3v3 PWM to 0-5V analog out

Cicero

Active Member

• Sep 23, 2015

• #1

Anyone got any clever ideas as to how to do this elegantly? Everything I come up with seems too bulky.

I should add: And try keep it as linear as possible.

PWM @ 30-40kHz

 

Last edited: Sep 23, 2015

alec_t

Well-Known Member

Most Helpful Member

• Sep 23, 2015

• #2

Is this close enough?

The graphs are for PWM duty cycles of 10% to 90% at 10% intervals.

 

Attachments

• LevelShiftedPWMtoVoltage.asc

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Cicero

Active Member

• Sep 23, 2015

• #3

Ah nice Alec - that'll work. I had a similar version, but I think my cap was too big because it didn't work very well.

I tried an opamp version, low pass into amplifier, but unless its properly rail to rail you lose a lot.

 

alec_t

Well-Known Member

Most Helpful Member

• Sep 23, 2015

• #4

Here's an alternative, giving a better approximation to linear :-

 

Attachments

• LevelShiftedPWMtoVoltage2.asc

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ronsimpson

Well-Known Member

Most Helpful Member

• Sep 23, 2015

• #5

Go to a parts vendor and search for this:
logic translator OR logic level shifter

Attached is one I use. It is bidirectional which you don't need so ground the DIR pin.
They come 1/IC or 2, 3,4 8, or 16.
This one converts up or down but some only go one way. There are some that only do the 3.3 to 5.0 translation.

 

Attachments

• sn74lvc1t45.pdf

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