基于Freescale的MC34704多路DC电源管理方案

Freescale 公司的34704A(8路)或34704B(5路)是多路开关电源稳压器,输出电压精度高达±2%,可用来管理各种多媒体应用的微处理器的电源.从单个电源输入(2.7V-5.5V),可提供5路或8路独立的输出电压.开关频率高达2MHz,非常适合手持设备的应用.本文介绍MC34704A/B主要特性,方框图,典型应用电路以及两种评估板电路图与材料清单(BOM):

MulTIple Channel DC-DC Power Management IC

The 34704 is a mulTI-channel Power Management IC (PMIC) used to address power management needs for various mulTImedia applicaTIon microprocessors. Its ability to provide either 5 or 8 independent output voltages with a single input power supply (2.7 and 5.5V) together with its high efficiency, make it ideal for portable devices powered up by Li-Ion/polymer batteries or for USB powered devices as well.

The 34704 is housed in a 7x7mm, Pb-free, QFN56 and is capable of operating at a switching frequency of up to 2MHz. This makes it possible to reduce external component size and to implement full space efficient power management solutions.

MC34704主要特性:

•8 DC/DC (34704A) or 5 DC/DC (34704B) switching regulators with up to ±2% output voltage accuracy

•Dynamic voltage scaling on all regulators.

•Selectable voltage mode control or current mode control on REG8

•I2C programmability

•Output under-voltage and over-voltage detection for each regulator

•Over-current limit detection and short-circuit protection for each regulator

•Thermal limit detection for each regulator, except REG7

•Integrated compensation for REG1, REG3, REG6, and REG8

•5.0μA maximum shutdown current (All regulators are off, 5.5V VIN)

•True cutoff on all of the boost and buck-boost regulators

•Pb-free packaging designated by suffix code EP


图1.MC34704简化应用框图

图2.MC34704内部方框图

图3.MC34704A典型应用框图

图4.MC34704B典型应用框图

KIT34704AEPEVBE 8路评估板


图5.KIT34704AEPEVBE 8路评估板外形图

This Evaluation Board demonstrates the capability of the MC34704A as a multi-channel power management IC (PMIC) meant to address power management needs for various multimedia application microprocessors. It provides 8 independent voltages through a terminal block connector for an easier out-of-the-box evaluation. A single terminal block connector for input power supply allows the user to supply the board with either a external DC power supply or a Li-Ion battery to fully evaluate the performance accordingly.

The KIT34704AEPEVBE has the ability to program the switching frequency of regulators 1 through 5 as well as the default soft start timing for all regulators during startup by changing few external components. All other features can be programmed via I2C communication using a standard 100mils 4-pin header to communicate with either the USB-I2C bridge included in this package or with any other I2C communication device preferred by the user.

KIT34704AEPEVBE 8路评估板主要特性:

•Input voltage operation range from 2.7V to 5.5V

•8 independent output voltages, accessible through terminal blocks.

•Capable to be programmed via I2C

•On/Off push button

•Programable Switching frequency for REG1-5 by changing external components

•Programable default soft start for all regulators by changing external components

•100mils 4-pin standard header connector for I2C communication

•Small Board Size (6.2cm x 6.2cm)

KIT34704AEPEVBE 8路评估板内容:

•KIT34704AEPEVBE

•KITUSBI2CEVME - USB to I2C bridge board for controlling PMIC

•USB A-B Cable

•4-pin female to female I2C communication cable

•CD34704A


图6.KIT34704AEPEVBE评估板电路图

KIT34704AEPEVBE评估板材料清单(BOM):




图7.KITUSBI2CEVME电路图(1)


图8.KITUSBI2CEVME电路图(2)

KITUSBI2CEVME材料清单(BOM):