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DLPLCR9000EVM: Mirror Flickering

Carl H
Prodigy 110 points

Part Number: DLPLCR9000EVM

Hello all,

I want to use my DMD for beamshaping in a cold atom experiment. One issue is "mirror flickering". This term describes that every 105 usec a pulse is sent such that all the mirrors are released for ~3usec. For a single white image in pattern on the fly mode this means that the intensity drops every 105 usec. Following the procedure in I took a look at the mentioned strb-signal and indeed the strb signal is correlated with the flickering. So every time the intensity drops I can detect three short pulses on the strb line. To control this behaviour I soldered a relais on it such that I can either let the signal pass or not (the switch is located next to TP15)

Even with the line interrupted the mirrors do not stick in their position. I can still measure the strb pulses on the mirror side of the relais. So do you know if there is another line transmitting these strb pulses?

Best C

  • 0
    TI__Expert 3020 points

    Hi Carl,

    Welcome to E2E Forum.

    We will check your query and get back to you.

    Thanks,
    Shivakumar

  • 0 in reply to SHIVAKUMAR R
    TI__Mastermind 43165 points

    Carl,

    This is the base video refresh pulse.  At its heart this is a video ASIC that has custom firmware to allow the various modes, but there is an underlying 105 us pulse.  

    I would have expected the interruption of the strobe line to stop the internal micromirror resets (MCP - mirror clocking pulse) from happening.

    Be aware that TI cannot guarantee reliable operation over time if these pulses are interrupted on an ongoing basis as alluded to in the paper you reference.

    It sounds like your relay is allowing some of the signal to pass inductively.  Are you using the same circuit that the paper outlined?

    Fizix