DMX-512 interface - DC/DC converter?

[rduck]

Hi

Sorry for writing in English - but I am better at writing in English than German (even though I can read and understand most German text).

I am trying to convert the schematic for the DMX-512 interface to include some components in SMD. But taking a close rlook at the schematic, I see that the DC/DC convert is a 2W model.. 2W at 5 V is 400mA - does the interface cirvuit really need this much power - or can a 1W converter be used instead ?

Regards
/R

[Christian]

Hi,


the ATmega8 needs something around 10mA and the LEDs something around 5-10mA. The SN75176 something around 60mA. So the complete circuit needs around 100mA. So we need a 5V*100mA=0.5W Type.

The 2W is a Standard-Type at our local store called "Reichelt". But if you can find a DCDC-Converter with less power it should work as well


kind regards,
Chris

[rduck]

Hi

The DC/DC converter does not power the ATmega, so it is only a question of powering the SN75176, the LED's, the 6N137 - and whatever power that might be sued on the DMX bus.
I have seen other shematics use a 1W converter - and that is also what I have by hand right now. I know about Reichelt, but since I'm shopping from abroad, I have to pay a shipping fee of €19 - which I think is quite expensive (another option is to buy via ebay from Hong Kong/China, but things will take about a month to arrive - and local shops are way too expensive, and also a bit hard to find).

I will try to test it with the 1W converter - and see what happen

Regards
/Brian

[Christian]

he DC/DC converter does not power the ATmega

Of course, you are right. I didn't looked at the circuit while writing the text. The 1W should work well.


bye,
Chris