high-side and push-pull notes and questions

[kjkoster]

Dear All,

Reading the data sheet of the DIO expansion module, you will find that for "Maximum current per output” it states "500 mA (high-side mode), 100 mA (push-pull mode)”. Yesterday I was asked about the difference between push-pull and high-side on the outputs of the DIO module. Being a software guy, I had to do a little reading to learn and I thought I'd share my notes and ask a few follow-up questions.

In my research I ran across Simply Put, a YouTube channel that explains basic electronic circuitry clearly and concisely. The channel seems to have stopped publishing new material, which I think is a shame. I really like his pace and how he works step-by-step towards the stated goal.

In spite of the name of the video, Simply Put actually explains both high-side and push-pull configurations for analog signals really well. Watching the video, he arrives at high-side at the 1:00 mark. From there, he builds the schema out to push-pull at around the 6:00 mark, optimising and simplifying the schema for the rest of the video. I humbly propose you watch the whole thing start to finish.

https://www.youtube.com/watch?v=9UYXzstco60

So if you are driving a relay (like we are), you’d use high-side mode. That is a simple, on/off load and gives you the maximum current for the load.

I can’t really think of a good example for a push-pull load, so if anyone knows of a good example of push-pull in the digital domain, that would help me.

Also, in the case of push-pull, you need a ground and a negative voltage ... I think. The X2 connector on the DIO module only gives me +24V and 0V inputs to the DO component. That still leaves me wondering what output I would see in push-pull mode. 0V/+12V/+24V perhaps? If not, what then?

Hope this helps, and I hope someone can help me understand push-pull on the DIO even better.

Kees Jan

PS. He does remind me of Hagrid, in a way.

[giuseppe]

Hello,
I can offer you the application notes for high-side and push-pull mode, which you can find at the following link.
How can I use the high-side or push-pull mode of the RevolutionPi DIO?