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參數(shù)資料
| 型號： | LTC4150IMS |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 模擬信號調(diào)理 |
| 英文描述： | Coulomb Counter/ Battery Gas Gauge |
| 中文描述： | SPECIALTY ANALOG CIRCUIT, PDSO10 |
| 封裝： | PLASTIC, MSOP-10 |
| 文件頁數(shù)： | 7/12頁 |
| 文件大?。?/td> | 136K |
| 代理商： | LTC4150IMS |
LTC4150
7
4150fa
SENSE VOLTAGE INPUT AND FILTERS
Since the overall integration time is set by internally
trimming the LTC4150, no external timing capacitor or
trimming is necessary. The only external component that
affects the transfer function of interrupts per coulomb of
charge is the sense resistor, R
SENSE
. The common mode
range for the SENSE
+
and SENSE
–
pins is V
DD
±
60mV, with
a maximum differential voltage range of
±
50mV. SENSE
+
is normally tied to V
DD
, so there is no common mode issue
when SENSE
–
operates within the 50mV differential limit
relative to SENSE
+
.
Choose R
SENSE
to provide 50mV drop at maximum charge
or discharge current, whichever is greater. Calculate R
SENSE
from:
R
mV
I
SENSE
MAX
=
50
(1)
The sense input range is small (
±
50mV) to minimize the
loss across R
SENSE
. To preserve accuracy, use Kelvin
connections at R
SENSE
.
The external filter capacitor C
F
operates against a total on-
chip resistance of 4k to form a lowpass filter that averages
battery current and improves accuracy in the presence of
noise, spikes and ripple. 4.7
μ
F is recommended for gen-
eral applications but can be extended to higher values as
long as the capacitor’s leakage is low. A 10nA leakage is
roughly equivalent to the input offset error of the integra-
tor. Ceramic capacitors are suitable for this use.
Switching regulators are a particular concern because
they generate high levels of current ripple which may flow
through the battery. The V
DD
and SENSE
+
connection to
the charger and load should be bypassed by at least 4.7
μ
F
at the LTC4150 if a switching regulator is present.
The LTC4150 maintains high accuracy even when Burst
Mode
switching regulators are used. Burst pulse “on”
levels must be within the specified differential input volt-
age range of 50mV as measured at C
F+
and C
F–
. To retain
accurate charge information, the LTC4150 must remain
enabled during Burst Mode operation. If the LTC4150
shuts down or V
DD
drops below 2.5V, the part resets and
charge information is lost.
APPLICATIU
W
U
U
Coulomb Counting
The LTC4150’s transfer function is quantified as a voltage
to frequency gain G
VF
, where output frequency is the
number of interrupts per second and input voltage is the
differential drive V
SENSE
across SENSE
+
and SENSE
–
. The
number of interrupts per second will be:
f = G
VF
V
SENSE
where
V
SENSE
= I
BATTERY
R
SENSE
Therefore,
f = G
VF
I
BATTERY
R
SENSE
Since I t = Q, coulombs of battery charge per INT pulse
can be derived from Equation 4:
(2)
(3)
(4)
One INT
G
R
Coulombs
VF
SENSE
=
1
(5)
Battery capacity is most often expressed in ampere-hours.
1Ah = 3600 Coulombs
Combining Equations 5 and 6:
(6)
One INT
G
R
VF
SENSE
=
1
3600
[Ah]
(7)
or
1Ah = 3600 G
VF
R
SENSE
Interrupts
The charge measurement may be further scaled within the
microcontroller. However, the number of interrupts, cou-
lombs or Ah all represent battery charge.
The LTC4150’s transfer function is set only by the value of
the sense resistor and the gain G
VF
. Once R
SENSE
is
selected using Equation 1, the charge per interrupt can be
determined from Equation 5 or 7.
Note that R
SENSE
is not chosen to set the relationship
between ampere-hours of battery charge and number of
interrupts issued by the LTC4150. Rather, R
SENSE
is
chosen to keep the maximum sense voltage equal to or
less than the LTC4150’s 50mV full-scale sense input.
(8)
Burst Mode is registered trademark of Linear Technology Corporation.
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LTC4150IMS#PBF | 功能描述:IC COUNTER/GAUGE GAS/BATT 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標準包裝:61 系列:- 功能:電源管理 電池化學:鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:4.35 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應商設備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4150IMS#TR | 功能描述:IC COUNTER/GAUGE BATTERY 10MSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標準包裝:61 系列:- 功能:電源管理 電池化學:鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:4.35 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應商設備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4150IMS#TRPBF | 功能描述:IC COUNTER/GAUGE GAS/BATT 10MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標準包裝:61 系列:- 功能:電源管理 電池化學:鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:4.35 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應商設備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4150IMSPBF | 制造商:Linear Technology 功能描述:Gas Gauge Li-Ion/NiCD/NiMH MSOP10 |
| LTC4150IMSTRPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Coulomb Counter/ Battery Gas Gauge |
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