EN2342QI Evaluation Board User Guide
15)
Pre-Bias Protection
– Pre-Bias protection
is disabled by default on the evaluation
board. To enable pre-bias protection,
remove R17 and connect TP33 to AVIN (a
zero ohm connection may be used). A fast
ENABLE signal greater than 3V/100µs must
be used in order for the Pre-Bias protection
to work properly. A signal generator is
recommended to test this feature. Be sure
to follow the sequence requirement where
the 12V rail is in regulation before the
device is enabled. Refer to the following
timing diagram or the EN2342QI Datasheet
for details on Pre-Bias Protection.
PVIN
ENABLE
0V
12V
3.3V
0V
VOUT
Soft Start Time ≈ 2ms
w/Css=47nF
Delay from ENABLE rising
edge to soft start begin
~ 1ms
Delay from ENABLE falling
edge to soft shutdown
begin ~ 1.5ms
Soft Shutdown
Time ≈ 1.3ms
w/Css=47nF
PVIN – Recommended
to be ramped down
after the Vout soft-
shutdown occurs
PVIN slew rate limitations
as per datasheet
www.altera.com/enpirion
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10592 December 16, 2014 Rev A
