MAX1647 Datasheet, PDF (20/24 Pages) Maxim Integrated Products – Chemistry-Independent Battery Chargers

Chemistry-Independent
Battery Chargers
Table 4. Relationship Between Current DAC Code and the ChargingCurrent( ) Value
CHARGE_
INHIBITED
(NOTE 1)
ALARM_
INHIBITED
ChargingVoltage( )
SEL
ChargingCurrent( )
CURRENT
DAC
CODE
SW REG
ON?
(NOTE 2)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
x
0
1
1
x
0
0x0010–0xFFFF
0V
0x0001–0x001F
0
0
0x0010–0xFFFF
0V
0x0020–0x003F
2
0
0x0010–0xFFFF
0V
0x0040–0x03DF
4–60
0
0x0010–0xFFFF
0V
0x03E0–0x03FF
62
0
0x0010–0xFFFF
0V
0x0400–0xFFFF
62
0
0x0010–0xFFFF open 0x0001–0x001F
0
0
0x0010–0xFFFF open 0x0020–0x003F
1
0
0x0010–0xFFFF open 0x0040–0x07DF
2–62
0
0x0010–0xFFFF open 0x07E0–0x07FF
63
0
0x0010–0xFFFF open 0x0800–0xFFFF
63
0
0x0010–0xFFFF
VL
0x0001–0x001F
0
0
0x0010–0xFFFF
VL
0x0020–0x003F
1
0
0x0010–0xFFFF
VL
0x0040–0x007F
1
0
0x0010–0xFFFF
VL
0x0080–0x0F9F
2–62
0
0x0010–0xFFFF
VL
0x0FA0–0x0FBF
63
0
0x0010–0xFFFF
VL
0x0FC0–0x0FFF
63
0
0x0010–0xFFFF
VL
0x0001–0xFFFF
63
0
x
x
0x0000
0
0
0x0010–0xFFFF
x
x
N/C
1
x
x
x
N/C
x
x
x
x
N/C
x
x
x
x
N/C
No
0
Yes
0
Yes
0
Yes
0
Yes
1
No
0
Yes
0
Yes
0
Yes
0
Yes
1
No
0
Yes
0
Yes
0
Yes
0
Yes
0
Yes
0
Yes
1
No
0
No
N/C
No
N/C
No
N/C
No
N/C
Note 1: Logical AND of THERMISTOR_HOT, HOT_STOP, NOT(THERMISTOR_UR).
Note 2: Value of CURRENT_OR bit in the ChargerStatus( ) register.
N/C = No change
Table 5. Effect of SEL Pin-Strapping on the ChargingCurrent( ) Data Bits
SEL
R1
(mΩ)
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
AGND 181 0
0
0
0
0
0 DA5 DA4 DA3 DA2 DA1 I4 I3 I2 I1 I0
Open 90 0
0
0
0
0 DA5 DA4 DA3 DA2 DA1 DA0 I4 I3 I2 I1 I0
VL 45 0
0
0
0 DA5 DA4 DA3 DA2 DA1 DA0 *
I4 I3 I2 I1 I0
*When SEL = VL, D5 = 1 forces DA0 to be 1 regardless of the D6 bit value.
With the switching regulator on, the current through R1
(Figure 3) is regulated by sensing the average voltage
between CS and BATT. A 6-bit current DAC controls
the current-limit set point. DA5–DA0 denote the bits in
the current DAC code. Figure 9 shows the relationship
between the current DAC code and the average volt-
age between CS and BATT.
When the switching regulator is off, DHI is forced to
LX and DLO is forced to ground. This prevents current
from flowing through inductor L1. Table 4 shows the
relationship between the ChargingCurrent( ) register
value and the switching regulator current DAC code.
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