Senior Design Newbie

[Deltat]

Hey whats up? Im new here. Im a senior at Purdue majoring in Electrical Engineering Technology. Im working on my senior design project right now. Its gonna be a subwoofer amplifier with digitally controllable volume and crossover. The amplifier is going to be a tripath TA3020, if can get it to work without blowing up. Im currently using a TK2150 with success. The crossover is a MAX260 and the volume is contolled by a DS1808 log pot. All the adjustments are being made with optical rotary encoders and there is a large 20x4 blue LCD that displays the adjustments. Oh and the micro is an Atmel Mega16.

If anyone has worked with the DS1808 or the TA3020, i could really use some help with these. Thanks

Kurt

[HFGuy]

Sounds like a fun project. Iam doing my 4th year thesis on MultiGbps Phase lock loop design. Its lame but alteast its still analog. BTW Booooooooooooooo Cadence

[JoeBob]

I'm dropping out.

Hahaha, no seriously, I'm not sure yet, but I applaud you for getting so far .

[thespeakerguy]

If you have specific questions on the DS1808, you can email tech support www.maxim-ic.com.

Are you going to do a linear or switcher power supply?

[Deltat]

I did a linear power supply. I wasnt really sure how to use a switching power supply in this application. I have +/-45V rails that can deliver over 10A.

Kurt

[HFGuy]

Probably not a great idea to use a switch mode supply and a class D amp. The switching freq of the amp and that of the power supply will be pretty close (unless you use large caps and/or inductor,or large supply ripple). personally i think it makes more sense to use a circuit with a high CMRR rather then use a regulated supply like a switch mode. Its too late for me to drop out i already have a God complex so i have to be an engineer

[Ahoy34]

hey deltat,

I am also doing a school design project using a Tripath Amplifier, the TK2150.

Were there any problems that you had making that work well, or any tips you have for me? I am in the process of laying out the board in expresspcb, and anything you got would be helpful.

thanks

[Deltat]

I had no problems with the TK2150, though i was using the evaluation board. Since its proprietarty technology i figured why make it myself and possibly make a mistake. Just make your you get your power supplies right. For some reason the cable i got with it was backwards and it blew the chip and an output FET. Also when you test it, you will need a load, otherwise all you will see on a scope will be the internal switching signal. Good luck

Kurt

[Ahoy34]

The amp worked great, there were only a few problems, which can be corrected easily. The output inductors get hot, which is because of core losses. Make sure if you build this to get an inductor with low loss, I'm currently getting the T106-2 from CWS Bytemark...one of the few places you can buy online. The other problem was hiss, caused by the op-amps in combination with the switching EMI, which can be eliminated by placing a resistor on the inputs.

The amp is powerful, clear, and stays cool (sans the inductors which will soon be replaced). For the power supply I used a toroidal xfmr from www.toroid.com and big caps from digikey.