MAX1667 Datasheet, PDF (21/28 Pages) Maxim Integrated Products – Chemistry-Independent, Level 2 Smart Battery Charger

Chemistry-Independent,
Level 2 Smart Battery Charger
Table 4. ChargingCurrent() Bit Functions
BIT POSITION
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6
FUNCTION
FS*
DA4 DA3 DA2 DA1 DA0
WEIGHT IN mA
(R_SENSE = 40mΩ)
3968*
2048 1024 512 256 128
* When SEL = VL, values above 0x0F80 set the output current to 3.968A.
When SEL = OPEN, values above 0x0B80 set the output current to 2.944A.
When SEL = GND, values above 0x0380 set the output current to 0.896A.
** Values below 0x0080 set the output current to 7mA.
D5 D4 D3 D2 D1 D0
IOUT**
7**
Table 5. Relationship Between IOUT Source Current and ChargingCurrent() Value
CHARGE_
INHIBITED
(Note 1)
ALARM_
INHIBITED
ChargingVoltage()
ChargingCurrent()
0
0
0
0x0000–0x000F
x
0
0
0
x
0x0000
0
0
0
0x0010–0xFFFF
0x0001–0x0007
0
0
0
0x0010–0xFFFF
0x0001–0x0007
0
0
0
0x0010–0xFFFF
0x0001–0x0007
0
0
0
0x0010–0xFFFF
0x0008–0x007F
0
0
0
0x0010–0xFFFF
0x0008–0x007F
0
0
0
0x0010–0xFFFF
0x0008–0x007F
0
0
0
x0x0010–0xFFFF
0x0080–0xFFFF
0
0
1
x
x
0
1
x
x
x
1
x
x
x
x
Note 1: THERMISTOR_HOT and HOT_STOP and NOT (THERMISTOR_UR).
CCV_LOW
VOLTAGE_
NOTREG
I_OUT
OUTPUT
CURRENT (mA)
x
x
0
x
x
0
0
x
7
1
0
0
1
1
7
0
x
7
1
0
0
1
1
7
x
x
0
x
x
0
x
x
0
x
x
0
If reverse-polarity protection for the DC input power is
not necessary, diode D4 can be omitted. This eliminates
the power lost due to the voltage drop on diode D4.
Thermistor Characterization
Figure 11 represents the expected electrical behavior
of a 103ETB-type thermistor (nominally 10kΩ at +25°C
±5% or better) to be used with the MAX1667. The
graph is typical of the suggested thermistor’s charac-
teristics.
THERMISTOR_OR bit is set only when the thermistor
value is > 100kΩ. This indicates that the thermistor is
open.
THERMISTOR_COLD bit is set only when the thermistor
value is > 30kΩ. The thermistor indicates a cold bat-
tery.
THERMISTOR_HOT bit is set only when the thermistor
value is < 3kΩ.
THERMISTOR_UR bit is set only when the thermistor
value is < 500Ω.
Multiple bits may be set depending on the values of the
thermistor (e.g., a 450Ω thermistor will cause both the
THERMISTOR_HOT and the THERMISTOR_UR bits to
be set). The thermistor may be replaced by fixed-value
resistors in battery packs that do not require the ther-
mistor as a secondary fail-safe indicator. In this case, it
is the responsibility of the battery pack to manipulate
the resistance to obtain correct charger behavior.
______________________________________________________________________________________ 21