I've gutted an old JVC all-in-one hifi to use the output section as a little workshop amp. One problem is the main piece I want is a single board with PSU and output IC -- but the output IC (Toshiba TA 8223H) needs a >3V input to turn it on.
The snag I've hit is that the turn-on pin is powered from a 6V regulated supply, but it's on the main control/input/tuner/etc board which I want to bin.
The easiest way forward is for me to build a small regulator on the board I want to keep -- but not sure of the easiest way to take 35V DC and reduce it to 6V. The switch-on pin will draw negligible current, but don't want to have to worry about heat with regular regulator (LM7805).
What's the easiest way ... found a buck regulator (LM2575 http://www.national.com/mpf/LM/LM2575.html). Will that do the trick, or is there an better/easier way? Maybe a voltage divider with a 10V zener into a 7805 since it will draw so little current?
The snag I've hit is that the turn-on pin is powered from a 6V regulated supply, but it's on the main control/input/tuner/etc board which I want to bin.
The easiest way forward is for me to build a small regulator on the board I want to keep -- but not sure of the easiest way to take 35V DC and reduce it to 6V. The switch-on pin will draw negligible current, but don't want to have to worry about heat with regular regulator (LM7805).
What's the easiest way ... found a buck regulator (LM2575 http://www.national.com/mpf/LM/LM2575.html). Will that do the trick, or is there an better/easier way? Maybe a voltage divider with a 10V zener into a 7805 since it will draw so little current?
