Can anyone explain to me how, in using a one-wire in parasitic mode, you can be providing power and sending a signal out the same terminal?

For instance, I've been involved in a project using a thermocouple IC in a TO-92 package that uses parasitic power. If you have a serial data bus that provides power through the data bus, you only need the output terminal and ground terminal of the TO-92 for it to function. You can also get a version with a dedicated VDD terminal, which makes a lot more sense to me currently.

Thanks!

 

Here is a link to the wikipedia article covering the 1-wire topic.

hgmjr

 

Ah, ok. Pull-up resistors allow you to pull the data line to ground for a 0, while an internal capacitor holds the charge from when the line was a 1. Very cool. Thanks. I didn't think to look on Wikipedia for some reason.

 

You got it. Parasitic is a clever way to power a low power consuming device.

hgmjr

 

Isn't that the way RFID tags work?

 

Isn't that the way RFID tags work?

Basically that is true beenthere. RFID does use a portion of the RF signal on which the data is being modulated to power the passive RFID tags.

hgmjr