Greetings,
I am having difficulty understanding the concept of voltage regulation with a battery, specifically with an LM317 (datasheet enclosed below). I understand how the differential voltage must be maintained at a certain threshold in relation to the available input and the desired output - I'm assuming due to the internal voltage drop of the LM317 itself, which is 2-3V. However, my frustration comes from how the output can be maintained if the battery will be depleted over time with use. For example, I have a 7.2V NiHM RC car battery and I want it to generate at least 5.5V to power a microcontroller. In accordance with the equation in the datasheet, I can achieve that with a 3k ohm and a 10k ohm resistor for R1 and R2, respectively. How does it know to maintain that given the input voltage from the battery would deplete over time?
http://www.ti.com/lit/ds/slvs044x/slvs044x.pdf
I am having difficulty understanding the concept of voltage regulation with a battery, specifically with an LM317 (datasheet enclosed below). I understand how the differential voltage must be maintained at a certain threshold in relation to the available input and the desired output - I'm assuming due to the internal voltage drop of the LM317 itself, which is 2-3V. However, my frustration comes from how the output can be maintained if the battery will be depleted over time with use. For example, I have a 7.2V NiHM RC car battery and I want it to generate at least 5.5V to power a microcontroller. In accordance with the equation in the datasheet, I can achieve that with a 3k ohm and a 10k ohm resistor for R1 and R2, respectively. How does it know to maintain that given the input voltage from the battery would deplete over time?
http://www.ti.com/lit/ds/slvs044x/slvs044x.pdf