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DS90UB928Q-Q1: <Request>DS90UB928Q circuit review

Lin Hsian
Expert 1580 points
Part Number: DS90UB928Q-Q1
Other Parts Discussed in Thread: DS90UB928Q,

Hi,

Our customer used DS90UB928Q for car display, the  DS90UB928Q circuit as attached file.

Please help to review and advise, thank you.

Warm Regards,

Kevin

mtv8(DS90UB928Q).pdf.pdf

  • 0
    TI__Mastermind 37500 points

    Hello,

    I have attached a schematic review checklist, 

    There are some concerns:

       pins 25, 29, 33 - these are caps to internal regulators, there should be no connection to 3.3v

       pins 6, 31, 38 - there is a suggestion, 9.2 to use ferrite beads, the EVM schematic also has .1uF added.

       pin 12 IDX - the ratio matches the table, but is slightly below the min ratio, please check

       pin 48 MODE_SEL - can't tell the desired function or resistor ratio

       there are layout additional items, for RIN0+, RIN0-, the LVDS output clock and data pairs, pair matching, and for LVDS length matching

       couldn't find I2C pullups

    Regards,

    Joe Quintal928reviewschematic_JQ031519.xlsx 

     

  • 0 in reply to Radio-Joe
    Expert 1580 points
    Hi Joe,
    Thanks for your input.
    Let me update to customer and discuss it.

    Warm Regards,
    Lin
  • 0 in reply to Lin Hsian
    Expert 1580 points
    Hi Joe,
    For the excel file, >=9via means over 9 via to GND?

    Warm Regards,
    Lin
  • 0 in reply to Lin Hsian
    TI__Mastermind 37500 points

    Hello

    Yes, 9 vias is a layout element used for Thermal GND to draw heat away from the GND PAD.

    Regards,

    Joe Quintal

  • 0 in reply to Radio-Joe
    Expert 1580 points
    Hi Joe,
    One more question:
    From DS90UB928Q-Q1 DS page 53=>PGND: When writing to indirect registers, this register
    contains the data to be written. When reading from
    indirect registers, this register contains the read back
    value.

    That's means we can set BIST screen by our self, right?

    Warm Regards,
    Lin
  • 0 in reply to Lin Hsian
    Expert 1580 points
    Hi Joe,
    Correct as below:
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    One more question:
    From DS90UB928Q-Q1 DS page 53=>PGID: When writing to indirect registers, this register
    contains the data to be written. When reading from
    indirect registers, this register contains the read back
    value.

    1)That's means we can set BIST screen by our self, right?

    And page52=>VCOM Pattern Reverse: Is YCBR to make sure flicker performance?
    2) If I want to set gray level pattern, can I do it?

    Warm Regards,
    Lin
  • 0 in reply to Lin Hsian
    Prodigy 180 points
    Hi Joe,
    about DS90UB928Q BIST-mode patterns,
    in spec. page52 Table8 1110: Custom color (or its inversion) configured in PGRS, PGGS, PGBS registers,
    if we want to build these patterns of graylevel16(G16), graylevel31(G31), graylevel63(G63), and crosstalk(CT), and
    these patterns display following the sequence of G16-->G31-->G63-->CT,
    Can we use this setting to achieve our target?

    Warm Regards,
    Sauron
  • 0 in reply to Sauron huang
    Prodigy 180 points
    Hi Joe,
    about DS90UB928Q power-sequence,
    the 3.3V must be power-on before 1.5ms, but
    had it demand on the power-off sequence (such as 3.3V must be down to low below ? ms)
  • 0 in reply to Lin Hsian
    TI__Mastermind 37500 points
    Hello the TI App Note AN-2198 describes that setting the PGIA address, and then writing to PGID, writes to the PGIA address.
    To read the value, set the PGIA address, then read from PGID.
    Note: you need to keep track of the PGIA address, allows update this before using PGID.
    Regards,
    Joe Quintal
  • 0 in reply to Lin Hsian
    TI__Mastermind 37500 points
    Hello
    1) BIST screen - if you mean BIST mode, section 8.3.9.1 in the datasheet indicates this is done with the BISTEN hardware pin, with the BISTC
    clock select hardware pin. the PASS hardware pin monitors the status. Also Figure 20 has a time line for BIST.

    There is an I2C address ox24 for BIST Control, if you are local to the DS90Ux928 I2C, you could read and write the BIST control register.

    2) VCOM Pattern Reverse - this reverses a specific color band. If you want a custom color, you can set the RGB values as custom color.
    this is not a color band, the entire active area of the pattern generator is this color.

    Regards,
    Joe Quintal
  • 0 in reply to Sauron huang
    TI__Mastermind 37500 points
    Hello
    On page 52, the three registers can set any RGB value, and the custom color is used for the entire active panel area.
    The AN2198 application note, discusses the Pattern Generator.
    If you have the 24bit RGB value or 18bit RGB value, you can program the color, select the mode, then enable the pattern generator.

    Regards,
    Joe Quintal