TAS5782M: How to Drive Capacitive Load

Hi Kato,

As far as I know, it is not a normal use for TAS5782M to drive a piezo speaker.  I'm wondering why your customer cannot choose a dedicated piezo speaker.

Andy

Hi Andy-san,

Thank you for your support.

We got the detailed information from our customer, so let's communicate off-line by email.

Best regards,
Kato

Hi Andy-san,

TI local FAE has already contacted your design team, so I would like to wait for their response.

Best regards,
Kato

Hi Sadanori,

how much is the capacitance of piezo?

Kai

Hi Kai-san,

The assumed capacitive load is 1 nF ~ 2 nF or 2nF ~ 4nF.

Best regards,
Kato

Hi Sadanori,

I don't think that such a low capacitance is a problem, as you have already 100nF in the output filter. So, if the amplifier is designed to work with a 100nF load capacitance, then it should work with a load capacitance of 104nF as well.

Kai

Hi Kai-san,

Thank you for your response.

I think there is concern about the oscillation due to the LC filter without the resistor load and the overcurrent at the high frequency.

Best regards,
Kato

Hi Sadanori,

you could mount a dummy load resistor.

Kai

Hi Kai-san,

Thank you for the information.

As mentioned above, I am considering inserting a series resistor in the capacitive load.

Best regards,
Kato

Hi Andy-san,

I greatly appreciate your cooperation.

Best regards,
Kato