Level Translator

AtomSoft

Well-Known Member

• Jan 20, 2021

• #1

Ive seen this around a lot..

Can i simply use a diode for one way communication?

 

P

Pommie

Well-Known Member

Most Helpful Member

• Jan 20, 2021

• #2

If it's one way use a resistor divider or if open collector a pullup should be fine. What is the signal and which way is it going? Ahh, missed the diode, the diode effectively makes it open collector so should work fine.

Mike.
Edit, just realised your diode is the wrong way around. What are you trying to do?

 

D

Diver300

Well-Known Member

Most Helpful Member

• Jan 20, 2021

• #3

No, that won't work. When the low side is at a low logic level, the high side will remain high.

You can buy level shifting buffers which work with no additional components for single direction communication.

 

AtomSoft

Well-Known Member

• Jan 20, 2021

• #4

actually the resistor is on the wrong side hah... I want to pull up so when i get a low on 5v side it goes low.. correct?

 

AtomSoft

Well-Known Member

• Jan 20, 2021

• #5

So when high side is 5v, the low side is pulled up and blocked by diode from high side... when high side is 0v it goes through diode and low side is 0v

 

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Pommie

Well-Known Member

Most Helpful Member

• Jan 20, 2021

• #6

That should work.

Mike.

 

V

Visitor

Well-Known Member

• Jan 20, 2021

• #7

The diode voltage drop may prevent the 3.3v side being pulled down enough to be a recognizable low.