TPA6133A2: Input bias

Tiger Yeh

Part Number: TPA6133A2
Other Parts Discussed in Thread: TPA6132A2

Hi~

There is a temporary voltage when pre-stage OP turned on and then slow discharging.

When TPA6133 is turned on, the temporary voltage will discharge or offset to 0V, I would like to check whether TPA6133 input side have no DC bias setting during SD, and set to 0V after start up?

over 6 years ago

0 Luis Fernando Rodriguez S. over 6 years ago

TI__Guru* 84915 points

Hi, Tiger,

We will take a look at this an we will answer as soon as possible.

Best regards,
Luis Fernando Rodríguez S.

0 Ivan Salazar over 6 years ago

TI__Guru** 110125 points

Hi Tiger,

The bias on the TPA6133A2 input side is close to 0V. This device has a charge pump in order to center the signal close to GND.
The transient you're seeing is most likely the bias from the previous stage being affected by the RC blocking capacitor.

Best regards,
-Ivan Salazar
Audio Applications Engineer - Low Power Audio and Actuators

0 Tiger Yeh over 6 years ago in reply to Ivan Salazar

TI__Expert 5535 points

Thanks Ivan.
Is there any other HP AMP that could make this temporary voltage at input to 0V?
That may IC still in charge pump during SD.

0 Ivan Salazar over 6 years ago in reply to Tiger Yeh

TI__Guru** 110125 points

Tiger,

Are you using TPA6132A2 in single-ended input?
I would recommend to use it with differential input, this way the discharge curves would cancel each other.

Best regards,
-Ivan Salazar
Audio Applications Engineer - Low Power Audio and Actuators

0 Tiger Yeh over 6 years ago in reply to Ivan Salazar

TI__Expert 5535 points

Yes, the application is single end input because pre-stage is only single end output.

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TPA6133A2: Input bias