Design-oriented characterisation of adaptive asynchronous ΣΔ modulation switching power amplifiers for bandlimited signals

This work addresses the analysis and characterisation of an improved asynchronous Sigma-Delta modulation, targeting modulating methods for switching amplifiers, dealing with low average switching frequencies (pursuing enhanced efficiency) and high-order output filters (aiming improved reconstruction processes). This work considers bandlimited random signals, which appropriately model actual communication and audio signals, upgrades the modulator with adaptive capabilities and optimises the output filter. Simulation results show that, tracking a 1 MHz-bandlimited random signal and compared with a conventional design based on a 2nd order filter PWM converter, it is feasible to reduce the switching frequency by 62% (from 10 MHz down to 3, 8 MHz) whilst keeping the same tracking error.