TPA3112D1: In fault on powerup

Steve Thompson88

Prodigy 80 points

Part Number: TPA3112D1

Hi, I'm having problems getting this amplifier to work , in that on power up It goes into fault.

Power supply = 12V

Speaker = 8R

I've removed all input cct and grounded inputs Via 1uF caps

There are no shorts nor o/c's, occurs on both boards I have, and for good measure I have replaced the TPA3112 on one of the boards

Power up sequence = Press and hold SW1 apply power wait 2 secs and release SW1 - result Fault LED comes on press SW1 briefly LED goes out then immediately back on.

Tested with and without snubber, with and without speaker, with and without 10R 1000uF series supply filter, with R4 = 100K and R4 = OR, with and without additional output filter.

Am I missing something?

Regards Steve

over 3 years ago

0 Steve Thompson88 over 3 years ago

Prodigy 80 points

0 Yanming Gong over 3 years ago in reply to Steve Thompson88

TI__Mastermind 19250 points

Hi Steve,

Did you capture output current when issue happened?

I suggest that you can simply circuit, remove 10ohm+1nF snubber and beads. Then check that if the issue still happen.

Regards,

Derek

0 Steve Thompson88 over 3 years ago in reply to Yanming Gong

Prodigy 80 points

Hi Yanming,

Snubbers in or out have no effect, and same result with 10K resistive load and no load and 6.8R resistive load and 8R speaker.

I've not tried with no ferrite beads, if the amp is that fussy about load then I'm not sure its the right part to use. The datasheet implys that providing max load is greater than 3R then it should just work.

I'm testing an alternative today (non-TI)

0 Yanming Gong over 3 years ago in reply to Steve Thompson88

TI__Mastermind 19250 points

Hi Steve,

Device can still switch without load connection and bead connection.

So you can remove the beads and check the PWM waveform on device pins. And also check the GVDD pin voltage.

Regards,

Derek

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TPA3112D1: In fault on powerup