一种音频功率放大器芯片的设计
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摘要
音频功率放大器广泛应用于家庭影院、音响系统、立体声唱机、伺服放大器等电子系统中。人们在追求高保真度音频功放的同时,也希望功放有大的输出功率和高效率。因此,设计一种失真度小,输出功率大,效率高的音频功放也有很重要的现实意义。
本文介绍了一种额定输出功率为20W的音频功率放大器芯片的设计。该芯片采用了AB类推挽输出级,内部有Miller补偿,可保证闭环稳定性。芯片内部设有过温保护电路,过流保护电路和过压保护电路,对芯片实施了三重保护,在输出大功率或驱动感性负载的同时,可保证芯片不被损坏。芯片能够在±25V的电源电压下为4?或8?的负载提供20W的输出功率。该电路设计采用了先进的电路结构,保证了大功率输出时的低失真度,同时具有100dB的开环增益,4A的电流容量,10V/μS的转换速率和40kHz的功率带宽等性能指标。
本文对各模块性能指标的设计做了详细介绍,同时也对版图设计注意事项做了简单介绍,还给出了芯片在典型应用下系统仿真的波形。最后,提出了芯片功能改进的方案及相应的后续工作。
该芯片采用4μm Bipolar高压工艺实现。利用Cadence Spectre对各部分电路进行了仿真,仿真结果完全满足设计要求,同时利用Cadence Virtuoso进行版图绘制。目前该芯片正在流片。
Audio Power Amplifier is widely used in high performance audio systems, stereo phonographs, servo amplifiers and instrument systems. Nowadays, people emphasize high power and high efficiency as well as high fidelity feature of audio power amplifier. So it’s worth to design an Audio Power Amplifier with the features of high power and high efficiency.
In this paper, a 20 watt audio power amplifier has been developed, which has class-AB output stage, and with Miller compensation internal to guarantee the stability of close loop. The chip has internal current limit、thermal shutdown and over-voltage protection circuit. When it is delivering high output power to the load or driving nonlinear reactive loads, the degradation of the output transistor or catastrophic failure of the whole circuit may happen without those internal protection circuit . It’s capable of delivering 20 watt of output to a 4 ? or 8 ? load at±25 V supplies. The design takes advantage of advanced circuit techniques and process technology to achieve extremely low distortion levels even at high output power. The chip also has the following features: open loop gain of 100dB, current capability of 4A, slew rate of 10V/μs and power bandwidth of 40 kHz.
Design of each block is described in detail, layout consideration is also presented in brief and the simulation waves are given. At last , the improvement of chip features is proposed as the feature work.
The 4μm High Voltage Bipolar process is used to fabricate this chip. We use Cadence Spectre to run simulation, and results of system simulation indicate that the performance of this circuit meets exactly with the design goals. Meanwhile, we use Cadence Virtuoso to edit layout, and the chip has been in fabrication now.
本文介绍了一种额定输出功率为20W的音频功率放大器芯片的设计。该芯片采用了AB类推挽输出级,内部有Miller补偿,可保证闭环稳定性。芯片内部设有过温保护电路,过流保护电路和过压保护电路,对芯片实施了三重保护,在输出大功率或驱动感性负载的同时,可保证芯片不被损坏。芯片能够在±25V的电源电压下为4?或8?的负载提供20W的输出功率。该电路设计采用了先进的电路结构,保证了大功率输出时的低失真度,同时具有100dB的开环增益,4A的电流容量,10V/μS的转换速率和40kHz的功率带宽等性能指标。
本文对各模块性能指标的设计做了详细介绍,同时也对版图设计注意事项做了简单介绍,还给出了芯片在典型应用下系统仿真的波形。最后,提出了芯片功能改进的方案及相应的后续工作。
该芯片采用4μm Bipolar高压工艺实现。利用Cadence Spectre对各部分电路进行了仿真,仿真结果完全满足设计要求,同时利用Cadence Virtuoso进行版图绘制。目前该芯片正在流片。
Audio Power Amplifier is widely used in high performance audio systems, stereo phonographs, servo amplifiers and instrument systems. Nowadays, people emphasize high power and high efficiency as well as high fidelity feature of audio power amplifier. So it’s worth to design an Audio Power Amplifier with the features of high power and high efficiency.
