Patent ID: 7639152
Filing Date: 2009-12-29
Classification: G06F

Abstract:
1. A fan failure alarm device comprising: a first digital-analog converting circuit configured for receiving a digital pulse signal from a first fan, and outputting a direct current (DC) voltage signal at an output terminal; a first diode with a cathode coupled to the output terminal of the first digital-analog converting circuit, the first diode turning on when the first fan stops rotating; a switching circuit with an input terminal coupled to an anode of the first diode, and outputting a first control signal when the fan rotates normally and outputting a second control signal when the fan stops rotating; an input-output (I/O) controller with an input terminal receiving the first and second control signals from the switching circuit, and an output terminal outputting an alarm signal when receives the second control signal; and an alarm circuit configured for receiving the alarm signal from the I/O controller, and activating an alarm to indicate a failure of the fan.