60V Battery Gas Gauge
The LTC
®
2944 multicell battery gas gauge makes direct measurements of 3.6V to 60V battery stacks. Absolutely no level shifting
circuitry is required to interface with multicell voltages, minimizing current consumption and preserving measurement accuracy.
The LTC2944 is a true high voltage gas gauge that measures charge, voltage, current and temperature to within 1% accuracy —
all of the essential parameters required to accurately assess battery state of charge (SOC).
Features
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CHARGE ERROR (%)
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Measures Accumulated Battery Charge and Discharge
3.6V to 60V Operating Range for Multicell Applications
16-Bit ADC Measures Voltage, Current and Temperature
1% Charge, Voltage, Current and Temperature Accuracy
I
2
C/SMBus Interface
Configurable Alert Output/Charge Complete Input
Quiescent Current <150µA
Small 8-Pin 3mm × 3mm DFN Package
Total Charge Error vs
Differential Sense Voltage
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
0.1
1
V
SENSE
(mV)
10
100
V
SENSE+
= 30V
Battery Gas Gauges and Power Monitors
Part Number
LTC2941/LTC2941-1
LTC2942/LTC2942-1
LTC2943/LTC2943-1
LTC2944
LTC4151
LTC2945
LTC2946
LTC2947
LTC4150
Operating
Range (V)
2.7 to 5.5
2.7 to 5.5
3.6 to 20
3.6 to 60
7 to 80
0 to 80
0 to 100
0 to 15
2.7 to 8.5
Interface
I
2
C
I
2
C
I
2
C
IC
I
2
C
I
2
C
I
2
C
I
2
C
Interrupt
30A
•
•
•
•
•
2
Integrated
Sense
Resistor
–/1A
–/1A
–/1A
Measures
Energy
Charge
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Power
Voltage
Current
Temperature
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Analog Devices, Inc.
All other trademarks are the property of their respective owners.
Power Management Multicell Battery Chargers
33V TO 60V
5m
IN
LT3845A
SHDN
V
C
14.7k
RST
CLN
IN
1.10M
1µF
VM
100k
ENC
CHRG
FLT
IIMON
10nF
10nF
IBMON
TMR
CL
24.9k
CX
22.1k
GND BIAS
ITH
CC
OUT
100µF
47nF
IID IGATE CSP
CSN
BGATE
BAT
OFB
47k
FBG
47k
BFB
NTC
1.13M
10k
1µF
V
DD
µP
Si7135DP
0.5A
LOAD
3.3V
2k
2k
2k
1.15M
5m
Si7135DP
V
OUT
30.4V, 15A
LTC4000
L
LTC2944
ALCC
SDA
SCL
L
1µF
SENSE
+
R
SENSE
100m
SENSE
–
GND
+
30V
LI-ION
BATTERY
0.1µF
The LTC4000 is a high voltage controller and power manager that converts virtually any externally compensated DC/DC power supply
into a full-featured battery charger. The LTC4000 is capable of driving typical DC/DC converter topologies, including buck, boost, buck-
boost, SEPIC and flyback. The device offers precision input and charge current regulation and operates across a wide 3V to 60V input
and output voltage range, making it compatible with a variety of input voltage sources, battery stacks and chemistries including lithium-
ion/polymer/phosphate and sealed lead-acid (SLA). Typical applications include high power battery charger systems, high performance
portable instruments, battery backup systems, industrial battery-equipped devices and notebook/subnotebook computers.
Battery Chargers for Multicell Applications
Maximum
V
BAT
Number of
Input
Charge
Range
Battery
Battery
Voltage
Part Number
Current (A)
(V)
Chemistry Cells (Series)
(V)
Switch Mode Multichemistry Buck (Step-Down) Battery Chargers
LTC4121
0.4
3.6 to 18
SLA
SLA
4.3 to 40
LiFePO
4
1-5 LiFePO
4
Li-Ion
1-4 Li-Ion
LT3652
2
3.3 to
SLA
SLA
4.9 to 32
†
14.4
LiFePO
4
1-4 LiFePO
4
Li-Ion
1-3 Li-Ion
LT3652HV
2
3.3 to 18
SLA
SLA
4.9 to 34
†
LiFePO
4
1-5 LiFePO
4
Li-Ion
1-4 Li-Ion
‡
/
LTC4009/LTC4009-1
4
2 to 28
NiMH NiCd
2-18 Ni,
6 to 28
LTC4009-2
‡
SLA Li-Ion
1-6 Li-Ion
LTC4012/LTC4012-1
‡
/
4
2 to 28
NiMH NiCd
2-18 Ni,
6 to 28
LTC4012-2
‡
/LTC4012-3
SLA Li-Ion
1-6 Li-Ion
LTC4015
15+
§
Up to 35
SLA
SLA
4.5 to 35
LiFePO
4
1-9 LiFePO
4
Li-Ion
1-8 Li-Ion
#
#$
§
LTC4000 /LTC4000-1
50
3 to 60
SLA
SLA
3 to 60
@
LiFePO
4
1-16 LiFePO
4
Li-Ion
1-14 Li-Ion
Switch Mode Multichemistry Buck-Boost Battery Chargers
LiFePO
4
Li-Ion
Switch Mode Li-Ion Buck (Step-Down) Battery Chargers
LTC4001/LTC4001-1*
LT3650-4.1/LT3650-4.2
LT3650-8.2/LT3650-8.4
LT3651-4.1/LT3651-4.2
LT3651-8.2/LT3651-8.4
2
2
2
4
4
4.1, 4.2
8.2, 8.4
4.1, 4.2
8.2, 8.4
4.2
Li-Ion
Li-Ion
Li-Ion
Li-Ion
Li-Ion
LTC4020
20+
§
2.5 to 55
1-15 LiFePO
4
1-13 Li-Ion
1
1
2
1
2
4.5 to 55
4 to 5.5
Integrated
Power
Charge
Package
Transistor Synchronous Termination (mm × mm)
~
~
~
–
–
–
–
~
–
–
~
~
~
–
Timer
Timer or C/10
Timer or C/10
External µC
External µC
Timer + C/X
Timer + C/X
3×3 QFN-16
3×3 DFN-12,
MSOP-12E
3×3 DFN-12,
MSOP-12E
4×4 QFN-20
4×4 QFN-20
5×7 QFN-38
4×5 QFN-28
SSOP-28
5×7 QFN-38
3×3 QFN-16
3×3 DFN-12
MSOP-12E
3×3 DFN-12
MSOP-12E
5×6 QFN-36
5×6 QFN-36
–
~
Timer + C/X
Timer
4.75 to
(40 Max)
9 to 32
†
(40 Max)
6.5 to 32
9 to 32
32
†
~
~
~
~
~
~
–
–
~
~
Timer + C/10
Timer + C/10
Timer + C/10
Timer + C/10
†
Minimum start-up voltage is +3.3V above V
‡
-1 and -2 versions are fixed voltage options for 1-4 Li-Ion cells
$
-1 option has MPPC (Maximum Power Point Control)
* 4.1V cell voltage
BATMAX
#
Charging controller requires externally compensated switching regulator
§
Depends on external components
@
Greater than 60V is possible without the input current regulation/measurement function
www.linear.com/LTC2944
n
1-800-4-LINEAR
0815