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參數(shù)資料
| 型號： | PWM5031-I |
| 廠商： | Aeroflex Inc. |
| 英文描述： | RadHard High Speed PWM Controller |
| 中文描述： | RadHard高速PWM控制器 |
| 文件頁數(shù)： | 15/17頁 |
| 文件大小： | 620K |
| 代理商： | PWM5031-I |
15
SCD5031 Rev B
Peimnay
This feedback can be accomplished in a number of different ways: pulse transformers, optocouplers, or capacitive
coupling are a few methods. The compensation network may need modification depending on the feedback method
chosen. The additional winding and rectifier on T1 are used to reset the transformer core after the PWM latches off M1
to prevent staircase saturation of the core.
Note the chip is powered directly from the main power bus (via a zener and current limit resistor) without the need for
additional bootstrap transformer windings. This is one of the main advantages this PWM chip provides over other
products. This scheme could not be implemented with other chips which draw significantly more current. On the other
hand, supplying bias to our PWM chip is about as simple as it gets.
5V to 1.8V Synchronous Buck Converter
A second application is a secondary side, non-isolated synchronous buck converter. The circuit takes a high voltage (5V
in this case) and steps down to a lower voltage (5V to 1.8V in this example, although as pointed out above, these values
are completely adjustable with proper component selection). The distinguishing feature of this implementation is the
synchronous rectification scheme used to replace the standard Schottky rectifiers for more efficient power conversion of
low voltage outputs.
FIGURE 11 – Buck Converter
The circuit switches M1 twice per cycle, chopping the 5V
DC
input into a fixed frequency pulse train whose DC average
is the desired output voltage. The LC filter then simply smoothes this pulse train to produce a clean DC output. The
control loop regulates against operating point perturbations (temperature, line, load) by adjusting M1's duty cycle. The
circuit is operated in the voltage mode since switch current is not referenced to circuit ground. Alternatively, a current
transformer may be used to properly reference the I
SENSE
signal to permit current mode control. An inverter is needed in
the output path to properly drive the P-channel MOSFET. For low current applications (less than -50mA output current),
it may be possible to use the PWM's output drive stage as the switching elements and eliminate M1 and D1 altogether.
R
SET
C
SET
I
NPUT
5V
Rcomp
1V/1.8V/2.5V/3.3V
M1
O
UTPUT
R
SOFT
C
SOFT
Ccomp
0.1μF
R
SET
C
SET
V
EE
DRVN
V
FB
COMP
50%
I
SENSE
Out A
V
CC
DRVP
SOFT
V
REF
D1
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PDF描述 |
|---|---|
| PWM5031-S | RadHard High Speed PWM Controller |
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| R1140Q281B-TL | SC82 120mA LDO REGULATOR |
| R1140Q281B-TR | SC82 120mA LDO REGULATOR |
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| PWM5031-S | 制造商:AEROFLEX 制造商全稱:AEROFLEX 功能描述:RadHard High Speed PWM Controller |
| PWM505 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC |
| PWM-50-59 | 制造商:Brady Corporation 功能描述:REFILL PAGES - LEGEND: 50-59 |
| PWM510 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC |
| PWM-6 | 制造商:Brady Corporation 功能描述: |
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