A digital input class-D audio amplifier with a sixth-order pulse-width modulation （PWM） modulator is presented. This modulator moves the PWM generator into the closed sigma-delta modulator loop. The noise and distor...A digital input class-D audio amplifier with a sixth-order pulse-width modulation （PWM） modulator is presented. This modulator moves the PWM generator into the closed sigma-delta modulator loop. The noise and distortions generated at the PWM generator module are suppressed by the high gain of the forward loop of the sigma-delta modulator. Therefore, at the output of the modulator, a very clean PWM signal is acquired for driving the power stage of the class-D amplifier. A sixth-order modulator is designed to balance the performance and the system clock speed. Fabricated in standard 0.18 μm CMOS technology, this class-D amplifier achieves 110 dB dynamic range, 100 dB signal-to-noise rate, and 0.0056% total harmonic distortion plus noise.展开更多
This paper presents a system-level method to decrease the power consumption of integrated audio Class-G amplifiers for mobile phones by using the same implementation of the level detector, but by changing the paramete...This paper presents a system-level method to decrease the power consumption of integrated audio Class-G amplifiers for mobile phones by using the same implementation of the level detector, but by changing the parameters of the switching algorithm. This method uses an optimization based on a simplified model simulation to quickly find the best power supply switching strategy in order to decrease the losses of the internal Class-AB amplifier. Using a few relevant equations of Class-G on the electrical level and by reducing the number of calculation points, this model can dramatically reduce the calculation time to allow power consumption evaluation in realistic case conditions compared to the currently available tools. This simplified model also evaluates the audio quality reproduction thanks to a psycho-acoustic method. The model has been validated by comparing model results and practical measurements on two industrial circuits. This proposed model is used by an optimizer based on a genetic algorithm associated with a pattern search algorithm to find the best power supply switching strategy for the internal Class-AB amplifier. The optimization results improve life-time performance by saving at least 25% in power consumption for typical use-case (1mW) compared to the industrial circuit studied and without losses in audio quality.展开更多
Lately, it is required that the bandwidth of PWM （pulse width modulation） power amplifier is extended. For example, it is in application of the testing power supply of a low frequency immunity examination, or a clas...Lately, it is required that the bandwidth of PWM （pulse width modulation） power amplifier is extended. For example, it is in application of the testing power supply of a low frequency immunity examination, or a class-D amplifier. In this paper, the authors show that the bandwidth of PWM power amplifier can be controller. This controller is implemented on a DSP （digital can be made wider with this controller. extended by using an approximate 2DOF （2-degree-of-freedom） digital signal processor）. It is demonstrated from experiments that the bandwidth展开更多
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
This paper describes a multimode high-resolution digital pulse width modulator.This modulator,based on a novel hybrid structure,not only has a programmable duty cycle but also realizes phase modulation.A 576 ps pulse ...This paper describes a multimode high-resolution digital pulse width modulator.This modulator,based on a novel hybrid structure,not only has a programmable duty cycle but also realizes phase modulation.A 576 ps pulse resolution is achieved based on a 13.56 MHz switching frequency for near field communication.Fabricated in a SMIC 0.18-μm EEPROM CMOS process,the total area of modulator is only 130×180μm2.Measurement results validate the multi-mode modulation function and high pulse resolution.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 High Technology Research and Development Program of China(No.2012AA012301)the National Natural Science Foundation of China(No.61171001)
文摘A digital input class-D audio amplifier with a sixth-order pulse-width modulation （PWM） modulator is presented. This modulator moves the PWM generator into the closed sigma-delta modulator loop. The noise and distortions generated at the PWM generator module are suppressed by the high gain of the forward loop of the sigma-delta modulator. Therefore, at the output of the modulator, a very clean PWM signal is acquired for driving the power stage of the class-D amplifier. A sixth-order modulator is designed to balance the performance and the system clock speed. Fabricated in standard 0.18 μm CMOS technology, this class-D amplifier achieves 110 dB dynamic range, 100 dB signal-to-noise rate, and 0.0056% total harmonic distortion plus noise.
文摘This paper presents a system-level method to decrease the power consumption of integrated audio Class-G amplifiers for mobile phones by using the same implementation of the level detector, but by changing the parameters of the switching algorithm. This method uses an optimization based on a simplified model simulation to quickly find the best power supply switching strategy in order to decrease the losses of the internal Class-AB amplifier. Using a few relevant equations of Class-G on the electrical level and by reducing the number of calculation points, this model can dramatically reduce the calculation time to allow power consumption evaluation in realistic case conditions compared to the currently available tools. This simplified model also evaluates the audio quality reproduction thanks to a psycho-acoustic method. The model has been validated by comparing model results and practical measurements on two industrial circuits. This proposed model is used by an optimizer based on a genetic algorithm associated with a pattern search algorithm to find the best power supply switching strategy for the internal Class-AB amplifier. The optimization results improve life-time performance by saving at least 25% in power consumption for typical use-case (1mW) compared to the industrial circuit studied and without losses in audio quality.
文摘Lately, it is required that the bandwidth of PWM （pulse width modulation） power amplifier is extended. For example, it is in application of the testing power supply of a low frequency immunity examination, or a class-D amplifier. In this paper, the authors show that the bandwidth of PWM power amplifier can be controller. This controller is implemented on a DSP （digital can be made wider with this controller. extended by using an approximate 2DOF （2-degree-of-freedom） digital signal processor）. It is demonstrated from experiments that the bandwidth
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.
基金Project supported by the Important National Science & Technology Specific Projects(No2009ZX03001-012-03)
文摘This paper describes a multimode high-resolution digital pulse width modulator.This modulator,based on a novel hybrid structure,not only has a programmable duty cycle but also realizes phase modulation.A 576 ps pulse resolution is achieved based on a 13.56 MHz switching frequency for near field communication.Fabricated in a SMIC 0.18-μm EEPROM CMOS process,the total area of modulator is only 130×180μm2.Measurement results validate the multi-mode modulation function and high pulse resolution.
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。
