Ultra-Low Frequency Amplification using Class D Topology

The application is to be suitable for in-home as well as automotive use. The input can be stereo or mono from any low impedance audio signals such as a compact disc or MP3 player. It’s a power amplifier that uses a class D geography for matching current range of class AB amplifiers, surpassing all other class D evaluation boards and chipsets when operated in a domestic surrounding. A class D amplifier is defined by the output transistors which is being hard switched between conducting and non-conducting or vice-versa. This differs from the other amplification classes that is operate from the output transistors in the linear operating range. The input should not exceed the maximum voltage level, since audio quality cannot be guaranteed at such levels. Different amplifiers of class D type have an inaccurate frequency response output, when they are connected to different loads and are only optimized for one load impedance. Other than this type of amplifier use feedback after the reconstruction filter to correct for this. Using feedback after the reconstruction filter creates a huge phase shift in the feedback and has a very negative effect on the amplifiers performance when playing musical signals and can cause them to become unstable, oscillate and distort. During initial stage of power up of the class D amplifier, the circuit actively measures the high frequency impedance of the load connected to the amplifier and adjusts its high level of frequency output level to ensure that the audio output response is always accurate. Finally, the chosen design performs almost perfectly to specifications, but under actual construction there is crystal clear output.