Re: Amp Problems...Need Help

> >Usually not. Most amplifiers don't dissipate more power with lower supply
> >voltage. It's usually the other way around, actually. I mean, if the
> >undervoltage condition was so bad that the PS was cycling on and off
> >because of it, then there might be an issue with the PWM controller
> >(depending on the specific circuit). But lower voltage simply means that
> >the MOSFETs on the output side of the switching are staying on for longer
> >but are passing less current from source to drain because of the decrease
> >in supply voltage. The verdict, IMO = no big deal.
>
> That's interesting. So, am I understanding correctly that with a
> lowered supply voltage, there IS more current going into the amp for a
> certain amount of output power, but that the extra current doesn't put
> any undue load on the internal components? I'll have to "get back in
> the books" and get smarter when it comes to regulated power supplies,
> then.

Even if there's more current, but there's certainly less power. Again,
unless there's some weird inductive kickback going on which is causing the
voltage "inside" to exceed the ratings of some of the components, the
lower voltage probably isn't going to cause any damage. And in most
switching PS's, the current will actually be LOWER but the duty cycle
increases. The reason the current is lower is because the voltage from
source to drain of the MOSFETs in the supply should be lower. PWM
supplies dictate that, to compensate for this, the duty cycle is extended.
But if we've established that lower power is being dissipated (a result
you can arrive at by looking at bench tests where they've tested 14v and
12v), then the increased duty cycle can't be the culprit.
.

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