Title :
A low THD clock-free Class-D audio amplifier with an increased damping resistor and cross offset cancellation technique
Author :
Ying-Wei Chou ; Meng-Wei Chien ; Shin-Chieh Chen ; Ke-Horng Chen ; Ying-Hsi Lin ; Tsung-Yen Tsai ; Chen-Chih Huang ; Chao-Cheng Lee ; Zhih Han Tai ; Yi Hsuan Cheng ; Chi Chung Tsai ; Hsin-Yu Luo ; Shih-Ming Wang ; Long-Der Chen ; Cheng-Chen Yang ; Huang T
Author_Institution :
Inst. of Electr. Control Eng., Nat. Chiao Tung Univ., Hsinchu, Taiwan
Abstract :
An increased damping resistor (IDR) replaces high-order loop filter to simply reduce the total harmonic distortion (THD) of Class-D audio amplifier. Besides, cross offset cancellation (COC) technique minimizes the system offset voltage to avoid dc current flows to the speaker in the bridge tied load (BTL) structure. Furthermore, variable switching frequency characteristic in self-oscillating modulation spreads the electro-magnetic interference (EMI) impact out on the output frequency spectrum. Experimental results demonstrate that the proposed Class-D amplifier can deliver 0.55W to the 8Ω load with a 3.3V supply voltage with 150-nm CMOS process. The power efficiency is over 90% and the output THD is smaller than 0.01% (80dB).
Keywords :
CMOS analogue integrated circuits; audio-frequency amplifiers; electromagnetic interference; harmonic distortion; resistors; BTL; CMOS process; COC technique; EMI impact; IDR; bridge tied load structure; cross offset cancellation technique; dc current; electromagnetic interference; high-order loop filter; increased damping resistor; low THD clock-free class-D audio amplifier; output frequency spectrum; power 0.55 W; resistance 8 ohm; self-oscillating modulation; size 150 nm; system offset voltage minimization; total harmonic distortion; variable switching frequency characteristic; voltage 3.3 V; CMOS integrated circuits; Clocks; Frequency modulation; Generators; Power harmonic filters; Switching frequency; Class-D audio amplifier; audio amplifier; clock-free; mobile application; offset cancellation; self-oscillating;
Conference_Titel :
Circuits and Systems (ISCAS), 2014 IEEE International Symposium on
Conference_Location :
Melbourne VIC
Print_ISBN :
978-1-4799-3431-7
DOI :
10.1109/ISCAS.2014.6865725
