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dc1605bf
DEMO MANUAL DC1605B
Demo BoarD use cases
USE CASE #1
A common configuration for the LTC2936 dedicates the
V1 pin to the highest supply in the system and uses V2-V6
to monitor other voltages. The V1 pin provides power to
the chip and also is used to detect an OV or UV on the V1
pin. For simplicity, the USB controller (DC1613) powers
the board and the LTC2936 is powered via the V1 pin with
the jumper set to INT 5V.
Each of the high comparator fault outputs is mapped to
GPIO1, indicating an active-low OV fault. Each of the low
comparator fault outputs are mapped to GPIO3, indicating
an active-low UV fault. These OV and UV conditions are
indicated in multiple places—LEDs next to the GPIO tur-
rets and also in the GUI. The GPIO2 pin has been mapped
as an active-low latched OV indicator. The latched ALERT
is cleared by pressing the GPI1 pushbutton. The GPIO
pins have a red-blue LED which is red when low and blue
when high.
The two GPI inputs are used to detect a manual reset
(MR) and margin disable (MARG) and activated when the
pushbutton switches are depressed.
GPIO1
→
OV fault
GPIO2
→
ALERT (latched)
GPIO3
→
UV fault
GPI1
→
MR (manual reset)
GPI2
→
MARG (ignore OV/UV when margining)
Let’s margin V5 and V6 low by typing a value of 1V and
0.9V into the respective DAC control boxes. You may also
move the DAC output by clicking the up/down arrows on
the individual DAC box or by double-clicking the DAC value
and entering a new value in the box. V5 and V6 will report
a UV, turning the LED on GPIO3 red. The dashboard in the
GUI indicates the V5 and V6 voltages are below the LO
thresholds of 0.95V and 1.1V. Also notice in the Telemetry
window a STATUS_WORD register, expand it. This register
is a live indicator of LO or HI fault conditions. Note the state
of LO_FAULT bits when the margin low button is selected.
We can demonstrate the effect of the GPI2 pushbutton at
this point. The GPI2 pin has been programmed to function
as MARG, enabling the LTC2936 to ignore all UV condi-
tions. Notice that when the pushbutton is depressed, GPIO3
returns high (blue). This is useful when the system does
not want to be informed of a UV condition during margin
low testing. Moving the DAC voltages back to 1.2V and
1V returns GPIO3 to a high state (blue), indicating there
is no UV condition.
