TDA7052 tiny 1W amp - single ended output possible?

[dave]

The TDA7052 1W audio amp chip has two output pins that connect directly to the
speaker. The circuit text say "Do not ground either speaker terminal". I'd like
to connect the output though to a PC soundcard line-in, which is single ended.
Is there an an easy way to do this? I don't want to use a transformer (as I
don't have one!). Can I do this with some RC network/series capacitors?
thanks

 

[dave]

On Mon, 28 Feb 2005 18:44:23 -0600, John Fields <jfields@austininstruments.com>
wrote:

On Mon, 28 Feb 2005 23:56:07 GMT, dave <dave@127.0.0.1> wrote:

The TDA7052 1W audio amp chip has two output pins that connect directly to the

[...]
Thanks John, just what I wanted!

 

[John Fields]

On Mon, 28 Feb 2005 23:56:07 GMT, dave <dave@127.0.0.1> wrote:

The TDA7052 1W audio amp chip has two output pins that connect directly to the
speaker. The circuit text say "Do not ground either speaker terminal". I'd like
to connect the output though to a PC soundcard line-in, which is single ended.
Is there an an easy way to do this? I don't want to use a transformer (as I
don't have one!). Can I do this with some RC network/series capacitors?

---
Connect either of the chip's outputs to the sound card line in
through a 100ľF capacitor and connect the chip's pins 6 and 3 to the
sound card ground. Let the other output float.

Connect the capacitor's + terminal to the chip's output and the -
terminal to the sound card's line input.

If you don't want to hear a "POP" when you apply power to the chip
and, assuming the input to the sound card is DC coupled, do this:


Vcc
|
O
|
+-----+--> |
| |
| +--+--+
| | OUT|---[+100ľf-]--------+---------> TO SOUND CARD
| +--+--+ |
| | \__CHIP |
| GND |
| C
+---[+22ľF-]---[100K]--+--- B 2N4401
| E
[1M] |
| |
GND GND


--
John Fields

 

[Winfield Hill]

John Fields wrote...

On Mon, 28 Feb 2005, dave wrote:

The TDA7052 1W audio amp chip has two output pins that connect
directly to the speaker. The circuit text say "Do not ground
either speaker terminal". I'd like to connect the output though to
a PC soundcard line-in, which is single ended. Is there an easy
way to do this? I don't want to use a transformer (as I don't have
one!). Can I do this with some RC network/series capacitors?

Connect either of the chip's outputs to the sound card line in
through a 100ľF capacitor and connect the chip's pins 6 and 3 to
the sound card ground. Let the other output float.

Connect the capacitor's + terminal to the chip's output and the -
terminal to the sound card's line input.

If you don't want to hear a "POP" when you apply power to the chip
and, assuming the input to the sound card is DC coupled, do this:


Vcc
|
O
|
+-----+--> |
| |
| +--+--+
| | OUT|---[+100ľf-]--------+---------> TO SOUND CARD
| +--+--+ |
| | \__CHIP |
| GND |
| C
+---[+22ľF-]---[100K]--+--- B 2N4401
| E
[1M] |
| |
GND GND

When the supply is switched on the transistor acts as a clamp on
the output until the 22uF cap is charged up. But watch out, Dave!
The TDA7052 is rated for up to 18V supply voltage, and can create
output swings of well over 13V peak-peak when powered from 15V or
more. 13V swings will drive -6.5V peaks to the 2n4401 collector,
pulling the base to -6V, and approaching emitter-base breakdown.
This is bad and should be avoided, especially with high currents.
However, TDA7052 supply voltages of 12V or less should be OK.


--
Thanks,
- Win