YD7377 4×10W radio amplifier, how can it output 4×25 W?

[budm]

Re: YD7377 4x10W radio amplifier, how can it output 4x25 W?

"Let's use Behemot's setup here as an example. You have four 2-Ohm speakers, and you are using the IC in single-ended mode to drive each channel. With a 14.4V supply and ignoring voltage drops in the amp IC, the maximum output power is 25.92 Watts RMS per channel into a 2-Ohm speaker"

Post 17 by fzabkar:
P = (Vrms x Vrms) / R = (Vpeak x Vpeak / 2) / R
= (14.4^2 / 2) / 4 = 25.92W

That's assuming that there is no distortion over the full peak-to-peak voltage swing for a bridged configuration.

So Per formula post 17: R= 4 Ohms, V supply is 14.4V, Bridged mode configuration
P = (Vrms x Vrms) / R = (Vpeak x Vpeak / 2) / R
In the example shows = (14.4^2 / 2) / 4 = 25.92W
The 14.4 is the peak Voltage due to bridge mode.

So in single end mode, the Vpeak will be only 14.4Vp-p/2 =7.2Vp
So using formula in post 17 with Vp of 7.2V due to the supply Voltage is 14.4 V and in single ended mode = (7.2^2 / 2)/2 Ohms = 12.96 W R.M.S. So where does 25.92 Watts RMS into 2 Ohms in single ended mode come from?
Am I missing something? From the Radio Amplifier manufacturer product spec sheet? Which will not be surprised.

[momaka]

Re: YD7377 4x10W radio amplifier, how can it output 4x25 W?

So in single end mode, the Vpeak will be only 14.4Vp-p/2 =7.2Vp
So using formula in post 17 with Vp of 7.2V due to the supply Voltage is 14.4 V and in single ended mode = (7.2^2 / 2)/2 Ohms = 12.96 W R.M.S. So where does 25.92 Watts RMS into 2 Ohms in single ended mode come from?
Am I missing something?

Nope, you are actually 100% correct . For some reason, it was stuck in my head that the power calculation that was done in post #17 was with a 2-Ohm load *and* SE mode operation. Apparently, a big brain fart on my part, because that calculation was done with a 4-Ohm load and BTL mode (*sigh*, that's why you don't post math calculations at 1 in the morning - or at least I shouldn't). Hence the bogus 25.92 Watts RMS in my post above. Sorry about the confusion there.

So yes, with 14.4V input supply and a 2-Ohm load, the theoretical maximum RMS is indeed 12.96 Watts, as you found.

But again, this does not take the peak output current limitation of the IC into account. Therefore, this still applies:

And what if you try to drive all four channels simultaneously and equally? Then that 3.5 A repetitive peak output current rating is split into 4 channels - i.e. each channel will be able to supply only 3.5 Amps / 4 = 0.875 Amps to each speaker. With that current limitation and the same 2-Ohm speakers, the maximum peak repetitive output power per speaker becomes as I stated in post #18:
P = (I^2)*R = (0.875^2) * 2 = 1.53125 Watts per channel, with all four channels driven simultaneously and equally.

... unless, of course, that peak output current, Io, is for a single channel. The datasheet doesn't say, though. But I wouldn't give it benefit of the doubt. When you have to make assumptions about parameters, always assume the worst case. Otherwise, kaboom may pay you a visit.