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參數(shù)資料
| 型號： | LM2524D |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | Regulating Pulse Width Modulator |
| 中文描述： | 調(diào)節(jié)脈沖寬度調(diào)制器 |
| 文件頁數(shù)： | 8/22頁 |
| 文件大小： | 1172K |
| 代理商： | LM2524D |
Functional Description
INTERNAL VOLTAGE REGULATOR
The LM3524D has an on-chip 5V, 50 mA, short circuit pro-
tected voltage regulator. This voltage regulator provides a
supply for all internal circuitry of the device and can be used
as an external reference.
For input voltages of less than 8V the 5V output should be
shorted to pin 15, V
IN
, which disables the 5V regulator. With
these pins shorted the input voltage must be limited to a
maximum of 6V. If input voltages of 6V–8V are to be used, a
pre-regulator, as shown in
Figure 1
, must be added.
OSCILLATOR
The LM3524D provides a stable on-board oscillator. Its fre-
quency is set by an external resistor, R
and capacitor, C
. A
graph of R
, C
vs oscillator frequency is shown is
Figure 2
.
The oscillator’s output provides the signals for triggering an
internal flip-flop, which directs the PWM information to the
outputs, and a blanking pulse to turn off both outputs during
transitions to ensure that cross conduction does not occur.
The width of the blanking pulse, or dead time, is controlled
by the value of C
, as shown in
Figure 3
. The recommended
values of R
T
are 1.8 k
to 100 k
, and for C
T
, 0.001 μF to
0.1 μF.
If two or more LM3524D’s must be synchronized together,
the easiest method is to interconnect all pin 3 terminals, tie
all pin 7’s (together) to a single C
, and leave all pin 6’s open
except one which is connected to a single R
. This method
works well unless the LM3524D’s are more than 6" apart.
A second synchronization method is appropriate for any
circuit layout. One LM3524D, designated as master, must
have its R
C
set for the correct period. The other slave
LM3524D(s) should each have an R
T
C
T
set for a 10% longer
period. All pin 3’s must then be interconnected to allow the
master to properly reset the slave units.
The oscillator may be synchronized to an external clock
source by setting the internal free-running oscillator fre-
quency 10% slower than the external clock and driving pin 3
with a pulse train (approx. 3V) from the clock. Pulse width
should be greater than 50 ns to insure full synchronization.
ERROR AMPLIFIER
The error amplifier is a differential input, transconductance
amplifier. Its gain, nominally 86 dB, is set by either feedback
or output loading. This output loading can be done with
either purely resistive or a combination of resistive and re-
active components. A graph of the amplifier’s gain vs output
load resistance is shown in
Figure 4
.
00865010
*Minimum C
O
of 10 μF required for stability.
FIGURE 1.
00865005
FIGURE 2.
00865006
FIGURE 3.
00865007
FIGURE 4.
L
www.national.com
8
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM2524DN | 功能描述:電壓模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
| LM2524DN/NOPB | 功能描述:電壓模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓?fù)浣Y(jié)構(gòu):Buck 輸出電壓:34 V 輸出電流: 開關(guān)頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
| LM2524DN/NOPB | 制造商:Texas Instruments 功能描述:, Input Voltage Primary Max:40V, Termina |
| LM2524J/A+ | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Voltage-Mode SMPS Controller |
| LM2524N/A+ | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Voltage-Mode SMPS Controller |
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