參數(shù)資料
型號: DS2782
廠商: Maxim Integrated Products, Inc.
英文描述: Stand-Alone Fuel Gauge IC
中文描述: 獨立式電量計IC
文件頁數(shù): 15/25頁
文件大?。?/td> 291K
代理商: DS2782
DS2782: Stand-Alone Fuel Gauge IC
15 of 25
Minimum Charge Current (IMIN):
IMIN
stores the charge current threshold used to detect a fully charged state.
The value is stored as a 1-byte value with units of 50 V and can range from 0 to 12.75mV. Assuming RSNS =
20m , IMIN can be programmed from 0mA to 637.5mA in 2.5mA steps. IMIN should be set marginally greater than
the charge current at the end of the charge cycle to ensure reliable charge termination detection. IMIN is located in
the Parameter EEPROM block.
Active Empty Voltage (VAE):
VAE stores the voltage threshold used to detect the Active Empty point. The value
is stored in 1-byte with units of 19.52mV and can range from 0V to 4.978V. VAE is located in the Parameter
EEPROM block. See the
Cell Characteristics
section for more information.
Active Empty Current (IAE):
IAE
stores the discharge current threshold used to detect the Active Empty point.
The unsigned value represents the magnitude of the discharge current and is stored in 1-byte with units of 200 V
and can range from 0 to 51.2mV. Assuming RSNS = 20m , IAE can be programmed from 0mA to 2550mA in
10mA steps. IAE is located in the Parameter EEPROM block. See the
Cell Characteristics
section for more
information.
Aging Capacity (AC):
AC stores the rated battery capacity used in estimating the decrease in battery capacity that
occurs in normal use. The value is stored in 2-bytes in the same units as the ACR (6.25 Vh). Setting AC to the
manufacturer’s rated capacity sets the aging rate to approximately 2.4% per 100 cycles of equivalent full capacity
discharges. Partial discharge cycles are added to form equivalent full capacity discharges. The default estimation
results in 88% capacity after 500 equivalent cycles. The estimated aging rate can be adjusted by setting AC to a
different value than the cell manufacturer’s rating. Setting AC to a lower value, accelerates the estimated aging.
Setting AC to a higher value, retards the estimated aging. AC is located in the Parameter EEPROM block.
Age Scalar (AS):
AS adjusts the capacity estimation results downward to compensate for cell aging. AS is a 1-byte
value that represents values between 49.2% and 100%. The lsb is weighted at 0.78% (precisely 2
). A value of
100% (128 decimal or 80h) represents an un-aged battery. A value of 95% is recommended as the starting AS
value at the time of pack manufacture to allow learning a larger capacity on batteries that have an initial capacity
greater than the nominal capacity programmed in the cell characteristic table. AS is modified by the cycle count
based age estimation introduced above and by the capacity Learn function. The host system has read and write
access to AS, however caution should exercised when writing AS to ensure that the cumulative aging estimate is
not over written with an incorrect value. Usually, writing AS by the host is not necessary because AS is
automatically saved to EEPROM on a periodic basis by the DS2782. (See the
Memory
section for details.) The
EEPROM stored value of AS is recalled on power-up.
CAPACITY ESTIMATION UTILITY FUNCTIONS
Aging Estimation
As discussed above, the AS register value is adjusted occasionally based on cumulative discharge. As the ACR
register decrements during each discharge cycle, an internal counter is incremented until equal to 32 times AC. AS
is then decremented by one, resulting in a decrease in the scaled full battery capacity of 0.78%. Refer to the AC
register description above for recommendations on customizing the age estimation rate.
Learn Function
Since Li+ cells exhibit charge efficiencies near unity, the charge delivered to a Li+ cell from a known empty point to
a known full point is a dependable measure of the cell capacity. A continuous charge from empty to full results in a
“l(fā)earn cycle”. First, the Active Empty point must be detected. The Learn Flag (
LEARNF
) is set at this point. Then,
once charging starts, the charge must continue uninterrupted until the battery is charged to full. Upon detecting full,
LEARNF
is cleared, the Charge to Full (
CHGTF
) flag is set and the Age Scalar (AS) is adjusted according to the
learned capacity of the cell.
ACR Housekeeping
The ACR register value is adjusted occasionally to maintain the coulomb count within the model curve boundaries.
When the battery is charged to full (
CHGTF
set), the ACR is set equal to the age scaled full lookup value at the
present temperature. If a learn cycle is in progress, correction of the ACR value occurs after the age scalar (AS) is
updated.
相關(guān)PDF資料
PDF描述
DS3234 Extremely Accurate SPI Bus RTC with Integrated Crystal and SRAM
DS3234S Extremely Accurate SPI Bus RTC with Integrated Crystal and SRAM
DS3234SN Extremely Accurate SPI Bus RTC with Integrated Crystal and SRAM
DS33Z11 Ethernet Mapper
DS33ZH11 Ethernet Mapper
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS2782_09 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Stand-Alone Fuel Gauge IC
DS2782BE 制造商:Maxim Integrated Products 功能描述:STAND ALONE FG IC 2WIRE 8P TSSOP - Rail/Tube
DS2782BE/T&R 制造商:Maxim Integrated Products 功能描述:STAND ALONG FG IC 2WIRE 8P TSSOP TR - Tape and Reel
DS2782E+ 功能描述:電池管理 Stand-Alone Fuel Gauge RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel
DS2782E+R 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Stand-Alone Fuel Gauge IC