![used power amplifier used power amplifier](https://www.kempelektroniksshop.nl/media/catalog/product/cache/1/image/1000x1231/17f82f742ffe127f42dca9de82fb58b1/k/e/keces-audio_s300_power-amplifier_front-angled.png)
If we want to put the previous block diagram into practice, we will stumble upon some problems. Theory is one aspect and practice is another. In the plot below, you can see how we transform a sinusoidal signal (the input) into a rectangular signal by comparing it to a triangle signal.Īt the positive peak of the sine wave, the duty cycle of the rectangular pulse is 100% whilst at the negative peak it is 0%. The actual frequency of the triangle signal is much higher, on the order of hundreds of kHz, so that we can later extract our original signal.Ī real filter, not an ideal one, does not have a perfect "brick-wall" transition from passband to stopband, so we want the triangle signal to have a frequency at least 10 times higher than 20KHz, which is the upper human hearing limit.
![used power amplifier used power amplifier](https://image.made-in-china.com/2f0j00QUkYDabhvCqB/PRO-Digital-Audio-Power-Amplifiers-Best-Linear-AMPS-FP13000-.jpg)
![used power amplifier used power amplifier](https://cdn11.bigcommerce.com/s-ope853byfp/images/stencil/1280x1280/products/2009/32911/Revox_A722_Audio_Amplifier_side__82481.1606302232.jpg)
Pulse-Width Modulation Using a Comparator There are other methods for converting the signal into pulses, such as ΔΣ (delta-sigma) modulation, but for this project we will be using PWM. The rectangular signal is amplified, and then a low-pass filter results in a higher-power version of the original analog signal. This basically means that the input is encoded into the duty cycle of the rectangular pulses. The input signal is converted into a pulse width modulated, rectangular signal using a comparator. For comparison, the class B amplifier can only achieve a maximum efficiency of 78.5% (in theory).īelow you can see the block diagram of a basic PWM Class-D amplifier, just like the one that we are building. Because of this, the amplifier does not generate a lot of heat and does not require a big heat sink like linear class AB amplifiers do. This allows a very high efficiency, up to 80 - 95%. Compare this to switching amplifiers, so called because the power transistors (the MOSFETs) are acting like switches, changing their state from OFF to ON. Traditional amplifiers, like the class AB, operate as linear devices. What is a Class-D audio power amplifier? The answer could be just a sentence long: It is a switching amplifier. But in order to fully understand how one works, I need to teach you all its nooks and crannies. I will explain to you how they work and then guide you step by step to make the magic happen all by yourself.
#Used power amplifier how to
If your answer is yes, then you should continue reading this article on how to build your own Class D amplifier. Have you always wanted to build your own audio power amplifier? An electronic project where you not only see the results but also hear them? The mighty Class-D amplifier-build one yourself and be amazed by its efficiency.