15W Amplifier Circuit Build - Help Needed - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 17th September 2012, 05:12 PM   #1
diyAudio Member
 
Join Date: Sep 2012
Default 15W Amplifier Circuit Build - Help Needed

Hi,


Iím seeking advice on a diy portable speaker project. I would like to power a single ~15W speaker driver with a battery and custom built amplifier circuit. I have a basic knowledge in electronics but also have the help of a friend for tinkering/assembly.


Iím looking for a combination of efficient amplifier IC and a circuit that will allow for the longest possible battery life.


Iím thinking of using a series of 3.7v Li-Pol batteries in order to supply the power needed (I presume to be around 12v).


A few queries I have (though there may be others I have yet to think of) are:


-What would be a suitable 15W amp IC with lowest possible power consumption.


-The best way to step up the battery voltage to reach the Voltage input for the amplifier.


-The best way to integrate the battery/ies for charging at 5v and discharging at 12v.


-Any other tips in creating a simple and efficient circuit design.


Thanks in advance,

Mike
  Reply With Quote
Old 17th September 2012, 05:31 PM   #2
Banned
 
Join Date: Jan 2005
You cannot build a class d amplifier unless you have good knowlege in the RF field, unless you go for a premade kits that you just solder together, such as the kits on 47hz.com
  Reply With Quote
Old 19th September 2012, 09:00 AM   #3
diyAudio Member
 
Join Date: Sep 2012
Hi,

Thanks for the reply. My friend has a fairly good working knowledge of electronics and will be able to help out when it comes to things like RF field.

I am looking to build form scratch and would appreciate any pointers in the right direction.
  Reply With Quote
Old 19th September 2012, 01:32 PM   #4
diyAudio Member
 
Join Date: Dec 2004
Location: Reston, Virginia
Quote:
Originally Posted by Mike75 View Post
Hi,
Thanks for the reply. My friend has a fairly good working knowledge of electronics and will be able to help out when it comes to things like RF field.
I don't agree with the comment about needing good RF knowledge. RF emission or susceptibility is just not a major problem in the 15W class D range, particularly for the newer "filterless" chips. You are going to be keeping wires short in a portable device, so radiation will be minimal. You might need simple choke filtering if the wires to the speaker are long, but all of the chip vendors provide adequate guidance that obviates complex RF engineering.

You would do well to look at this thread: Purpose-built Boominator PCB project. This thread covers all of the issues for a portable boombox design--there is a lot of good info. The ADAU1592 amp in that thread is no longer available, but the design can be adapted to use ADI's current offering--the SSM3302, or else use one of the new TI or Maxim chips.

I've got a board that has part of the circuitry you need: it has the DSP (ADAU1701) and two SSM3302 chips (for stereo active 2-way speakers). It works, and right now I'm in the long process of finalizing the software to manage the ADAU1701. The board doesn't have the battery charging or solar cell management circuitry, so it doesn't solve your problem. Also, it's got a microprocessor that monitors the chip temperature and programs the ADAU1701, and interfaces to a PC, so it has complexity you don't need to deal with. But you can see how simple the amp circuitry can be--the four power amp channels are those two chips at the bottom of the board.

The SSM3302 is a good choice for your project because of the high efficiency and low distortion. However, it is a little pricey. If budget is a concern then the TI TPA3110 series of chips could do the job. Or look at the Maxim MAX98400 chips. Also, Sure electronics has those low-cost TPA3110 boards ($9 at Parts Express) that would work well for this application.

Click the image to open in full size.
  Reply With Quote
Old 19th September 2012, 03:18 PM   #5
Banned
 
Join Date: Jan 2005
And twisting the speaker wires also reduces radiated EMI with these "filterless" class d ic's.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
15w amplifier with housing pbutterfly Class D 2 28th June 2010 05:50 AM
Help with 10-15W class d amplifier yasar262 Class D 7 16th May 2010 03:29 PM
suggestion for a 15W amplifier? dimitrij Solid State 2 15th November 2009 07:01 PM
Headphone Amplifier ( Circuit needed) Ayne Headphone Systems 21 5th May 2007 04:56 AM
15W SE amplifier schematic SteveS Solid State 11 11th April 2002 10:03 PM


New To Site? Need Help?

All times are GMT. The time now is 09:16 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2