Product # PQ60120HPA20
Phone 1-888-567-9596
www.synqor.com
Doc.# 005-2HP612K Rev. F
08/12/09
Page 11
Input:
Output:
Current:
Package:
35-75 V
12 V
20 A
Half-brick
Technical Specification
APPLICATIONCONSIDERATIONS
Over-Temperature Shutdown: A temperature sensor on
the converter senses the average temperature of the module.
Thethermalshutdowncircuitisdesignedtoturntheconverter
off when the temperature at the sensed location reaches the
Over-Temperature Shutdown value. It will allow the converter
toturnonagainwhenthetemperatureofthesensedlocation
fallsbytheamountoftheOver-TemperatureShutdownRestart
Hysteresisvalue.
Figure D: Typical application circuit (negative logic unit, permanently enabled).
Vin
External
Input
Filter
Trim
Vin(+)
I
load
C
load
Vout(+)
R
trim-up
or
R
trim-down
Vsense(+)
ON/OFF
Vin(_)
Vout(_)
Vsense(_)
Electrolytic
Capacitor
47F
Figure E: Internal Input Filter Diagram (component values
listed on page 3)
.
C
2
C
1
L
Vin(+)
Vin(_)
Input System Instability: This condition can occur because
any DC/DC converter appears incrementally as a negative
resistance load. A detailed application note titled “Input System
Instability” is available on the SynQor web site (www.synqor.
com) which provides an understanding of why this instability
arises, and shows the preferred solution for correcting it.
Application Circuits:FigureDbelowprovidesatypicalcircuit
diagramwhichdetailstheinputfilteringandvoltagetrimming.
Input Filtering and External Capacitance: Figure E below
providesadiagramshowingtheinternalinputfiltercomponents.
This filter dramatically reduces input terminal ripple current,
whichotherwisecouldexceedtheratingofanexternalelectrolytic
input capacitor. The recommended external input capacitance
isspecifiedinthe“InputCharacteristics”section.Moredetailed
information is available in the application note titled “EMI
Characteristics”ontheSynQorwebsite.
Startup Inhibit Period:TheStartupInhibitPeriodensuresthat
theconverterwillremainoffforapproximately200mswhenitis
shutdownforanyreason.Whenanoutputshortispresent,this
generates a 5Hz “hiccup mode,” which prevents the converter
fromoverheating.Inall,therearesevenwaysthattheconverter
canbeshutdown,initiatingaStartupInhibitPeriod:
Input Under-Voltage Lockout
Input Over-Voltage Shutdown (not present in Quarter-brick)
Output Over-Voltage Protection
Over Temperature Shutdown
Current Limit
Short Circuit Protection
Turned off by the ON/OFF input