ICS1700A Datasheet, PDF (12/24 Pages) List of Unclassifed Manufacturers – QuickSaver Charge Controller for Nickel-Cadmium and Nickel-Metal Hydride Batteries

ICS1700A
• Using no temperature sensor:
If a temperature sensor is not used, the THERM pin must be
grounded.
Voltage Input: VIN Pin
The battery voltage must be normalized by an external resistor
divider network to one cell. The electrochemical potential of one
cell is about 1.2V. For example, if the battery consists of six cells
in series, the voltage at the VIN pin must be equal to the total
battery voltage divided by six. This can be accomplished with two
resistors, as shown in Figure 11. To determine the correct resistor
values, count the number of cells to be charged in series. Then
choose either R1 or R2 and solve for the other resistor using:
R1 = R2 * (# of cells -1) or R2 =
R1
(# of cells -1)
# of cells
VIN pin
R1
R2
Voltage Reference: VREF Pin
A 1.26V reference is present at this pin. The reference sets internal
voltage references such as the 0.5V and 2.0V internal thresholds
used by the controller for battery polling/fault detection and the
analog/digital converter range.
The reference provides a fast way of checking the internal
thresholds. Measuring VREF with a high input impedance volt
meter (>1MΩ) is required. The reference can only be used if it is
buffered with a high impedance device having an input impedance
greater than 1MΩ. Buffering is essential to ensure that the internal
voltage thresholds and analog/digital converter range and
resolution are not altered.
The reference may be overridden by an external 1.2V to 1.3V
reference.
Power: VDD Pin
The power supply for the device must be connected to the VDD
pin. The voltage should be +5 VDC and should be supplied to the
part through a regulator that has good noise rejection and an
adequate current rating. The controller requires up to a maximum
of 11mA with VDD=5.00V.
Grounding: VSS, AVSS Pins
There are two ground pins. Both pins must be connected together
at the device. This point must have a direct connection to a solid
ground plane.
Figure 11: Resistor divider network
at the VIN pin
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