Datasheet

DataSheet
40W, Single Output
VER:00 Page 24 of 31 Issued Date：2009/03/02
Input Source Impedance
The power module should be connectedto a low impedance input source. Highly inductive sourceimpedance
can affect the stability of the DC-DC converter. Input external L-Cfilter is recommended to minimize input reflected
ripple current.The inductorhas a simulated source impedanceof 12μH and thecapacitor is Nippon chemi-con KZE
series 47μF/100V.The capacitormust be located as close as possible to the input terminals of the converter forlower
impedance.
Output Over Current Protection
When excessive output currents occur in the system, circuit protection is required on all converters
. Normally,
overload current is maintained at approximately 150 percent of rated current for PXF40-xxWsxx series.
Hiccup-mode is a method of operation in the converter whose purpose is to protect the converter
from being
damaged during an over-current fault condition. It also enablesthe converter to restart when the fault is removed.
One of the problems resulting from over current is that excessive heat may be generated in power devices;
es
pecially MOSFET and Schottky diodes and the temperature of those devices may exceed their specified limits. A
protectionmechanism has to be used to prevent those power devices from beingdamaged.
Output Over Voltage Protection
The output over-voltage protectionconsists of an output Zenerdiode that monitors the voltage on theoutput
terminals. If the voltage on the output terminals exceeds the over-voltageprotection threshold, then the Zener diode
clamps the output voltage.