SWITCHING POWER SUPPLY DEVICE

摘要

In the present invention, a control circuit (24) has a calculation means (28) that decides the ON time and OFF time for a primary switching element (14) and a drive pulse generation means (30) that generates drive pulses that turn the primary switching element (14) ON and OFF. A control function formula that prescribes the relationship between an output voltage (Vo) and an output differential value by a negative linear function or such is defined in the calculation means (28). The calculation means (28) samples an input voltage signal (Vi) and an output voltage signal (Vo) at a timing interval synchronized to the switching cycle of the primary switching element (14), and calculates the ON time and OFF time of the primary switching element (14) thereafter so as to satisfy the control function formula. The drive pulse generation means (30) generates drive pulses (V14) that turn the primary switching element (14) ON and OFF, on the basis of the ON and OFF times determined by the calculation means (28).