The paper addresses the algorithmic and architectural design of digital input power audio amplifiers. A modelling platform, based on a meet-in-the-middle approach between top-down and bottom-up design strategies, allows a fast but still accurate exploration of the mixed-signal design space. Different amplifier architectures are configured and compared to find optimal trade-offs among different cost-functions: low distortion, high efficiency, low circuit complexity and low sensitivity to parameter changes. A novel amplifier architecture is derived; its prototype implements digital processing IP macrocells (oversampler, interpolating filter, PWM cross-point deriver, noise shaper, multilevel PWM modulator, dead time compensator) on a single low-complexity FPGA while off-chip components are used only for the power output stage (LC filter and power MOS bridge); no heatsink is required. The resulting digital input amplifier features a power efficiency higher than 90% and a total harmonic distortion down to 0.13% at power levels of tens of Watts. Discussions towards the full-silicon integration of the mixed-signal amplifier in embedded devices, using BCD technology and targeting power levels of few Watts, are also reported.
|Autori:||SAPONARA S; TERRENI P|
|Titolo:||Mixed-Signal Architectures for High Efficiency and Low Distortion Digital Audio Processing and Power Amplification|
|Anno del prodotto:||2010|
|Digital Object Identifier (DOI):||10.1155/2010/394070|
|Appare nelle tipologie:||1.1 Articolo in rivista|