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PTEA404120 Datasheet, PDF (7/14 Pages) Texas Instruments – 50-W, 48-V INPUT, 12-V OUTPUT, ISOLATED DC/DC CONVERTER
PTEA404120
www.ti.com
SLTS274A – DECEMBER 2006 – REVISED JANUARY 2007
Differential Remote Sense
The remote sense pins allows the converter to precisely regulate the DC output voltage at a remote location.
This might be a power plane on an inner layer of the host PCB. Connecting Sense(+) directly to +VO, and
Sense(–) to –VO will improve output voltage accuracy. In the event that the sense pins are left open-circuit, an
internal 10-Ω resistor between each sense pin and its corresponding output prevents an excessive rise in the
output voltage. For practical reasons, the amount of IR voltage compensation should be limited to 0.5 V
maximum.
The remote sense feature is designed to compensate for limited amounts of IR voltage drop. It is not intended to
compensate for the forward drop of a non-linear or frequency dependent components that may be placed in
series with the converter output. Examples of such components include OR-ing diodes, filter inductors, ferrite
beads, and fuses. Enclosing these components with the remote sense connections effectively places them
inside the regulation control loop, which can affect the stability of the regulator.
Using the Remote On/Off Function on the PTEA404120 DC/DC Converter
For applications requiring output voltage On/Off control, the PTEA404120 DC/DC converter incorporate a
Remote On/Off control (pin 2). This feature can be used to switch the module off without removing the applied
input source voltage. When placed in the Off state, the standby current drawn from the input source is typically
reduced to 3 mA.
Negative Output Enable (NEN)
Models using the negative enable option, the Remote On/Off (pin 2) control must be driven to a logic low voltage
for the converter to produce an output. This is accomplished by either permanently connecting pin 2 to –VI (pin
3), or driving it low with an external control signal. Table 1 shows the input requirements of pin 2 for those
modules with the NEN option.
VIH
Disable
VIL
Enable
Vo/c
Open-Circuit
II
Pin 2 at –VI
Table 1. On/Off Control Requirements
for Negative Enable
PARAMETER
MIN
2.4
–0.2
TYP
MAX UNITS
20
V
0.8
9
15
–0.75
mA
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