In this paper, a 20 watt audio power amplifier has been developed, which has class-AB output stage, and with Miller compensation internal to guarantee the stability of close loop. The chip has internal current limit、thermal shutdown and over-voltage protection circuit. When it is delivering high output power to the load or driving nonlinear reactive loads, the degradation of the output transistor or catastrophic failure of the whole circuit may happen without those internal protection circuit . It’s capable of delivering 20 watt of output to a 4 ? or 8 ? load at±25 V supplies. The design takes advantage of advanced circuit techniques and process technology to achieve extremely low distortion levels even at high output power. The chip also has the following features: open loop gain of 100dB, current capability of 4A, slew rate of 10V/μs and power bandwidth of 40 kHz.
Design of each block is described in detail, layout consideration is also presented in brief and the simulation waves are given. At last , the improvement of chip features is proposed as the feature work.
The 4μm High Voltage Bipolar process is used to fabricate this chip. We use Cadence Spectre to run simulation, and results of system simulation indicate that the performance of this circuit meets exactly with the design goals. Meanwhile, we use Cadence Virtuoso to edit layout, and the chip has been in fabrication now.
引文
[1] 孙庆有, 门秀萍. 音频功率放大器设计. 北京:《家庭影院技术》杂志社, 2000
[2] 周全才, 李斌. 数字音频功率放大器的技术与现状. 声频工程和设备, 2000: 85～90
[3] 雷张伟. D类音频功率放大器设计[硕士学位论文]. 成都: 电子科技大学图书馆, 2001
[4] 康华光. 电子技术基础/模拟部分(第四版). 北京: 高等教育出版社, 1988
[5] 建华. 谈谈高保真音响. 家庭科技, 1999, (8): 13
[6] 莫爱雄. 音色纯美的纯直流Hi-Fi大功率纯甲类功放DIY. 家庭电子, 2005, (6): 38～39
[7] 戴春风. 音响技术的新台阶——浅析数字功率放大器. 实用影音技术,2004,(8): 34～36
[8] 陈景银, 叶润涛. 功率集成电路. 杭州: 浙江大学出版社, 1995
[9] 张廷庆. 半导体集成电路. 上海: 上海科学技术出版社, 1986
[10] 张虔铭. 浅谈音频功放失真. 视听世界, 2002, (3): 21, 40～41
[11] 张刚强. 一种考虑集成功率三极管热效应的SOA保护电路. 中国集成电路, 2005, (75): 32～36
[12] NIKOLAIDIS T, RICHIER C, REFFAY M, et al. INFLUENCE OF PARASITIC STRUCTURES ON THE ESD PERFORMANCE OF A PURE BIPOLAR PROCESS. Microelectron. Reliab., 1996, 36( 11): 1723～1726
[13] GREINER R A, GDAUGHERTY D. Low Distortion and High Thermal Stability in Transistor Audio Power Amplifiers. IEEE Transaction on Audio, 1964: 26～29
[14] Oliveira D S , Bissochi C A, Vincenzi R S. Proposal of a New Audio Amplifier. IEEE CIEP, 2000: 15～19
[15] 徐卿, 许维胜, 吴启迪. 功率集成电路中过热保护电路的设计. 传感器技术,2004, 23(2): 47～49
[16] 张虔铭. 浅析音频功放的保护. 视听世界, 2002, (11): 13～16
[17] 宋德武. 浅谈功放滤波电容的对称. 家庭电子, 2001, (7): 41
[18] GREINER R A, GDAUGHERTY D. Some Design Objectives for Audio Power Amplifier. IEEE Transactions on Audio and Electroacoustics ,1966, 14(1): 43～48
[19] FEWER. D R. Design Principles for Junction Transistor Audio Power Amplifiers. IRE TRANSACTIONS ON AUDIO, 1955: 183～201
[20] TRENT R L. Design Principles of Junction Transistor Audio Power Amplifiers. IRE TRANSACTIONS ON AUDIO, 1955: 143～161
[21] Woll H J, Putzrath F L. A note on noise in audio amplifiers. TRANSACTIONS OF THE IRE, 1954: 39～42
