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TLC5928: Power-up Time?

Art Mecina
Genius 16585 points
Part Number: TLC5928

Hello Guys,

Good day.

We have a customer designing a LED matrix board (high volume once released) and is considering to use TLC5928. Their concern is that the device has no power saving mode, but he can bypass this limitation by adding a VCC power switch when display is blank. 

He wanted to know  what is the maximum power up time (time between "Vcc>Vccmin" and "device ready for operation"), with Vcc=3.2V and T° amb between -10°C and +60°C ?

Thanks in advance!

Art

  • 0
    TI__Genius 16585 points

    Hello Guys,

    Any update on this?

    Thanks!

    Art

  • 0 in reply to Art Mecina
    TI__Genius 16585 points

    Hello Hardy,

    Any update regarding this inquiry?

    In addition, customer wanted to know if he need to respect any specific power off / power on timings (slew rate min / max) and levels (especially the minimum level of Vcc the power supply must fall below to ensure your power on circuitry to reset correctly).

    Best regards,

    Art

  • 0 in reply to Art Mecina
    TI__Genius 12915 points

    Hi Art,

    Sorry for late reply that we are on vacation for national day. I did not find validation data of power up time of sequence. Could you help to ask how much power-up time customer could provide on their system? It is better customer could provide a waveform when powering up VCC. We could ask design team to simulate it to see if have any potential risks.

  • 0 in reply to Hardy Wu
    TI__Genius 16585 points

    Hello Hardy,

    No worries about that. I will inform customer about this and will get back to you as soon as I have their answer.

    Art

  • 0 in reply to Art Mecina
    TI__Genius 16585 points

    Hello Hardy,

    Below are the information I got from the customer

    The power rail (16 drivers) will be switched on/off by a power switch device that integrates a 70-200ohms pull down resistor when switched off.

    He don't have specific requirements for power on / off timings, but he need to know the limits to optimize power consumption with maximum reliability.

    Unfortunately, he just have launched 10 prototypes boards, He will be able to check the power rise/fall rates (slew rate controlled by the switch) and switched off low level and will provide waveforms before the end of november.

    Thanks!

    Art

  • 0 in reply to Art Mecina
    TI__Genius 16585 points

    Hello Hardy,

    In addition to above information, customer wanted to kno, before he can measure the power rise/fall sequence, how much time he should wait between Vcc > Vccmin and starting to send data to bus and display it ?

    Thanks!

    Art

  • 0 in reply to Art Mecina
    TI__Genius 12915 points

    Hi Art,

    I think 5ms should be enough for internal blocks initialization.