M1-ATX not enough, which combo is best?

**SAPiens** · 06-08-2005, 05:40 PM

So the M1-ATX will not power my complete system:
- MII10000
- 512MB
- regular HDD
- regular CD-DVD
- motorized in dash
- soundblaster Live USB
- CF GPS with external antenna
- USB keyboard and mouse

I'm looking to combine it with something else. Possibilities:
- OPUS 80W(12V output only), could be overkill because the M1 has start up and shutdown built in.
- PW200M,
- the new PSU from Dragon, it could be that we have to wait a little while longer for that to arrive.

So which is best or sufficient and how should I combine them. M1-ATX to power the mobo, the secondary to power the hdd, DVD-CD and LCD. Should I let the secondary start from ignition or from the M1 somehow? Will the secondary then draw power even when PC is off?

Thanks everyone for the tremendous help so far!!

**rando** · 06-08-2005, 07:40 PM

It might simpler and not much more expensive to simply replace you HD and DVD with their lower power laptop counterparts. These typically use only the 5V rail instead of both the 12V and 5V. The M1 will more than handle everything you mentioned in that case.

If you must keep the desktop components, another alternative to using two supplies is to replace the M1 with one of the other supplies that has slightly more capability on the 12V rail. The Opus 90W, 150W, or a Carnetix + PWxx solution would work for you.

If you really want to run multiple supplies, you probably don't need a solution to to power your HD, DVD and LCD. The M1 should easily do one if not two of those at the same time. If you can get the HD and DVD to work on the M1, then powering your screen with a simple linear regulator based circuit would work -- perhaps with dimming or power cycling during crank. You could also sample a TI 12V switcher module (search the forums) to handle the screen.

**Rickertsen2** · 06-08-2005, 07:44 PM

ok if you use as 2nd PSU, heres what you do. Tie the green wires (pin 14 on the ATX connectors) of both power supplies together. If oyu do this, both power supplies will come on together. The green wire is used to signal the power supply to turn on. I'm pretty sure you will also have to tie the ground wires together on both power supplies. The power supplies will turn on and off as if they were one.