[22] Jack D Grimes, Stephen S Mosher, Joseph M Brown. An Innovatavie Audio Power Amplifier. IEEE Transactions on Audio and Electroacoustics, 1971, 19(4): 262～269
[23] 朱正涌. 半导体集成电路(第一版). 北京: 清华大学出版社, 2001
[24] Razavi B. Design Of Analog CMOS Integrated Circuits. International Edition 2001. Singapore: McGraw-Hill Book Co- Singapore,2001
[25] Chai Yeh. Analysis of a single-ended push-pull audio amplifier. TRANSACTIONS OF THE IRE-PGA, 1953: 9～19
[26] Peterson A, Sinclair B. A Single-Ended Push-Pull Audio Amplifier. IRS, 1952, 40 (5): 7～11
[27] FARAN J J, FULKS R G. High Impedance Drive for the Elimination of Crossover Distortion. IRE TRANSACTIONS ON AUDIO, 1962: 99～105
[28] FRITZ LANGFORD SMITH. Audio Amplifier. IRE Transaction on Audio, 1957: 25～30
[29] Lin H C. Quasi–complementary transistor amplifier. Electronics, 1956: 173～175
[30] John DeCelles, Troy Huebner. Overture Series High Power Solutions. NationalSemiconductor Application Note 1192, 2004
[31] Ruehs R G. High power audio amplifiers with short circuit protection. Motorola Application Note AN-485, 1969
[32] Marco Berkhout. Integrated overcurrent protection system for class-D audio power amplifiers. IEEE Journal of Solid-State Circuits, 2005, 40(11): 2237～2245
[33] Manoj Sachdev. Catastrophic defects oriented testability analysis of a class AB amplifier. IEEE International Workshop on Defect and Fault Tolerance in VLSI Systems, 1993: 319～326
[34] Marshall Leach W. Feedforward compensation of the amplifier output stage for improved stability with capacitive loads. IEEE Transactions on Consumer Electronics, 1988, 34 (2): 334～338
[35] 潘飞蹊, 俞铁刚, 郭超,等. 一种高精度带隙基准源和过温保护电路. 微电子学, 2005, 32(2): 192～195
[36] DWIGHT V JONES. Low Cost Amplifier with Silicon Transistors. IEEE Transactions on Audio and Electroacoustics , 1966, 14 (1): 40～42
[37] Alan Hastings. The Art of Analog Layout. 北京: 清华大学出版社. 2004
[38] 王家斌, 高勇进, 黄绪江, 等. 感性负载驱动控制 IC 版图设计. 半导体技术, 2004, 29 (10): 53～56
[39] 董艳燕, 邓先灿, 夏冠群. 电机驱动 IC 芯片中功率输出管的版图设计. 杭州电子科技大学学报, 2005, 25 (5): 45～48
[40] Philip E Allen. CMOS Analog Circuit Design. 2nd. 北京: 电子工业出版社, 2002
[41] Gray P R, Mayer R G. Analysis and Design of Analog Integrated circuits. 4th. 北京: 高等教育出版社, 2002
[42] 杨帮文. 新型实用功率放大电路集锦. 北京: 人民邮电出版社, 1999
[2] 周全才, 李斌. 数字音频功率放大器的技术与现状. 声频工程和设备, 2000: 85～90
[3] 雷张伟. D类音频功率放大器设计[硕士学位论文]. 成都: 电子科技大学图书馆, 2001
[4] 康华光. 电子技术基础/模拟部分(第四版). 北京: 高等教育出版社, 1988
[5] 建华. 谈谈高保真音响. 家庭科技, 1999, (8): 13
[6] 莫爱雄. 音色纯美的纯直流Hi-Fi大功率纯甲类功放DIY. 家庭电子, 2005, (6): 38～39
[7] 戴春风. 音响技术的新台阶——浅析数字功率放大器. 实用影音技术,2004,(8): 34～36
[8] 陈景银, 叶润涛. 功率集成电路. 杭州: 浙江大学出版社, 1995
[9] 张廷庆. 半导体集成电路. 上海: 上海科学技术出版社, 1986
[10] 张虔铭. 浅谈音频功放失真. 视听世界, 2002, (3): 21, 40～41
[11] 张刚强. 一种考虑集成功率三极管热效应的SOA保护电路. 中国集成电路, 2005, (75): 32～36
[12] NIKOLAIDIS T, RICHIER C, REFFAY M, et al. INFLUENCE OF PARASITIC STRUCTURES ON THE ESD PERFORMANCE OF A PURE BIPOLAR PROCESS. Microelectron. Reliab., 1996, 36( 11): 1723～1726
[13] GREINER R A, GDAUGHERTY D. Low Distortion and High Thermal Stability in Transistor Audio Power Amplifiers. IEEE Transaction on Audio, 1964: 26～29
