| 摘要 |
A DC-DC converter, wherein: a comparison is made between the voltage (Vd) of the connection point (A) at the connection of a switching transistor with an inductor, and the threshold voltage (Vth) that is set within the range of fluctuation of the voltage (Vd) of the connection point (A) during the switching operation of the switching transistor; and when the polarity obtained by comparing the voltage (Vd) and the threshold voltage (Vth) does not vary during a detection period (Td) that is longer than a prescribed period of a drive circuit, it is determined that the switching transistor is operating in an active state in which there is risk of heating. |
