An audio amplifier providing up to 1 Watt in standard digital 90-nm CMOS

An audio amplifier in a standard 90-nm dual gate-oxide CMOS technology is designed for direct connection to the battery in a mobile phone. Special techniques have been applied to run it from a supply voltage of up to 5.5 V. The circuit does not require a dedicated supply voltage generator; it can be integrated on the same chip with the digital signal processor, and provides high output power, good power supply rejection, and good efficiency