LTC4150 Linear Technology, LTC4150 Datasheet - Page 9

• Manufacturer Part Number: LTC4150
• Description: Coulomb Counter/ Battery Gas Gauge
• Manufacturer: Linear Technology

APPLICATIO S I FOR ATIO
AUTOMATIC CHARGE COUNT INTERRUPT AND CLEAR
In applications where a CLR pulse is unavailable, it’s easy
to make the LTC4150 run autonomously, as shown in
Figures 5 and 6. If the microcontroller V
equal to the battery V
CLR, as in Figure 5. The only requirement is that the
microcontroller should be able to provide a high logic level
of 1.9V to SHDN. If the microcontroller V
Figure 5. Application with INT Direct Drive of CLR and Separate Microprocessor Supply V
U
Figure 6. Application with INT Driving CLR and Separate Microprocessor Supply V
V
BATTERY
DD
2.7V TO 8.5V
, INT may be directly connected to
BATTERY
BATTERY
R
R
< V
U
SENSE
SENSE
CC
+
+
4.7µF
4.7µF
C
C
F
F
W
1
2
3
4
5
1
2
3
4
5
CC
CC
SENSE
SENSE
C
C
SHDN
SENSE
SENSE
C
C
SHDN
F
F
F
F
is greater than
is less than or
+
–
+
–
LTC4150
LTC4150
+
–
+
–
U
GND
GND
CLR
POL
CLR
V
POL
V
INT
INT
DD
DD
10
9
8
7
6
10
9
8
7
6
R3
R4
SHUTDOWN
the battery V
and SHDN keep the voltages at these pins within the
LTC4150’s V
11 and R1-R4 values using Equation 13. In either applica-
tion, the LTC4150 will capture the first assertion of INT and
wait at least 1µs before resetting it. This insures that INT
pulses low for at least 1µs but gives automatic INT reset.
C2
4.7µF
C2
4.7µF
R
L
PROCESSOR
R
R2
R1
L
R
V
µP
L
CC
PROCESSOR
DD
R
DD
L
V
, use Figure 6. The resistor dividers on CLR
µP
range. Choose an R
CC
C
47µF
L
POWER-DOWN
SWITCH
C
47µF
L
POWER-DOWN
SWITCH
CC
LOAD
4150 F05
> V
CC
L
DD
≤ V
value using Equation
LOAD
4150 F06
DD
LTC4150
4150fa
9