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TPS659037: Startup with internal RC oscillator

Hiroshi Sato98
Prodigy 180 points
Part Number: TPS659037
Other Parts Discussed in Thread: AM5716

Hello,

Our customer evaluating TPS6590377 with AM5716.

For cost reduction, they would like to use TPS6590377 without external oscillator or clock source.

However, it seems OSC16M_CFG OTP bit is 0, so it requires external oscillator.

Is there any method to startup TPS6590377 with only internal RC oscillator ?

Thanks and best regards,

Hiroshi 

  • 0
    TI__Genius 10000 points
    Hiroshi,

    Welcome to E2E! The TPS6590377 requires an external oscillator. This bit is set by OTP and cannot be changed after start up. I would recommend switching to the TPS6590379 (a new OTP), however, this still requires an oscillator.

    See our user guide for the configuration options: www.ti.com/.../sliu011

    Thanks,
    Nastasha
  • 0 in reply to Nastasha
    Prodigy 180 points

    Hello Nastasha-san,

    Thank you for replying, I understand.

    Now, the customer have just started evaluation with replace from TPS6590377 to TPS6590379,

    however, there are some issues.

    Their circuit is almost same with AM571x Indstrial Development Kit EVM.

    Please see TPS part with attached schematic.

    1. TPS6590379 has only outputs VRTC, all other outputs was 0V.

       (Regardless with or without pushing SW3, the result was same)

    --> By changing from R18 10k ohm  to DNI and R931 from DNI to 10k ohm, the issue had solved (without pushing SW3).

        Is this appropriate workaround ? 

    2. Not only power supply, also CLK32KGO did not output any signal

       even after the power outputs issue has fixed.

    --> Is there any cause ?

    Thanks and best regards,

    Hiroshi 

    SCH-sprr242.pdf

  • 0 in reply to Hiroshi Sato98
    TI__Genius 10000 points

    Hiroshi,

    Once power is supplied (VCC1), the device will not turn on until there is an ON request. This means a push button on PWRON, or pulling POWERHOLD (GPIO_7) high. This is why, when you connect GPIO_7 to VRTC, the device turns on.

    In addition to VCC1, you must also supply VIO_IN. How are you supplying this pin? VIO_IN powers the digital components (including the clock). This should be supplied after VCC1. For example, you could use SMPS9 to power VIO_IN (connect the output voltage of SMPS9 to VIO_IN pin).

    Thanks,

    Nastasha

  • 0 in reply to Nastasha
    Prodigy 180 points

    Hello Nastasha-san,

    Thank you for your comment, I'll explain that to our customer.

    So, how about issue 2. ? We would like to have your opinion for that too.

    Thanks and best regards,

    Hiroshi 

  • 0 in reply to Hiroshi Sato98
    Prodigy 180 points
    Hello Nastasha-san,

    Excuse me, I forgot to tell you about VIO_IN.
    VIO_IN is connected to SMPS9 output, the customer's circuit is same as AM571xEVM in that section.


    Thanks,
    Hiroshi
  • 0 in reply to Hiroshi Sato98
    TI__Genius 10000 points

    Hiroshi,

    Can you share a scope shot of VIO_IN and CLK32KGO?

    Thanks,

    Nastasha

  • 0 in reply to Nastasha
    Prodigy 180 points
    Hello Nastasha-san,

    Excuse me, the customer said that they has to verify many other section (AM57xx it self and peripherals),
    so please wait for a week to send waveform.

    Thanks and best regards,
    Hrioshi