TLE2426: Audio splitter

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sorry

Thank you Clemens,

HI Luigi,

Let us know if you have questions.

Best Regards,

Luis

Hello Clemens, thanks for your reply.

I think I'm in quite borderline situation, the total current consumption from the op amps should be from 12 to 18 mA.

My main doubt concerns the connection of GND on the pcb, especially regarding the signal input and output connectors which should be connected respectively to a signal generator and an oscilloscope

Luigi,

The op-amps are powered by the unipolar +12V supply, where the current flows from the unipolar supply +12V to the supply GND. The virtual GND splitter output is connected to the non-inverting input terminals of the op-amp which are high impedance, and the 1MΩ resistors, therefore you will not reach current limit in this case.

You are correct, in general, the housing of the oscilloscope is internally coupled to the earth potential.  Hence, if your single +12V supply is allowed to float with respect to the earth GND, such a battery, or if the supply has galvanic isolation, this will work.  However, if the negative terminal of the single +12V supply is referred to the same oscilloscope GND or function generator GND, or if the unipolar supply does not offer galvanic isolation, this will create an issue. 

Regards,

Luis

Hello Luis, thanks a lot for your help, I realy appreciate that.

The final scope of this project is to create a 2x audio splitter for connections from signal generator to stereo audio apparatus, powered by a simple wall switching power supply. Following what you said, I can't use a common wall power supply and I can't even connect it to a signal generator normally connected to the earth. Right?

Hello Luigi,

The virtual GND generator or rail splitter is generally used on a unipolar supply configuration to generate an "analog virtual GND", or a Vs/2 reference potential for the analog circuitry when using a single unipolar supply. However, this is not the same as generating a bipolar supply with respect to chassis GND.  In essence, your PCB circuit is using a unipolar supply, with the analog circuits referred to the supply Vs/2 potential.

If your supply does not offer galvanic isolation with respect to the oscilloscope GND and/or function generator GND, then you would need to refer the coaxial connectors to the unipolar supply GND, and then offset or level shift the signals by Vs/2.  Alternatively, refer all the analog circuit/connectors to GND, and use +/- bipolar supplies - two separate supplies referred to GND.

Regards,

Luis