Pulse amplitude modulation (PAM) method and circuit for improving the performance of a D-class audio amplifier

A PAM (Pulse Amplitude Modulation) method for improving the performance of a D-class audio amplifier, the D-class audio amplifier is inputted with a PWM signal and designed to have a dead time design for time-delay function, in order to decrease the distortion of an output signal caused by the dead time design, the method comprising the following steps:

• connecting a resistor and a loudspeaker in series to an output terminal of the D-class audio amplifier, and designing a decision circuit to determine the polarity of the current flowing through the resistor;
• adding a voltage adjustment circuit to a power source of the D-class audio amplifier to lower the voltage of the power source of the D-class audio amplifier from high voltage to low voltage during dead time when the current of the resistor is negative;
• adding a voltage compensation circuit to a low voltage point of the D-class audio amplifier to compensate the voltage of the low voltage point of the D-class audio amplifier for ascending the voltage of the low voltage point from low voltage to high voltage during the dead time when the current of the resistor is positive.