6
dc2442af
DEMO MANUAL DC2442A
Powering Up
Connect power supply capable of 220A at 0V to 20V to the
12V input as shown in Figure 1. Verify that the cabling,
shown in extra bold lines, is capable of carrying 200A
safely. The GND connection does not handle high current
so no high current cabling is required.
Generally, an electronic load will be used. If this is true, use
it in the constant resistance mode. Use in constant current
will prevent start-up because of current foldback in the
LTC4282. To minimize power dissipation in the MOSFETs,
current is initially limited to approximately 30% of the full
current limit that is available when the output voltage is
above 10V. If a constant current load is used and set to
200A, the LTC4282 will not start-up and a current fault
will be reported.
UV/OV Thresholds
With no load on the output, slowly increase the voltage
on the input to the board. Observe the input voltage when
LED D2 (OUT) illuminates. This voltage should be between
10.7V and 11.4V. Continue increasing voltage until D2 is
extinguished. This should occur between 14.4V and 15.3V.
Output Voltage Slew Rate
With no load connected, observe the output voltage be-
tween 12V
OUT
(E5), and GND. Apply 12V to the
+12V
IN
connector. The output voltage should slew from
0V to 12V in 10ms to 25ms.
Output Current Limit
Turn off power supply and connect electronic load to the
DC2442 as shown in Figure 1. Disable electronic load.
Adjust power supply to 12V and verify its current level is
set to > 200A.
Slowly increase conductance of the electronic load while
monitoring current. As the load increases to around 200A,
the output voltage and current will fall to zero. Note the
current where this occurs. This should be between 200A
to 210A.
Ability to Charge Output Capacitor
Turn off power supply and disconnect electronic load.
Replace load with a 20,000μF capacitor rated at 15V or
greater. Turn on power supply and observe that the output
voltage rises to 12V indicating the DC2442 has connected
to the load and successfully charged the output capacitance.
This should happen within 400ms to 500ms.
QUICK START PROCEDURE (WITHOUT SOFTWARE)
LTpowerPlay
®
is a convenient PC software GUI that gives
complete access to the registers of the LTC4282 and many
other Linear Technology Power System Management parts.
Use it in off-line mode to build a system configuration file
even with no hardware plugged-in, and use it with hard-
ware connected to configure and debug your application.
LTpowerPlay communicates using the I
2
C bus in the demo
system (covered in this manual), or in your real-world
product environment. It provides unprecedented control
over the Linear Technology chips on the I
2
C bus. Use it
during board bring-up to tune and optimize the power
system parameters. Use it during system debug to view
critical system information and troubleshoot board design
or manufacturing issues. LTpowerPlay includes extensive
help and documentation under the Help menu. Online help
includes quick-start videos and tutorials, and detailed
technical documentation from the Linear Technology
website. Getting started with LTpowerPlay is easy. Simply
download and install the PC software from here:
http://www.linear.com/LTpowerPlay
WARNING:
The LTC4282 comes preprogrammed in the Low
Stress Staged Start configuration with specific settings,
which support a 200A application. Changing the LTC4282’s
programming on the DC2442 is strongly discouraged to
ensure safety and proper operation of the board. Exercise
caution if changing register settings and refer to Table 7
for key register settings, which should remain untouched.
SOFTWARE CONTROL WITH LTpowerPlay
