公开(公告)号：US20050099226A1

公开(公告)日：2005-05-12

申请号：US10712746

申请日：2003-11-12

申请人： Lars Risbo ,  Anker Josefsen

发明人： Lars Risbo ,  Anker Josefsen

IPC分类号： H03F3/217 ,  H03F3/38 ,  H03F3/45

CPC分类号： H03F3/217 ,  H03F3/45085 ,  H03F2203/45636

摘要： A technique to implement removal of dead time control circuitry from the back-end of a digital switching amplifier system 100 and add dead time control circuitry on the front-end digital modulator chip. The front-end dead time control circuitry adaptively adjusts timing of the output PWM control signals 124 to optimize performance and power consumption, i.e. operate with minimum dead time for all transitions. The front-end dead time control circuitry controls all propagation delays associated with the digital switching amplifier system 100.

摘要翻译： 一种实现从数字开关放大器系统100的后端去除死区时间控制电路并在前端数字调制器芯片上增加死区时间控制电路的技术。 前端死区时间控制电路自适应地调节输出PWM控制信号124的定时，以优化性能和功耗，即以最小死区时间进行所有转换。 前端死区时间控制电路控制与数字开关放大器系统100相关联的所有传播延迟。

公开(公告)号：US20050083114A1

公开(公告)日：2005-04-21

申请号：US10962767

申请日：2004-10-12

申请人： Lars Risbo

发明人： Lars Risbo

IPC分类号： H03F3/217 ,  H03F3/38 ,  H03F3/68

CPC分类号： H03F3/68 ,  H03F3/217 ,  H03F3/38 ,  H03F2200/66 ,  H03F2200/78

摘要： A class AD audio amplifier system (10) with improved recovery from clipping events is disclosed. The amplifier system (10) includes multiple audio channels (20), each of which can be constructed to include a pulse-width-modulator (PWM) (24). The PWM modulator (24) includes a pair of comparators (39A, 39B; 52+, 52−) that generate complementary PWM output signals based upon the comparison between a filtered difference signal and a reference waveform. Clip detection logic (26) is provided to detect clipping at the output of the channel (20), preferably by detecting successive edges of the reference waveform without an intervening edge of a PWM output signal. In response to detecting clipping, a first integrator (30; 45) is reset to remove residuals and to eliminate the first integrator (30; 45) from the loop filter of the modulator (24). A saturation level circuit (35) applies a clamping voltage, preferably in both clipping and non-clipping situations, to a second integrator (36; 47). As a result, the loop filter is prevented from entering extreme conditions during clipping, which greatly reduces the clipping recovery time.

摘要翻译： 公开了一种具有改进的剪辑事件恢复的AD类音频放大器系统（10）。 放大器系统（10）包括多个音频通道（20），每个音频通道可被构造成包括脉宽调制器（PWM）（24）。 PWM调制器（24）包括一对比较器（39A，39B; 52+，52-），其基于滤波差分信号和参考波形之间的比较产生互补的PWM输出信号。 提供了片段检测逻辑（26），以优选地通过检测参考波形的连续边缘而无需PWM输出信号的中间边缘来检测信道（20）的输出处的限幅。 响应于检测限幅，第一积分器（30; 45）被复位以去除残差并从调制器（24）的环路滤波器消除第一积分器（30; 45）。 饱和电平电路（35）将钳位电压（优选地在限幅和非限幅状态）施加到第二积分器（36; 47）。 结果，环路滤波器被阻止在限幅期间进入极端条件，这大大降低了修复恢复时间。

公开(公告)号：US20050017799A1

公开(公告)日：2005-01-27

申请号：US10846281

申请日：2004-05-14

申请人： Lars Risbo ,  Claus Neesgaard

发明人： Lars Risbo ,  Claus Neesgaard

IPC分类号： H03F3/217 ,  H03F3/38

CPC分类号： H03F3/2171 ,  H03F3/217 ,  H03F2200/331 ,  H03F2200/78

摘要： A class-D amplifier circuit (30; 30′) providing improved open-loop error for base-band frequencies, such as the audio band, is disclosed. The amplifier circuit (30; 30′) includes a comparator (35) for generating a pulse-width-modulated output signal that is applied to an output power stage (37). An LC filter (32) is at the output of the power stage (37). The amplifier circuit (30; 30′) includes a loop filter having multiple feedback loop paths, with at least one feedback loop path coupled to the output of the power stage (37), and optionally, at least one feedback loop path coupled to the output of the LC filter (32). The transfer function (Hmae(s)) of the loop filter has a real part that has a much steeper slope (on the order of 80 dB/decade) at frequencies above the pulse-width-modulation switching frequency than the slope of its magnitude characteristic at frequencies below this switching frequency.

