Hi, I'm using a TPS61165 to drive high brightness LEDs, and I'm not sure from the datasheet how the PWM control works. I'm hoping to flash the LEDs at a low frequency (visible to the human eye, so less than 60 Hz), and vary the dimming at the same time to create an interesting display for a class project. On page 10 of the datasheet, it says that the optimum PWM frequency is 5 kHz to 100 kHz, but it also mentions that an external RC network can be used for lower frequencies (also see Fig. 17). The question that comes to mind is--why? Since the dimming is controlled by the duty cycle and not the frequency, why would someone want to use a frequency outside the recommended range?
If I use a layout similar to that of Fig. 19, will it be possible to use the low frequency to flash the LEDs? I'm a little concerned that the chip will enter shutdown mode every time I turn the LEDs off--is that an issue? (See page 8.)
A quick reply would be greatly appreciated. Thanks!