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[原创] ADI AD7284八路锂电池检测系统方案

关键词:电源管理 电池检测 AD7284

时间:2017-06-06 11:02:00       作者:ADI       来源:中电网

ADI公司的AD7284是八路锂电池检测系统,包含了混合动力汽车和备份锂电池所有的通用监测功能,电池电压精度(TUE)±3 mV,ADC分辨率14位,VDD工作电压10V-40V,片内集成了5V稳压器,主要用在锂电池检测,电动和混合动力汽车以及固定的电源应用.本文介绍了AD7284主要特性,功能框图,应用电路以及包括EV-AD7284TMSDZ(主板)和EV-AD7284SSSDZ(从板)在内的评估板AD7284主要特性和框图以及两个器件菊花链接图.

The AD7284 contains all the functions required for the general-purpose monitoring of stacked Li-Ion batteries, as used in hybrid electric vehicles and battery backup applications.

The AD7284 has multiplexed cell voltage and auxiliary, analog-to-digital converter (ADC) measurement channels supporting four to eight cells of battery management. The device provides a maximum total unadjusted error, TUE, (cell voltage accuracy) of ±3 mV that includes all the internal errors from input to output. The primary ADC resolution is 14 bits.

The AD7284 also includes an integrated secondary measurement path that validates the data on the primary ADC. Other diagnostic features include the detection of open inputs, communication, and power supply related faults.

The AD7284 cell balancing interface outputs control the external field effect transistors (FETs) to allow discharging of individual cells.
 
There are two on-chip 2.5 V voltage references: one reference for the primary measurement path, and one for the secondary measurement path.

The AD7284 operates from one VDD supply, ranging from 10 V to 40 V. The device provides eight differential analog input channels to accommodate large common-mode signals across the full VDD range. Each channel allows an input signal range, VPINx− VPIN(x − 1) and VSINx – VSIN(x − 1), of 0 V to 5 V, where x = 0 to 8. The input pins assume a series stack of eight cells. The AD7284 includes four auxiliary ADC input channels that can be used for temperature measurement or system diagnostics.

The AD7284 has a differential daisy-chain interface that allows multiple devices to be stacked without the need for individual device isolation. By design, this interface allows both device to device communication within the same module and communication between devices on different modules.

AD7284主要特性:

8 analog input channels, integrated secondary monitor
±3 mV maximum cell voltage accuracy, TUE, 14-bit ADC
Very low measurement latency across 96 cells
Stack voltage measurement
±16 mV typical battery stack voltage (TUE) accuracy
Cell balancing interface, with individually programmable on time
4 auxiliary analog input channels, 14-bit ADC
Suitable for thermistor inputs and external diagnostics
Buffered reference output for ratiometric measurements
Internal temperature sensor
VDD operating range: 10 V to 40 V
On-chip 5 V regulator
Watchdog timer
IDD matching current: 100 μA
Robust, proprietary daisy-chain interface
SPI to host controller
CRC protection on read and write commands
2 general-purpose outputs
64-lead low profile quad flat package, exposed pad (LQFP_EP)
Junction temperature range: −30℃ to +120℃
Qualified for automotive applications

AD7284应用:

Li-Ion battery monitoring
Electric and hybrid electric vehicles
Stationary power applications

图1.AD7284功能框图

图2.AD7284八电池主配置图

图3.三个AD7284菊花链配置

评估板AD7284包括EV-AD7284TMSDZ(主板)和EV-AD7284SSSDZ(从板)

The AD7284 is a complete, 14-bit resolution, lithium ion (Li-Ion) battery monitoring system, integrating multiple voltage and auxiliary analog-to-digital converter (ADC) input channels. Full details about the device are available in the AD7284 data sheet from Analog Devices, which should be consulted in conjunction with this user guide when using the evaluation kit.

This user guide describes the four evaluation kits for the AD7284: the EV-AD7284MSDZ, EV-AD7284TMSDZ (containing the AD7284 master board), EV-AD7284SSDZ, and EV-AD7284SSSDZ (containing the AD7284 mini transformer isolated slave board). On-board components on the master board include isolated power and interface using the ADuM1201 and the ADuM5401 digital isolators, and power using the ADP3303 and the ADP7104 regulators.

The AD7284 master board is used in conjunction with the EVAL-SDP-CB1Z system demonstration platform (SDP) board available from Analog Devices, which must be purchased separately from the evaluation board.

评估板AD7284主要特性:

Full featured evaluation board for the AD7284
Separate master and slave evaluation kits
Direct current daisy chain or isolated daisy-chain options
Master configuration kit
EVAL-SDP-CB1Z compatible
Standalone capability
Isolated power and interface
Slave configuration kit
To be used in conjunction with an AD7284 master evaluation kit
Direct interface to the AD7284 master board
Daisy-chain capability for chains of up to 20 devices
PC software for control and data analysis when used with the Analog Devices, Inc.,SDP, EVAL-SDP-CB1Z

评估板AD7284包括:

Four evaluation kits are available for the AD7284
Isolated daisy chain kits
EV-AD7284TMSDZ kit
EV-AD7284TMSDZ master evaluation board
USB cable
9 V (2 A) power supply
Direct current daisy chain kits
EV-AD7284MSDZ kit
EV-AD7284xSDZ master evaluation board
USB cable
9 V (2 A) power supply
EV-AD7284SSDZ kit
EV-AD7284xSDZ slave evaluation board
EV-AD7284SSSDZ kit, containing an AD7284 mini transformer isolated slave board.

图4.EV-AD7284TMSDZ(主板)框图

图6.EV-AD7284SSSDZ(从板)框图

图7.两个器件菊花链接建立图
详情请见:
http://www.analog.com/media/en/technical-documentation/data-sheets/AD7284.pdf
http://www.analog.com/media/en/technical-documentation/user-guides/EV-AD7284-UG-1010.pdf
AD7284.pdf
EV-AD7284-UG-1010.pdf

 

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