Hi Team, we have two products with the TS4984 BTL amplifier designed in. We would like to mix the signals at the output stage into a single 8 Ohm speaker.

[DHadd.1]

Is it possible to operate 2 x TS4984 amplifier as a PBTL only using the Left channel from each product. (Both products share the same power domain)

We have prototyped a small interface consisting of 4 x 100uF non-polarized capacitors to mix the differential outputs to a single output channel which then connects to the load (8 Ohm speaker). Seems to work well, just need confirmation this approach will operate safely, not harming the amplifiers I.e audio signals not the same/synced.

Product (A) will be playing music, whilst Product (B) will be mixing in a secondary audio signal (i.e Alert Beeps, Speech).

Kind regards,

Daniel

[MasterT]

No. You can't connect two outputs. Essentially outputs stage is Low impedance circuits would seen as short circuits for another amp.

It's possible to parallel like PBTL, if inputs also are connected. Still small series resistance may be required to null out offset difference, or capacitors

[DHadd.1]

Thanks MasterT this was our concern.

So if we have output DC blocking capacitors (like image below), can we also add series resistance with caps to null the offset, if so what value is recommended?

[MasterT]

Value of the capacitors depends on required low end frequency, C= 1/(2*PI()*R*F), where R is load resistance 8 OHm, F - frequency in Hz.

Another option is to set 4 OHms resistors inplace of capacitors.

[DHadd.1]

Thanks we will proceed with capacitor solution, appreciate your help confirming.