Integrated circuit for class-d audio amplifier and associated control method

An integrated circuit (IC) for a class-D audio amplifier, comprising:

• a first pin configured to receive a first pulse modulated signal;
• a second pin configured to receive a second pulse modulated signal;
• a third pin configured to provide a first output voltage via amplifying the first pulse modulated signal, wherein the third pin is configured be coupled to a first end of a load via a first output filter;
• a fourth pin configured to provide a second output voltage via amplifying the second pulse modulated signal, wherein the fourth pin is configured be coupled to a second end of the load via a second output filter;
• a first power stage comprising a first high-side power switch and a first low-side power switch coupled in series between a first power supply voltage and a second power supply voltage, wherein the first high-side power switch is coupled to the first low-side power switch to form a first output node, and the first output node is coupled to the third pin;
• a second power stage comprising a second high-side power switch and a second low-side power switch coupled in series between the first power supply voltage and the second power supply voltage, wherein the second high-side power switch is coupled to the second low-side power switch to form a second output node, and the second output node is coupled to the fourth pin;
• and
• a controller coupled to the first pin to receive the first pulse modulated signal and coupled to the second pin to receive the second pulse modulated signal, and configured to provide a first and a second switching control signals based on the first pulse modulated signal, and provide a third and fourth switching control signals based on the second pulse modulated signal, wherein the first and second switching control signals are configured to turn on the first high-side power switch and the first low-side power switch alternately, the third and fourth switching control signals are configured to turn on the second high-side power switch and the second low-side power switch alternately;
• wherein
• the controller is configured to adjust a first time interval between turning off the first low-side power switch and turning on the first high-side power switch and adjust a second time interval between turning off the first high-side power switch and turning on the first low-side power switch in response to a first output current flowing through the third pin, and the controller is configured to adjust a third time interval between turning off the second low-side power switch and turning on the second high-side power switch and adjust a fourth time interval between turning off the second high-side power switch and turning on the second low-side power switch in response to a second output current flowing through the fourth pin.

A control method of a class-D audio amplifier, comprising:

• receiving a pulse modulated signal which is converted from an audio signal;
• providing a first switching control signal and a second switching control signal based on the pulse modulated signal to control a high-side power switch and a low-side power switch respectively;
• providing an output voltage at an output node formed by the high-side power switch and the low-side power switch;
• connecting the output node to a first power supply voltage during when the high-side power switch is turned on and the low-side power switch is turned off, and connecting the output node to a second power supply voltage during when the low-side power switch is turned on and the high-side power switch is turned off;
• and
• in response to a rising transition of the output voltage from the second power supply voltage to the first power supply voltage, adjusting a first time interval between turning off the low-side power switch and turning on the high-side power switch based on to an output current flowing through the output node;
• and
• in response to a falling transition of the output voltage from the first power supply voltage to the second power supply voltage, adjusting a second time interval between turning off the high-side power switch and turning on the low-side power switch based on the output current.