8.3.2.4 PWM-Input Direct Control

With PWM-input direct control the output PWM directly follows the input PWM frequency and duty cycle. Due to the internal logic structure the input is clocked with the 5-MHz clock or the PLL clock (if it is enabled). The output PWM delay can be 5 to 6 clock cycles from input PWM.

In the direct control mode several of the advanced features are not available: Phase Shift PWM (PSPWM), brightness slope, dither, Hybrid PWM and Current dimming, and LED current limitation with external NTC.

Dimming ratio can be calculated as the ratio between the brightness PWM input signal and sampling clock (5-MHz or PLL clock) frequencies. In direct mode PWM duty cycle must be less than 100%. Boost adaptive mode turns off at 100% duty cycle.