Greetings Adam,
Nope it's real! The DC meter is measuring the averageRandom:
I’m measuring 0.4V on the greens and 0.3V on the red resistors, but I imagine my multimeter is averaging out the duty cycle, so I don’t think the reading is very accurate :p.
current, which is 0.4/330 = 1.2mA over eight time slots.
The LED pulse current is therefore 9.6mA peak.
If you have a second LED matrix, power it from DC with
resistors to get 9.6mA and 1.2mA, and compare the
brightness to MUX’d design. I’m confident you will
get the same intensity at 1.2mA DC as the 9.6mA
pulsed, even though LEDs are said to be more efficient
under pulse conditions.
In general, or have you destroyed this particular device?Random:
The shift registers don’t warm up at all during operation, and usually I’ve found these chips get warm to the touch before dying?
What is happening is that overheating is a long term
condition that allows heat to build up and the die
will fail at the hot spot. Before total failure the device
may continue to operate, but suffer other failure
(increased leakage current or skewed timing for
example).
Another type of failure is short term overstress where
the device fails but did not get warm to the outside.
The energy to fuse metallization or puncture an oxide
(insulator) layer may spread through the device and only
raise the average temp by a very small amount.
In short, IC failures are not always dramatic, involve
heat, or allow smoke to escape.
Comments Welcome!