What is Class D power amplifier?

by:Gisen     2019-12-26
What is Class D power amplifier? Class D power amplifier refers to Class D audio power amplifier ( Sometimes also called digital power amplifier). By controlling the ON/OFF of the Switch unit, the amplifier driving the speaker is called Class D amplifier. Class D amplifiers were first proposed in 1958 and have gradually become popular in recent years. It has been published for many years. Compared with the general linear class AB power amplifier circuit, Class D power amplifier has the characteristics of high efficiency and small volume. Class D power amplifier principle Class D power amplifier is an amplification mode in which the amplification element is in the working state of the switch. When there is no signal input, the amplifier is off and does not consume power. When working, the transistor is saturated by the input signal, and the transistor is equivalent to an on switch, which directly connects the power supply to the load. The ideal transistor does not consume power because there is no saturation voltage drop. In fact, the transistor always has a small saturation voltage drop and consumes part of the power. This kind of power consumption is only related to the characteristics of the tube, but not to the size of the signal output, so it is especially beneficial to the case of super power. Advantages of Class D power amplifier 1. Class D power amplifier has a wide range of uses, and its connected load impedance minimum value can reach very low. In addition, no matter how the load impedance value changes, the conversion rate of its battery can basically be said to be unchanged. 2. Class D power amplifier is very suitable for mass production of products. As long as the installation of the components is ensured, the product can have good consistency, and the production process does not require any debugging, safe and reliable. 3. Class D power amplifier has a high energy usage conversion rate, and its volume is very small and has strong reliability. The battery utilization rate of Class D power amplifier can reach more than 90%, which meets the requirements of environmental protection. 4. Class D power amplifier can directly realize Group control, remote control, monitoring and other functions without adding any devices. 5. Class D power amplifier has no relative changes in high frequency, medium frequency and low frequency. Its sound is very clear and its audio-visual image has a very accurate positioning. Disadvantages of Class D power amplifier 1. The potential close to the ground will fluctuate during the initial connection and final shutdown of the power transistor of Class D power amplifier, thus increasing noise. 2. Speakers of Class D power amplifiers may be distorted for some reason. 3. There is no special switch for class D power amplifiers. If the installed power transistors do not match well with other devices, the quality of the whole product will not be up to standard. 4. The output circuit of Class D power amplifier may have dead zone, etc.
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