PQ60120QEX25 Datasheet, PDF (9/13 Pages) SynQor Worldwide Headquarters – Quarter-brick DC/DC Converter

Technical Specification
Input: 35-75 V
Output: 12 V
Current: 25 A (300W)
Package: Quarter-brick
BASIC OPERATION AND FEATURES
The PowerQor Exa series converter uses a two-stage power
conversion topology. The first stage keeps the output voltage
constant over variations in line, load, and temperature. The
second stage uses a transformer to provide the functions of input/
output isolation and voltage step-down to achieve the low output
voltage required.
Both the first stage and the second stage switch at a fixed frequency
for predictable EMI performance. Rectification of the transformer’s
output is accomplished with synchronous rectifiers. These devices,
which are MOSFETs with a very low on-state resistance, dissipate
significantly less energy than Schottky diodes, enabling the
PowerQor converter to achieve high efficiency.
Dissipation throughout the converter is so low that it does not
require a heatsink for operation. Since a heatsink is not required,
the PowerQor converter does not need a metal baseplate or potting
material to help conduct the dissipated energy to the heatsink. As
an open frame module, the PowerQor converter can be built more
simply and reliably using high yield surface mount techniques on
a PCB substrate.
The PowerQor series of half-brick, quarter-brick and
eighth‑brick converters uses the industry standard footprint and pin-
out configuration.
ON/OFF
ON/OFF
ON/OFF
Vin(_)
Remote Enable Circuit
Vin(_)
Negative Logic
(Permanently Enabled)
Vin(_)
Positive Logic
(Permanently Enabled)
ON/OFF
5V
CMOS
ON/OFF
CONTROL FEATURES
REMOTE ON/OFF (Pin 2): The ON/OFF input, Pin 2, permits
the user to control when the converter is on or off. This input
is referenced to the return terminal of the input bus, Vin(-). The
converter is available with either positive or negative logic used for
the ON/OFF input.
In the positive logic version, the ON/OFF input is active high
(meaning that a high voltage turns the converter on). In the negative
logic version, the ON/OFF signal is active low (meaning that a low
voltage turns the converter on). Figure A details five possible circuits
for driving the ON/OFF pin.
REMOTE SENSE(+) (Pins 7 and 5): The SENSE(+) inputs correct
for voltage drops along the conductors that connect the converter’s
output pins to the load.
Pin 7 should be connected to Vout(+) and Pin 5 should be connected
to Vout(-) at the point on the board where regulation is desired. If
these connections are not made, the converter will deliver an output
voltage that is slightly higher than its specified value.
Note: The output over-voltage protection circuit senses the voltage
across the sense leads (pins 7 and 5) to determine when it should
trigger, not the voltage across the converter’s output pins (pins 8
and 4).
OUTPUT VOLTAGE TRIM (Pin 6): The TRIM input permits the
user to adjust the output voltage across the sense leads up or down
according to the trim range specifications. SynQor uses industry
standard trim equations.
To decrease the output voltage, the user should connect a resistor
between Pin 6 (TRIM) and Pin 5 (SENSE(–) input). For a desired
decrease of the nominal output voltage, the value of the resistor
should be:
( ) ^Rtrim-down ⁼
511
D%
_ _10.22
kW
where
^{D% =}
Vnominal – Vdesired
Vnominal
x 100%
Vin(_)
Open Collector Enable Circuit
Vin(_)
Direct Logic Drive
Figure A: Various circuits for driving the ON/OFF pin.
Product # PQ60120QEA25
Phone [phone]
www.synqor.com
Doc.# 005-2QE612J Rev. B
03/24/09
Page 9