US Patent 7227476 Dither scheme using pulse-density modulation (dither PDM)

Dithering for the output of a digital pulse width modulator is provided by a pulse-density modulator formed from an adder incrementing a pulse-density count and generating a carry signal latched to a plus-one generator, which in turn adds a phase-division period to each of one or more selected pulses within a predetermined series of pulses from the digital pulse width modulator. Selected pulses are advanced by triggering a leading edge of the pulse at a time one phase-division period before the system clock edge, allowing trailing edges to be extended and providing minimal latency delay.