Modulating PWM into a Shift Register

Papabravo

Joined Feb 24, 2006
15,761
I'd like to pint out that if you given us a proper schematic drawing instead of a BS kiddie drawing a great deal of ambiguity and back and forth nonsense could have been avoided.
 

Ian0

Joined Aug 7, 2020
1,893
So, how about a 74HC173? It's a D-type latch, parallel-in parallel-out, and it has an output enable to which you could connect the PWM (tristate, so you'd need pulldowns). Or a 74HC573 or 74HC574 which would give 8 channels. In each case, inputs are all together on one side, and output all together on the other side.
But if your data was serial, you could accomplish the whole damn lot, 8 outputs at a time, with a TPIC6B595
https://www.ti.com/lit/ds/symlink/tpic6b595.pdf?ts=1617311501983&ref_url=https%3A%2F%2Fwww.google.ro%2F
 

Thread Starter

ElectricSpidey

Joined Dec 2, 2017
1,565
Yes, in a perfect world my data would be serial and I could use that chip for both the PWM and the driver, but in my world the data is parallel.
 

Thread Starter

ElectricSpidey

Joined Dec 2, 2017
1,565
Damn, nice find...but no good, not enough drive current. :(

But I'm going to put that chip in my useful chip list...thanks!

So anyway thanks for the help guys but I have decided to go with FPGA, and make my life easer.
 

Thread Starter

ElectricSpidey

Joined Dec 2, 2017
1,565
The current will vary anywhere from 400mA to 900mA per any 3 channels at full brightness. (approx.)

These chips won't drive the LEDs directly, but they could replace the shift register or a CD4081, but they are expensive.

No constant current...just resistors.
 
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