Hi,
I'm attempting to use the TLC5940, bypassing the PWM grayscale registers and pulsing the LED in DC mode. A potential issue I'm running into is that there is no hardware delay between outputs when using the dot correction (DC) registers.
For the PWM inputs, there is a 20ns delay between each output channel to reduce in-rush currents (as shown on the block diagram on pg 1 of the datasheet, and described on pg 14, in the "delay between outputs" section.)
I think I'm running into these same in-rush currents by trying to pulse LEDs simulataneously at high current using DC mode. The symptom I see is that after one pulse, the TLC chip becomes non-responsive. There appears to be a voltage spike on the VCC line, as the LEDs turn off from their first pulse (from parasitic inductance?).
Am I interpreting this problem correctly, and is there a preferred solution?
Thanks!
Isaac