Patent ID: 7067941

Claim:
A controller for generating a control signal for driving an electrical load, comprising: a signal generator for repeatedly generating and outputting pulse-width-modulated signals based on drive data representing signal hold times at respective first and second levels per signal cycle; a calculator for calculating said drive data at a predetermined calculation cycle and storing said drive data in a data storage device; a clock for repeatedly clocking a half-cycle time of said pulse-width-modulated signal asynchronously from said calculation cycle of said calculator; period establishing means for, at first and second determination periods, establishing respective clock periods which are said half-cycle times clocked by said clock in an alternating manner; drive-data acquiring means for acquiring drive data from said data storage device at each clocking start of said half-cycle time by said clock; and signal level determining means for determining, when a clock period of said clock has been established by said period-determining means at said first determining period and based on drive data acquired by said drive-data acquiring means, whether said clock time according to said clock has reached a second time which is half of a time at which said signal per pulse-width-modulated signal cycle is to be held at a second level, and when determined to have reached said second time, to establish a signal level of said pulse-width-modulated signal at a first level, and to determine, when a clock period of said clock has been established by said period-determining means at said second determining period and based on drive data acquired by said drive-data acquiring means, whether said clock time according to said clock has reached a first time which is half of a time at which said signal per pulse-width-modulated signal cycle is to be held at a first level, and when determined to have reached said first time, to establish a signal level of said pulse-width-modulated signal at a second level; said signal generator for outputting a pulse-width-modulated signal at a signal level established by said signal-level determining means.