Circuit Design Help

[jesteban]

Good Morning,
I have a problem that maybe you can Help me with. I need a circuit that can satisfy the table below. Taking into account that RL = 1 Mohm and that opto-isolators are used

I attach a preliminary sketch I did, but I don't know if this will work or the values of the resistors that will make it work

Any help will be greately appreciated. If you make any comments on the attachment itself you can send to directly to me at: [email protected]

Thanks,
Driving Voltages
   D0   D1   D2   D3   D4
Stage1   0   0   1   0   1
Stage2   0   1   1   0   1
Stage3   1   0   1   1   1
Stage4   1   1   1   1   1
Stage5   0   0   1   0   0
Stage6   0   0   0   0   0

Jose Betances

Opto.pdf

[audioguru]

Hi Jose,
Welcome to our forum.
Are you trying to make your own D to A converter?

[jesteban]

Yes! I have to do a test for a Train inverter and designing this DAC circuit will help me a lot.
Thank you!

[jesteban]

Please!!!! I really need some help with this. Can anyone help me?

[audioguru]

Google has 27,100 articles about "digital to analog converter" and this is just one of them:
http://www.play-hookey.com/analog/d2a_converter.html

[MP]

Jesteban,
For a digital to analog converter, you are converting a binary number to analog.
For example, binary #s in a 5 bit word are 16, 8, 4, 2, 1. 16 is Most Significant bit (MSB) and 1 is Least Significant Bit (LSB) in your 5 bit binary word. Therefore, you will use resistor values MSB = R, LSB = 16R to make the output voltage correct when it is summed. This sounds backwards, but you want the LSB voltage to be the smaller one coming out of the DAC.
If this does not clear it up for you, then there is a pretty good explanation here:
http://www.ibiblio.org/obp/electricCircuits/Digital/DIGI_13.html
For your example, look down the page 6 or 7 diagrams.

Hope it is helpful.

MP