- Nov 30, 2006
- Hickory, MS
At Peavey we had a digital group with years (decades) of experience designing class D amplifiers while high power switching device technology was not quite up to that task back a few decades ago, like it is now. Switching PS are relatively easier, but not trivial. Chip makers often have detailed application notes including preferred PCB layouts, but I agree it is not worth the trouble for onesy-twosey projects.abbey road d enfer said:Building high-power smps is enough to occupy a whole lifetime. I'm not that patient.
I know the guys at Powersoft. They spent their evenings at uni making sm power amps and PS. One was designing, the other replaced the exploded FET's! ;D
Agreed for one-offs or as a small manufacturer using off the shelf OEM solutions makes sense. Back a couple decades ago (consulting after I quit Peavey) I inherited supporting a low volume DSP product using a custom switching supply. They cleverly tried to get two regulated rails from one switcher using a transformer. I killed a lot of brain cells trying to make that transformer quiet (it buzzed like an angry hornet). I finally used the Gordian knot solution, simplifying the design to just a single regulated switching rail, and added a common pass regulator for the lower voltage rail. The small loss in efficiency was well worth it for the dead silence gained by using a cheap standard off the shelf inductor. I never even found a second source for the obscure transformer that buzzed. (That was the same switcher that I piggy backed a small cap value, HF cap doubler/tripler to make a 48V phantom rail).