公开(公告)号：US07312654B2

公开(公告)日：2007-12-25

申请号：US11314203

申请日：2005-12-20

申请人： William J. Roeckner ,  Pallab Midya ,  Patrick L. Rakers ,  Lawrence E. Connell ,  Daniel A. Mavencamp ,  Bradley C. Stewart

发明人： William J. Roeckner ,  Pallab Midya ,  Patrick L. Rakers ,  Lawrence E. Connell ,  Daniel A. Mavencamp ,  Bradley C. Stewart

IPC分类号： H03F3/38

CPC分类号： H03F3/2173 ,  H03F1/305 ,  H03F3/2171 ,  H03F3/72 ,  H03F2200/03 ,  H03F2200/351 ,  H03K17/161

摘要： A closed loop audio amplifier system and method of powering up/down the system without producing audible artifacts are provided. During power up, a prebias voltage is provided to each output connected to a speaker to increase the voltage to a nominal output level. High impedance switches are then driven at a 50% duty cycle. Feedback from the output is supplied to a servo, which is enabled to fine tune the output voltage. Low impedance switches are then driven at a 50% duty cycle at a quarter cycle timing. The order of the feedback loop depends on which of the high or low impedance switches are driven. The prebias voltage is then removed before audio signals to be amplified are supplied to the system. Timing of driving of the switches is programmable. To power down, essentially the reverse sequence is provided.

摘要翻译： 提供一种闭环音频放大器系统以及在不产生可听见的伪影的情况下对系统加电/下电的方法。 在上电期间，向连接到扬声器的每个输出端提供预偏置电压以将电压增加到额定输出电平。 然后以50％占空比驱动高阻抗开关。 输出端的反馈信号被提供给一个伺服控制器，可以对输出电压进行微调。 然后，在四分之一周期的时间，以50％的占空比驱动低阻抗开关。 反馈环路的顺序取决于驱动高阻抗或低阻抗开关中的哪一个。 然后在将要放大的音频信号提供给系统之前，去除预偏置电压。 开关的驱动时序是可编程的。 为了断电，基本上提供了相反的顺序。

公开(公告)号：US06775387B1

公开(公告)日：2004-08-10

申请号：US09452035

申请日：1999-11-30

申请人： Daniel A. Mavencamp ,  Ronnie Bean ,  Tim Colvin

发明人： Daniel A. Mavencamp ,  Ronnie Bean ,  Tim Colvin

IPC分类号： H04B1500

CPC分类号： H03F3/181 ,  H03F1/14 ,  H03F1/305 ,  H04R3/007

摘要： Provided is a method (500) and audio circuit (100) for reducing popping noise in a load (140, 145) connected to the audio circuit, especially during audio circuit start-up. The method applies a time varying voltage (364) to the load that has a smooth, S-shaped curve when plotted over time. The device include an integrated circuit (IC) set as a channel block (110), a load connected between the channel block and ground, a bypass control (150) connected to the channel block for producing a controlled ground reference voltage having an S-shaped curve to the channel block, a shunt control (170) controlling the voltage delivered across the load, and a ground capacitor (160) coupled between the bypass control and ground. The channel block typically includes an amplifier which supplies the output voltage across the load. The bypass circuit generally includes a bypass generator and a transistor selectively providing a charge to the ground capacitor.

摘要翻译： 提供了一种用于减少连接到音频电路的负载（140,145）中的突然噪声的方法（500）和音频电路（100），特别是在音频电路启动期间。 该方法对随时间绘制的具有平滑S形曲线的负载施加时变电压（364）。 该装置包括设置为通道块（110）的集成电路（IC），连接在通道块与地之间的负载;连接到通道块的旁路控制（150），用于产生具有S- 控制跨越负载的电压的分流控制（170）以及耦合在旁路控制和地之间的接地电容器（160）。 通道块通常包括在负载上提供输出电压的放大器。 旁路电路通常包括旁路发生器和选择性地向接地电容器提供电荷的晶体管。