A 250 W audio amplifier with straightforward digital input-PWM output conversion

A switching audio amplifier which features high output power (250 W), high efficiency (90 %) while performing a 96 dB dynamic range is presented. The amplifier is based on a single-chip integrated circuit that converts a digital input data stream at frequency fsinto an 8fsPulse Width Modulated (PWM) output power signal, without using intermediate filter. An embedded I²S input interface is capable of receiving digital words up to 24-bit at a rate fsranging from 32 kHz to 48 kHz. The chip is fabricated with a 0.6 µm Bipolar-CMOS-DMOS (BCD) technology and assembled in a surface-mount package. Due to the high output power, it drives four external power MOS transistors.