About TDA7294

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Jackdaniel

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heya all

just want to build a subwoofer amp using TDA7294, so i want your opinion and your help about TDA7294, i dont know how to look up a datasheet for the TDA7294(not any1 else's!) so can anyone help me and give me a good schematic?..
 
Thanx, and what do u know abt TDA7294? Is it a good ic for a subby? Pls lemme know your opinion about TDA7294, because i want a better subwoofer amp out of it
 
The TDA7294 is a pretty good audio amp IC but it is spec'd with an output of only 70W. Many sub-woofers use hundreds of Watts then you can feel the deep bass..
 
i read lots of bad comments abt the tda7294 from net, most of them was abt "frying them".so anyone has ever tried them? And how to use its stand-by/mute system? Should i connect them to "GND" To achieve these functions? And Please post a good schematic of Tda7294 for me.
 
Obviously if you fry the chip, you're doing it wrong. These people most likely shorted the output with a a speaker that was too low of an impedance for the voltage they were using or they just supplied it with too much voltage all together. The IC has a simple temperature sensor in it that senses possible shorts to prevent thermal over load, however if you short the output you've killed the amp before the IC even gets hot.

In figure 18 of the data sheet, it has some ways you can protect the IC from self destruction. You can add a capacitor to the output to isolate the speaker from the amp, or you can add a resistor to limit it's output current.

The Mute and Stand-by functions are activated when the respective Mute pin (pin 10) and Stand-by pin (pin 9) are connected to a voltage between 1.5V and 3.5V. If you connect the each pin to the voltage supply, the IC will remain on. Try to limit the input current to these pins to avoid destroying them as seen in figure 18 of the data sheet.
 
Dragon Tamer said:
Obviously if you fry the chip, you're doing it mp, or you can add a rt.
Click to expand...

how can i reduce voltage to 1.5v or 3.5v? Can i put a resistor from powersupply to reduce the voltage? And what is the max powersupply i can give to the ic? Can i use a dual 12v supply?..too many questions lol sorry i am only a noob thus i must ask those
 
The datasheet has many graphs. The 3rd graph answers your question about using a dual 12V supply.
 

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Jack, you should try to read the data sheet yourself. Even if you don't understand it, read it a few times and most of it will start to make sense. Then when you come for help on the forum you will be better informed and we will be able to help you more easily.

That being said AG pointed out a good chart from the data sheet. It shows the power output of the amp (on the left) as the voltage increases (on the bottom), just remember that the voltage listed is for a dual power supply, so a 15V supply on the chart would be a +15 -15 supply.

I also think that you may have been mistaken, the IC enters Mute or Stand-by mode when the input is between 1.5V and 3.5V. You can add a voltage divider to make the voltage withing this range. If you do not want the IC to enter Mute or Stand-by mode, connect these pins right to the positive power supply.
 
Jackdaniel said:
and what if i connected the mute/standby pins to nothing? Does the ic still work?
Click to expand...

Well, again, learning how to read and interpret the datasheet can come in handy here.

Looking at the Thomson datasheet (from the Datasheet Catalog), page 3, it says:

Mute function (Ref: -Vs or GND)
Vmon Mute on threshold: 1.5V
Vmoff Mute off threshold 3.5V

It's telling us that the mute function voltage is measured referenced to Vs/ground. "Threshold" tells us that the function is on a sloped line of some shape, with voltages higher than 3.5 volts triggering the mute "off" function (in other words, no muting).

So you tell us now: what happens if this pin is left unconnected? Hint: what is the voltage on the pin (referenced to ground) in this condition?
 
i cant understand carbo, what is vmon, **broken link removed**is a datasheet of a Tda2030a for easy learning and i am gonna ask you a bunch of nooby questions from the datasheet,so please help me


  • datasheet page 1 and 2: what is non inverting input?
  • what is inverting input
  • what is Vs?(full form of it) (voltage?).
  • what is diffential input voltage?
  • what is peak output current?
  • what is total power dissipiation?
  • junction temperature?
  • storage temperature?
  • input bias current?
  • slew rate?
  • input noise current and voltage?
  • input resistance?
  • thermal shut-down?
 hope U will all help this noob,
 
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Jackdaniel said:
i cant understand carbo, what is vmon, UTC.TDA2030A.pdf is a datasheet of a Tda2030a for easy learning and i am gonna ask you a bunch of nooby questions from the datasheet,so please help me
Click to expand...

How about one thing at a time? Let's stick to the mute function on the original IC, 'k?

"Vmon" means "the voltage needed to turn the mute function on", and Vmoff is the opposite.

The voltages are given as thresholds, which means that the function is turned on (or off) when the voltage crosses that threshold. In other words, when the voltage reaches or goes over 3.5 volts, the mute function is turned off (meaning that the amp is not muted--the music plays through the amp).

Given this, figure out and tell us: what happens when the voltage to the mute input goes to or below 1.5 volts? (Keep in mind that voltages are measured with respect to ground.)

So based on that, what happens if you leave the mute pin unconnected? (That was your question back in post #13 up there.)

You should be able to do this.
 
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carbonzit said:
Given this, figure out and tell us: what happens when the voltage to the mute input goes to or below 1.5 volts? (Keep in mind that voltages are measured with respect to ground.)
Click to expand...
maybe the mute function is activated when the voltage goes below 3.5.sorry aint it?

carbonzit said:
So based on that, what happens if you leave the mute pin unconnected? (That was your question back in post #13 up there.)
.
Click to expand...

the amp won't play if those pins are unconnected.. True? Nd a schematic would be useful..pls
 
Jackdaniel said:
how many volts the ic requires to output 70w? 28v?
Click to expand...
The datasheet shows a typical max output of 70W into 8 ohms when the supply is plus and minus 35v but the distortion is high. The minimum max output is 60W for a few of them. The distortion graph shows low distortion when the typical output is 65w into 8 ohms.

When the speaker is 4 ohms then a plus and minus 27V supply produces the same power and distortion.

what if i connected the mute/standby pins to nothing? Does the ic still work?
Click to expand...
Maybe not. The mute /standby circuit is shown in figure 17 and is explained to be 0V when it is muted and +5V when it plays. It can be driven by Cmos logic.
 

No. As I said, the mute function is activated when the voltage goes to or above 3.5 volts.

So looking at the datasheet, what happens to the mute function when the voltage goes to or below 1.5 volts?

You should be able to figure this out.

Look at it this way: I could give you a fish for one day, or I could teach you how to fish ...
 
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