Figure 18: Plot of PI2121 response time to reverse current detection (Example 1, Figure 22)
Application Information
The PI2121 is designed to replace ORing diodes in
high current, low voltage redundant power
architectures. Replacing a traditional diode with a
PI2121 will result in significant power dissipation
reduction as well as board space reduction,
efficiency improvement and additional protection
Blanking Timer:
Connect the blanking timer pin (BK) to GND to
program the device for the fastest reverse
comparator response time of 160ns typical. To
increase the blanking time, connect the BK pin to
GND via a resistor to avoid the fault response to
short reverse current pulses. Refer to the plot in the
reverse comparator functional description for resistor
values versus the reverse blanking time.
features.
This section describes in detail the
procedure to follow when designing with the PI2121
Active ORing solution. Two Active ORing design
examples are presented.
Auxiliary Power Supply (Vaux):
Fault Indication:
Vaux is an independent power source required to
supply power to the VC input. The Vaux voltage
should be 5V higher than Vin (redundant power
source output voltage) to fully enhance the internal
MOSFET.
The
output pin is an open collector and should
FT
be pulled up to the logic voltage or to the controller
VC via a resistor (10KΩ).
Picor Corporation • picorpower.com
PI2121
Rev. 1.0 Page 13 of 21
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