1.8 PWM Dimming

The PWM dimming can be achieved through the UDIM pin and SDIM pin. The UDIM pin can be driven with a PWM signal which controls the synchronous NFET operation. The brightness of the LEDs can be varied by modulating the duty cycle (DDIM) of the signal using a Schottky diode with anode connected to UDIM pin. The SDIM pin is controlled with an external shunt FET PWM dimming. Extremely high dimming range and linearly is achieved by shunt FET dimming operation with the SDIM and SDRV pin. When higher frequency and time resolution PWM dimming signal is applied to the SDIM pin, the SDRV pin provides an inverted signal of the same frequency and duty cycle that can be used to drive the gate of a shunt NFET directly across the LED load.