adamd@rhi.hi.is (Adam David) (03/15/91)
I would like to operate a typical computer off car batteries or similar. The power requirements are 1 to 10 Amps at 5V and 0 to 2 Amps at 12V. The 12V section does not have to be on all the time and would be controlled by 5V logic so it is there needed and otherwise on standby. Are there any magic components which I need to know about? It is important that this be a DC-DC convertor and if possible manage without transformers. A medium frequency toroidal transformer might be acceptable if there's no other way. Dissipation has to be minimal and the input voltage may vary from 6 to 18 Volts but is usually in the range 9V to 15V. It would be acceptable to have separate circuits (and batteries) for 5V and 12V outputs. The 12V is only needed to power harddisk motors, everything else is 5V. Maybe there would be less power loss within the convertor if the input and output voltages are fairly close together. If so then I would consider using a 6V battery and then have to decide whether to use a separate 12V system or to generate 12V from 6V. I don't know and that's why I'm asking this. Any suggestions are welcome, this is for a home system running 24 hrs a day. It is better to power down the harddisk motors during long periods of inactivity and leave them running while access is fairly frequent. I am not happy with using a commercial UPS which doesn't operate according to my requirements. The original switched-mode power supply dissipates 3 times as much power as it delivers. I don't mind paying for exotic parts if less electricity is wasted. -- Adam David. (adamd@rhi.hi.is)