Circuit and method for modulating pulse width

Abstract

Signal C=[Cn−1, Cn−2, . . . , C1, C0] generated by a ring counter 1 is converted at a logic circuit 2 to a triangle pulse signal Q in which the carrier frequency of the PWM signal is equal to the frequency of the signal C raised to power of 2. The signal Q is input to the B input of a magnitude comparator 3. On the other hand, the modulation data D held by a data holding circuit 4 is compared with the converted signal Q in the magnitude comparator 3, and when the data D is greater than the signal Q, a PWM signal is obtained from the comparison result A>B. This PWM signal has no phase change and high resolution and is a low pulsating component. The resolution of the PWM signal per cycle of the ring counter 1 is held at n bits, and the carrier frequency is equal to the ring counter frequency raised to mth power of 2.

Dependencies are inferred from the claim text.