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ICS1735EB
Galaxy Power, Inc.'s ICS1735 Evaluation Board helps provide
a practical way of evaluating the ICS1735 conditioning/charge
method on lead acid batteries. The evaluation board provides
some circuit options for interfacing to an external regulating
current to voltage charging source or for building an adjustable
regulating source for charging 6V, 12V, and 24V lead acid
batteries.
The board provides a constant current discharge circuit, so R1,
R2, and R3 are jumpers. The added .51Ω, 1W resistor and
2N3903 NPN transistor provides constant amplitude 1.25A
discharge pulses for conditioning the battery through out the
charging process. The amplitude of the discharge current is
independent of battery voltage and may be increased or decreased
by changing the value of the .51Ω resistor. The amplitude of the
current is typically 0.64V/.XXΩ. Jumper provisions are provided
for selecting a charge time for performance improvement
evaluations. The board includes a bread- boarding area consisting
of a matrix of holes for user added components.
Before using the ICS1735 Evaluation Board, the user should
review the ICS1735 data sheet to become familiar with the
operation of the IC. The board can be purchased either as an
ICS1735EB or an ICS1735EB/CVR. The CVR version provides
a parts kit for the user to make an adjustable, regulating charging
source.
Setting-up for Your Application
Refer to the evaluation board schematic diagram. If the
ICS1735EB is to interface to an external regulating current to
voltage source, both the current and the voltage of the external
source must be set according to the battery manufacturer’s
requirements. Two charge signal options are provided to control
an external charging source. There is a CHG output which uses a
logic high for switching on an external charging source and
another signal which uses a logic low for switching on an external
charging source. If the CVR kit is installed to provide an on-board
adjustable current to voltage regulator, a 1N52XXB type diode
must be installed by the user per Table 1. A regulated input supply
is required per Table 2 when using the on board charging source.
Cells Battery Type * ZD (V)
36V 1N5231B (5.1V)
612V 1N5242B (12V)
12 24V 1N5252B (24V)
*User provides ZD1 and associated components (SD103A schottky
diode is made by Diodes Inc.)
The ICS1735EB/CVR contains a parts kit for configuring an
LM317T as an adjustable current to voltage regulating charging
source on the board. The charging current is set by the value of
R15 and the forward voltage drop of D5 1N5822. The maximum
current the LM317T provides for this on-board application is
1.25A. In this application with R13 = 3K, U3 LM317 regulates a
voltage difference of about 1.35 volts between its OUT and ADJ
pins. With the 1N5822 D5 voltage drop equal to .4V at 1.25A,
(1.35V-.4V)/1.25A makes R15 a .75Ω, 2W resistor.
With all of the ICS1735EB/CVR kit and user provided
components installed, connect only a voltmeter between +BAT
terminal and a GND terminal of the board and apply regulated
input power per Table 2 below. About 3.5 minutes after the CHG
LED lights, adjust the 500Ω potentiometer until the pulsed voltage
on the +BAT terminal reads the required end of charge voltage per
the battery manufacturer. Table 2
Cells Battery Type +V (Reg. Input)
36V 12V
612V 18V
12 24V 30V
Whenever input power is applied to the board, the ICS1735 starts a
charge sequence. A logic low applied to the RESET terminal of the
board holds the ICS1735 in reset and all of its outputs stay off.
When RESET is removed by a logic high or an open, or by
releasing the board’s push button reset switch SW1, a new charge
sequence begins.
The amplitude of the discharge current may be increased or
decreased by changing the value of the .51Ω resistor. The
amplitude of the current is typically 0.64V/.XXΩ. Normally the
amplitude of the discharge pulse is set to the same amplitude as the
current setting of the charging source.