Hello,
The SEPIC is known for its difficulty when used with high crossover frequency. As such, are there specific problems encountered when PWM dimming a SEPIC converter with the LM3421 (and using a dimming FET in series with the LEDs)
Can we be sure that the voltage on the COMP pin will not rise when the LM3421 is on the OFF time of PWM dimming?......since we don't want the led current to overshoot when the dimming fet is turned back on during PWM dimming cycles.