents of ISAFEU sets ICHGU =
ISAFEU.
Table 20. USB Charging I_CHARGE Limit as a Function of the ISAFEU Bits
BIN
HEX ^VRSENSE
I_SAFE (mA)
(mV) 68m 100m
000
00 37.4
550
374
001
01 44.2
650
442
010
02 51.0
750
510
011
03 57.8
850
578
100
04 64.6
950
646
101 05 71.4 1,050 714
110 06 78.2 1,150 782
111 07 85.0 1,250 850
Any attempt to write a value to OREGU that is higher than the value in the Max. OREG column
(below) results in OREGU = Max OREG.
Table 21. V_OREG Limit as a Function of the VSAFEU Bits when Charging from
VBUS
DEC
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
BIN
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Max OREG
( REG2[7:2] )
100011
100100
100101
100110
100111
101000
101001
101010
101011
101100
101101
101110
101111
110000
110001
110010
VOREG
MAX
4.20
4.22
4.24
4.26
4.28
4.30
4.32
4.34
4.36
4.38
4.40
4.42
4.44
4.44
4.44
4.44
© 2010 Fairchild Semiconductor Corporation
FAN54300 • Rev. 1.0.4
37
www.fairchildsemi.com