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dc2518af
DEMO MANUAL DC2518A
The LTC2975 has a multiplexed ADC that is used to pro-
vide voltage, current, and temperature readback values.
The telemetry plot in the GUI is similar to a multi-channel
oscilloscope which is capable of displaying any parameter
that is displayed in the telemetry window. Due to the nature
of a multiplexed ADC converter, it has an associated ADC
loop time of approximately 160ms.
Creating a Fault
There is a pushbutton on the DC2518A board that is used
to force a fault and demonstrate the demo board’s ability
to detect it and respond according to the configuration.
When depressed, the Fault pushbutton creates a fault
(shorts V
SENSE
node to ground) on CH0, the +12V output
(GUI channel U0:0). When faulted, all channels power
down immediately and the GUI’s system tree indicates
the color red for the status portion of that channel. You
should see all outputs power off, the fault LED momentarily
illuminate, the alert LED illuminate continuously, and all
rails sequence back on after a retry period. You may also
hold the FAULT pushbutton indefinitely to demonstrate
the fault behavior and retry timing.
COMMON BOARD OPERATIONS
Clearing a Fault
To clear a fault, you can click the CF icon in the GUI or
simply push the RESET pushbutton (SW2) on the DC2518A
demo board. In both cases, the red (+) on the CF icon and
alert LED on the board are both cleared. Notice that all
rails are automatically re-enabled after a programmable
retry period. A dialog box may pop up after clicking the
Clear Faults (CF) icon. If a fault log is present, a dialog will
ask if you would like to clear the fault log as well as clear
system faults. After clearing faults, the system tree will
return to “green” and fault logs are re-armed. For further
information, see the ‘Working with the Fault Log’ section.
“Why Am I Off?” Tool
Use the “Why am I Off” tool in the LTpowerPlay GUI to
diagnose the cause for a power supply channel being in
an off state. The tool is located in the top right corner of
the GUI, above the “Register Information” tab. Hover your
cursor over the tab to show the tool.
First select an output channel in the system tree. The
tool collects various status information and provides a
diagnosis.
Figure 8. “Why Am I Off” tool in the LTpowerPlay GUI
