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Voltage Level Shifting

Voltage Level Shifting

Voltage Level Shifting

(OP)
I am trying to figure out the best way, with the least number of components to translate a voltage from -12V-5V to 0V-5V.  I am using a comparator to compare negative voltages and the only negative voltage I have available to me on my board is -12V, so I have to use this voltage to supply the comparator.  I am able to get the +5V with a pullup, but my low level output is -12V.  I am going into some CMOS Tinylogic gates that only accept -0.5V to 7V for inputs.  Any help would be appreciated!

RE: Voltage Level Shifting

A voltage divider using resistors.  Say, 1k Ohm to 5V and 2.4K to the comparator output.

RE: Voltage Level Shifting

"...from -12V-5V..."

The 2nd '-': minus or dash? In other words, is that -12v to -5v, or -12v to 5v?  I assume the latter.

Perhaps all that it required is a diode to block the minus voltages, effectively turning minus into zero. In other words, -12v to +5v, through a diode, becomes 0v to +5v.

You might (?) need a resistor (100k?) to swamp out the input Z if high in reverse bias.

 

RE: Voltage Level Shifting

Are you trying to convert from RS232 to TTL?  If so, you can buy that online...

RE: Voltage Level Shifting

(OP)
Yes I am talking about -12V to 5V....and no I am not converting between RS232 and TTL.  But I have actually found a solution to my problem that does not require any voltage translation.  Thank you for the suggestions, though!!

RE: Voltage Level Shifting

What is it?  Perhaps we could all benefit from it.

RE: Voltage Level Shifting

please tell us your solution. I was going to suggest a dual voltage-supply comparator like the AD8564 but that would require reducing the neg rail to -9V and using resistor dividers.

What was you solution?

DH

RE: Voltage Level Shifting

I think he's got it patented

RE: Voltage Level Shifting

Why not explain the solution in detail (and the problem for that matter)?  That is the entire point of this community.

RE: Voltage Level Shifting

A "solution" could have been a rearrangement of the problem itself, rather than solving the original problem.  Such as removing the need for comms altogether...

Dan - Owner
http://www.Hi-TecDesigns.com

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