Question on DC switching frequency and LED luminaires

Hi, I have a background with AC power but very little in the way of DC, I also work with lighting. Hoping someone would be able to explain to me regarding the switching frequency of DC LED drivers.

In relation to LED luminaires such as the Philips/Signify one below, generally talking in the range of 20W to 1000+W (not small individual LED's),

I am unclear why there is a DC switching frequency (generally in the range of 1000's of Hertz). My understanding is that the AC waveform is converted to a steady DC voltage which doesn't have a frequency, but the LED drivers switch the DC supply at extremally high frequencies. I know this switching can be used for dimming, but if it's not being dimmed why wouldn't it be a stead DC supply?

In which Philips' document did you see the DC switching frequency? From prior reading, my thought is that PWM LED drivers are sometimes used to increase the intensity of the light. A large, but short pulse of current results in a more intense light while keeping the average power about the same, so no heat penalty. The Philips ClearFlood is a whopper of a light at 44000 lm.
See: "LED Light Intensity using PWM" at