What are the advantages and disadvantages of class

by:Gisen     2020-06-16
Class D amplifier refers to Class D audio power amplifier (sometimes called digital amplifier). By controlling the ON / OFF of the switch unit, the amplifier driving the speaker is called a class D amplifier. Class D amplifiers were first proposed in 1958 and have gradually become popular in recent years. It has been in existence for many years. Compared with the general linear class AB power amplifier circuit, the class D power amplifier has the characteristics of high efficiency and small size. Working principle of d power amplifier Class D amplifier design considerations are completely different from class AB amplifiers. At this time, the linearity of the power amplifier tube has no meaning, and the more important switch response and saturation voltage drop. Because the pulse frequency processed by the power amplifier tube is dozens of times that of the audio signal, and it is required to maintain good front and back edges of the pulse, the switching response of the tube is better. In addition, the efficiency of the whole machine is entirely due to the pipe consumption caused by the saturation pressure drop of the pipe. Therefore, the small pressure drop of the saturated tube not only has high efficiency, but also the heat dissipation structure of the power amplifier tube can be simplified. A few years ago, the price of such high-frequency high-power tubes was expensive, which limited the development of Class D amplifiers to a certain extent. Now MOSFETs with small current control and large currents have been widely used in the industrial field. Especially in recent years, UHC MOSFETs have been applied to Hi-Fi amplifiers, and the obstacles of the devices have been eliminated. Modulation circuit is also a special link of Class D amplifier. To modulate the audio below 20KHz into a PWM signal, the triangle wave frequency must reach at least 200KHz. If the frequency is too low to meet the same requirements as the THD standard, the components of the passive LC low-pass filter are high and the structure is complex. The frequency is high, the sawtooth of the output waveform is small, which is closer to the original waveform, the THD is small, and the filter can be made with a relatively low value, small volume, and relatively low inductance and capacitance, which reduces the cost. But at this time, the switching loss of the transistor will increase with the increase of frequency. The high-frequency loss in the passive device and the skin effect of RF will reduce the efficiency of the whole machine. Radio frequency interference will also occur at higher modulation frequencies, so the modulation frequency cannot be higher than 1MHz. At the same time, the shape of the triangular waveform, the accuracy of the frequency and the jitter of the clock signal will all affect the difference between the restored signal and the original signal and produce distortion. So to achieve high fidelity, many of the same considerations as digital audio fidelity have emerged. Another factor that has a lot to do with sound quality is the passive filter between the drive output and the load. The low-pass filter works under high current, and the load is the speaker. Strictly speaking, the change in speaker impedance should be taken into account in the design, but it is not feasible to specify the speaker as a power amplifier product, so there is a world of enthusiasts in the combination of class D amplifiers and speakers. It is actually proved that when the distortion requirement is below 0.5%, the second-order Butterworth flattest response low-pass filter can meet the requirement. If higher requirements are required, a fourth-order filter is required. At this time, cost and matching issues must be considered. In recent years, general-purpose Class D amplifiers have integrated circuit chips, and users only need to design low-pass filters as required. What are the advantages and disadvantages of d power amplifier Class D power amplifier advantages There are many advantages of d power amplifiers. Let me talk about them in detail. 1. Class d power amplifier has a high energy use conversion rate, and its small size and strong reliability. The battery usage rate of class d power amplifier can reach more than 90%, which meets the requirements of environmental protection. 2. Class d power amplifiers are used in a wide range. The minimum value of the connected load impedance can be very low. In addition, no matter how the load impedance changes, the conversion rate of the battery can basically be said to be unchanged Class 3, Class D amplifiers have no relative changes in high frequency, intermediate frequency, and low frequency. Its sound is very clear, and the sound image has a very accurate positioning. Class 4, d amplifiers are very suitable for mass production of products. As long as the installation of the correct components is ensured, the product can have a good consistency, and it does not require any debugging during the production process, which is safe and reliable. 5, class d power amplifier can directly realize the functions of group control, remote control, monitoring, etc., without adding any device. What are the advantages and disadvantages of d power amplifier Disadvantages of Class D power amplifier Class D power amplifiers have many advantages, but they also have many shortcomings, and these shortcomings seriously affect the development of class D power amplifiers. I will specifically talk about the disadvantages of class D power amplifiers. What are the advantages and disadvantages of d power amplifier 1. Class D power amplifiers do not have special switches. If the installed power transistors are not well matched with other devices, the quality of the entire product will be insufficient. 2. The power transistors of Class D power amplifiers will fluctuate in the potential close to the ground during their initial connection and final shutdown, which increases noise. 3. The output circuit of Class D power amplifier may have a dead zone. 4. Class D power amplifier speakers may appear distorted for some reason. What are the advantages and disadvantages of d power amplifier
Custom message
Chat Online 编辑模式下无法使用
Chat Online inputting...