| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a PWM control device which is used for a switching power supply circuit, is capable of freely determining a switching frequency, and is capable of spreading the frequency on a predetermined frequency band evenly. <P>SOLUTION: A PWM control device outputs a PWM signal for switching input DC power while changing the power within a range of a predetermined frequency based on a reference frequency. The PWM control device has a configuration comprising: frequency determination means (1) for determining the reference frequency on the basis of an output current value detected by a current detector 4; frequency changing means (1) for changing a frequency of the PWM signal within the range of the predetermined frequency based on the determined reference frequency; means 5 for detecting a voltage value input to a switching power supply circuit; calculation means (1) for calculating a duty ratio of the PWM signal on the basis of the detected input voltage value and a target voltage value; means 8 for detecting an output voltage value of the switching power supply circuit; and correction means (1) for correcting the duty ratio on the basis of calculated difference between the detected output voltage value and the target voltage value. <P>COPYRIGHT: (C)2013,JPO&INPIT |
