雙輸出多相電流模式同步控制方案

ADI公司的LTCR7852/LTC7852-1是6相雙輸出電流模式同步降壓開關(guān)穩(wěn)壓器控制器，和外接功率器件如DrMOS，功率區(qū)塊或分立N溝MOSFET和相關(guān)的柵極驅(qū)動器。它可以進(jìn)行1-，2-，3-，4-，5-和6相配置。采用兩個IC并聯(lián)可配置成8-，10和12相，以得到高達(dá)400A電流。亞毫歐姆DCR檢測或DrMOS電流檢測改善了效率，總輸出電壓精度±0.5%，具有靈活的相位配置和雙輸出電流監(jiān)視，雙差分遙測放大器，可編頻率范圍從250kHz到1.2MHz，VIN范圍不受IC所限，VCC范圍4.5V-5.5V，VOUT范圍從0.5V到2.0V.主要用在計(jì)算機(jī)系統(tǒng)，通信和數(shù)據(jù)系統(tǒng)以及DC電源分布系統(tǒng)。本文介紹了LTC7852-1主要特性，功能框圖，典型應(yīng)用電路和多種應(yīng)用電路，以及演示板DC2631A主要特性，框圖，測試建立圖，以及電路圖，材料清單和PCB設(shè)計(jì)圖。

The LTCR7852/LTC7852-1 is a six-phase， dual outputcurrent mode synchronous step-down switching regulatorcontroller that works in conjunction with externalpower train devices such as DrMOS， power blocks ordiscrete N-channel MOSFETs and associated gate drivers.

Its flexible design enables 1-， 2-， 3-， 4-， 5-， and 6-phaseconfigurations. The LTC7852 offers a unique feature thatenhances the signal-to-noise ratio of the current sensesignal， allowing the use of inductors with very low DCwinding resistances for maximum efficiency. The controllerachieves a minimum on-time of just 40ns， permitting theuse of high switching frequency at high step-down ratios.

8-， 10- or 12 phases with two ICs can be paralleled forvery high current requirements up to 400A.The remote sense differential amplifiers and a precisereference provide accurate output voltages between 0.5Vand 2.0V. The input voltage is not limited by the controller. Hiccup mode protection from output shorts or overcurrentminimizes the thermal dissipation.

The LTC7852-1 is designed specifically for DrMOS withan internal current sense signal.

LTC7852-1主要特性：

Sub-Milliohm DCR Sensing or DrMOS with CurrentSense Improves Efficiency

Operates with Power Blocks， DrMOS or ExternalGate Drivers and MOSFETs

±0.5% Total Output Voltage Accuracy

Flexible Phase Configuration

Dual Output Current Monitoring

tON（MIN） = 40ns， Capable of Very Low Duty Cycles atHigh Frequency

Dual Differential Remote Sensing Amplifiers

Programmable Frequency Range of 250kHz to 1.2MHz

VIN Range Is Not Limited by IC

VCC Range： 4.5V to 5.5V

VOUT Range： 0.5V to 2.0V

48 Lead （5mm × 6mm） GQFN for LTC7852

36 Lead （4mm × 5mm） QFN for LTC7852-1

LTC7852-1應(yīng)用：

Computer Systems

Telecom and Datacom Systems

DC Power Distribution Systems

圖1.LTC7852-1典型應(yīng)用電路

圖2.LTC7852-1功能框圖

圖3.帶分立驅(qū)動器和MOSFET的LTC7852單輸出6相1V/200A轉(zhuǎn)換器電路

圖4.帶DRMOS的LTC7852雙輸出4相0.9V/120A和2相1.2V/60A轉(zhuǎn)換器電路

演示板DC2631A

Demonstration circuit 2631A features the LTC?7852 in two high output current， high efficiency step down converters each with its own assembly type. The converter for the -A assembly provides two 3-phase outputs of 1.0V/100A and 1.5V/100A. The -B assembly provides a single 6-phase 1.0V/200A output. Block diagrams are shown in Figure 3. Both converters operate over a 7V to 14V input voltage range at a switching frequency of 400kHz.

The power stage for each phase consists of a 5mm × 5mm DrMOS and 11.3mm × 11.0mm 0.25μH ferrite inductor with a DCR of 0.32mΩ typical. The LTC7852 employs a peak current mode architecture which allows accurate DCR sensing and sharing with sub-mOhm DCR inductors. The LTC7852 provides a three-state compatible PWM output for each DrMOS.

演示板DC2631A主要特性：

Additional features of the DC2631A include：

lDifferential sensing for the output voltages of VOUT1 and VOUT2

lIMON pins to monitor the inductor current of each rail.

l Optional resistors and jumpers to change the phase arrangement for VOUT1 and VOUT2：

q VOUT1： 4ph， VOUT2： 2ph

q VOUT1： 5ph， VOUT2： 1ph

q Note， the default arrangement is： VOUT1： 3ph， VOUT2： 3ph

l Optional resistors and jumpers to parallel VOUT1 and VOUT2.

l RUN， PGOOD， PLLIN and CLKOUT pins

The LTC7852 data sheet provides a complete descrip-tion of the IC operation and application information. The data sheet must be read in conjunction with the quick start guide.

圖5.演示板DC2631A-A測試建立圖

圖6.演示板DC2631A-B測試建立圖

圖7.演示板DC2631A-A/DC2631B-B框圖

圖8.演示板DC2631A電路圖（1）

圖9.演示板DC2631A電路圖（2）

演示板DC2631A-A材料清單：

演示板DC2631A-B材料清單：

圖10.演示板DC2631A PCB設(shè)計(jì)圖（1）

圖11.演示板DC2631A PCB設(shè)計(jì)圖（2）

圖12.演示板DC2631A PCB設(shè)計(jì)圖（3）

圖13.演示板DC2631A PCB設(shè)計(jì)圖（4）

圖14.演示板DC2631A PCB設(shè)計(jì)圖（5）

圖15.演示板DC2631A PCB設(shè)計(jì)圖（6）

圖16.演示板DC2631A PCB設(shè)計(jì)圖（7）

圖17.演示板DC2631A PCB設(shè)計(jì)圖（8）

圖18.演示板DC2631A PCB設(shè)計(jì)圖（9）