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參數(shù)資料
| 型號： | IR3638SPBF |
| 廠商： | International Rectifier |
| 英文描述： | HIGH FREQUENCY SYNCHRONOUS PWM BUCK CONTROLLER FOR TRACKING APPLIACTIONS |
| 中文描述： | 高頻同步PWM降壓控制器進行跟蹤APPLIACTIONS |
| 文件頁數(shù)： | 7/15頁 |
| 文件大?。?/td> | 300K |
| 代理商： | IR3638SPBF |
IR3638SP
b
F
3/19/07
Circuit Description
7
THEORY OF OPEARTION
Introduction
The
IR3638
synchronous controller and operates with a fixed
400kHz switching frequency, allowing the use of
small external components. The output voltage is
set by feedback pin (Fb) and the external
reference voltage (Vp). These are two inputs to
error amplifier. The error signal between these
two inputs is compared to a fixed frequency
linear sawtooth ramp and generates fixed
frequency pulses of variable duty-cycle (D) which
drivers N-channel external MOSFETs.
The timing of the IC is controlled by an internal
oscillator circuit that uses on-chip capacitor to set
the switching frequency.
is
a
voltage
mode
PWM
Under-Voltage Lockout
The under-voltage lockout circuit monitors the
Vcc and Enable input and assures that the
MOSFET driver outputs remain in the off state
whenever the Vcc or Enable voltages drop below
set thresholds.
Pre-Bias Startup
IR3638 is able to start up into pre-charged
output,
which
prevents
disturbances of the output voltage.
The output starts in asynchronous fashion and
keeps the synchronous MOSFET off until the soft
start reaches about 2.0V. Figure 4 shows a
typical Pre-Bias condition at start up.
Depends on system configuration, specific
amount of output capacitors may be required to
prevent discharging the output voltage
.
oscillation
and
Error Amplifier
The IR3638 is a voltage mode controller. The
error amplifier is of transconductance type and it
is
capable
of
operating
compensation control scheme using low ESR
output capacitance.
with
Type
III
Short Circuit Protection
The output is protected against the short-circuit.
The IR3638 protects the circuit for shorted output
by sensing the output voltage (through the
external resistor divider). The device shuts down
the PWM signals and latches off when the output
voltage drops below 0.4V.
Start Up / Down Considerations
The “Typical Application” on page1 shows a
standard configuration where multiple input
supplies are available.
This configuration minimizes the required extra
components compared with a single input supply
configuration. As it is shown the converter
voltage (Bus Voltage) is set to 5V while the IC
including the gate driver voltage are biased with
12V supply.
In order to maintain a proper start up, it is
required that the Bus Voltage ramps up first
followed by Vcc, Vc supply.
The system will be enabled when the Vp voltage
passes the under voltage lock out threshold.
Figure 5 shows start up / down sequencing.
Vo
Time
Pre-Bias Voltage
(Output Voltage before startup)
Fig. 4: Pre-Bias start up
V
5V Bus Voltage
12V (Vcc, Vc)
V_CPUCore (Vp of IR3638)
POR of IR3638
SS (IR3638)
V
out
0.65V
0.60V
Fig. 5: Start Up / Down Sequence
(Refer to Figure1)
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| IR3638STRPBF | 功能描述:電壓模式 PWM 控制器 HI FREQ SYNC PWM 400kHz 0.6V Track 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 |
| IR3640MPBF | 功能描述:IC REG CTRLR BUCK PWM VM 20-MLPQ RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:4,000 系列:- PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1.5MHz 占空比:66.7% 電源電壓:4.75 V ~ 5.25 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 85°C 封裝/外殼:40-VFQFN 裸露焊盤 包裝:帶卷 (TR) |
| IR3640MTRPBF | 功能描述:開關變換器、穩(wěn)壓器與控制器 HI FREQ SYNC PWM 4.5 to 5.5V 1.5MHz RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| IR3651 | 制造商:IRF 制造商全稱:International Rectifier 功能描述: |
| IR3651SPBF | 功能描述:IC REG CTRLR BUCK PWM VM 14-SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標準包裝:4,000 系列:- PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1.5MHz 占空比:66.7% 電源電壓:4.75 V ~ 5.25 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 85°C 封裝/外殼:40-VFQFN 裸露焊盤 包裝:帶卷 (TR) |
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