VARIABLE FREQUENCY CLOCK OUTPUT CIRCUIT AND APPARATUS, MOTOR DRIVING APPARATUS, AND IMAGE FORMING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a highly versatile variable frequency clock circuit or the like, which can perform acceleration/deceleration at different acceleration speeds up to various target frequencies, in a relatively simple constitution. SOLUTION: A variable frequency clock output circuit, comprising: a target value register 131 which stores a target value T corresponding to an arbitrarily set target frequency; an increase/decrease value register 132 which stores an arbitrarily set increase/decrease value S; an adder-subtractor 133 which has an input portion into which a current output value is input and outputs a calculation result obtained by adding/subtracting the increase/decrease value S stored in the increase/decrease value register to/from the current output value input into the input portion based on an addition/subtraction instruction signal; a comparator 136 which compares an output value of the adder-subtractor with the target value stored in the target value register, and outputs an addition/subtraction instruction signal to the adder-subtractor until the output value of the adder-subtractor and the target value coincide; and a clock generator 14 which outputs a clock signal having a frequency proportional to the output value of the adder-subtractor. COPYRIGHT: (C)2008,JPO&INPIT