A 4Ω 2.3W class-D audio amplifier with embedded DC-DC boost converter, current-sensing ADC and DSP for adaptive speaker protection

The trend in portable devices such as smart phones and tablets is towards higher audio output power. This can be achieved by lowering the speaker impedance or increasing the voltage swing at the amplifier output by boosting the supply voltage [1-4]. Typical speakers in portable devices are quite fragile and can be damaged easily when the voice coil temperature or membrane excursion exceeds the rated limits. This work presents a smart speaker driver system that maximizes acoustic output while ensuring the speaker is not damaged.

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