Questions on bridged, single supply TDA2030

[wwenze]

I am contemplating building a cheap low-power gainclone and am going for bridged TDA2030s so I can run it off a laptop power brick. Attached is the split-supply bridged schematic from ST's datasheet.

I will generate a virtual ground using TLE2496 or similar. The question is about the zobel of each amplifier's output. Can I safely assume that the amount of current flowing into the virtual ground at any time will be negligible - less than 20mA? Also, is it possible to connect a zobel directly between the two outputs instead of between output and ground?

Second question: Which arrangement for power capacitor is better in this case? (see second attachment)

[pacificblue]

The Zobel in a single supply application connects to the real ground not the virtual ground.

You should not use capacitors on the output of a TLE2496, especially not big ones like in the right schematic.

[wwenze]

Thanks for the reply, this makes construction much simpler.

That also motivated me to look at the TLE2426's datasheet, and saw the graph on stability vs load capacitance. Important point noted.

[sregor]

Quick question - with a bridged amp, why use a virtual ground. Should be able to build it without (but Zobels would still go to ground) ...just wondering...

[wwenze]

Originally Posted by sregor

Quick question - with a bridged amp, why use a virtual ground. Should be able to build it without (but Zobels would still go to ground) ...just wondering...

To bias the + input at the midpoint between V+ and 0V.

[sregor]

Originally Posted by wwenze

To bias the + input at the midpoint between V+ and 0V.

I am in the keep it simple camp - two resistor voltage divider - or 3 and a large cap to decouple power supply (input resistance parallel of two resistors after cap). Nothing wrong with doing it your way. Good luck.