[14] Oliveira D S , Bissochi C A, Vincenzi R S. Proposal of a New Audio Amplifier. IEEE CIEP, 2000: 15～19
[15] 徐卿, 许维胜, 吴启迪. 功率集成电路中过热保护电路的设计. 传感器技术,2004, 23(2): 47～49
[16] 张虔铭. 浅析音频功放的保护. 视听世界, 2002, (11): 13～16
[17] 宋德武. 浅谈功放滤波电容的对称. 家庭电子, 2001, (7): 41
[18] GREINER R A, GDAUGHERTY D. Some Design Objectives for Audio Power Amplifier. IEEE Transactions on Audio and Electroacoustics ,1966, 14(1): 43～48
[19] FEWER. D R. Design Principles for Junction Transistor Audio Power Amplifiers. IRE TRANSACTIONS ON AUDIO, 1955: 183～201
[20] TRENT R L. Design Principles of Junction Transistor Audio Power Amplifiers. IRE TRANSACTIONS ON AUDIO, 1955: 143～161
[21] Woll H J, Putzrath F L. A note on noise in audio amplifiers. TRANSACTIONS OF THE IRE, 1954: 39～42
[22] Jack D Grimes, Stephen S Mosher, Joseph M Brown. An Innovatavie Audio Power Amplifier. IEEE Transactions on Audio and Electroacoustics, 1971, 19(4): 262～269
[23] 朱正涌. 半导体集成电路(第一版). 北京: 清华大学出版社, 2001
[24] Razavi B. Design Of Analog CMOS Integrated Circuits. International Edition 2001. Singapore: McGraw-Hill Book Co- Singapore,2001
[25] Chai Yeh. Analysis of a single-ended push-pull audio amplifier. TRANSACTIONS OF THE IRE-PGA, 1953: 9～19
[26] Peterson A, Sinclair B. A Single-Ended Push-Pull Audio Amplifier. IRS, 1952, 40 (5): 7～11
[27] FARAN J J, FULKS R G. High Impedance Drive for the Elimination of Crossover Distortion. IRE TRANSACTIONS ON AUDIO, 1962: 99～105
[28] FRITZ LANGFORD SMITH. Audio Amplifier. IRE Transaction on Audio, 1957: 25～30
[29] Lin H C. Quasi–complementary transistor amplifier. Electronics, 1956: 173～175
[30] John DeCelles, Troy Huebner. Overture Series High Power Solutions. NationalSemiconductor Application Note 1192, 2004
[31] Ruehs R G. High power audio amplifiers with short circuit protection. Motorola Application Note AN-485, 1969
[32] Marco Berkhout. Integrated overcurrent protection system for class-D audio power amplifiers. IEEE Journal of Solid-State Circuits, 2005, 40(11): 2237～2245
[33] Manoj Sachdev. Catastrophic defects oriented testability analysis of a class AB amplifier. IEEE International Workshop on Defect and Fault Tolerance in VLSI Systems, 1993: 319～326
[34] Marshall Leach W. Feedforward compensation of the amplifier output stage for improved stability with capacitive loads. IEEE Transactions on Consumer Electronics, 1988, 34 (2): 334～338
[35] 潘飞蹊, 俞铁刚, 郭超,等. 一种高精度带隙基准源和过温保护电路. 微电子学, 2005, 32(2): 192～195
[36] DWIGHT V JONES. Low Cost Amplifier with Silicon Transistors. IEEE Transactions on Audio and Electroacoustics , 1966, 14 (1): 40～42
[37] Alan Hastings. The Art of Analog Layout. 北京: 清华大学出版社. 2004
[38] 王家斌, 高勇进, 黄绪江, 等. 感性负载驱动控制 IC 版图设计. 半导体技术, 2004, 29 (10): 53～56
[39] 董艳燕, 邓先灿, 夏冠群. 电机驱动 IC 芯片中功率输出管的版图设计. 杭州电子科技大学学报, 2005, 25 (5): 45～48
[40] Philip E Allen. CMOS Analog Circuit Design. 2nd. 北京: 电子工业出版社, 2002
[41] Gray P R, Mayer R G. Analysis and Design of Analog Integrated circuits. 4th. 北京: 高等教育出版社, 2002
[42] 杨帮文. 新型实用功率放大电路集锦. 北京: 人民邮电出版社, 1999