TDA8954 at 4ohms bridge

[alarrr]

There is a note that those stereo half bridges of that chip can be made to full bridge mono. At 8 ohms with 420 watt of power. Now I want to connect 4 ohm speaker there.
It should just take lower voltage to reach that 420watts and not to hit current limit. Current plans would be feed it with 30+-(maybe it needs even less?).

What ya think? Will it instantly explode? Would it work?


http://www.nxp.com/documents/data_sheet/TDA8954.pdf

 

[DUG]

Current limit of 12A and each drive would see 2R.

4R speaker impedance curve would dip below 4R. This would make the current limit come on even sooner.

So at 8R BTL they can run +/-42V.

For 4R BTL perhaps +/-21V might be a good start.

IMHO

 

[Pafi]

DUGs calculation is correct.

Maybe you can get a little extra power with 24...30 V PSU this way at the expense of doubled loss compared to single channel single ended operation.

The protection will prevent explosion, but there is not much benefit.

 

[alarrr]

There is a few things I noticed. Tda7498E gives 160 watts at +36V and it's full bridge.
Tda8954 at voltage diffrence +/-21V total swing diffrence 42V, 420W? Something dosen't match up here

 

[Pafi]

Yes. You will never get 420W into 4 ohm, this is the basic problem.

As I wrote little extra power with 24...30 V PSU this way at the expense of doubled loss compared to single channel single ended operation. Probably 250W.

 

[Pafi]

V=I*R. P=V*I. Effective voltage (and current) is 0.71*peak Voltage. Calculate!

 

[alarrr]

Would those irs2092 driven work better=?

NEW Assembled HIFI Stereo IRS2092 Class D Power amplifier board 345W+345W

FULL BRIDGE! Voltage is in acceptable limits. There isnt much written about it.

 

[alarrr]

Would those irs2092 driven work better=?

NEW Assembled HIFI Stereo IRS2092 Class D Power amplifier board 345W+345W

FULL BRIDGE! Voltage is in acceptable limits. There isnt much written about it.

Actually never mind. If Ill gona put over 100 dollars on amplifier I could add another 100 and get properly built one.
Skytec Sky 3000 MKII Professional PA Amplifier Mobile Party DJ Power Amp 3000W | eBay

 

[Pafi]

Would those irs2092 driven work better=?

NEW Assembled HIFI Stereo IRS2092 Class D Power amplifier board 345W+345W

FULL BRIDGE! Voltage is in acceptable limits. There isnt much written about it.

Who do you write to and why?!?

CURRENT LIMIT! Peak current for 400 W @ 4 ohm is higher than the ICs built in limit.

Physics is the same.

Just buy a complete one, good idea!

 

[Th3 uN1Qu3]

That Skytec amp is junk btw, you are better off getting bigger modules and an amplifier chassis from ebay and building it yourself...