SNVSAC2A March 2015 – June 2020 LM317A
PRODUCTION DATA.
Using three LM317A devices in parallel increases load-current capability (see Figure 33). Output voltage is set by the variable resistor tied to the noninverting terminal of the operational amplifier, and reference current to the transistor is developed across the 100-Ω resistor. When output voltage rises, the operational amplifier corrects by drawing current from the base, closing the transistor. This effectively pulls ADJ down and lowers the output voltage through negative feedback.