| 摘要 |
PROBLEM TO BE SOLVED: To prevent an increase in an output voltage at a high input and light load, and to prevent a malfunction of a main switching element due to noise in a power supply device. SOLUTION: An output voltage detector detects the output voltage. A trapezoidal wave generation means uses a ground level as a reference, has a width corresponding to an on-width of the main switching element, and generates a trapezoidal wave which can prevent a malfunction due to a variation factor such as a variation or the like of an element characteristic. Then, a comparator compares a voltage of an output signal of the output voltage detector with a voltage of the generated trapezoidal wave, and outputs a signal when a difference between the voltages reaches a preset value. A drive means turns off the main switching element according to the signal from the comparator. COPYRIGHT: (C)2011,JPO&INPIT |
