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Problem with audio amplifier

Started by eryer September 16, 2009
Hi,
I have a problem with this audio amplifier (i'm new in this field, so
excuse me for my questions):
http://focus.ti.com/lit/ds/symlink/tpa2005d1.pdf
I've used it as single ended amplifier. It is connected to a DAC:
between DAC and IN- a CR high pass filter is present.
DAC can generete signals from 0 to Vdd (the same Vdd of TPA2005); so a
value between -Vdd/2 +Vdd/2 is present in IN-. From datasheet i can
obtain a value between -Vdd/+Vdd at loudspeaker; so i've decided a
gain=2 for ampifier. Audio sounds well, but loudspeaker's volume is
very low....where is the problem?
Thanks in advance
On Sep 16, 7:24=A0am, eryer <idkfaidkfaid...@gmail.com> wrote:
> Hi, > I have a problem with this audio amplifier (i'm new in this field, so > excuse me for my questions):http://focus.ti.com/lit/ds/symlink/tpa2005d1.=
pdf
> I've used it as single ended amplifier. It is connected to a DAC: > between DAC and IN- a CR high pass filter is present. > DAC can generete signals from 0 to Vdd (the same Vdd of TPA2005); so a > value between -Vdd/2 +Vdd/2 is present in IN-. From datasheet i can > obtain a value between -Vdd/+Vdd at loudspeaker; so i've decided a > gain=3D2 for ampifier. Audio sounds well, but loudspeaker's volume is > very low....where is the problem? > Thanks in advance
Do you establish a common mode voltage on one of the resistors inputs, then AC couple to the other? I am assuming you drive it single ended, but use the bridged output .Otherwise you would have DC going through the speaker.
On 16 Set, 21:18, "m...@sushi.com" <m...@sushi.com> wrote:
> Do you establish a common mode voltage on one of the resistors inputs, > then AC couple to the other? I am assuming you drive it single ended, > but use the bridged output .Otherwise you would have DC going through > the speaker.
Thanks for the answer... I'm using configuration in Figure 34 of pag.11 of datasheet http://focus.ti.com/lit/ds/symlink/tpa2005d1.pdf I've done these calculations 1. GAIN=2 => Ri=150Kohm 2. high pass corner frequency=321Hz => Ci=3.3nF I think there is a DC in the speaker (because it is very hot), but i don't understand what's wrong... Thanks