PWM SIGNAL OUTPUT CIRCUIT

摘要

PURPOSE: A PWM(Pulse Width Modulation) signal output circuit is provided to improve torque efficiency by suppressing the sudden change of a current flowing in a motor. CONSTITUTION: An up counter(40) is reset when a motor driving IC starts. A control circuit(41) outputs a count value since a motor rotates. A PWM signal generating circuit(42) generates a PWM signal. A duty detection circuit(43) detects the PWM signal of a duty ratio of 100%. A selector(45) outputs the PWM signal of a duty ratio of 99% or less. [Reference numerals] (21) Driving signal output circuit; (40) Up counter; (41) Control circuit; (42) PWM signal generating circuit(100%); (43) Duty detection circuit; (44) PWM signal generating circuit(90%); (46) Duty ratio change circuit; (47) H-bridge control circuit