PWM converting circuit, D/A converter and PWM converting method with improved resolution

摘要

A PWM converting circuit includes a pulse generator for generating two pulse signals for each bit of a basic clock pulse train in response to the value of digital input data, and a differential amplifier for outputting a differential amplification component between the two pulse signals as a PWM signal. The pulse generator varies a pulse width of one of the two pulse signals on a bit-by-bit basis of the basic clock pulse train in response to the value of the digital input data, and holds a level of the other of the two pulse signals throughout the entire bits of the basic clock pulse train within the period of the pulse of the PWM signal.