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Grix / helios_dac

Helios Laser DAC
https://bitlasers.com/helios-laser-dac/
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DC to DC converter supply issues #26

Open KuusamoMart opened 2 months ago

KuusamoMart commented 2 months ago

The +/- 9V DC to DC converters are becoming very difficult to procure; suggest changing to +/- 12V 1W converters instead, ensuring 4.7uF capacitors are appropriately rated. The Op-Amps can operate with +/- 15V rails, so there is no requirement to make changes to the amplifier section. As a side benefit, the ILDA specified 10V control voltage range can now be achieved, which was a limitation with the 9V converters.

Grix commented 2 months ago

12V can and has been used interchangeably. However I must note that there was never any problem with the ILDA spec. I'm guessing the 10V voltage you are referring to is the XY signals, however the differential signal is 10V, meaning that each line is 5V and -5V with respect to ground, so the +/-9V converter has no problem with it.

TrevorPage commented 2 months ago

The BOM already states a +/-12V part, and did so at least as far back as 2022 when I ordered components.

For added information, here in the UK I successfully used Farnell part numbers 3652675 and https://uk.farnell.com/multicomp-pro/mpa0512xt-1w/dc-dc-converter-2-o-p-1w/dp/3652640.

KuusamoMart commented 2 months ago

Ah, the BOM in the repository has been updated, but because I generated the Gerbers in KiCAD from scratch, the BOM only showed the 9V converter. The change needs to be flowed back to the KiCAD design.

TrevorPage commented 2 months ago

Ah, gotcha! Nice to meet someone else building this BTW! (Slight cheeky hijack: If it's any interest, I'm personally using my fork of https://github.com/TrevorPage/laser-dac within my own software for this interface.)