Datasheet

TIME
VOLTAGE
Measured
Battery
Voltage
V
LOW
Limit
ALERT pin
(Active Low)
DISCHARGE CYCLE
TIME
VOLTAGE
Measured
Battery
Voltage
V
High
Limit
ALERT pin
(Active Low)
RECHARGE CYCLE
V
IN
SCL
GND
V
A
ADC101C021
REF
[LP2980-2.8]
R
120 nF
20 kÖ
-+
SDA
ALERT
Low
Battery
Indicator
V
BATT
To Controller...
20 kÖ
ADC101C021, ADC101C027
www.ti.com SNAS446D –FEBRUARY 2008–REVISED FEBRUARY 2013
Figure 35. Intelligent Battery Monitor Circuit
Figure 36. Recharge Cycle
Figure 37. Discharge Cycle
In addition to the window supervisory feature, the ADC101C021 will allow the controller to read the battery
voltage at any time during operation.
The accurate voltage reading and the alert feature will allow a controller to improve the efficiency of a battery-
powered device. During the discharge cycle, the controller can switch to a low-battery mode, safely suspend
operation, or report a precise battery level to the user. During the recharge cycle, the controller can implement an
intelligent recharge cycle, decreasing the charge rate when the battery charge nears capacity.
Trickle Charge Controller
While a battery is discharging, the ADC101C021 can be used to control a trickle charge to keep the battery near
full capacity (see Figure 38). When the alert output is active, the battery will recharge. An intelligent recharge
cycle will prevent over-charging and damaging the battery. With a trickle charge, the battery powered device can
be disconnected from the charger at any time with a full charge.
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Product Folder Links: ADC101C021 ADC101C027