I'm working on a hobby project that involves continuously powering a 5 watt handheld radio for long periods of time off a 12v automotive electrical system (in reality the input will be more like 13-14v). The battery that comes with the radio is 7.6v and the radio draws ~2 amps during transmission.
The radio is designed to be charged while the battery is attached, however the final solution does not need to include the battery at all. I plan to connect the output of whatever circuitry I build/buy directly to the contacts on the radio where the battery would normally interface.
What would be the best way to build a voltage regulator for this application relatively cheaply? I'm not against buying something off the shelf, but I've found very little that is rated above 1000 ma.
EDIT: The original body of this question said the radio drew 7.6 amps. This was a typo, the peak current draw is ~2 amps. Sorry for the confusion.
Best Answer
At your power levels (60W), you really want to be looking at a switcher. Maybe you can find a off the shelf Dc-DC converter for your voltages and power, but probably not. That leaves making one yourself. Since this is a one-off a few extra dollars for the chip doesn't matter. Linear Technology, National (now part of TI), and TI have a decent assortment of buck regulator chips. For simplicity, go to the Linear Tech site and look around. At 8A, you will need a chip that drives a external switch as apposed to one with the switch built in, but there are plenty of those. If I remember right, Linear also has a decent set of app notes.