更大限度核减启动器尺寸和降低热负荷的汽车音频擘画注意事项

2019-12-06 15:33:22 泉源:德州仪器
These higher-channel-count systems in an infotainment system may integrate:
那些信息好耍系统中的高通道数系统可能性集成:

  • A center speaker.
    中置扩音机。
  • Separate tweeter/midrange/woofer speakers.
    天下无双高频扩音机/中音号扩音机/汽车低音炮扩音机。
  • Instrument cluster chimes or warning tones.
    汽车仪表盘图标解释警报声或提示音。
  • Additional speakers to communicate information, such as warning drivers to take control of steering or braking if the vehicle is operating in a semi-autonomous driving mode.
    其他得天独厚传授信息的扩音机,如警告司机招聘网在车子处于活动驾驭模式时控制舵轮或刹车在什么位置。
Some higher-end car models may actually have as many as 20 speakers. The speakers in these audio systems are driven by an external amplifier typically placed near the trunk of the car. These audio systems also incorporate more advanced sound algorithms such as active noise cancellation to deliver a more personalized audio experience.

一些高端汽车模型信息实际上是指可能性有多达20个扩音机。那些音频系统中的扩音机由通常安装在汽车键钮后备箱附近的外部启动器使得。那些音频系统还包括更先进的传奇外传声音怎么关间离法,如得天独厚提供更加城市化音响感受的肯干降噪新认定高新技术企业。

With each subsequent model year, automakers are adding more and more electronics. Coupled with the need to drive six to eight speakers directly from the infotainment system, space behind the dashboard is now at an all-time premium. Therefore, it’s becoming a priority for audio hardware designers to develop smaller automotive audio amplifier solutions with lower heat dissipation. In this paper, I’ll describe four factors that drive overall audio amplifier size:

在随后的每一番车型年,汽车分销商正在努力加载中由小到大越是多的电子元件。再抬高急需直白从信息好耍系统使得6到8个扩音机,汽车仪表盘图标解释后边的绵阳装修新空间现在是前所街道未部分出色。音频硬件的擘画师的婚纱应首先开发散热更低的小型汽车音频启动器飞凌开发板。我将叙说使得整体家居提制音频启动器的四个因素英文:

  • Efficiency/thermal performance.
    机械效率/热性能。
  • Switching frequency.
    开关频率。
  • Inductor size.
    片式电感器尺寸。
  • Package design.
    装进擘画。
Efficiency/thermal performance
机械效率/热性能


Designers have traditionally designed car radios using Class- AB linear audio amplifiers. Class-AB linear amplification is drastically less efficient than the newer but well-established Class-D switching technology. Figure 1 highlights the difference.
历史观上,擘画人口采用AB类线性音频启动器来擘画汽车好爱收音机。AB类线性放大新认定高新技术企业远完了新的,但相当老练的D类串换新认定高新技术企业迅猛。图1卓绝了其差别读后感。


Class-AB efficiency loss leads directly to additional internal heat generation, which then requires dissipation outside the audio amplifier. The need for a larger heat sink in Class-AB designs also exacerbates the challenge to continuously reduce the overall automotive audio amplifier system solution size.

AB类机械效率损失直白致使之中产生额外热量,过后急需在音频启动器外部进行散热。鉴于AB类擘画急需更大的累加器,这也使此起彼伏核减满门汽车音频启动器系统飞凌开发板尺寸变得更加困难。

Class-D amplifiers can achieve the same output power but dissipate significantly less heat, enabling designers to use a much smaller and less complex heat sink to transport dissipated power to the ambient environment.

D类启动器能够拿走雷同的入口功率,但散热明白减少,这使得擘画人口能够采用更小,更简单的累加器将管道散热量计算传导到周围环境中。

Switching frequency
开关频率


The number of electronics mounted behind the dashboard in a relatively tight space increases the possibility that circuits can emit interfering signals in close proximity. Ultimately, modern radios and audio amplifiers must provide better immunity from electromagnetic interference (EMI) in the AM band to meet these challenges.

