Alternative to HT16K33 for a common-anode bi-color matrix?
deʃhipu wrote 03/22/2017 at 19:26 • 1 pointThe bi-color matrices I ordered turned out to be common-anode ones, and not common-cathode as I expected. This means that I can't drive them with the HT16K33 chip as I planned, as it only has 8 cathode pins. I can't even use two such chips to drive the two colors of the matrix, because the anodes are common, so the two chips would fight with each other and possibly burn (unless there is a way to synchronize them that I'm missing). So now I'm looking for an alternative, preferably in a single chip.
I found some examples for using two MAX7219 chips, and switching them on and off very quickly -- but again, the common anode will make the chips fight with each other (they still pull the pins high/low when switched off), so that's not an option.
Another option I found is to use a TLC5940 sink driver, and a separate MIC5891 source driver, but I found it very difficult to fit everything on a 1" PCB. So a single-chip solution would be much preferable. I have trawled the web in search of such a chip, but so far without much success. Is it possible that no such chip exists?
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I just learned about the TM* series of chips: http://titanmec.com/index.php/product/lists/typeid/59.html
They are cheap and seem to be very interesting. Just like the HT16K33 chip, they also do keys.
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i recently got the IS31FL3733 working. maybe something else in that series?
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Wow, that chip looks extremely interesting! It still only has 12 cathode outputs, but I'm sure I can find something in that family. Thank you for the pointer!
I did know the IS31FL3731 before, bot that's for a charlieplexed display. I didn't know there are ones for a matrix too.
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Hmm, I'm looking at the drivers on offer here: http://www.issi.com/US/product-analog-fxled-driver.shtml
They are very strange. Half of them is for charlie-plexed displays, which of course won't work with the LED matrices -- still very interesting for other projects, maybe.
But the ones for the matrices have very strange dimensions. For instance, the chip that can drive 192 LEDs only supports 16x4 RGB matrices -- instead of 8x8... That's just crazy.
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I now also found the HT1632C chip, and it looks like what I was looking for. I even found one in my drawer, so I will start experimenting immediately.
UPDATE: I found it in my drawer, and that chip is HUGE. I'm not sure I will be able to fit it, unless I will use some novel techniques with SMD-mounting the matrix...
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