参数资料
型号: IR3081
厂商: International Rectifier
英文描述: XPHASE VR 10.0 CONTROL IC
中文描述: XPHASE村10.0控制IC
文件页数: 12/20页
文件大小: 396K
代理商: IR3081
IR3081
Page 12 of 20
9/1/03
The IR3081 can accept changes in the VID code while operating and vary the DAC voltage accordingly. The
sink/source capability of the VDAC buffer amp is programmed by the same external resistor that sets the oscillator
frequency. The slew rate of the voltage at the VDAC pin can be adjusted by an external capacitor between VDAC
pin and the VOSNS- pin. A resistor connected in series with this capacitor is required to compensate the VDAC
buffer amplifier. Digital VID transitions result in a smooth analog transition of the VDAC voltage and converter
output voltage minimizing inrush currents in the input and output capacitors and overshoot of the output voltage.
It is desirable to prevent negative inductor currents in response to a request for a lower VID code. Negative current
transforms the buck converter into a boost converter and transfers energy from the output capacitors back into the
input voltage. This energy can cause voltage spikes and damage the silver box or other components unless they
are specifically designed to handle it. Furthermore, power is wasted during the transfer of energy from the output
back to the input.
The IR3081 includes circuitry that turns off both control and synchronous MOSFETs in response to a lower VID
code so that the load current discharges the output capacitors instead of the inductors. A lower VID code is
detected by the VID step-down detect comparator which monitors the “fast” output of the DAC (plus 7mV for noise
immunity) compared to the “slow” output of the VDAC pin. If a dynamic VID step down is detected, the body brake
latch is set and the output of the error amplifier is pulled down to 75% of the DAC voltage by the VID body brake
clamp. This triggers the Body Braking
function in the phase ICs causing them to turn off both their drivers.
The converter’s output voltage needs to be monitored and compared to the VDAC voltage to determine when to
resume normal operation. Unfortunately, the voltage on the FB pin can be pulled down by its compensation network
during the sudden decrease in the Error Amp’s output voltage so an additional pin BBFB is provided. The BBFB pin
is connected to the converter output voltage and VDRP pin with resistors of the same value as on the FB pin and
therefore provides an un-corrupted representation of converter output voltage. The regulation detect comparator
compares the BBFB to the VDAC voltage and resets the body brake latch releasing the error amp’s output and
allowing normal operation to resume. Body Braking
during a transition to a lower VID code can be disabled by
connecting the BBFB pin to ground.
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IR3081A 制造商:IRF 制造商全称:International Rectifier 功能描述:XPHASETM VR 10 CONTROL IC
IR3081AM 制造商:IRF 制造商全称:International Rectifier 功能描述:XPHASETM VR 10 CONTROL IC
IR3081AMPBF 功能描述:IC CTRLR XPHASE VR10.0 28MLPQ RoHS:是 类别:集成电路 (IC) >> PMIC - 电源管理 - 专用 系列:XPhase™ 应用说明:Ultrasound Imaging Systems Application Note 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:37 系列:- 应用:医疗用超声波成像,声纳 电流 - 电源:- 电源电压:2.37 V ~ 6 V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:56-WFQFN 裸露焊盘 供应商设备封装:56-TQFN-EP(8x8) 包装:管件
IR3081AMPBF 制造商:International Rectifier 功能描述:Controller IC Package/Case:28-MLPQ
IR3081AMTR 制造商:IRF 制造商全称:International Rectifier 功能描述:XPHASETM VR 10 CONTROL IC