Highly efficient class-G amplifier and control method thereof

A highly efficient class-G amplifier comprising:

• an amplifier circuit coupled between a positive power rail and a negative power rail for amplifying an audio input signal;
• a boost inverting power converter coupled to the positive and negative power rails for converting a supply voltage to a positive rail voltage and a negative rail voltage on the positive and negative power rails respectively;
• and
• an audio level detector coupled to the boost inverting power converter for detecting the audio input signal for the boost inverting power converter to adjust the positive and negative rail voltages;
• the boost inverting power converter comprising:
• a boost inverting power stage coupled to the positive and negative power rails and a power input terminal receiving the supply voltage;
• and
• a controller coupled to the boost inverting power stage for switching the boost inverting power stage between a boost mode and an inverting mode;
• the boost inverting power stage comprising:
• an inductor;
• a first power switch coupled between the power input terminal and inductor;
• a second power switch coupled between the inductor and a ground terminal;
• a first diode coupled between the negative power rail and inductor;
• a second diode coupled between the inductor and positive power rail;
• a first capacitor coupled to the negative power rail;
• a second capacitor coupled to the positive power rail;
• a first voltage divider coupled to the negative power rail for dividing the negative rail voltage to generate a first feedback signal for the controller;
• and
• a second voltage divider coupled to the positive power rail for dividing the positive rail voltage to generate a second feedback signal for the controller.