The device will undergo two steps during the transition from shutdown to hybrid dimming mode. (Please keep ADIM/HD pin always low.)
Firstly, you need to follow the startup sequence shown in Section 8.3.4 and Figure 8-2 from the datasheet so that the device will be ready for dimming mode selection ("Dimming Mode Start" = high). The easiest way is to keep the EN/PWM pin high until the device is ready for dimming mode selection.
Secondly, you need to pull EN/PWM pin to low for a period of no shorter than 1us so that the device will enter into hybrid dimming mode. Then you can input your EN/PWM signal at the targeted duty and frequency. Please be noted that it takes 2 cycles for the device to detect the first targeted duty cycle after entering into hybrid dimming mode. Later it only takes 1 cycle to detect the targeted duty.
The TPS922055 / TPS922054 / TPS922053 / TPS922052 implements soft start feature to avoid inrush current during startup.
Please refer to the below graphical illustration.
