PWM CONTROL SYSTEM

摘要

PROBLEM TO BE SOLVED: To prevent a transistor for switch from being broken by the overcurrent by preventing a PWM from turning on the transistor for switch for a long time, in the PWM control of the power supply voltage. SOLUTION: A transistor 12 for switch is prevented from being broken by the overcurrent by performing a soft start when the power supply is started and when a switch for the PWM output is turned on, and the transistor 12 for switch is prevented from being broken by the overcurrent by connecting a limiter 26 to an oscillation circuit 2 so that the pulse width of the PWM output does not exceed a specified fixed value.