To reach a better grasp on the principles, by experimenting with an interactive animated simulator...
Here is a link that will open the falstad.com/circuit website, load my schematic, and run it on your computer. It is similar to my post #3.
https://tinyurl.com/cjwmsxa
Change values by right-clicking on a component, and select Edit.
Try different loads, Vref, hysteresis feedback resistor value, etc.
I do not know for certain how well this circuit can be made to work with hardware.
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Here is an interactive simulation where you (the user) can click a switch to start the switch-On cycle.
Then let up to see the switch-Off cycle.
http://tinyurl.com/cnnkhcg
You can see how the duty cycle needs to be timed, as you try to obtain 5V at the load.