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TPS92602-Q1: DIAG issue

Patrick Chen
Mastermind 8875 points
Part Number: TPS92602-Q1

Hello

             Customer meet two issue as below. 

1. DIAG  issue : 

For 60W LED device can be normal work on DIAG pin on each channel.

But 12W LED device not all channel can be normal work on DIAG pin.

 

In lighting control board this project. Customer software team found DIAG pin no signal on some channel as attached waveform.

They removed 0 Ohm from DIAG pin to MCU’s connect. And mark the PWM duty & channel as file name.

Please help to check what happen. And what can we do?

2. Plug issue : 

When customer remove & plug the LED device(2.5A) sometimes no output at channel 3.

After check it always happen on PWM duty 90%~100%. And they will try to remove & plug the LED device(2.5A) on this moment.

Does it about OVP or others protection? Waveform are below. 

BR

Patrick

  • 0
    TI__Expert 5475 points
    Hi Patrick,

    Sorry but the description is not that clear to me. Could you please clarify a little more?

    1. Diag issue
    What is the waveform that you think DIAG is abnormal? I do not see this waveform.

    2. Plug issue
    What do you mean by channel 3, since this device should have only 2 channels outputs?
    What is the waveform on DIAG pin when this happens? It's better to look at the waveform of DIAG to see what fault is triggered.

    Thanks so much.
  • 0 in reply to Shirley He
    Mastermind 8875 points

    Hello

               Shirley, please refer to below .

    1. Diag issue
    What is the waveform that you think DIAG is abnormal? I do not see this waveform.

    Ans: LED4 is normal waveform and others abnormal.

    LED1_30%_DIAG

    LED2_100%_DIAG

    LED3_50%_DIAG

    LED4_50%_DIAG



    2. Plug issue
    What do you mean by channel 3, since this device should have only 2 channels outputs?
    What is the waveform on DIAG pin when this happens? It's better to look at the waveform of DIAG to see what fault is triggered.

    Ans: 

    After check each channel may happen. And also attached the DIAG waveform when this happen.

    remove abnormal

    remove abnormal2

    remove abnormal3

    remove abnormal4

    BR

    Patrick

  • 0 in reply to Patrick Chen
    TI__Expert 5475 points
    Hi Patrick,

    1. Diag issue

    What is the required output current of channel 1-4? When you say channel1-3 are abnormal, are their output current normal?

    1. Plug issue

    According to the waveform of DIAG pin which is above 3V, overcurrent protection is triggered. Why does customer need to remove and then plug the LED in such a short time?

    Sorry for keeping asking questions, because it's still not easy to figure out what happened based on the information you provided. Besides that, the schematic is so unclear. Would you mind inserting a clear one? Thanks.
  • 0 in reply to Shirley He
    TI__Expert 5475 points
    Hi Patrick,

    I'll close this thread due to inactivity. If you have more questions, just reply to it directly and it will open again. Thanks a lot.