TPS61181: How does the dimming operate when the ISET pin is in analog dimming configuration?

Dear TI team :

Here is a RD engineer from Taiwan. I have a question about dimming with TPS61181.
As the datasheet said, TPS61181 already has DCTRL pin to dim with PWM.
However, there is a document called "Analog Dimming with the TPS61181" where Two analog dimming method are introduced.

1. So, does it mean that I can dim the LEDs in two ways (using DCTRL and ISET pin) at the same time?
Or should I choose one of them?

2. If I choose the way shown in Figure 2, can the PWM input in in Figure 2 be the same as the PWM Dimming on DCTRL pin?
Or should I need to fix the frequency and duty cycle of one of them?


Best regard, Alan