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參數(shù)資料
| 型號： | SG3524N |
| 廠商： | 意法半導(dǎo)體 |
| 英文描述： | REGULATING PULSE WIDTH MODULATORS |
| 中文描述： | 調(diào)控脈寬調(diào)制器 |
| 文件頁數(shù)： | 5/9頁 |
| 文件大?。?/td> | 93K |
| 代理商： | SG3524N |
PRINCIPLESOF OPERATION
The SG2524/3524 is a fixed frequency pulse-
with-modulation voltage regulator control circuit.
The regulator operates at a frequency that is pro-
grammed by one timing resistor (R
T
) and one tim-
ing capacitor (C
T
). R
T
established a constant
charging current for C
T
. This results in a linear
voltage ramp at C
T
, which is fed to the compara-
tor providing linear control of the output pulse
width by the error amplifier. the SG2524/3524
contains, an on-board5V regulatorthat serves as
a
reference
as
well
SG2524/3524’s internal control circuitry and is
also useful in supplying external support functions.
This reference voltage is lowered externally by a
resistor divider to provide a reference within the
common mode range the error amplifier or an ex-
ternal reference may be used. The power supply
output is sensed by a second resistor divider net-
work to generalea feedbacksignal to error ampli-
fier. The amplifier output voltage is then com-
pared to the linear voltage ramp at C
T
. The
resulting modulated pulse out of the high-gain
comparator is then steered to the appropriateout-
put pass transistors (Q
A
or Q
B
) by the pulse-
steering flip-flop, which is synchronously toggled
by the oscillator output. The oscillator output
pulse also serves as a blanking pulse to assure
both output are never on simultaneously during
the transition times. The width of the blanking
pulse is controlled by the value of C
T
. Theoutputs
may be applied in a push-pull configuration in
which their frequency is half that of the base oscil-
lator, or paralleled for single-endedapplicationsin
which the frequencyis equal to that of the oscilla-
tor. The output of the error amplifier shares a
common input to the comparator with the current
limiting at shutdown circuitry and can be overrid-
den by signals from either of these inputs. This
common point is also available externally and
may be employed to control the gain of, or to
compensate, the error amplifier, or to provide ad-
ditional controlto the regulator.
as
powering
the
RECOMMENDED OPERATING CONDITIONS
Supply voltage V
IN
Reference Output Current
Current trough C
T
Terminal
Timing Resistor, R
T
Timing Capacitor, C
T
8 to 40V
0 to 20mA
- 0.03 to -2mA
1.8 to 100K
0.001 to 0.1
μ
F
TYPICALAPPLICATIONS DATA
OSCILLATOR
The oscillator controls the frequency of the
SG2524 and is programmed by R
T
and C
T
ac-
cording to the approximateformula:
f
=
1.18
R
T
C
T
where:
R
T
is in K
C
T
is in
μ
F
f is in KHz
Pratical values of C
T
fall between 0.001 and
0.1
μ
F. Pratical values of R
T
fall between 1.8 and
100K
. This results in a frequency range typically
from 120Hzto to 500KHz.
BLANKING
The output pulse of oscillator is used as a blank-
ing pulse at the output. This pulse width is con-
trolled by the value of C
T
.If small values of C
T
are
required for frequency control, the oscillator out-
put pulse width may still be increased by applying
a shunt capacitance of up to 100pF from pin 3 to
ground. If still greater dead-time is required, it
should be accomplished by limiting the maximum
duty cycle by clamping the output of the error am-
plifier. This can easily be done with the circuit be-
low:
SYNCRONOUS OPERATION
When an external clock is desired, a clock pulse
of approximately3V can be applied directly to the
oscillator output terminal. The impedance to
ground at this point is approximately 2K
. In this
configuration R
T
C
T
must be selected for a clock
period slightly greater than that the external clock.
If twomore SG2524regulatorsare to be operated
synchronously, all
oscillator output terminals
should be tied together, all C
T
terminals con-
nected to a single timing capacitor, and timing re-
sistor connected to a single R
T
terminal. The
other R
T
terminals can be left open or shorted to
V
REF
. Minimum lead lengths should be used be-
tween the C
T
terminals.
Figure6.
SG2524- SG3524
5/9
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SG3524P | REGULATING PULSE WIDTH MODULATORS |
| SG3524S | Regulating Pulse Width Modulator |
| SG3546 | 3.3 V UNDERVOLTAGE SENSING CIRCUIT |
| SG3546DM | 3.3 V UNDERVOLTAGE SENSING CIRCUIT |
| SG3546LP | 3.3 V UNDERVOLTAGE SENSING CIRCUIT |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SG3524N | 制造商:STMicroelectronics 功能描述:IC PWM CONTROLLER 3524 DIP16 |
| SG3524N | 制造商:Texas Instruments 功能描述:IC PWM CONTROLLER 3524 DIP16 |
| SG3524NE4 | 功能描述:電壓模式 PWM 控制器 Regulating Pulse Width Modulator RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓撲結(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 |
| SG3524NS | 制造商:TI 制造商全稱:Texas Instruments 功能描述:REGULATING PULSE-WIDTH MODULATORS |
| SG3524NSR | 功能描述:電壓模式 PWM 控制器 Regulating Pulse Width Modulator RoHS:否 制造商:Texas Instruments 輸出端數(shù)量:1 拓撲結(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 |
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