I'm designing a circuit where I'll run a 3W LED using the CAT4101 Led driver, like in the in picture below. VCC will be a 2s Li-Ion battery, at 8.4 - 7.2V DC.
As I'll use PWM to DIM the led, there'll be a lot of fast on's and off's between the VCC line (LED +) and the LED - pin (which is not directly a GND pin).
If I connect a LDO to get the 8.4V VCC to 5V (maybe an ALS1117 LDO, with it's recommended capacitors) between the VCC and GND, to run an MCU at 5V and also to power the VIN pin of the CAT4101 (which needs 5V), would this fast switching by the PWM on the VCC line through the LED cause any problems to get a stable 5v output on the LDO?
Can I use the VCC normally to supply other circuits, independent of the led state, if it's on, off, or being PWM'd?