Power Supply for Class D Amplifiers

[adailton]

Hi Guys,

Im building a class d amplifier (traditional,not ucd), Im using a signal generator for triangle reff signal and HIP4080 gate driver for mosfets. My amplifier will be BTL class and has max 30-50 W for 4 Ohm speaker. My question is about power supply.

I don't want to build a power supply, I wanna buy new one. For my amplifiers specs., what is power supply's spec. be? I think 20-25V 4A max current smps is enough for me. What do you think? And how am I calculate current and voltage requirements from supply?

And last silly question. My amplifiers power is (RMS current on load(speaker))^2 * impedance of speaker ? is it so easy?

Thanks..

[nigelwright7557]

Yes power is I squared R.

You can use a SMPS or a normal power supply.
Have a look on ebay.

[adailton]

Originally Posted by nigelwright7557

Yes power is I squared R.

You can use a SMPS or a normal power supply.
Have a look on ebay.

Thank you. But i want to learn which spec. is supply has?(for in spacing that i said)

For ex, how much current is my circuit take(max current)?

[nigelwright7557]

It takes about 100VA.
I would go for 150VA supply.

[adailton]

My notebook's power supply(smps) is 20Vdc and 3,25 A. Is it enough for experiment? I don't need high power, because of BTL structure. Can I use? Is max current of supply inhibitory?

[shon35us]

Can you use a transformer that unregulated output?

[trevmar]

Originally Posted by shon35us

Can you use a transformer that unregulated output?

No, usually the transformer-based unregulated power 'bricks' have a much higher no-load voltage than the rated value.

Any laptop power-supply 'brick' is usually OK, however. You can usually tell by the shape and weight whether they are transformer based (bad) or switching-supplies (good).