參數(shù)資料
型號(hào)： bq2945
廠商： Benchmark Technology Group
英文描述： Gas Gauge IC with SMBus Interface(Gas Gauge芯片（帶SMBus 接口）)
中文描述： 氣體計(jì)IC，帶有SMBus接口（電量監(jiān)測(cè)計(jì)芯片（帶的SMBus接口））
文件頁(yè)數(shù)： 9/32頁(yè)
文件大?。?/td> 256K
代理商： BQ2945
the current drops below 256mA and the voltage is
less than 105% of ChargingVoltage.
Overcurrent:
An overcurrent fault exists when the
bq2945 measures a charge current more than 25%
above the ChargingCurrent. If the ChargingCurrent
is less than 1024mA, an overcurrent fault exists if the
charge current is more than 256mA above the
ChargingCurrent.
When the bq2945 detects an
overcurrent condition, the requested charge current
is set to 0 and the Terminate_Charge_Alarm bit is set
in Battery Status. The alarm bit is cleared when the
current drops below 256mA.
Maximum
temperature exceeds the programmed maximum
temperature, the requested charge current is set to
zero
and
the
Over_Temp_Alarm
Terminate_Charge_Alarm bits are set in Battery
Status.
The
alarm
bits
temperature drops below 50
°
C.
Temperature
:
When
the
battery
and
the
are
cleared
when
the
Low Temperature:
When the battery temperature
is less than 0
°
C, the requested charge current is set
to the maintenance rate.
above 5
°
C, the requested charge current is set to the
fast rate.
Once the temperature is
Undervoltage:
When the battery voltage is below
the EDVF threshold, the requested charge current is
set to the maintenance rate.
above EDVF, the requested charge current is set to
the fast rate.
Once the voltage is
Count Compensations
Charge activity is compensated for temperature and
state-of-charge before updating the RM and/or DCR.
Self-discharge estimation is compensated for tempera-
ture before updating RM or DCR.
Charge Compensation
Charge efficiency is compensated for state-of-charge,
temperature, and battery chemistry.
ciency is adjusted using the following equations:
The charge effi-
1.)RM
RM *
Q
(
Q
EFC
ET
=
)
where RelativeStateOfCharge < FullChargePercentage,
and Q
is the programmed fast-charge efficiency vary-
ing from 0.75 to 1.0.
2.)RM
RM
Q
Q
ETC
ET
=
* (
)
where RelativeStateOfCharge
≥
FullChargePercentage
and Q
is the programmed maintenance (trickle)
charge efficiency varying from 0.75 to 1.0.
Q
is used to adjust the charge efficiency as the battery
temperature increases according to the following:
Q
if T
ET
=
<
0
30
°
C
Q
C
T
C
ET
=
°
≤
<
°
002
.
30
40
if
Q
T
C
ET
=
≥
°
005
.
40
if
Q
ET
is 0 over the entire temperature range for Li-Ion.
Digital Magnitude Filter
The bq2945 has a programmable digital filter to elimi-
nate charge and discharge counting below a set
threshold, V
SRD
. Table 2 shows typical digital filter
settings. The proper digital filter setting can be calcu-
lated using the following equation.
DMF =
45
V
SRD
Error Summary
Capacity Inaccurate
The FCC is susceptible to error on initialization or if no
updates occur. On initialization, the FCC value includes
the error between the design capacity and the actual ca-
pacity. This error is present until a qualified discharge
occurs and FCC is updated (see the DCR description).
The other cause of FCC error is battery wear-out. As
the battery ages, the measured capacity must be ad-
justed to account for changes in actual battery capacity.
Periodic qualified discharges from full to empty will
minimize errors in FCC.
Current-Sensing Error
Table 3 illustrates the current-sensing error as a function
of V
SR
. A digital filter eliminates charge and discharge
counts to the RM register when -V
SRD
< V
SRO
< + V
SRD
.
Display
The bq2945 can directly display capacity information
using low-power LEDs. The bq2945 displays the battery
charge state in either absolute or relative mode. In rela-
tive mode, the battery charge is represented as a per-
centage of the FCC. Each LED segment represents 20%
of the FCC.
9
bq2945
DMF
DMF Hex.
V
SRD
(mV)
75
4B
0.60
0.45
0.30
0.26
0.23
100
150
175
200
64
96
AF
C8
Table 2. Typical Digital Filter Settings
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
BQ294502 制造商:TI 制造商全稱:Texas Instruments 功能描述:Overvoltage Protection for 2-Series and 3-Series Cell Li-Ion Batteries
BQ294502DRVR 功能描述:電池管理 Overvltg Prot Device 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
BQ294502DRVT 功能描述:電池管理 Overvltg Prot Device 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
BQ294502EVM-033 功能描述:電源管理IC開發(fā)工具 bq294502 Eval Mod RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V
BQ294504 制造商:TI 制造商全稱:Texas Instruments 功能描述:Overvoltage Protection for 2-Series and 3-Series Cell Li-Ion Batteries
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