Disclaimer:The following are my notes. As I am learning electronics, I am making my notes available. I hope they will be of benefit. However, I do not guarantee the accuracy of my work. I recommend the reader exercise critical thinking.
SMP with 317
LM317 and a Switching Power Supply
I was researching methods for charging batteries when I began to debate whether to use
a switching power supply versus a linear regulator.
While reading the datasheet for the LM317 regulator, I discovered you can make a switching power supply using this regulator. (See the "Typical Applications" section of the datasheet.)
In the past, I used pulse width modulation to implement switching power supplies. I did this
with a 555 chip and a PIC18F chip. However, this LM317 schematic had no pulse width generator!
It seem to operate on feedback alone.
I had to see if this really worked. I built a close approximation of the schematic
in the datasheet. It worked indeed!
