John Larkin wrote:

Eeyore wrote:
John Larkin wrote:
Eeyore wrote:
John Larkin wrote:

I like to protect transistors by digitizing their voltages and
currents, and the heatsink temperature, running a realtime thermal
simulation, and limiting *junction temperature*.

Digitising ? That's not going to be cheap.

Digitizing is cheap, especially when it lets you safely get, say,
twice the usable power from a given mass of transistors and heatsinks.

You don't. Audio amps already push output devices pretty much as far as they're
happy with.

But they don't do it intelligently. A proper protection scheme can
deliver a lot more usable power for the same amount of "push."

You're missing the point. The 'push' is determined by the audio signal. Mess with that and
you have distortion.

You're missing my point. If you can get twice the undistorted output
by using a smarter protection circuit, it's still twice the output.

How can you increase the allowable dissipation with a protection circuit ? Dissipation is
determined by the audio signal and load impedance.


The amplifier must function unimpeded for any valid combination of input level and output
load.

What does "unimpeded" mean for a huge input and a shorted load?

A short isn't a valid load.

Graham