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Hello!! and MCU and Digital pot?¿

Jeff Lampe
Intellectual 530 points
Other Parts Discussed in Thread: RM48L950

Hello all

I am working on a programable Laser control board for a laser projector.

The way I see this working is like this..

This control board will have a MCU's that reads the analog input signal and adjusts a digital pot on the Adjust pin of a LM350,, so it will adjust the out put power to a laser.

The user interface should give a choice of 1 or 4 analog read signels per color,, for now we only are looking at  two colors Red and Blue.

This is the single analog input per color idea,,, I need to control 4 red and 4 blue and the way I see this happining the first red Laser begins to lase at a set analog input level say 0.35V and as the wave reaches say 1.35V the second red laser lases,,, as the wave reaches reaches its peak 5V all 4 come up to the full preset user interface value.

Here is the second user interface choice,,, multi analog read,,, each analog signal controles its own Laser to its preset user interface value. 

The MCU I have is the RM48L950 and it has 54 I/O ports which 48 are used control 8 TPL8002-25PWR,, will their still be enough to add a digital display with a user interface control? I mean their is only 6 I/O ports and 8 analoge ports left?  

Is their a downloadable autocad foot print?¿ Even better is their a down loadable,, general foil pattern for the RM48L950 that I can mod?¿

is their a basic schemadic for it?

Thanks Jeff.

 

 

       

 

  • TI__Expert 7650 points

    Hello Jeff,

    I am assuming that you are using the "ZWT" bga package.  Please see the HDK wiki page for its schematics and layout source files including the footprint/foil pattern we used on our boards.  If you are using the PGE package, you can find the footprints on our web page.  Also, http://www.ti.com/lit/ml/mtqf017a/mtqf017a.pdf may be helpful.

    AS to the digital display and user interface, you have a few options.  You may want to use one of the available SPI/MiBSPI ports and a SPI-based display and/or key pad.

  • in reply to Brian Fortman
    Intellectual 530 points

    Thank you for the quick reply.

    That gave me some time to look everything over. 

    I have the PGE package.

    So I converted your pdf into a cad file.

    Well I have been thinking about this and for the first one,, I want to go one digital pot per 4 LM350s and I will go Red, Green and Blue,,  and thats a little less I/Os used,,, (like 30 less) That will give me more options for the user interface and high speed shutters.

    I was also thinking,, maybe changing the digital pot to the TPL0401a 50K with 128 tap points and have that adjusting the output power on a PTH12040W for the Blue Laser Diodes, And then have one controling a PTH08T250W for the Reds and do the same for the Green (another PTH08T250W).

    That will get me to the target output power of 10 Watts 532nm / Green,,, 10 Watts 445nm / Blue and 18 Watts 650 nm / Red.

    with the LM350 will work for the Reds and Blues and I would only be off by the green because the green requires a 40 watt 808nm that runs at 1.8 volt at 43 Amp and a high powered Ndyvo4+LBO crystal set to get 532nm / Green. 

    Which one would you go with? 

    I feel I need to tell you I am mainly in power management so I will be needing more when it comes to the programing of the chip.

    Thanks Jeff