SEMICONDUCTOR DEVICE AND SWITCHING POWER UNIT THEREWITH

摘要

PROBLEM TO BE SOLVED: To improve power efficiency and facilitate producing into semiconductor integrated chipping by reducing the consuming power of a switching element at light load times. SOLUTION: This semiconductor device includes the switching element 5 and a control circuit 4 for controlling the switching operation of the switching element, where the control circuit comprises a voltage conversion element 18 of which voltage changes with the power voltage of the control circuit, a light- load state detecting circuit 40 for determining the condition as a light load condition, if the voltage Va of the voltage conversion element is reference voltage Va0 or higher, and a 0 switching operation control circuit 41 for controlling the operation of the switching element.