| 摘要 |
The present invention is to reduce the possibility that a DC-DC converter stops in the case where supply power is small and load current is large. Output terminals use a DC output voltage of a DC-DC converter so that an external battery can be charged or power can be supplied to a power-reception-side system on the outside, and a current limiting circuit limits load current of a power supply switch transistor flowing from a converter output terminal to the output terminals. An input voltage detecting circuit detects level of a DC input voltage of an input terminal, generates a detection signal, and supplies the detection signal to the current limiting circuit. In the case where the DC input voltage of the input terminal is at the low level, the current limiting circuit controls the maximum current by current limitation of the power supply switch transistor to a small current. |
