| T O P I C R E V I E W |
| aravindj36 |
Posted - Apr 08 2011 : 01:59:31 AM
I'am planning to make a USB-powered amplifier using the ic tda7057 with a circuit found here http://www.payalo.at.ua/index/0-191 And in the datasheet it is said it can deliver 3watts of power into 16ohm speakers in stereo.I had a few 4ohm 3watt speakers lying around so would it be ideal to connect those to the ic and power it from usb.also approximately how much power can I get as the output. .Sorry the given link is in russian |
| 6 L A T E S T R E P L I E S (Newest First) |
| wasssup1990 |
Posted - Apr 08 2011 : 11:37:04 PM
For what it's worth I would just like to say that when I was 13 I was starting to teach myself how to use microcontrollers. I was pulling apart my RC cars and fitting them with brains (microcontrollers). |
| aravindj36 |
Posted - Apr 08 2011 : 12:52:57 PM
Well the problem is that I cant get hold of any of the ti's ic's in our local electronics store.In fact I could find a few tda7057Q's in there thats why I started this thread.I'am just a 13y.o so I have no idea about microcontrollers or adc's.Audioguru you need to wait some time for the given link to load otherwise all you can see is a piece of wood.  |
| wasssup1990 |
Posted - Apr 08 2011 : 10:03:27 AM
aravindj36 do you want to design one?
TI have excellent products and application notes. I suggest you make a class-D amplifier. You can make them very tiny and they don't waste much power. The way they work is very simple. You can make them using discrete components or for more compact designs you can remove several components simply by using a microcontroller. This may be out of your realm though. You could just follow the reference designs they have on their website if you don't want to design one yourself.
Take a look at their audio products. They may give you some ideas.
http://focus.ti.com/analog/docs/audiooverview.tsp?familyId=376§ionId=630&tabId=2700
EDIT:
You may be particualy interested in the headphone amplifier section since you stated that you want to power your amplifier off only 5V. |
| audioguru |
Posted - Apr 08 2011 : 09:10:14 AM
The TDA7057 amplifier IC is obsolete and is not made anymore.
The Russian page shows a piece of wood, no schematic of a TDA7057 amplifier.
Why not look at an English datasheet from the manufacturer of the TDA7057?
It shows the output power is 3.5W with a horrible sounding 10% clipping distortion when the load is 16 ohms and the supply is 12V.
The IC is not spec'd with a 4 ohm load. With a supply that is only 5V then its output power is almost nothing.
A linear power amplifier heats when it produces power in a speaker. You can get 5V x 500mA= 2.5W max from USB. If you can find a power amplifier that works when the supply is only 5V and is stereo then each channel will have an output of only 0.75W and the heating will be 1W. With a 5V supply and an output of only 0.75W then the load is only about 2 ohms but you won't find a low power amplifier that drives 2 ohms. |
| aravindj36 |
Posted - Apr 08 2011 : 05:53:35 AM
Actually Iam a bit confused whether it was safe to connect a 4ohm load to the ic and it is not mentioned in the datasheet how much power it can deliver into a 4ohm @5volts .And the given link can be translated using google translate into english. .If you want to obtain 500ma of power from the usb port just short both the data pins.[size=3] |
| wasssup1990 |
Posted - Apr 08 2011 : 03:27:29 AM
Correct me if I'm wrong please. The USB can supply 5V at a maximum of 500mA. I think it's limited to 100mA by default and can be increased to 500mA upon request by the device plugged into the USB hub.
Maximum average output power for USB:
5V * 500mA = 2.5W
Sorry but it seems the USB can only deliver 2.5W average. By simply saying 3W into a 16ohm speaker, I make the reasonable assumption that 3W is an RMS value. So it looks like you will be able to power two 16 ohm speakers with a power of 1.25W per channel for stereo. Peak power to your speakers may cause the device to reset, so make sure you have an adequate ripple capacitor on the 5V supply.
Sorry I don't have time to look at the device in question, nor the design page you posted. Besides I can't read Russian. |
