Patent ID: 8190005

Claim:
A motor driving circuit that receives an error signal having a digital value, which indicates a deviation between a current driving state of a motor to be driven and its target driving state, so as to drive the motor, comprising: a pulse modulator that generates a pulse signal, having a duty ratio in accordance with the error signal, by utilizing an input clock signal; and a switching circuit that controls the energization state of the motor on the basis of the pulse signal output from the pulse modulator, wherein the pulse modulator generates the pulse signal as a set of k (k is an integer of 2 or more) continuous sub-pulses, and determines the average value of the duty ratios of k sub-pulses on the basis of the error signal, wherein the pulse modulator generates k sub-pulses in such a manner that the average value of the duty ratios of the sub-pulses becomes approximately a/2 n , when the bit number of the error signal is n (n is a natural number) and the magnitude of the error signal is a (a is an integer) in decimal notation.