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| 型号： | IRU3046CFTR |
| 厂商： | International Rectifier |
| 文件页数： | 5/20页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 24TSSOP |
| 标准包装： | 1 |
| PWM 型： | 电压模式 |
| 输出数： | 2 |
| 频率 - 最大： | 450kHz |
| 占空比： | 90% |
| 电源电压： | 5 V ~ 12 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | 0°C ~ 70°C |
| 封装/外壳： | 24-TSSOP（0.173"，4.40mm 宽） |
| 包装： | 剪切带 (CT) |
| 产品目录页面： | 1384 (CN2011-ZH PDF) |
| 其它名称： | *IRU3046CFTR IRU3046CFCT |
IRU3046
THEORY OF OPERATION
Introduction
The IRU3046 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 can be
configured as two independent controller or 2-phase con-
troller with current sharing. The timing of the IC is pro-
vided through an internal oscillator circuit. These are two
out of phase oscillators and can be programmed by us-
ing an external resistor from 200KHz to 400KHz per
phase. Figure 11 shows switching frequency versus ex-
ternal resistor.
Soft-Start
The IRU3046 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, VcH2, VccLDO
and V SEN 33 rise above their threshold and generates the
Power On Reset (POR) signal. Soft-start function oper-
ates by sourcing an internal current to charge an exter-
nal capacitor to about 3V. Initially, the soft-start function
clamps the E/A’s output of the PWM converter. As the
charging voltage of the external capacitor ramps up, the
PWM signals increase from zero to the point the feed-
back loop takes control.
Independent Mode
In this mode the IRU3046 provides two independent out-
puts with either common or different input voltages. The
output voltage of the individual channel is set and con-
trolled by the output of the error amplifier, this is the
amplified error signal from the sensed output voltage and
the reference voltage. This voltage is compared to the
ramp signal and generates fixed frequency pulses of vari-
able duty-cycle, which drives the two N-channel exter-
nal MOSFETs.
Current Sharing Mode
In the current sharing mode, the two converter’s outputs
tied together and provide one single output (see Figure
1). In this mode, one control loop acts as a master and
sets the output voltage as a regular Voltage Mode buck
controller and the other control loop acts as a slave and
monitors the current information for current sharing. The
current sharing is programmable and sets by using two
external resistors in output currents’ path. The slave's
error amplifier, error amplifier 2 (see Block Diagram) mea-
sures the voltage drops across the current sense resis-
tors, the differential of these signals is amplified and
compared with the ramp signal and generate the fixed
frequency pulses of variable duty cycle to match the
output currents.
Out of Phase Operation
The IRU3046 drives its two output stages 180 o out of
phase. In 2-phase configuration, the two inductor ripple
currents cancel each other and result to a reduction of
the output current ripple and contribute to a smaller out-
put capacitor for the same ripple voltage requirement.
In application with single input voltage, the 2-phase con-
figuration reduces the input ripple current. This results in
much smaller RMS current in the input capacitor and
reduction of input capacitor.
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.
Power Good
The IRU3046 provides a power good signal. This is an
open collector output and it is pulled low if the output
voltages are not within the specified threshold. This pin
can be left floating if not used.
Short-Circuit Protection
The outputs are protected against the short circuit. The
IRU3046 protects the circuit for shorted output by sens-
ing the output voltages. The IRU3046 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.
Frequency Synchronization
The IRU3046 can be synchronized with an external clock
signal. The synchronizing pulses must have a minimum
pulse width of 100ns. If the sync function is not used,
the Sync pin can be either connected to ground or be
floating.
Rev. 1.9
09/27/02
www.irf.com
5
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相关代理商/技术参数 |
参数描述 |
|---|---|
| IRU3046CFTRPBF | 制造商:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER WITH CURRENT SHARING CIRCUITRY AND LDO CONTROLLER |
| IRU3047 | 制造商:IRF 制造商全称:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER WITH CURRENT SHARING CIRCUITRY AND LDO CONTROLLER |
| IRU3047CW | 制造商:IRF 制造商全称:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER WITH CURRENT SHARING CIRCUITRY AND LDO CONTROLLER |
| IRU3047CWTR | 功能描述:IC REG CTRLR BUCK PWM VM 20-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| IRU3048 | 制造商:IRF 制造商全称:International Rectifier 功能描述:DUAL SYNCHRONOUS PWM CONTROLLER CIRCUITRY AND LDO CONTROLLER |
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