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參數(shù)資料
| 型號(hào)： | AFL27028DW |
| 英文描述： | DC to DC Converter |
| 中文描述： | DC至DC轉(zhuǎn)換器 |
| 文件頁數(shù)： | 6/10頁 |
| 文件大?。?/td> | 137K |
| 代理商： | AFL27028DW |
6
AFL27000S Circuit Description
Figure I. AFL Single Output Block Diagram
ERROR
AMP
& REF
OUTPUT
FILTER
INPUT
FILTER
OUTPUT RETURN
DC INPUT
INPUT RETURN
FB
CONTROL
1
2
4
3
5
6
SYNC INPUT
CURRENT
SENSE
+ SENSE
- SENSE
SENSE
AMPLIFIER
ENABLE 2
SHARE
SHARE
AMPLIFIER
7
11
10
9
12
8
+ OUTPUT
SYNC OUTPUT
ENABLE 1
CASE
PRIMARY
BIAS SUPPLY
Circuit Operation and Application Information
The AFL series of converters employ a forward
switched mode converter topology. (refer to Figure
I.) Operation of the device is initiated when a DC
voltage whose magnitude is within the specified
input limits is applied between pins 1 and 2. If pin 4
is enabled (at a logical 1 or open) the primary bias
supply
will
begin
generating
housekeeping voltage bringing the circuitry on the
primary side of the converter to life. Two power
MOSFETs used to chop the DC input voltage into a
high frequency square wave, apply this chopped
voltage to the power transformer. As this switching
is initiated, a voltage is impressed on a second
winding of the power transformer which is then
rectified and applied to the primary bias supply.
When this occurs, the input voltage is shut out and
the primary bias voltage becomes exclusively
internally generated.
a
regulated
The switched voltage impressed on the secondary
output transformer winding is rectified and filtered to
provide the converter output voltage. An error
amplifier on the secondary side compares the output
voltage to a precision reference and generates an
error signal proportional to the difference. This error
signal is magnetically coupled through the feedback
transformer into the controller section of the
converter varying the pulse width of the square
wave signal driving the MOSFETs, narrowing the
width if the output voltage is too high and widening it
if it is too low.
Remote Sensing
Connection of the
+
and
-
sense leads at a remotely
located load permits compensation for resistive
voltage drop between the converter output and the
load when they are physically separated by a
significant distance. This connection allows
regulation to the placard voltage at the point of
application. When the remote sensing feature is not
used, the sense leads should be connected to their
respective output terminals at the converter. Figure
III. illustrates a typical application.
Inhibiting Converter Output
As an alternative to application and removal of the
DC voltage to the input, the user can control the
converter output by providing TTL compatible,
positive logic signals to either of two enable pins
(pin 4 or 12). The distinction between these two
signal ports is that enable 1 (pin 4) is referenced to
the input return (pin 2) while enable 2 (pin 12) is
referenced to the output return (pin 8). Thus, the
user has access to an inhibit function on either side
of the isolation barrier. Each port is internally pulled
"high" so that when not used, an open connection on
both
enable
pins
permits
operation. When their use is desired, a logical "low"
on either port will shut the converter down.
normal
converter
Figure II. Enable Input Equivalent Circuit
Pin 4 or
Pin 12
1N4148
100K
290K
150K
2N3904
+5.6V
Disable
Pin 2 or
Pin 8
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AFL27012D | Hi-Rel DC-DC Standard Dual Converter in a AFL package |
| AFL27015D | Hi-Rel DC-DC Standard Dual Converter in a AFL package |
| AFL27028DX | DC to DC Converter |
| AFL27028DY | DC to DC Converter |
| AFL27028DZ | DC to DC Converter |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AFL27028DW/CH | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:DC to DC Converter |
| AFL27028DW/ES | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:DC to DC Converter |
| AFL27028DW/HB | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:DC to DC Converter |
| AFL27028DW-CH | 制造商:IRF 制造商全稱:International Rectifier 功能描述:ADVANCED ANALOG HIGH RELIABILITY HYBRID DC/DC CONVERTERS |
| AFL27028DW-ES | 制造商:IRF 制造商全稱:International Rectifier 功能描述:ADVANCED ANALOG HIGH RELIABILITY HYBRID DC/DC CONVERTERS |
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