安装在汽车仪表盘图标解释后边对立狭小绵阳装修新空间内的电子元件多少由小到大了pcb电路板厂家得天独厚近距离打靶干扰信号的可能性性英语怎么说。更最主要的是。现世好爱收音机和音频启动器须要在AM波段中提供更好的抗电磁干扰性能(EMI),以酬对那些挑战。

In the U.S., AM radio stations broadcast in the 535-kHz to 1705-kHz frequency band. Existing Class-D audio amplifier designs typically operate with a fundamental switching frequency in the 400-kHz to 500-kHz range. These lowers-witching- frequency Class-D amplifier designs create harmonics that occur directly within the AM band, as shown in Figure 2.

艾曼妞在美国AM广播电台的波段范围为535-kHz至1705-kHz。现部分D类音频启动器擘画通常在400 kHz至500 kHz范围内以根本开关频率运行。那些低开关频率D类启动器擘画直白在AM波段内产生脑电波,如图所示2所示。


The harmonics create interfering signals that reduce the sensitivity of the AM receiver, thereby hindering AM radio station reception. Implementing an AM avoidance scheme on Class-D amplifier designs mitigates the effects of these harmonics.

脑电波会产生降低AM无线网络兼职吸收器听阈的干扰信号。据此有碍于AM广播电台吸收。在D类启动器擘画上运用AM幸免新认定高新技术企业能够减轻那些脑电波的反馈。

Class-D audio amplifiers require reconstruction filters to convert the pulse-width modulation (PWM) signal from the amplifier output into the desired analog audio signal. These output filters are made with inductors (L) and capacitors (C) (as shown in Figure 3) for a typical bridge-tied load (BTL) amplifier circuit, and help minimize EMI from the highspeed switching transients on the output stages of Class-D amplifiers.

D类音频启动器急需重建主存储器将启动器入口的脉冲星宽度调制(PWM)信号转换为所需的模仿音频信号。那些入口主存储器由片式电感器(L)和电解电压器(C)结缘(如图所示3所示)。用于典型的桥接负载(BTL)启动器pcb电路板厂家,且能够更大限度地减少D类启动器入口级上的高速上烧饭做菜开关瞬态电磁干扰。

Automotive Class-D audio amplifiers that operate at a 2.1-MHz switching frequency provide significant margin above the AM band, as shown in Figure 4. This design is free of any lower-frequency spikes that would interfere with the AM band, thus eliminating the need for an AM avoidance scheme.
 
在2.1-MHz开关频率下运行的汽车D类音频启动器在AM波段上端提供明白裕度,如图所示4所示。此擘画不存在任何会干扰AM波段的低频巅峰,因而不再急需AM幸免新认定高新技术企业。
As an additional benefit, a 2.1-MHz switching frequency enables a lower inductance value for the output filter due to the inherent reduction in ripple current. A lower inductance for an equivalent current rating leads to a smaller inductor, reducing printed circuit board (PCB) area and subsequently the EMI footprint.
 
另一番好处是,鉴于纹波电流单位的内在减少。2.1-MHz开关频率美瞳得天独厚使眼睛变大入口主存储器的电感值更低。等效额定电流单位的低电感会致使电感较小。据此减少印刷电池板(PCB)面积,且随后减少EMI占用面积。
Inductor size
片式电感器尺寸

For Class-D automotive audio amplifiers, the value of the inductor required in the LC filter to ensure the proper PWM demodulation filter characteristic depends on the switching frequency. As shown in Figure 5, a 400-kHz automotive audio amplifier typically uses either a 10-μH or 8.2-μH inductor value, while a 2.1-MHz higher-switching-frequency amplifier design can take advantage of a much smaller and lighter-weight inductor in the range of 3.3 μH to 3.6 μH (assuming that each amplifier provides the same output power).

对此D类汽车音频启动器,LC主存储器所需的电感值(用以打包票恰到好处PWM解调主存储器特性)取决开关频率。如图所示5所示。400-kHz汽车音频启动器通常采用10-μH或8.2-μH电感值,而2.1-MHz高开关频率启动器擘画得天独厚利用3.3μH至3.6μH范围内更小更轻的片式电感器(假设每种启动器提供雷同的入口功率)。

As I mentioned earlier, a typical car radio design has at least four channels to drive two front speakers and two rear speakers. This simple configuration requires eight inductors for a Class-D automotive audio amplifier, since each channel requires two inductors, as shown earlier in Figure 3. Thus, the size of each inductor is multiplied by 8, which is a significant contribution to overall PCB size and design weight. As a general reference, the transition from 8.2-μH inductors to 3.3-μH inductors can save over 85% in inductor space on the PCB and over 85% in weight.

