一种用于G类音频功放的带自适应输出的双模电荷泵

本文设计了一种给G类音频功率放大器提供自适应电源的双模电荷泵电路。根据输入信号的幅度,该电荷泵可以提供两档电压轨来节省功耗。它在重载下工作于电流控制模式,轻载下工作于脉冲频率调制(PFM)模式来降低功耗。在PFM工作模式下,引入功率管尺寸动态调整的技术来减小PFM模式下的输出电压纹波并防止开关频率进入音频范围。该电荷泵电路采用0.18μm,3.3V的CMOS工艺制备。试验结果表明该电荷泵在1/2x模式下可以实现79.5％的最高效率,在1x模式下可以实现83.6％的最高效率。在PFM控制模式下,电荷泵在负载电流小于120mA的范围内,其输出纹波小于15mV;在电流控制模式下,在负载电流小于300mA的范围内,其纹波小于18mV。测试结果与文中提出的功率分段的PFM控制模式的纹波、效率的解析模型得到的计算及仿真结果基本一致,验证了模型与分析方法的正确性。     

基于SINS的塔式起重机高精度信号采集技术研究

塔式起重机的区域保护和防碰撞装置经常因为精度低和可靠性差而丧失作用,为此,文中设计了一种塔式起重机区域保护和防碰撞信号采集系统,该系统使用捷联惯导模块结合激光测距模块来获取变幅小车、起重臂臂端和吊钩的位置信息,利用位置信息构建单塔机平面模型,进而实现区域保护和防碰撞功能。经过仿真分析,提出的位置信息采集最大误差9cm左右,可大幅度提高塔式起重机的工作效率和区域保护的精度,也为构建塔式起重机区域保护和防碰撞的高精度数字孪生模型打下基础。     

塔式起重机钢结构腐蚀损伤宏观表征研究

文中针对塔式起重机钢结构防腐层会从薄弱位置开始失效并会产生腐蚀疲劳损伤的情况,以损伤力学的理论为基础,使用Ansys APDL命令流建立多尺度模型对塔式起重机钢结构腐蚀的不同阶段进行模拟,通过其宏观表征（标准节损伤主肢顶端特征点沿起重臂方向的位移）的变化,定性的判断腐蚀过程中不同阶段不同要素对于宏观表征的影响。结果表明：自然腐蚀阶段对于特征点位移差值影响较小,会出现拐点,但不同地区腐蚀程度差距较大;应力腐蚀中出现腐蚀坑阶段,损伤所在位置处的应力大小是影响特征点位移差值的主要因素,其次是腐蚀坑的深度及个数。应力腐蚀中腐蚀断裂阶段,横向腐蚀断裂相较于纵向腐蚀断裂对于特征点位移差值影响较大,且会随着深度的增加二者对于特征点位移差值影响的差距逐渐增大。     

高效率I类单电源音频功率放大器

设计了一种高效率单电源I类线性音频功率放大器。采用动态电源电压降低了功率管的压降,从而提高了放大器的效率。峰值输出功率时的最高效率超过80%。采用增益压缩技术使得该电路能够在单电源下工作。避免了使用电荷泵产生负电压,从而降低了电路的复杂度和芯片的面积。采用共模电压共享和对称版图布局降低了电路的非线性。在电源电压转换前后测得的THD N分别是0.01%和0.05%。向8欧姆负载提供的最大输出功率为410mW。与开关型的放大器相比,I类放大器是线性放大器因此具有比较低的EMI。高效率和低EMI的优点使得I类放大器适用于对射频干扰敏感的便携式设备。     

A dual mode charge pump with adaptive output used in a class G audio power amplifier

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.     

一种用于单相电源G类和I类音频功放的扬声器驱动电路

A speaker driver applied to class G/classⅠwith a single phase power supply is presented.Gain expanding and compressing technology are employed in the signal processing circuit to optimize power dissipation.The circuit is implemented in 0.18μm N-well CMOS.Experimental results show that the speaker driver has a good audio sound quality and power efficiency.Less than 0.006%THD at a low power range and less than 0.4%at a medium power range can be obtained with a 1 kHz sine wave signal.Maximum output power of...     

A speaker driver for a single phase supply class G & I

A speaker driver applied to class G/classⅠwith a single phase power supply is presented.Gain expanding and compressing technology are employed in the signal processing circuit to optimize power dissipation.The circuit is implemented in 0.18μm N-well CMOS.Experimental results show that the speaker driver has a good audio sound quality and power efficiency.Less than 0.006%THD at a low power range and less than 0.4%at a medium power range can be obtained with a 1 kHz sine wave signal.Maximum output power of 360 mW can be gained at a load of 8Ω.The power efficiency is about twice that of a traditional class AB driver at the power range of 80 mW and shows more than 18%improvement at the higher output power range.     

应用于全数字发射机的射频信号发生器

提出了一种应用于全数字发射机的射频信号发生器。设计中采用高速带通ΣΔ调制技术和对系数量化不敏感的有限长单位脉冲冲激响应(FIR)数字滤波技术,在保证速度和精度的同时,有效降低功耗。芯片采用TSMC65nm1P9M GP CMOS工艺实现。测试结果表明,在1.1V电源电压下,芯片可工作在1.408GHz,单频输入带内信噪比(SNR)为53.19dB。输入不同采样频率WCDMA信号时,调制器输出邻信道功率比(ACPR)均满足相关协议要求,最大功耗为32mW。