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Topic: Sinking current on a 8x8 matrix (Read 895 times) previous topic - next topic

8rmfyj5U3Qk

Feb 02, 2013, 10:21 pm Last Edit: Feb 02, 2013, 10:34 pm by 8rmfyj5U3Qk Reason: 1
Hello,

I have a 8x8 LED Matrix. I control the output with a 74HC595 chip, this basically controls the line for the display (given a particular column it controls which LED will be displayed). In this configuration 1 of 8 pins get connected to +5V. This works.

Now I need to controller the column and it depends on which pin is connected to the GND. In this configuration 1 of 8 pins get connected to 0V. This need to be done.

What inexpensive chip exist to do that?

Searching on the forum I saw the PCF8574 but it's not clear to me if it's right and the simplest inexpensive solution for me.

Thanks in advance!

EDIT: or should I use a ULN2803 ??

fungus

The TLC5916.

It's just like your 74HC595 but it has eight current controlled inputs.
No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

8rmfyj5U3Qk

It does not seem to be in the catalog of my current vendor. Are there any other alternatives?

CrossRoads

ULN2803, one output low at a time. Buffer arduino outputs with it, or outputs of 74CH595.
Even better, use a TCIP6B595 open drain shift register with high current sinking capability.

Who's your current vendor?
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

8rmfyj5U3Qk

#4
Feb 03, 2013, 12:21 pm Last Edit: Feb 03, 2013, 12:56 pm by 8rmfyj5U3Qk Reason: 1
It seems the ULN2803 needs 8 pins to be controlled, is that right? It's a bit extreme.

I can't find the other ships on http://www.reichelt.de/

EDIT: I found the TPIC6B595,  thank you. (it's TPIC not TCIP)

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