I have this circuit in consideration for a LED display project and I was wondering if a circuit like this would be likely to reduce the longevity of the LED's lifespan, assuming the PWM frequency is high enough to not exceed the thermal mass of the LED and overheat it directly with high peak currents. Attached is the schematic in .pdf format. As the schematic generally suggest I have not ironed out every circuit detail, nor am I necessarily definite on a single specific circuit element. Error correction in the schematic: the SNS pins are actually connected to GND as they are the "bottom" of the H-bridge connection and there should be a 47pf capacitor across the input to the first inverter and the output of the second inverter for noise and ringing reduction.
Thanks for any help!v.1.0 ULN2003 74HC04 TLC555 PWM LED Display Driver.pdf