正如事前谈起的,典型汽车好爱收音机擘画至十年九不遇4个通道来使得2个前端扬声器工作原理和2个后端扬声器工作原理。这种简单的配备急需8个片式电感器以用于D类汽车音频启动器,因为每种通道急需2个片式电感器,如图所示3所示。每种片式电感器的尺寸倍增8,对整体家居提制PCB尺寸和擘画份额有着最主要的反馈。正如,从8.2-μH片式电感器转换到3.3-μH片式电感器得天独厚节省电池板上85%之上的片式电感器绵阳装修新空间和核减85%之上的份额。

Package design
装进擘画


Another audio amplifier consideration that can greatly contribute to the overall system solution size of an automobile’s infotainment system is the design of the amplifier package.

另一番能够大大核减汽车信息好耍系统中整体家居提制系统飞凌开发板尺寸的音频启动器注意事项是启动器装进的擘画。

A square-shaped package design has inputs on the bottom of the package and two audio outputs with LC filters orthogonally placed on either side of the amplifier. As you can see in Figure 6, this type of package design greatly contributes to the overall PCB footprint.
十字架形装进擘画在装进底部有入口。还有两个音频入口,且LC主存储器正交放置在启动器的一侧屁股疼。如图所示6所示,这种类型的装进擘画大大由小到大了满门PCB的占用面积。

 
A better option is a rectangular package that has a “flowthrough” audio signal design. Figure 7 illustrates how the analog input signals come into the amplifier on one side of the chip; amplification of the audio signal takes place on the opposite side of the amplifier, where the signals are then delivered into external output filters.
 
带有“流式”音频信号擘画的十字架形装进是更好的采择。图7说明了模仿入口信号哪些加入硅片一侧屁股疼的启动器;音频信号的放大时有发生在启动器的另一侧屁股疼,信号随后被转交到外部入口主存储器中。

The TPA6304-Q1 audio amplifier uses a 2.1-MHz highswitching- frequency Class-D amplifier technology that features TI Burr-Brown™ technology. By combining 3.3-μH metal alloy inductors and a flow-through package design, the TPA6304-Q1 delivers a four-channel automotive Class-D amplifier solution size that measures only 17 mm by 16 mm. See Figure 8.

TPA6304-Q1音频启动器采用具有TI Burr-Brown™新认定高新技术企业的2.1-MHz高开关频率D类启动器新认定高新技术企业。TPA6304-Q1通过结合3.3-μH金属合金片式电感器和直流装进擘画,得天独厚提供一番尺寸只有17 mm x 16 mm的4通道汽车D类启动器飞凌开发板。见图8。

 
The TPA6304-Q1, including all of the passive electronic components for the full system solution implementation, is even smaller than the traditional Class-AB amplifier by itself, as shown in Figure 9.
 
TPA6304-Q1(包括用于整体家居提制系统飞凌开发板的所有吉比特无源光纤wifi元器件)比历史观的AB类启动器还要小,如图所示9所示。


Conclusion
结论

The more electronics added to a car, the more the overall heat signature increases in an already tightly confined space behind the dashboard. Thus, the challenge for automotive audio hardware designers is to implement smaller and smaller audio solutions with lower and lower heat dissipation. Audio amplifier efficiency will only become more important in the future of infotainment system design.

汽车上安装的电子元件越多,汽车仪表盘图标解释后狭小绵阳装修新空间内的整体家居提制热量就越是高。汽车音频提供智能拼音硬件擘画人口惨遭的挑战是实现更小,散热更低的音频飞凌开发板。音频启动器的机械效率只会在明晨的信息好耍系统擘画中变得更加最主要。
The TPA6304-Q1 makes replacing a Class-AB automotive audio amplifier easy. Its 2.1-MHz switching frequency and tiny system solution size allow you to achieve Class-D efficiency at a Class-AB system cost.
TPA6304-Q1可易如反掌代替AB类汽车音频启动器。TPA6304-Q1的2.1-MHz开关频率和小型系统飞凌开发板尺寸得天独厚让你以AB类系统洗车店成本实现D类机械效率。


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