Datasheet

Data Sheet

Jul. 20, 2010

PXB15-xxWSxx

15W, Single Output

EMC considerations (Continued)

This Common ChokeL1 is defined as follow:

■

L: 325μH±35% / DCR: 35Ω, max

Aheight: 8.8 mm,Max

■ Test condition: 100KHz / 100mV

■ Recommended through hole: Φ0.8mm

■ All dimensions in millimeters

Input Source Impedance

Thepower module should be connected to a lowimpedanceinput source. Highly inductive source impedance can

affect the stability of the power module. The addition of an external C-L-

C filter is recommended to minimize input

reflected ripple current. The inductor is simulated source impedance of 12μH and capacitor is Nippon chemi-

con KZE

series 10μF/100V&10μF/100V. The capacitor must be located

as close as possible to the input terminals of the power

module for lower impedance.

Output Over Current Protection

When excessive output currents occur in the system, circuit protection is required on all power supplies. Normally,

overload current ismaintained at approximately 150 percent ofratedcurrent for PXB15W singleoutputseries.

Hiccup-mode is a met

hod of operation in a power supply whose purpose is to protect the power supply from being

damaged during anover-current fault condition. It also allows thepower supplytorestart when the fault is removed.

One of the problems resulting from over curren

tis that excessive heatmaybe generatedin power devices;especially

MOSFET and Schottky diodes and the temperature of those devices may exceed their specified limits. A protection

mechanism has to be used to prevent those power devices from being damaged.

Output Over Voltage Protection

Theoutput over-voltage protectionconsists ofa Zener diodethatmonitors theoutput voltage onthefeedback loop.I

the voltage onthe output terminals exceeds the over-voltage protection threshold, then the Zenerdiode will send a

signal to the control IC to limit the outputvoltage.