Tda7265 mute pin problem(play dont work)

[KBarn.1]

I have a problem with the following:

I built the single power supply circuit which mentioned in the datasheet (second picture). I use 20.5V Vs and 2x15W 8ohm speaker for output.

I measured the Mute pin(5) with multimeter and always showed me 14V.

It is enough for play mode. Nothing came out.

Then tried to ground the Mute Pin also.

The drawings are ok in the circuit.

Anybody has an idea what should I try?

st.com/resource/en/datasheet/tda7265.pdfPage 2/11 Fig 2: Typical Application Circuit in Single Supply

thanks!

[Peter BENSCH]

Welcome, @Kondér Barna​, to the community!

The pin MUTE/ST-BY is not compared with respect to GND, but against VS+, which is stated a little confusingly. The voltage to be applied to MUTE/ST-BY must therefore be set according to the limits given in the table on page 3 of the data sheet for MUTE and STAND-BY :

• for guaranteed STAND-BY between VS and VS-1.5V
• for guaranteed MUTE between VS-3.5V and VS-5V and
• for guaranteed PLAY be less than VS-7V

(measured against Pin 1/6 in each case).

In the data sheet, page 6, its function is described in more detail, in figure 15 using example thresholds of VS-2.5V and VS-6V.

The voltage at MUTE (pin 5) or collector Q1 in the circuit shown in Fig. 2 must be VS-5.1V for the MUTE function, so for your supply voltage of 20.5V it should be abpout 15.4V.

However, if you switch Q1 to PLAY mode by connecting 5V to the base of Q1, this results in an emitter current of approx. (5V-0.7V)/15k = 0.287mA. Since the same current also flows through R3, this results in a voltage of 4.3V at R3, which is added to the voltage of the zener D1, so that at MUTE (pin 5) there is then a voltage of ca (VS-5.1V-4.3V)=VS-9.4V, which should safely put the TDA7265 into PLAY mode.

Does this description help?

Regards

/Peter

[KBarn.1]

Dear Mr Bensch,

So I did the same , zB I measure 15.3V on Mute Pin.

Actually Nothing sound on the Output.

By the Way before the Output Capacitors (470uF) 18.85V DC voltage appear.

Do you have any other idea?

[Peter BENSCH]

Well, it is difficult to make a statement about your construction without having it in front of you. If necessary, you could upload photos of all relevant views of your construction so that we can get an idea.

As I said before, there must be a voltage of less than 13.5V at the MUTE pin at VS=20.5V for the TDA7265 to be able to output sound.

The DC voltage at the outputs is not defined and is only relevant to a limited extent.

Please check the voltage at R1 again, which should also be about 15.4V. Have you also connected both pins 1 and 6 to GND?

Regards

/Peter

[KBarn.1]

All right,

Yes 1 and 6 Pin is connected to GND.

Now I rised a little bit the transistor voltage,

and on Mute Pin I reached the 13.4V.

But still nothing ! The input audio sound is measurable by scope!