自动双向限幅D类功放的前置放大器设计  

Design of Automatic Bidirectional Limited Sine Wave Amplitude Preamplifier for Class D Audio Power Amplifier

作　　者：严添明[1] 严艳 YAN Tianming;YAN Yan(College of Information and Engineering,Liming Vocational University,Quanzhou,Fujian 362000,China;School of Information Engineering,Quanzhou Ocean Institute,Quanzhou,Fujian 362700,China)

机构地区：[1]黎明职业大学信息与工程学院,福建泉州362000 [2]泉州海洋职业学院信息工程学院,福建泉州362700

出　　处：《自动化应用》2024年第21期171-174,共4页Automation Application

基　　金：泉州市自然科学基金(校(院)地协同创新专项)“1bitADC技术通用D类音频功率放大器的研制”(Z[2014]0222)。

摘　　要：为了解决D类功放器高音不够高、低音不够低、声音硬不悦耳以及SPWM信号发生器会产生过调制现象,从而烧毁驱动电路元件和电流开关功率元件的问题,设计了一款具有自动双向限幅阻容耦合宽带D类功放的前置放大器。采用瓷介电容进行高频提升;采用旁路电容提高超低频增益;采用固定偏置单电源电路供电,充分使放大器工作在线性区;采用滤波和负反馈方式降低噪声干扰,提高电路的信噪比;采用波谷灌电流法提高低谷电平,并采用波峰分电流法实时降低波峰处的过冲峰值电压,从而消除音频信号或高频恒幅三角波调制引起的过调制。该前置放大器具有频带响应宽(0.10 Hz~750 kHz)、线性好、无失真以及无噪声的特点,大幅度提高了D类音频功率放大器的性能。此外,该前置放大器还具有高效率、低功耗、高保真、低成本、大功率、小体积的优点,为全面推广做好了充分准备。To solve the problems of insufficient treble and bass,hard and unpleasant sound,and over modulation caused by SPWM signal generator in Class D audio power amplifiers,which can burn out components of driving circuit and current switch power.A preamplifier with automatic bidirectional limiting resistor-capacitor coupling broadband Class D audio power amplifier has been designed.Using ceramic capacitors for high-frequency enhancement.Using bypass capacitors to improve ultra-low frequency gain.Using a fixed bias circuit fulling operate the amplifier in the linear region with a single power supply.Using filtering and negative feedback methods to reduce noise interference and improve the signal-to-noise ratio of the circuit.Adopting the valley current injection method to increase the valley level,and using the peak current division method to reduce the overshoot peak voltage at the peak in real time,thereby eliminating the overshoot caused by audio signals or high-frequency constant amplitude triangular wave modulation.This preamplifier has the characteristics of wide frequency response(0.10 Hz~750 kHz),good linearity,no distortion,and no noise,greatly improving the performance of Class D audio power amplifiers.In addition,it also has the advantages of high efficiency,low power consumption,high fidelity,low cost,high power,and small size,which fully prepares for comprehensive promotion.

关 键 词：D类功放器 前置放大器 电路设计 

分 类 号：TN912[电子电信—通信与信息系统]