PQ60280FTA26 Datasheet, PDF (10/14 Pages) SynQor Worldwide Headquarters – Full-brick DC/DC Converter

Technical Specification
Input: 36-75 V
Output: 28 V
Current: 26 A
Package: Full-brick
BASIC OPERATION AND FEATURES
The PowerQor series converter uses a two-stage power conver-
sion 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 isola-
tion and voltage step-down to achieve the low output voltage
required.
Both the first stage and the second stage switch at a fixed fre-
quency 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 resis-
tance, dissipate far less energy than Schottky diodes. This is the
primary reason that the PowerQor converter has such high effi-
ciency, even at very low output voltages and very high output cur-
rents.
Dissipation throughout the converter is so low that it does not
require a heatsink for operation. Since a heatsink is not required,
the PowerQor series of converters do not need a metal baseplate
or potting material to help conduct the dissipated energy to the
heatsink. The PowerQor series of converters can thus be built
more simply and reliably using high yield surface mount tech-
niques on a PCB substrate.
The PowerQor series converters use the industry standard foot-
print and pin-out configuration.
VIN (+)
I ON/OFF
+ON/OFF
-ON/OFF
V_IN (-)
VOUT (+)
SENSE ⁽⁺⁾
SENSE (-)
V_OUT (-)
Figure A: Typical circuit for driving the ON/OFF pin.
V_IN (+)
I _ON/OFF
+ON/OFF
-ON/OFF
V_IN (-)
VOUT (+)
SENSE ⁽⁺⁾
SENSE (-)
V_OUT (-)
Figure B: Another circuit for driving the ON/OFF pin.
CONTROL FEATURES
REMOTE ON/OFF (Pin 3): The (+)ON/OFF input, Pin 3, per-
mits the user to control when the converter is on or off. This input
is referenced (-)ON/OFF. There are two versions of the converter
that differ by the sense of the logic used for the ON/OFF input.
In the positive logic version, the ON/OFF input is active high
(meaning that a high I_ON/OFF turns the converter on). In the neg-
ative logic version, the ON/OFF signal is active low (meaning
that a low I_ON/OFF turns the converter on). Figures A & B detail
two possible circuits for driving the ON/OFF pin.
REMOTE SENSE(+) (Pins 11 and 12): The SENSE(+) inputs
correct for voltage drops along the conductors that connect the
converter’s output pins to the load.
Pin 11 should be connected to Vout(+) and Pin 12 should be con-
nected to Vout(-) at the point on the board where regulation is
desired. A remote connection at the load can adjust for a voltage
drop only as large as that specified in this datasheet, that is
Pins 11 and 12 must be connected for proper regulation of the
output voltage. If these connections are not made, the converter
will deliver an output voltage that is slightly higher than its speci-
fied value.
Note: the output over-voltage protection circuit senses the voltage
across the output (pins 16 and 13) to determine when it should
trigger, not the voltage across the converter’s sense leads (pins 11
and 12). Therefore, the resistive drop on the board should be
small enough so that output OVP does not trigger, even during
load transients.
OUTPUT VOLTAGE TRIM (Pin 10): The TRIM input permits
the user to adjust the output voltage across the sense leads up or
down according to the trim range specifications.
To decrease the output voltage, the user should connect a resistor
between Pin 10 and Pin 12 (SENSE(-) input). For a desired
decrease of the nominal output voltage, the value of the resistor
should be
( ) ^Rtrim-down ⁼
732
D
- 8.94
(kW)
where
D% =
Vnominal – Vdesired
Vnominal
x 100%
Product # PQ60280FTA26
Phone [phone]
www.synqor.com
Doc.# 005-2FT628P Rev. C
5/21/08
Page 10