A novel sampling process and pulse generator for a low distortion digital pulse-width modulator for digital class D amplifiers

We propose a novel Direct Interpolation (DI) sampling process and novel hybrid pulse generator for a Pulse Width Modulator (PWM) for a digital Class D amplifier. The DI sampling process features the lowest harmonic distortion compared to other algorithmic sampling processes. The computation for the DI process is simple, leading to small IC area and very low power dissipation (7 μW@1.1 V). We analytically derive the double Fourier expression for the DI process and show that the THD is very low (<0.03%). The novel hybrid pulse generator embodies a counter, noise shaper, and novel 1-bit frequency doubler. The complete PWM features a simple circuit implementation (small IC area), micropower low voltage operation (∼60 μW@1.1 V), low sampling rate (48 kHz) and low harmonic distortion (∼0.03%).