Application Information - Analog Devices DC2374B Demo Manual

DEMO MANUAL DC2374B

APPLICATION INFORMATION

Changing Board Configuration
This board is optimized for a 24V to 14V lead acid bat-
tery with 5A charge current, however it can be modified
for other charging topologies, different charge currents,
plus different DCIN and battery voltages. The DC2374B
can also accommodate higher power outputs. There are
optional capacitors, inductor, FETs, and a catch diode on
the bottom of the board that can be used for larger com-
ponents if needed. The layout was designed with ample
copper and vias to provide enough thermal relief for 300W.
Refer to the data sheet for the sizing of all of the required
components and changes as needed.
No Battery Operation
The LTC4013 will operate without a battery, however there
needs to be at least 2V on the SENSE pin, V
4.5V, DCIN must be above V
100mV, plus the ENAB pin must also be above its rising
threshold to startup. For single input FET applications V
will increase to DCIN – V
f
dual input FET applications a resistor can be used to bleed
current across the first FET to allow V
10
must be above
IN
and above V by about
IN BAT
of the input FET body diode. For
to charge up. For
IN
MPPT applications, the added resistor should provide an
RC constant (R • C
VIN
One way to raise the SENSE pin above to 2V is to provide
a weak pullup from INTV
the BAT pin when no battery is present. V
greater than INTV
CC
Without a Battery" section of the LTC4013 data sheet for
more information on this.
Connecting a High Voltage Battery
When connecting a battery to the DC2374B demo board,
the battery will instantaneously charge the bulk capaci-
tors on the BAT and the V
capacitors have very low ESR, the instantaneous current
can be 10's or 100's of amps when the battery is first
connected and can damage the components in its path.
It is recommended to pre-charge the BAT terminals of the
DC2374B prior to connecting a low ESR battery. This can
be done by connecting the battery thru a current limiting
IN
resistor first, then short across the resistor. Refer to the
Plugging in a Battery section of the LTC4013 data sheet
for more information.
) greater than 10ms.
with a blocking diode on
CC
FLOAT
for this method. Refer to the "Starting
nodes. Since the battery and
IN
must be
Rev. 0