Part Number: TPA3255
Hello,
I run TP3255 in PBTL mode. Overall, the design works very satisfactorily. Only I get too little power. With 3 ohm load, the board goes at 27V in fault, with 6 ohm load at 54V. With sine wave, quite independend of frequency, 100 Hz, 1kHz, 10kHz. Then I have reconfigured in BTL. The behavior remains exactly the same. With fault I mean a latching fault, which means according to datasheet OC shutdown.
I then tried modifications of the output filter. No change. As an additional check, the original EVM was rebuilt so that it runs with exactly the same filter components as my own board. But with EVM on the same power supply (54V) with same filter components I get with 6 ohms load about 84V to clipping, so all fine. My design is on the power side quite similar to the EVM. Only a bit longer traces in order to have the large capacitors on the top side. The OC resistor is 22k, thus OC shutdown should actually happen at 17A, or is it even higher at PBTL? Only the power supplies for both 12V supplies and the analog input stage are very different from EVM. Anyone a tip, what else could be responsible? I have built in total four prototype boards and with all the same.
Best regards
Ralf