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Topic: Way to cheat 74HC595 maximum continuous operating current? (Read 5040 times) previous topic - next topic

arunalva24

And yes, raschemmel  thank you, the persistence of vision concept was what I was referring to in regards to this topic

raschemmel

Well if you learned something from the experience then we have all done our job.

arunalva24

#17
Aug 04, 2014, 09:04 am Last Edit: Aug 04, 2014, 09:21 am by arunalva24 Reason: 1
Ahhh now I understand Grumpy_Mike  and Paul_B 's original points about why multiplexing in this case
makes no sense /is pointless. If I'm merely doing it to lower the current for the sake of the chip,
it visually accomplishes the same thing as simply decreasing the current by adding more resistors to the LEDs. That's why it would be better to just get a better chip to avoid this hassle. And also, even with multiplexing, controlling more than a few LEDs with 1 output without transistors will just sag the voltage.

Ok, I fully understand now, I'll save learning about multiplexing for another project where it makes more sense to do haha.

CrossRoads

May be OBE, I missed this thread earlier:

TPIC6D595 would be great for that - combines the 74HC595 and the transistor drive into one package. Still need the current limit resistor.
TPIC6D595, good for 100mA continuous.
TPIC6B595, good for 150mA continuous.

Drive G/ (output enable) with a PWM pin for brightness control too.
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.

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