摘要翻译： 公开了提供诸如音频带的基带频率的改进的开环误差的D类放大器电路（30; 30'）。 放大器电路（30; 30'）包括用于产生施加到输出功率级（37）的脉冲宽度调制输出信号的比较器（35）。 LC滤波器（32）位于功率级（37）的输出端。 放大器电路（30; 30'）包括具有多个反馈环路径的环路滤波器，其中耦合到功率级（37）的输出的至少一个反馈回路路径，以及可选地至少一个耦合到功率级 LC滤波器（32）的输出。 环路滤波器的传递函数（Hmae（s））具有在比脉冲宽度调制开关频率高于其幅度的斜率的频率处具有更陡峭的斜率（大约80dB /十倍）的实部 频率低于该开关频率的特性。

公开(公告)号：US06518838B1

公开(公告)日：2003-02-11

申请号：US09890757

申请日：2002-01-09

申请人： Lars Risbo

发明人： Lars Risbo

IPC分类号： H03F338

CPC分类号： H03F3/2175 ,  H03F1/30 ,  H03F2200/331

摘要： In a digital amplifier of the PCM-UPWM type there is no negative feedback stage, which means that noise caused by the switching output stage of such an amplifier directly affects the audio signal. A regulation loop is inserted between the output and the input of the digital amplifier, the regulation loop being adapted to form a compensation signal c(k) which is multiplied by the audio signal to compensate noise and errors from the switching output stage. In an embodiment, the regulation loop consists of a multiplying D/A converter (2) which is adapted to multiply the compensation signal c(k) by a multiplicative error signal m(t), and a summation unit (3), by summation of the output of the multiplying D/A converter (2) and a reference voltage (6), forms a second error signal e(t) which is fed to a low-pass filter (4) that is fed to the input of an ADC circuit (5) to form the multiplicative error signal c(k), which, optionally via a second adaptation filter (21), is fed to a multiplier (11) and the multiplying D/A converter (2). Expediently, the circuit of the invention is formed in full or in part by an integrated circuit.

摘要翻译： 在PCM-UPWM型数字放大器中，没有负反馈级，这意味着由这种放大器的开关输出级引起的噪声直接影响音频信号。 在数字放大器的输出端和输入端之间插入一个调节环路，调节环路适于形成一个与音频信号相乘的补偿信号c（k），以补偿来自开关输出级的噪声和误差。 在一个实施例中，调节回路包括乘法D / A转换器（2），其适于将补偿信号c（k）乘以乘法误差信号m（t）和求和单元（3），通过求和 乘以D / A转换器（2）的输出和参考电压（6）形成第二误差信号e（t），该第二误差信号被馈送到低通滤波器（4），该低通滤波器被馈送到 ADC电路（5）以形成乘法误差信号c（k），其可选地经由第二自适应滤波器（21）馈送到乘法器（11）和乘法D / A转换器（2）。 有利地，本发明的电路全部或部分地由集成电路形成。

公开(公告)号：US06373336B1

公开(公告)日：2002-04-16

申请号：US09744575

申请日：2001-04-27

申请人： Niels Anderskouv ,  Lars Risbo

发明人： Niels Anderskouv ,  Lars Risbo

IPC分类号： H03F338

CPC分类号： H03F1/32 ,  H03F1/26 ,  H03F3/2173 ,  H03F2200/351 ,  H03F2200/372

摘要： According to the invention, a method and an amplifier e.g. of the class D type, in particular connected as class BD, wherein an audio signal is pulse-with modulated in that two sets of switches are adapted to make and break signal paths transferring pulses representing the non-inverted or inverted part of the audio signal, comprise attenuating noise and zero crossing distortion which occur because of crosstalk between modulator and control circuit halves in the amplifier. Noise and zero crossing distortion are attenuated by delaying the pulses which represent the non-inverted part and the inverted part, respectively, of the audio signal relative to each other, when the audio signal is in the vicinity of the value 0, thereby achieving modulation of the audio signal which contains characteristics from pulse with modulation of both class AD and BD type. The advantage of this is that at low signal levels the amplifier obtains the linear properties of the class AD amplifiers at zero crossing and the low noise of the class BD amplifier. The pulse-with modulation type is here called class ABD.

摘要翻译： 根据本发明，一种方法和放大器，例如， 的类D类型，特别地连接为类别BD，其中音频信号是脉冲调制的，因为两组开关适于产生和断开传送表示音频信号的非反相或反相部分的脉冲的信号路径 包括由于放大器中的调制器和控制电路之间的串扰而发生的衰减噪声和过零失真。 当音频信号在0附近时，分别通过延迟表示音频信号的非反相部分和反相部分的脉冲来衰减噪声和过零失真，从而实现调制 包含具有类AD和BD类型的调制的脉冲的特性的音频信号。 其优点在于，在低信号电平下，放大器获得过零时的AD类放大器的线性特性和BD类放大器的低噪声。 脉冲调制类型在这里称为ABD类。