SNVSAC2A March 2015 – June 2020 LM317A
PRODUCTION DATA.
The LM317A can be used in a battery charger application shown in Figure 32, where the device maintains either constant voltage or constant current mode depending on the current charge of the battery. To do this, the part senses the voltage drop across the battery and delivers the maximum charging current necessary to charge the battery. When the battery charge is low, there exists a voltage drop across the sense resistor RS, providing constant current to the battery at that instant. As the battery approaches full charge, the potential drop across RS approaches zero, reducing the current and maintaining the fixed voltage of the battery.
Use of RS allows low charging rates with fully charged battery. |