Hi TI support team,
we found an issue that TPA3221 cannot start up without PWM output.
Schematics below
Summary of the test
- We connected IN1_M and 1N2_M in the circuit and used a common cap, does it impact the performance of the amp?
- There is the current source in IN1_P/ IN1_M /IN2_P /IN2_M and charge to these AC couple cap when amp startup, does it relevant to the previous item?
- We did some changes in the circuit and sequence of power, the test result is in the following for you to reference.
When the problem occurs, the waveform as shown below
- Test of issue: IN1_P goes down to 0 and no PWM output
- Change R23, R141 to 47K, and R32, R86 to 100K
- Amp startup with PWM output and IN1_P trigger to 5.4V and change to 2.48V after reset pull up, need to test to check the performance
Please advise what is the problem of the circuit and would you provide the explanation and solution to this startup issue. Thanks
regards
Kelvin