100W的D類功率放大器的設計

電氣工程論文編號:DQ077   論文字數:10637,頁數:24

摘要.…………………………………………………………………..………….…..Ⅰ
英文摘要………………………………………………………………………….…...Ⅱ
緒論……………………………………………………………….……………….…1
 1.1  前言…………………………………………………………………………..…….……..1
 1.2  D類功率放大器目前水平……………………………………………………………….2
第二章  D類放大器的放大電路設計……………………………………………….……3
 2.1  D類放大器的基本結構………………………………………………………………….3
 2.2  D類放大器的設計思路………………………………………………………………….4
    2.2.1 基本設計方案……………………………………………………………………….4
 2.3  D類放大器的工作原理………………………………………………………………….7
 2.4 寬帶調制（PWM）………………………………………………………………………..11
 2.5 改進全橋PWM方案的模擬實現方法……………………………………………….…..12
 2.6改進全橋PWM方案的數字實現方法……………………………………………………13
第三章 其他輔助電路設……………………………………………………………………..14
  3.1 短路保護電路…………………………………………………………………………...…14
 3.2 噪聲和干擾屏蔽設計…………………………………………………….…….……….....15
 3.2.1噪聲和干擾………………………………………………………………..………..15
 3.2.2  屏蔽的基本原理………………………………………………...…….….………15
第四章 進一步改進措施…………………………………………………………..…..…….17
 4.1盡量減少靜態功耗和動態功耗………………………………………………..………….17
第五章 總結……………………………………………………………………………………18
參考文獻…………………………………………………………………………..…..……......19
致謝………………………………………………………………………………………………20
附錄……………………………………………………………………………….……………...21

摘  要

 本文設計了一種以100W功率放大器為核心的D類功率放大器。本設計采用全橋改進PWM方案實現的D類放大器具有效率高、降低濾波器要求等特點。采用CPLD實現改進的全橋PWM方案，并結合DSP實現串并轉換、數字插值和噪聲整形等處理，可實現高保真的音頻放大器。設計的數字功率放大器可對數字音源輸出的音頻信號進行直接放大，為數字音源和功率放大的整合提供了完整的解決方案。它改進了PWM方案，輸出開關管采用高速MOSFET管，連接成互補對稱H橋式結構，平均效率可達到85%左右，兼有輸出1：1雙變單電路，噪聲和干擾的屏蔽方法，此外還有輸出短路保護。其工作原理為：輸入信號與三角波信號在通過比較器比較之后，產生一個脈沖信號，送至前置放大電路，再經過低通濾波器濾波，以保證輸出信號在一定的帶寬內。D類放大器之所以能實現這樣的效率，是因為D類放大器與開關模式電源的工作方式相似，其中輸出MOSFET要么是完全啟動(飽和)，要么是完全關閉(切斷)的。因而可以減小晶體管的功率損耗，增加放大器的效率。
 
關鍵詞：D類功率放大；改進PWM方案；短路保護；干擾屏蔽

Abstract
 The designed D class amplification has characterized of improver full PWM program high efficiency and lower filter requirements. CPLD realization of adopted full-bridge PWM improvement program, and combined with the realization by DSP SERDES, digital interpolation and noise shaping processing, etc., can be realized by high-fidelity audio amplifier. Digital power amplifier designed for digital audio output to the audio signal directly to amplification, digital sound and power was amplified to provide a complete integrated solution. It has been improved PWM program, the output pipe by using high-speed switching MOSFET tubes, are connected into a complementary symmetric H-bridge structure, the average efficiency of around 85% can be achieved by the combination of 1:1 two-change single-output circuits, noise and interference by shielding methods, in addition to short-circuit protected output. Its working principle is: the input signal with the triangular wave signal is compared by comparing the device after a pulsed signal to the preamp circuit, and then, after filtering low-pass filter to ensure that the output .signal within a certain bandwidth. Class D amplifiers can achieve this because of efficiency, because the D-type switch-mode power amplifier with the work, which is similar or the output MOSFET is fully activated (saturated), or is completely closed (cut off) of the. Transistors can be reduced and thus the power loss and increase efficiency by amplifier.

Key Words: D class power amplification；Programs to improve the PWM ；pulse-width modulation；current overload protection；