A 9–11 bits phase-interpolating digital pulse-width modulator with 1000X frequency range

A design of a new hybrid-type digital pulse-width modulator (DPWM) with a 1000:1 frequency range from 10kHz to 10-MHz, maximum resolution of 11-bits, and power dissipation of 2.36-mW is presented. The key to such a wide frequency range and low power dissipation is to use a phase interpolator circuit for fine duty-cycle adjustment instead of the delay lines used in the previous literature. The proposed hybrid DPWM realizes the upper 5-bit resolution using a digital counter and lower 6-bit using a phase interpolator. The prototype IC fabricated in a 0.25-μm HV CMOS demonstrates the 1000:1 frequency range and excellent linearity for 9~11-bit resolutions.