Thanks, I wish there was a way to disable the sleep feature. If I was to use a 15 KHz PWM for example it means I would have to start off by sending a 75% duty cycle to enable the chip. I’ll think about this some more but it does complicate things as I want to ramp up the pwm from 0 to 100%. Not sure if that 75% duty cycle pulse would be visible if it is so short?
Why do you want to PWM at such a high frequency?
The problem is that at 15kHz, the PWM period is 66uS. Even if you only want 8 bit control ( which is often not enough), the granularity is 250nS.
Any switchmode LED driver will be running at typically a few hundred kHz, which is about an order of magnitude slower than your desired PWM frequency. See a problem there?
Do you have control over what type of LEDs you are using? In a situation like this, I’d look at using LEDs with multiple die, for a much higher Vf ( 24v+), and lower current, so you can use a simple linear constant current driver like the various TLC series devices directly.
Luxeon do some nice 3x3mm devices with 6 and 12 die for 24 and 48v operation
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