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TPS92691: 6.3W LED fail issue

Patrick Chen
Mastermind 8875 points
Part Number: TPS92691

Hello

     Customer found our 6.3W LED device can’t be work normal. But 55W device seems ok.They make some modify on EVM board likes attached circuit BOM value.

But PR16 change to 150k and PR22 POP. Just using IADJ(Analog dimming).

Please check the circuit and waveform if any customer can try.

If this solution can’t be support CV mode they may consider to change solution. Has any comments for 6.3W LED fail issue？ Thank you. 

 

Our device spec show as below.

  1. LED 55W; CV mode 24V, 2.26A
  2. LED 6.3W; CV mode 24V, 0.26A

 

BR

Patrick

               

  • 0
    Mastermind 8875 points

    Hello

          Customer  found it seems trigger the OVP for LED 6.3W. 

           The OVP pin voltage over 1.24V. Could you let us know why make it OV?

    BR

    Patrick

  • 0 in reply to Patrick Chen
    Mastermind 8875 points

    Hello

             Customer used TPS92602 EVM board to do Boost-to-Battery architecture to meet our requirement.

    But the VLED/ILED waveform seems strange at PWM 50% duty.

    Vin: DC24V, LED Vout: DC24V, LED current: 2.5A max. CV mode control.

    1. LED 55W; CV mode 24V, 2.26A
    2. LED 6.3W; CV mode 24V, 0.26A

    50% PWM duty

    100% PWM duty

    BR

    Patrick

  • 0 in reply to Patrick Chen
    TI__Mastermind 18890 points

    Hi Patrick,

    There is a lot of data here to digest.  Please give us a few days to get back to you on this.

    Thanks Tuan

  • 0 in reply to Tuan Tran74
    TI__Mastermind 18890 points

    Hi Patrick,

    I'll answer for the TPS92691 since I am responsible for that part.  You'll have to re-post for the TPS92602 as a separate post since they are two different parts and issue.  This is so it can be routed to the right application engineer.

    For the TPS92691:  What is the input voltage range...I see nominal as 24V on the schematic?  What do you mean by CV?  This is a current controller.

    Can we have a scope capture of OVP pin voltage to verify that it's tripping the OVP ans zoom into the rising edge of the OVP. 

    We cannot read any of the values with the schematic you capture here.  Can we get a better schematic file? 

    In general, it can be design to work with both case.  It's very confusing here that you mentioned that OVP is the issue.  Are they using the same LED?  What is the forward LED voltage?  You mention 24V for both...This is the confusing part.  The output voltage should be the same for both.

    Thanks Tuan

  • 0 in reply to Tuan Tran74
    TI__Mastermind 18890 points

    Hi Patrick,

    We have not heard back from you so we believe you may have solved the issue.  The thread will close now but will reopen if you reply.

    Thanks Tuan