DS2715: NiMH Battery Pack Charge Controller
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
dT/dt Blanking Time t
BLANK
3.85 4.3 4.75 Min
PRECHARGE Timeout t
PC-TO
30 Min
FAST-CHARGE Timer
Range
t
FC
0.5 6 Hours
DS2715 1:2
TOPOFF to FAST-
CHARGE Duration Ratio
DS2715B 1:4
Note 1: Voltages relative to V
SS
.
Note 2: Does not include current through V
CH
, R
T
, and DIV pins.
Note 3: Below this voltage no I/O pins are active.
Note 4: Does not include tolerance of R
T
resistor.
Note 5: V
BIAS
and resistor tolerances must be added to determine actual threshold.
Note 6: Specified temperature thresholds are only valid if recommended thermistor types are used.
Note 7: Specification is guaranteed by design.
DETAILED PIN DESCRIPTION
PIN NAME DESCRIPTION
1 C
BIAS
Bypass for Internal Voltage Regulator
2 V
CH
Cell Stack Charge Control Output
3 V
SS
Chip Supply Return and Local Ground Reference
4 LED1 Charging Indicator Output
5 DNC Do Not Connect
6 V
SS
Chip Supply Return and Local Ground Reference
7 CTG Connect to Local Ground (V
SS
)
8 CTG Connect to Local Ground (V
SS
)
9 MODE
Mode Select. Connect to V
SS
for linear mode of operation or C
BIAS
for comparator
mode of operation.
10 DIV
Thermistor Divider. Stable output to form a resistor divider for measuring
temperature on THM
11 SNS+ Positive Current Sense. Connect to the charge source side of the sense resistor
12 SNS- Negative Current Sense. Connect to the cell stack side of the sense resistor
13 V
DD
Chip Supply Input: +4.5V to +16.5V range
14 R
T
Failsafe Timeout. Timeout is selected by an external resistor from R
T
to V
SS
15 THM
Thermistor Input. Connect to a thermistor located in the cell pack and a divider
resistor from the Div pin
16 V
BATT
Battery Voltage Sense Input. Connect to a divider from the positive terminal of the
cell stack to measure the voltage of a single cell
