20110096571 | SWITCHING POWER SUPPLY UNIT - A control function formula which provides a relationship between an output voltage signal Vo and an output differential value with, for example, a negative linear function is defined in a calculation means. The calculation means samples an input voltage signal, an output voltage signal and an output differential signal at time instants in synchronization with a cycle of switching of a main switching element, and calculates subsequent ON and OFF durations of the main switching elements such that the control function formula might be satisfied. A drive pulse generation means generates a drive pulse with which the main switching element is turned on and off based on the ON and OFF durations determined by the calculation means. The output differential signal is generated by, for example, a capacitor current detection means or an observer device which detect a current of a smoothing capacitor. | 04-28-2011 |