There are a couple of ways to do a digital PWM. One is to use a counter based approach. PowerXR has an eight bit resolution digital PWM which would require a 384MHz clock at a switching frequency of 1.5MHz. A high frequency clock consumes a large amount of power, so instead MaxLinear has patented technology where a digital DLL is used with a sigma delta technique. The result is that designers can get 8-bit resolution at 1.5MHz switching frequency with only a 48MHz clock internally. At 800kHz switching frequency designers only need a 25.6MHz clock and this keeps the power consumption of MaxLinear's digital controller low; it is one of the unique pieces of IP in the PowerXR family.