Re: Audio amplifier IC or other low parts count method

Oct 18, 2008 2 Replies

Rate this thread:

MooseFET 17 years ago

THere are two ways to do reverse protection. =A0One is, as you noted, a s=

eries

diode in line with the supply. =A0THe other one is a diode to ground that
> blows the fuse. =A0That one costs you nothing in headroom. =A0It is a bit=

inconvenient, but if the hamhand wiring it up blows the fuse, then hamhan=

gets to fix it.

I prefer the series diode method because the equipment is used in a environment where an external fuse holder is asking for trouble. The ham-handed guy never admits to the error. The word that comes back is "it was DOA".

Vote

langwadt 17 years ago

polyfuse maybe?

I think you could get close to what you want with an ADSL driver maybe two in parallel, but most only go as high as 24V supply, same with the few opamps that are r-r and high enough current

-Lasse

Vote

MooseFET 17 years ago

series

It comes down to a question of the amount of heat to get rid of driving the package size. If someone made a TO-220-N packaged power op-amp with the specs, it could work but a SO-8 package just can't get rid of the heat so you need many of them.

The Polyfuses can't be trusted. If you take one, a very stiff 35V supply, a hefty relay and a strong slow signal generator, you can kludge together a tester for them. Testing them this way at about one trip per every few minutes, very few last more than a few hours before they no longer meet their specs. Some fail after only a few cycles. They can take repeated cycles at low currents but at high currents, they get damaged.

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required