Based on the difference close-loop feedback technique and the difference pre-amp, a high efficiency PWM CMOS class-D audio power amplifier is proposed. A rail-to-rail PWM comparator with window function has been embed...Based on the difference close-loop feedback technique and the difference pre-amp, a high efficiency PWM CMOS class-D audio power amplifier is proposed. A rail-to-rail PWM comparator with window function has been embedded in the class-D audio power amplifier. Design results based on the CSMC 0.5μm CMOS process show that the max efficiency is 90%, the PSRR is -75 dB, the power supply voltage range is 2.5-5.5 V, the THD＋N in 1 kHz input frequency is less than 0.20%, the quiescent current in no load is 2.8 mA, and the shutdown current is 0.5 pA, The active area of the class-D audio power amplifier is about 1.47 × 1.52 mm^2. With the good performance, the class-D audio power amplifier can be applied to several audio power systems.展开更多
A type of plant audio generator was introduced in the paper including its circuit configuration, principle of working and used to deal with spinach in order to discuss effect of audio frequency on plant growth.
A dual mode charge pump to produce an adaptive power supply for a class G audio power amplifier is presented.According to the amplitude of the input signals,the charge pump has two level output voltage rails available...A dual mode charge pump to produce an adaptive power supply for a class G audio power amplifier is presented.According to the amplitude of the input signals,the charge pump has two level output voltage rails available to save power.It operates both in current mode at high output load and in pulse frequency modulation （PFM） at light load to reduce the power dissipation.Also,dynamic adjustment of the power stage transistor size based on load current at the PFM mode is introduced to reduce the output voltage ripple and prevent the switching frequency from audio range.The prototype is implemented in 0.18μm 3.3 V CMOS technology.Experimental results show that the maximum power efficiency of the charge pump is 79.5%@ 0.5x mode and 83.6%@ lx mode.The output voltage ripple is less than 15 mV while providing 120 mA of the load current at PFM control and less than 18 mV while providing 300 mA of the load current at current mode control.An analytical model for ripple voltage and efficiency calculation of the proposed PFM control demonstrates reasonable agreement with measured results.展开更多
IP话机喇叭功率较小,导致外放响度不如预期。若增加数字增益,则会导致破音和喇叭损坏,影响用户体验。为解决此问题,文章提出一种基于时频域动态压缩器的智能功放算法。该算法在整体音频上应用动态压缩器,并结合设备的硬件特性对音频的...IP话机喇叭功率较小,导致外放响度不如预期。若增加数字增益,则会导致破音和喇叭损坏,影响用户体验。为解决此问题,文章提出一种基于时频域动态压缩器的智能功放算法。该算法在整体音频上应用动态压缩器,并结合设备的硬件特性对音频的低频、中频及高频进行精细化处理,从而显著提高音频响度。实际测试表明,本文算法比网页即时通信(Web Real-Time Communication,WebRTC)自动增益控制(Automatic Gain Control,AGC)提升了21.80%的响度,提高了会议通话的质量和体验。展开更多
基金supported by the National Outstanding Young Scientist Foundation of China (No. 60725415)the National Natural ScienceFoundation of China (No. 60676009)+1 种基金the Doctor Foundation of Ministry of Education (No. 20050701015)the InnovationFunds (No. 07C26226101993).
文摘Based on the difference close-loop feedback technique and the difference pre-amp, a high efficiency PWM CMOS class-D audio power amplifier is proposed. A rail-to-rail PWM comparator with window function has been embedded in the class-D audio power amplifier. Design results based on the CSMC 0.5μm CMOS process show that the max efficiency is 90%, the PSRR is -75 dB, the power supply voltage range is 2.5-5.5 V, the THD＋N in 1 kHz input frequency is less than 0.20%, the quiescent current in no load is 2.8 mA, and the shutdown current is 0.5 pA, The active area of the class-D audio power amplifier is about 1.47 × 1.52 mm^2. With the good performance, the class-D audio power amplifier can be applied to several audio power systems.
文摘A type of plant audio generator was introduced in the paper including its circuit configuration, principle of working and used to deal with spinach in order to discuss effect of audio frequency on plant growth.
文摘A dual mode charge pump to produce an adaptive power supply for a class G audio power amplifier is presented.According to the amplitude of the input signals,the charge pump has two level output voltage rails available to save power.It operates both in current mode at high output load and in pulse frequency modulation （PFM） at light load to reduce the power dissipation.Also,dynamic adjustment of the power stage transistor size based on load current at the PFM mode is introduced to reduce the output voltage ripple and prevent the switching frequency from audio range.The prototype is implemented in 0.18μm 3.3 V CMOS technology.Experimental results show that the maximum power efficiency of the charge pump is 79.5%@ 0.5x mode and 83.6%@ lx mode.The output voltage ripple is less than 15 mV while providing 120 mA of the load current at PFM control and less than 18 mV while providing 300 mA of the load current at current mode control.An analytical model for ripple voltage and efficiency calculation of the proposed PFM control demonstrates reasonable agreement with measured results.
文摘IP话机喇叭功率较小,导致外放响度不如预期。若增加数字增益,则会导致破音和喇叭损坏,影响用户体验。为解决此问题,文章提出一种基于时频域动态压缩器的智能功放算法。该算法在整体音频上应用动态压缩器,并结合设备的硬件特性对音频的低频、中频及高频进行精细化处理,从而显著提高音频响度。实际测试表明,本文算法比网页即时通信(Web Real-Time Communication,WebRTC)自动增益控制(Automatic Gain Control,AGC)提升了21.80%的响度,提高了会议通话的质量和体验。
文摘设计了一种用于D类音频功率放大器中产生死区时间的互锁电路,通过对功率管的输出状态进行检测,使得在每种状态下只有一个功率管导通,有效地防止了上下功率管的同时导通,从而减小了功率级的损耗,提高了放大器的效率.针对该互锁电路提出了一种死区时间设计方法,使得在有效抑制功率管导通的同时引入最小的失真,同时对引入死区时间所产生的影响做了详细分析.仿真结果表明:该互锁电路在输出信号的上升沿产生的死区时间为13.6 ns,在输出信号的下降沿产生的死区时间为15.5 ns.
