| 摘要 |
PROBLEM TO BE SOLVED: To reduce power consumption of a communication unit which relays radio communication between a radio hot water supplier and a remote control. SOLUTION: In a communication unit 2 which layers the radio communication between the main-body equipment 1 of a radio hot water supplier and a remote control 2, a power supply monitoring section 8 which monitors the voltage at the power line 4 from the equipment 1 to the unit 3 is composed of a voltage detecting IC 10 and a pull-up resistor 11 for open drain output. When a power supply section 7 supplies electric power to a radio communication section 5 and a microcomputer 6 from the power line 4, the monitoring section 8 discriminates whether or not the voltage at the line 4 is sufficient to the power supply section 7 based on the voltage detected by means of the IC 10 and outputs a signal to the microcomputer 6 through an interface section 9. Therefore, the power consumption of the monitoring section 8 can be reduced by low current consumption and high-input impedance of the IC 10. |
