Type D Amplifier：Cautions for Heat Dissipation of Loudspeaker IC

Compared with class AB amplifier, type D amplifier has higher efficiency and better thermal performance. Nevertheless, the heat dissipation of type D amplifier still needs careful consideration. This application note analyses the thermal performance of type D amplifier, and illustrates the principles of good design through several common examples. When evaluating the performance of type D amplifier in laboratory, continuous sine wave is often used as signal source. Although it is convenient to use sinusoidal wave for measurement, such measurement results are the thermal load of the amplifier in the worst case. If the type D amplifier is driven by a continuous sinusoidal wave near the maximum output power, the amplifier will often enter a thermal shutdown state.

Amplifier Performance - Compared with G-type boost power supply commonly used in smart amplifiers, the integrated H-type 11-volt DC-DC boost converter can improve the power supply voltage and maintain higher efficiency. By tracking the audio level adaptively, class H boost converter can improve system efficiency, minimize power consumption and prolong battery life. Audio Eenhancement - Playback can be fine tuned to specific microspeakers used in mobile systems. Enhancing the algorithms of equalizer, compressor and psychoacoustics can improve the clarity and loudness of sound. The filter guarantees the unique frequency response of the loudspeaker and eliminates the pre-ringing in the traditional linear phase filter. This enables audio engineers to make full use of small speakers to improve the gaming and video streaming audio experience of mobile device users.

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