Datasheet

TIME
VOLTAGE
Measured
Battery Voltage
V
LOW
Limit
ALERT pin
(Active Low)
V
LOW
+V
HYST
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
ADC121C021, ADC121C021Q, ADC121C027
www.ti.com SNAS415F –JANUARY 2008–REVISED MARCH 2013
Figure 39. Recharge Cycle
Figure 40. Discharge Cycle
In addition to the window supervisory feature, the ADC121C021 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 ADC121C021 can be used to control a trickle charge to keep the battery near
full capacity (see Figure 41). 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.
Figure 41. Trickle Charge
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Product Folder Links: ADC121C021 ADC121C021Q ADC121C027