CDROM power supply

[DC Dave]

I'm in the process of designing a power supply for my CDROM drive. It will need +12v and +5v at about 1.5A. For the transformer I was thinking of using the AMVECO 62081 which is a 50VA with dual 9 volt secondaries. After rectification that should give me the 12 volts I need.

I was going to run one of the secondaries through the bridge rectifier to the 12 volt regulator, and the other secondary to the 5 volt regulator. Is this the correct was to do it?

For the regulators I was looking at the LM323AK 5v, 3A, and the LM7812 12v 1A. Big heat sinks will be utilized. Add a few caps, and thats it.

Does this design sound like it would work? Anyother ideas. I could not find any PSU designs like this on the net (in english atleast!)

[DC Dave]

I just read over some datasheets and with the LM323 regulator I chose I will need 20volts at its input so the 9volt secondary on the tranny will not be enough. A 15 volt secondary would work but a 50VA tranny would only give 1.66 amps, which could be enough for most CDROMs, but I think slightly bigger would be better. So now I need a slightly larger transformer, maybe 80VA. Anyone know of somewhere to get affordable toroidal transformers?

[makuy]

http://www.circuitstoday.com/wp-cont...-converter.JPG

Notes.

• For car stereo applications you don’t need the transformer,rectifier and the 7812 regulator.12V will be available from battery.You just need to produce a 5V from it using a 7805 based regulator. Connect the corresponding voltages to the connector as shown in figure 1 and connect the connector to drive.Done.
• The amplifier for the car audio CD player must be one operating from 12V.