DS90UB926Q-Q1: FPD LINK III

Part Number: DS90UB926Q-Q1
Other Parts Discussed in Thread: DS90UB928Q-Q1

Tool/software:

Background:
A Qualcomm 8295 platform car product requires the use of TI's FPD LINK chip.


Question:
We want to use the DS90UB928Q-Q1  to use FPD LINK III. However, the current screen resolution of 480 * 480 is not sufficient to meet the requirement of PCLK>25M for FPD LINK III.

If the resolution is increased to a resolution of 584 * 720, it can meet PCLK>25M, but the estimated MIPI rate exceeds 500Mbps and does not meet the requirements of the display module.


I would like to ask if there is any solution to solve this problem.

  • Hello,

    Do you have a block diagram of the video path (serializer, deserializer, TCON/display) so I can make sure everything is clear? 

    If the resolution is increased to a resolution of 584 * 720, it can meet PCLK>25M, but the estimated MIPI rate exceeds 500Mbps and does not meet the requirements of the display module.

    How are you calculating that a MIPI rate of 500Mbps would be exceeded with a PCLK around 25MHz? For a PCLK of 25MHz, a DSI rate can be calculated by (PCLK * 12 / Number of Lanes) * 2. How many MIPI lanes are used?

    Best,

    Jack

  • Hi Jack,

    The block diagram is as shown:

    I have to transfer a 584*720 resolution image to ensure that PCLK > 25M.

    The display module support only 1 data lane, so the DSI rata for 584*720 resolution would be 600Mbps (25MHz * 12 / 1 * 2) which could not meet the requirement of the display module.

    Is there a way to use FPD LINK III while keeping the DSI rate below 500Mbps?

  • Hi Tengfei,

    The minimum PCLK supported by the 983 in FPD-Link III mode is 25MHz. This is the only DP serializer so if the serializer cannot be changed then I do not see a solution beyond seeing if there is a display module that can support more than one DSI lane.

    If the serializer could be changed, a potential solution would be using a DP to LVDS converter IC (non-TI part) and using a DS90UB927-Q1 as the serializer. 

    Best,

    Jack