SWITCHING MODE POWER SUPPLY UNIT AND METHOD FOR MEASURING POWER SUPPLY VOLTAGE OF THE SAME

摘要

PURPOSE: A switching mode power supply unit and a method for measuring power supply voltage of the same are provided to evaluate a current passing the first coil and a time lapse of a current measure signal by using an output terminal generating a signal under a control of power supply voltage. CONSTITUTION: A switch permits a clock control of variable power supply voltage(V) to the first coil(L1) of a transformer. The first current measure unit(MA;R1) generates a current(IL) of a current measure signal(VS) influenced by the first coil(L1). An evaluation circuit(AWS) is connected with the first current measure unit(MA;R1) and evaluates the current(IL) and a time lapse of the current measure signal(VS). A current measure unit(R1) measures the current(IL) flowing through the fitst coil(L1).