WPA60R48DC Datasheet, PDF (4/31 Pages) Murata Power Solutions Inc. – 60 Watt Dual Output Quarter Brick DC/DC Converter

APPLICATION NOTES
Operation
Output Voltage Trim
Remote ON/OFF Function
Each of the WPA60C’s output voltages may be simulta-
neously adjusted above or below the nominal set point
by a value as indicated on the Product Data Sheet. As
shown in Figure 1, to raise the converter output volt-
age a resistor must be placed between the Trim pin and
Return pin.
+ Vin
ON/OFF
- Vin
+ Vout1
Trim
WPA60C
(Top View) ^Return
+ Vout2
R_L1
R_T
R_L2
Figure 1 – Trim Up Circuit
To lower the converter output voltage a resistor must
be placed between the Trim pin and Vout1 pin as
shown in Figure 2.
The WPA60C is equipped with a primary ON/OFF
pin used to remotely turn the converter on or off via a
system signal. The input is TTL open-collector and/or
FET open-drain compatible. For the positive logic
model a system logic low signal will turn the unit off.
For negative logic models a system logic high signal will
turn the converter off. For negative logic models where
no control signal will be used the ON/OFF pin should be
connected directly to –Vin to ensure proper operation.
For positive logic models where no control signal will
be used the ON/OFF pin should be left open for normal
operation.
Control Signal
+ Vin
ON/OFF
- Vin
+ Vout1
Trim
WPA60C
(Top View) ^Return
+ Vout2
+ Vin
ON/OFF
- Vin
+ Vout1
Trim
WPA60C
(Top View) ^Return
+ Vout2
R_T
R_L1
R_L2
Figure 2 – Trim Down Circuit
The resistance value required to achieve the desired
amount of positive/negative trim can be determined by
referring to the trim graph for each model. If trimming
is not desired then the Trim pin should be left uncon-
nected.
Figure 3 – Remote ON/OFF Control Circuit
Protective Functions
Temperature Shutdown
The over temperature shutdown feature of the
WPA60C will cause the unit to shutdown at a typical
pwb temperature of 120^oC. This protective feature is
comprised of a thermistor in the unit control loop. At a
temperature of 120^oC this circuit will cause the PWM
to go into an idle mode, resulting in no output from
the converter and preventing damage to the converter
components. When the temperature of the unit drops
below 120^oC the fault condition will clear and the
converter will resume normal operation. If the cause
of the over temperature condition is not identified and
corrected the unit will continue to cycle on and off.
Product: www.cd4power.com
WPA60R48DC REV A: RoHS 08/2006
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