| 摘要 |
PROBLEM TO BE SOLVED: To suppress the power consumption in a power source monitoring device for monitoring the voltage of cable power supply in data communication by an interface capable of supplying power with a communication cable. SOLUTION: A power source monitoring part 11a for monitoring the cable power supply of an interface is provided with a CPS terminal 21 for inputting a cable power supply voltage, a resistor R2 connected between the CPS terminal 21 and the ground, a comparator 15 for comparing the voltage inputted from the CPS terminal 21 with a a reference voltage Vref, a PS register 13 for storing the output of the comparator 15, and a sleep terminal 23 for inputting the sleep signal for controlling the power source monitoring part 11a into sleep state to stop the operation. When the sleep signal is active (in the sleep state), the output of the PS register 13 is fixed at a prescribed value regardless of a voltage inputted to the CPS terminal 21. |
