This paper presents a high-efficiency audio DAC with a class-AB power output stage in the analog reconstruction filter. This closed-loop solution reduces power stage noise and linearity specs, reduces the active device number, and, definitively, reduces power consumption, increasing efficiency. Moreover, a novel control system allows, at the same time, to reduce output offset and idle tone generated by the digital structure. In a 0.15μm CMOS technology at 2.7V supply, the powerDAC performs 94dB-SNR, and -76dBTHD on 8Ω-load. The output offset is reduced to be lower than 500μV. The efficiency FoM defined as DeliveredPower/QuiescentPower of the overall analog block is >40 (on a 16W load), while the efficiency FoM of the earphone PA stand alone is 56. In both case the proposed device efficency outperforms the state-of-the-art [6-9]. ©2010 IEEE.
Baschirotto, A., Bollati, G., Colonna, V., Gandolfi, G. (2010). A 94dB-SNR 76dB-THD high-efficiency hybrid audio power-DAC for loudspeaker (4Ω/8Ω) and earphone (16Ω/32Ω). In ESSCIRC, 2010 Proceedings of the (pp.226-229) [10.1109/ESSCIRC.2010.5619888].
A 94dB-SNR 76dB-THD high-efficiency hybrid audio power-DAC for loudspeaker (4Ω/8Ω) and earphone (16Ω/32Ω)
BASCHIROTTO, ANDREA;
2010
Abstract
This paper presents a high-efficiency audio DAC with a class-AB power output stage in the analog reconstruction filter. This closed-loop solution reduces power stage noise and linearity specs, reduces the active device number, and, definitively, reduces power consumption, increasing efficiency. Moreover, a novel control system allows, at the same time, to reduce output offset and idle tone generated by the digital structure. In a 0.15μm CMOS technology at 2.7V supply, the powerDAC performs 94dB-SNR, and -76dBTHD on 8Ω-load. The output offset is reduced to be lower than 500μV. The efficiency FoM defined as DeliveredPower/QuiescentPower of the overall analog block is >40 (on a 16W load), while the efficiency FoM of the earphone PA stand alone is 56. In both case the proposed device efficency outperforms the state-of-the-art [6-9]. ©2010 IEEE.
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