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參數(shù)資料
| 型號： | IRU3048CF |
| 廠商： | International Rectifier |
| 元件分類： | 基準(zhǔn)電壓源/電流源 |
| 英文描述： | DUAL SYNCHRONOUS PWM CONTROLLER CIRCUITRY AND LDO CONTROLLER |
| 中文描述： | 雙同步PWM控制器電路和LDO控制器 |
| 文件頁數(shù)： | 5/18頁 |
| 文件大小： | 154K |
| 代理商： | IRU3048CF |
IRU3048
5
Rev. 1.7
09/12/02
www.irf.com
THEORY OF OPERATION
Introduction
The IRU3048 is designed for multi-outputs applications.
It includes two synchronous buck controllers and a lin-
ear regulator controller. The two synchronous controller
operates with fixed frequency voltage mode and is con-
figured as two independent controllers. The timing of the
IC is provided through an internal oscillator circuit. These
are two out of phase oscillators.
Soft-Start
The IRU3048 has a programmable soft start to control
the output voltage rise and limit the current surge at the
start-up. To ensure correct start-up, the soft-start se-
quence initiates when the Vcc, VcH1 and VcH2 rise
above their threshold and generates the Power On Re-
set (POR) signal. Soft-start function operates by sourc-
ing an internal current to charge an external capacitor to
about 3V. Initially, the soft-start function clamps the E/
A’s output of the PWM converter. As the charging volt-
age of the external capacitor ramps up, the PWM sig-
nals increase from zero to the point the feedback loop
takes control.
Out of Phase Operation
The IRU3048 drives its two output stages 180
8
out of
phase. In application with single input voltage, the out of
phase operation reduces the input ripple current. This
results in much smaller RMS current in the input ca-
pacitor and reduction of input capacitors.
Shutdown
The converter can be shutdown by pulling the soft-start
pin below 0.5V. This can be easily done by using an
external small signal transistor. During shutdown the
MOSFET drivers and the LDO controller turn off.
Short-Circuit Protection
The outputs are protected against the short circuit. The
IRU3048 protects the circuit for shorted output by sens-
ing the output voltages. The IRU3048 shuts down the
PWM signals and LDO controller, when the output volt-
ages drops below the set values.
Under-Voltage Lockout
The under-voltage lockout circuit assures that the
MOSFET driver outputs and LDO controller remain in
the off state whenever the supply voltages drop below
set parameters. Normal operation resumes once the
supply voltages rise above the set values.
APPLICATION INFORMATION
Design Example:
The following example is a typical application for IRU3048
in current sharing mode. The schematic is Figure 9 on
page 12.
For Switcher
V
IN1
= 12V
V
OUT1
= 3.3V
I
OUT1
= 4A
V
IN2
= 5V
V
OUT2
= 1.8V
I
OUT2
= 4A
V
OUT
= 75mV
f
S
= 200KHz
PWM Section
Output Voltage Programming
Output voltage is programmed by reference voltage and
external voltage divider. The Fb1 pin is the inverting input
of the error amplifier, which is internally referenced to
1.25V. The divider is ratioed to provide 1.25V at the Fb1
pin when the output is at its desired value. The output
voltage is defined by using the following equation:
Fb1
IRU3048
V
OUT1
R
8
R
6
When an external resistor divider is connected to the
output as shown in Figure 3.
Figure 3 - Typical application of the IRU3048 for
programming the output voltage.
Equation (1) can be rewritten as:
( )
V
OUT1
= V
REF
×
1+
---(1)
( )
R
6
R
8
Will result to:
V
OUT1
=3.3V
V
REF
=1.25V
R
8
=1K, R
6
=1.64K
V
OUT2
=1.8V
V
REF
=1.25V
R
15
=1K, R
14
=442
R
6
= R
8
×
- 1
V
OUT1
V
REF
For Linear Regulator
V
IN3
= 3.3V
V
OUT3
= 2.5V
I
OUT3
= 2A
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| IRU3048CFTR | 功能描述:IC REG CTRLR BUCK PWM VM 16TSSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:75 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.3 V ~ 13.5 V 降壓:是 升壓:是 回掃:是 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:0°C ~ 70°C 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:管件 產(chǎn)品目錄頁面:1051 (CN2011-ZH PDF) 其它名稱:296-2543-5 |
| IRU3048CS | 制造商:IRF 制造商全稱:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER CIRCUITRY AND LDO CONTROLLER |
| IRU3048CSTR | 功能描述:IC REG CTRLR BUCK PWM VM 16-SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:75 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:1MHz 占空比:81% 電源電壓:4.3 V ~ 13.5 V 降壓:是 升壓:是 回掃:是 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:0°C ~ 70°C 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:管件 產(chǎn)品目錄頁面:1051 (CN2011-ZH PDF) 其它名稱:296-2543-5 |
| IRU3048CSTRPBF | 制造商:International Rectifier 功能描述:Dual Synchronous PWM Controller Circuitry and LDO Controller 16-Pin SOIC N T/R |
| IRU3055 | 制造商:IRF 制造商全稱:International Rectifier 功能描述:5-BIT PROGRAMMABLE 3-PHASE SYNCHRONOUS BUCK CONTROLLER IC |
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