MAX1647 Maxim, MAX1647 Datasheet - Page 20

• Manufacturer Part Number: MAX1647
• Description: Chemistry-Independent Battery Chargers
• Manufacturer: Maxim

Chemistry-Independent
Battery Chargers
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.
Table 4. Relationship Between Current DAC Code and the ChargingCurrent( ) Value
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
* When SEL = VL, D5 = 1 forces DA0 to be 1 regardless of the D6 bit value.
20
INHIBITED
CHARGE_
AGND
Open
SEL
VL
______________________________________________________________________________________
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
(mΩ)
181
R1
90
45
(NOTE 1)
D15
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
x
1
x
0
0
0
D14
0
0
0
INHIBITED
ALARM_
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
x
x
D13
0
0
0
D12
ChargingVoltage( )
0
0
0
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
0x0010–0xFFFF
DA5
D11
0
0
x
x
x
x
DA5
DA4
D10
0
DA5
DA4
DA3
D9
open
open
open
open
open
SEL
0V
0V
0V
0V
0V
VL
VL
VL
VL
VL
VL
VL
x
x
x
x
x
DA4
DA3
DA2
D8
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.
ChargingCurrent( )
0x0040–0x03DF
0x0040–0x07DF
0x0FA0–0x0FBF
0x0FC0–0x0FFF
0x0001–0x001F
0x0020–0x003F
0x03E0–0x03FF
0x0400–0xFFFF
0x0001–0x001F
0x0020–0x003F
0x07E0–0x07FF
0x0800–0xFFFF
0x0001–0x001F
0x0020–0x003F
0x0040–0x007F
0x0080–0x0F9F
0x0001–0xFFFF
DA3
DA2
DA1
D7
0x0000
x
x
x
x
DA2
DA1
DA0
D6
DA1
DA0
D5
*
CURRENT
CODE
DAC
4–60
2–62
2–62
D4
N/C
N/C
N/C
N/C
I4
I4
I4
62
62
63
63
63
63
63
0
2
0
1
0
1
1
0
D3
I3
I3
I3
SW REG
ON?
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
No
D2
I2
I2
I2
D1
I1
I1
I1
(NOTE 2)
N/C
N/C
N/C
N/C
0
0
0
0
1
0
0
0
0
1
0
0
0
0
0
0
1
0
D0
I0
I0
I0