Patent ID: 7746243

Claim:
A pump failure alarm device, comprising: two digital-analog converting circuits configured for receiving digital pulse signals respectively from two pumps, and respectively outputting a direct current (DC) voltage signal at an output terminal when the pumps run normally, wherein each digital-analog converting circuit comprises a resistor and a capacitor, one terminal of each of the resistors is coupled to a corresponding pump, the other terminal of each of the resistors acting as the output terminal of each digital-analog converting circuits coupled to one terminal of a corresponding capacitor, another terminal of each of the capacitors is coupled to ground; a voltage sampling circuit with two input terminals respectively coupled to the output terminals of the two digital-analog converting circuits, and outputting a first voltage signal when the two pumps run normally and outputting a second voltage signal when either or both of the pumps stop running; a controlling circuit configured for receiving the voltage signals from the voltage sampling circuit, and outputting a first control signal when it receives the first voltage signal and outputting a second control signal when it receives the second voltage signal; an input-output (I/O) controller with an input terminal receiving the control signals from the controlling circuit, and outputting an alarm signal at an output terminal when it receives the second control signal; and an alarm circuit configured for receiving the alarm signal from the I/O controller, and activating an alarm.