ICS1708 Datasheet, PDF (9/16 Pages) List of Unclassifed Manufacturers – QuickSaver Charge Control IC for Nickel-Cadmium and Nickel-Metal Hydride Batteries

ICS1708
The 1C (60 minute rate) is selected by using a 10K pull-up resistor from CMN pin 3 to VDD pin 8 (+5V REG.) as shown in
Figure 9A "Charging System Diagram". The 10K pull-up resistor is required even if an LED with a current limited pull-up to
VDD pin 8 (+5V reg.) is used. The C/2.5 (150 minute) rate is selected using the 330/1.3K resistor divider with a general
purpose LED as shown in Figure 9B. Based on the LED selection, this configuration should provide the 2.5V +/- 0.5V on
CMN pin 3 prior to the start of fast charge to activate the C/2.5 (150 minute) rate as shown in Figure 9B. Setting the 4C (15
minute) rate involves setting the voltage at CMN pin 3 below 0.5V prior to the start of fast charge as shown in Figure 9C. A
10K pull-up resistor, a 2K pull-down resistor and a 1N4148 or equivalent diode is used to keep CMN below 0.5V at power up
or upon battery removal. When CMN goes low to ground of its own accord, the base of a 2N3903 or equivalent NPN
transistor is pulled low via the 1N4148 diode allowing the LED indication for fast charge.
DC INPUT
CONSTANT
CURRENT
SOURCE
IN
OUT
ON/OFF
+5V REG.
*10K
* SELECTS 1C
CHARGE RATE
ICS1708
1 _CHG
2 _MMN
3 _CMN
4 _VSS
VDD ⁸
VIN ⁷
6
OPREF
RC ⁵
4.7uF
15k
100pF
.047uF
R3
.047uF
PTC
or
R1 _TS
R2
+
FIGURE 9A: Charging System Diagram for 1C (60 minute) Charge Rate
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