Power supply controller having reduced acoustic noise and method of reducing acoustic noise

A power supply controller for use in a power supply circuit to reduce an acoustic noise of a multi-layer ceramic capacitor (MLCC), wherein the power supply control circuit is configured to operably generate a control signal according to a voltage identification (VID) signal and a voltage sensing signal, to control a power switch in a power stage circuit for converting an input voltage to an output voltage, and wherein the power supply control circuit is configured to operably adjust the output voltage from a present level to a requested level, wherein the MLCC is coupled to the output voltage;

• the power supply controller comprising:
• a conversion circuit including:
• a digital-to-analog converter, which is configured to operably generate an analog voltage identification (AVID) signal according to the VID signal;
• and
• a slope control circuit coupled to the digital-to-analog converter, wherein under a situation where the power supply controller operates in an acoustic noise reduction mode and under a situation where the present level is higher than the requested level, the slope control circuit is configured to operably adjust a descending slope of the analog voltage identification signal, so as to generate an adjusted AVID signal, wherein the adjusted AVID signal is configured to operably restrain a decrease velocity of the output voltage to be higher than zero but not higher than a predetermined velocity;
• and
• a pulse width modulation (PWM) control circuit coupled to the conversion circuit, wherein the PWM control circuit is configured to operably generate the control signal according to the adjusted AVID signal and the voltage sensing signal.