Technical Specification
Quarter
24V 15V
6.7A
out
in
Brick
referenced to the return terminal of the 24V input bus. There
are two versions of the PowerQor series converter that differ
by the sense of the logic used for the ON/OFF input. In the
PQxxyyyQGAzzPxx version, the ON/OFF input is active
high (meaning that a high turns the converter on). In the
PQxxyyyQGAzzNxx version, the ON/OFF signal is active
low (meaning that a low turns the converter on). Figure A
details five possible circuits for driving the ON/OFF pin.
Figure B shows detail of the internal ON/OFF circuitry.
voltage across the output (pins 8 and 4) to determine when
it should trigger, not the voltage across the converter’s sense
pins (pins 7 and 5). Therefore, the resistive drop on the
board should be small enough so that output OVP does not
trigger, even during load transients.
Pin 6 (TRIM): The TRIM input permits the user to adjust the
output voltage across the sense leads up or down. To lower
the output voltage, the user should connect a resistor
between Pin 6 and Pin 5, which is the SENSE(-) input. To
raise the output voltage, the user should connect a resistor
between Pin 6 and Pin 7, which is the SENSE(+) input.
Pins 7 and 5 (SENSE(+)): The SENSE(+) inputs correct
for voltage drops along the conductors that connect the con-
verter’s output pins to the load.
A resistor connected between Pin 6 and Pin 5 will decrease
the output voltage. For a desired decrease of ∆ percent of
the nominal output voltage, the value of this resistor should
be
Pin 7 should be connected to Vout(+) and Pin 5 should be
connected to Vout(-) at the point on the board where regu-
lation is desired. That is,
511
R
(kΩ)
- 10.22
=
[Vout(+) - Vout(-)] – [SENSE(+) - SENSE (-)] < 10%Vout
trim-down
(∆% )
Pins 7 and 5 must be connected for proper regulation of the
output voltage. However, if these connections are not made,
nothing catastrophic will happen to the converter under nor-
mal operating conditions—the converter will simply deliver
an output voltage that is slightly higher than its specified
value.
where
and
VNOM – VDES
=
x 100%
∆
( )
VNOM
VNOM = Nominal Voltage
VDES = Desired Voltage
Note: the output over-voltage protection circuit senses the
ON/OFF
ON/OFF
ON/OFF
_
_
_
5V
Vin( )
Vin( )
Vin( )
Vin(+)
Negative Logic
(Permanently Enabled)
Positive Logic
(Permanently Enabled)
Remote Enable Circuit
100k
ON/OFF
5V
50k
ON/OFF
TTL
TTL/
CMOS
ON/OFF
100pF
50k
_
_
Vin( )
Vin( )
_
Vin( )
Open Collector Enable Circuit
Direct Logic Drive
Figure A: Various circuits for driving the ON/OFF pin.
Figure B: Internal ON/OFF pin circuitry (detail)
Product # PQ24150QGA07
Phone 1-888-567-9596
Doc.# 005-2QG215D_A
3/1/02
Page 9
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