LTC2943_15 Datasheet, PDF (1/20 Pages) Linear Technology – Multicell Battery Gas Gauge with Temperature, Voltage and Current Measurement

LTC2943
Multicell Battery Gas Gauge
with Temperature, Voltage
and Current Measurement
FEATURES
n _{Measures Accumulated Battery Charge and Discharge}
n _{3.6V to 20V Operating Range for Multiple Cells}
Application
n _{14-Bit ADC Measures Voltage, Current and}
Temperature
n _{1% Voltage, Current and Charge Accuracy}
n _{±50mV Sense Voltage Range}
n _{High Side Sense}
n _{General Purpose Measurements for Any Battery}
Chemistry and Capacity
n _I²_{C/SMBus Interface}
n _{Configurable Alert Output/Charge Complete Input}
n _{Quiescent Current Less Than 120µA}
n _{Small 8-Lead 3mm × 3mm DFN Package}
APPLICATIONS
n _{Power Tools}
n _{Electric Bicycles}
n _{Portable Medical Equipment}
n _{Video Cameras}
DESCRIPTION
The LTC^®2943 measures battery charge state, battery volt-
age, battery current and its own temperature in portable
product applications. The wide input voltage range allows
use with multicell batteries up to 20V. A precision coulomb
counter integrates current through a sense resistor between
the battery’s positive terminal and the load or charger.
Voltage, current and temperature are measured with an
internal 14-bit No Latency ΔΣ™ ADC. The measurements
are stored in internal registers accessible via the onboard
I²C/SMBus Interface.
The LTC2943 features programmable high and low thresh-
olds for all four measured quantities. If a programmed
threshold is exceeded, the device communicates an alert
using either the SMBus alert protocol or by setting a flag
in the internal status register. The LTC2943 requires only
a single low value sense resistor to set the measured
current range.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
No Latency ∆Σ and PowerPath are trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
TYPICAL APPLICATION
3.3V
CHARGER
1A
LOAD
1µF
2k 2k 2k
LTC2943
V_DD
ALCC
SENSE⁺
R_SENSE
µP
SDA
SENSE^–
50mΩ
SCL
+
GND
MULTICELL
LI-ION
2943 TA01a
Total Charge Error vs
Differential Sense Voltage
2.0
V_SENSE+ = 10V
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
0.1
1
10
V_SENSE (mV)
100
2943 TA01b
For more information www.linear.com/LTC2943
2943fa
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