原标题：ADI AD7280A1锂离子电池监测系统解决方案

　　ADI 公司AD7280A1是12位ADC,包括了监测锂离子电池组监测系统所有功能,主要用混合动力汽车,备份电池和电动工具等.AD7280A1具有内部±3 ppm/℃的基准电压,电池电压精度±1.6 mV,器件工作电压8V-30V.本文介绍AD7280A1主要特性,方框图,六个电池的配置框图和菊花链配置图,以及AD7280A锂离子电池监测系统评估板方框图,电路图,材料清单和PCB元件配置图.

　　The AD7280A1 contains all the functions required for general- purpose monitoring of stacked lithium ion batteries as used in hybrid electric vehicles, battery backup applications, and power tools. The part has multiplexed cell voltage and auxiliary ADC measurement channels for up to six cells of battery management. An internal ±3 ppm/℃ reference is provided that allows a cell voltage accuracy of ±1.6 mV. The ADC resolution is 12 bits and allows conversion of up to 48 cells within 7 μs. The AD7280A operates from a single VDD supply that has a range of 8 V to 30 V (with an absolute maximum rating of 33 V). The part provides six differential analog input channels to accommodate large common-mode signals across the full VDD range. Each channel allows an input signal range, VIN(+) −VIN(−), of 1 V to 5 V. The input pins assume a series stack of six cells. In addition, the part includes six auxiliary ADC input channels that can be used for temperature measurement or system diagnostics. The AD7280A includes on-chip registers that allow a sequence of channel measurements to be programmed to suit the application requirements.

　　The AD7280A also includes a dynamic alert function that can detect whether the cell voltages or auxiliary ADC inputs exceed an upper or lower limit defined by the user. The AD7280A has cell balancing interface outputs designed to control external FET transistors to allow discharging of individual cells. The AD7280A includes a built-in self-test feature that internally applies a known voltage to the ADC inputs. A daisy-chain interface allows up to eight parts to be stacked without the need for individual device isolation. The AD7280A requires only one supply pin that accepts 6.9 mA under normal operation while converting at 1 MSPS. All this functionality is provided in a 48-lead LQFP package operating over a temperature range of −0℃ to +105℃.

　　AD7280A1主要特性:

　　12-bit ADC, 1 μs per channel conversion time

　　6 analog input channels, common-mode range 0.5 V to 27.5 V

　　6 auxiliary ADC inputs

　　±1.6 mV cell voltage accuracy

　　On-chip voltage regulator

　　Cell balancing interface

　　Daisy-chain interface

　　Internal reference: ±3 ppm/oC 1.8 μA power-down current

　　High input impedance

　　Serial interface with alert function

　　1 SPI interface for up to 48 channels

　　CRC protection on read and write commands

　　On-chip registers for channel sequencing

　　VDD operating range: 8 V to 30 V

　　Temperature range: −0℃ to +105℃

　　48-lead LQFP

　　Qualified for automotive applications

　　AD7280A1应用:

　　Lithium ion battery monitoring

　　Electric and hybrid electric vehicles

　　Power supply backup

　　Power tools

　　图1.AD7280A1方框图

　　图2.AD7280A1六个电池的配置框图

　　图3.AD7280A1菊花链配置图

　　图4.AD7280A1电池平衡配置图

　　AD7280A锂离子电池监测系统评估板

　　Lithium Ion Battery Stack Monitor with Both Signal and Power Isolation(CN0197

　　Lithium ion (Li-Ion) battery stacks contain a large number of individual cells that must be monitored correctly in order to enhance the battery efficiency and prolong the battery life. The 6-channel AD7280A devices in the circuit shown in Figure 1 act as the primary monitor providing accurate measurement data to the Battery Management Controller (BMC).

　　The AD7280A contains an internal ±3 ppm reference that allows a cell voltage measurement accuracy of ±1.6 mV. The ADC resolution is 12 bits and allows conversion of up to 48 cells within 7 μs.

　　The AD7280A, which resides on the high voltage side of the Battery Management System (BMS) has a daisy-chain interface, which allows up to eight AD7280A’s to be stacked together and allows for 48 Li-Ion cell voltages to be monitored. Adjacent AD7280A’s in the stack can communicate directly, passing data up and down the stack without the need for isolation. The AD7280A master device on the bottom of the stack uses the SPI interface to communicate with the BMC, and it is only at this point that high voltage galvanic isolation is required in order to protect the low-voltage side of the BMS. The ADuM1201 digital isolator and the ADuM5401 isolator with integrated dc-to-dc converter combine to provide the required six channels of isolation in a compact and cost effective solution.

　　This user guide describes the evaluation board kit for the AD7280A (EVAL-AD7280AEDZ), which is a complete, 12-bit resolution lithium ion battery monitoring system, integrating multiple voltage and temperature input channels. Full details about the part are available in the AD7280A data sheet from Analog Devices, Inc., which should be consulted in conjunction with this user guide when using the evaluation board.

　　On-board components include the ADG3308 and ADG3301 bidirectional logic level translators, the ADG849 switch and the ADuM1201, and the ADuM5401 digital isolators.

　　AD7280A锂离子电池监测系统主要特性:

　　Full-featured evaluation board for the AD7280A

　　EVAL-CED1Z compatible

　　Standalone capability

　　Various linking options

　　Daisy chain capability

　　PC software for control and data analysis when used with the EVAL-CED1Z

　　图5.AD7280A锂离子电池监测系统方框图

　　AD7280A锂离子电池监测系统材料清单: