| 摘要 |
<p>PROBLEM TO BE SOLVED: To stop output of an output voltage at the time of overload, with a small configuration, without increasing a circuit scale and a member of a power source device.SOLUTION: A power source device includes an inductor Ls, an FET1 which controls an output voltage that is outputted through the inductor Ls, a comparator Cmp 1 which controls the FET1 on the basis of a result of comparison between a voltage corresponding to the output voltage and a reference voltage, a transistor Tr 1 which, when a current that flows the FET1 exceeds a predetermined value, inputs a voltage which is superposed with an input voltage Vin into the comparator Cmp 1, for overload protection, a transistor Tr 2 which, when an output current Iout comes to be a predetermined current value or larger, inputs the voltage superposed with the input voltage Vin on an input side by the transistor Tr 1 into the comparator Cmp 1, and a detection circuit for detecting frequency of the FET1. The detection circuit, when detects that the frequency of the FET1 is a predetermined frequency or higher, makes the transistor Tr 2 stop outputting of the output voltage Vout.</p> |
