Digital to analog converter circuit and digital to analog conversion method

A Digital to Analog Converter (DAC) circuit, configured to operably convert a digital signal to an analog output signal, wherein the digital signal is an input signal to the DAC circuit or a modulated signal generated from the input signal, the digital signal representing a number in a numerical range, the DAC circuit comprising:

• a Pulse Width Modulation (PWM) encoding circuit, configured to operably convert the digital signal to a first PWM signal and a second PWM signal, whereby a combination of the first PWM signal and the second PWM signal becomes a PWM encoded signal of at least 3 levels including a positive, a zero and a negative level, wherein in one PWM cycle period, the first PWM signal includes a first predetermined number of rising edges and falling edges, and the second PWM signal includes a second predetermined number of rising edges and falling edges, wherein when the digital signal represents a middle number in the numerical range, the first PWM signal has a minimum duty larger than 0 and the second PWM signal has a minimum duty larger than 0;
• and
• a demodulation circuit, configured to operably generate the analog output signal according to the first and the second PWM signals,
• wherein the zero level of the PWM encoded signal has a duty which decreases as an absolute difference between the number represented by the digital signal and the middle number increases.