| 摘要 |
PROBLEM TO BE SOLVED: To control an electricity by digital PWM of a high resolving power without increasing ripples with an equal count clock by setting a plurality (integral multiple) of PWM periods defined as an integral multiple of a reference clock to be a PWM control cycle. SOLUTION: 256 counts of reference clocks 1 are set as a PWM repeat period, and 16 periods is set as one PWM control period. An on time of an electric switch 6 is controlled under a condition regulated by a PWM count data 3, thereby controlling an electricity to be supplied to a motor 7 by digital PWM. At this time, the 12-bit PWM count data 3 is separated to a basic count data of upper 8 bits and an additional count data of lower 4 bits. The basic count data is used as the number of basic counts in forming an on signal for the switch 6 by a counter 4, and the additional count data serves to judge the presence/absence of additional counts by an additional count detector 11.
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