PI3740-00 Datasheet, PDF (44/48 Pages) Vicor Corporation – Parallel capable with single wire current sharing

System Design Considerations
Inductive Loads: As with all power electronic applications,
consideration must be given to driving inductive loads that
may be exposed to a fault in the system which could result in
consequences beyond the scope of the power supply primary
protection mechanisms. An inductive load could be a filter, fan
motor or even excessively long cables. Consider an instantaneous
short circuit through an un-damped inductance that occurs when
the output capacitors are already at an initial condition of fully
charged. The only thing that limits the current is the inductance
of the short circuit and any series resistance. Even if the power
supply is off at the time of the short circuit, the current could
ramp up in the external inductor and store considerable energy.
The release of this energy will result in considerable ringing,
with the possibility of ringing nodes connected to the output
voltage below ground. The system designer should plan for this
by considering the use of other external circuit protection such
as load switches, fuses, and transient voltage protectors. The
inductive filters should be critically damped to avoid excessive
ringing or damaging voltages. Adding a high current Schottky
diode from the output voltage to PGND close to the PI3740-00 is
recommended for these applications.
Low Voltage Operation: There is no isolation from an SELV
(Safety-Extra-Low-Voltage) power system. Powering low voltage
loads from input voltages as high as 60V may require additional
consideration to protect low voltage circuits from excessive
voltage in the event of a short circuit from input to output. A fast
TVS (transient voltage suppressor) gating an external load switch
is an example of such protection.
PI3740-00
Cool-Power^® ZVS Switching Regulators
Page 44 of 48
Rev 1.4
04/2017
vicorpower.com
800 927.9474