Abstract: A pulse detection circuit, a method of operation and a fan assembly test circuit employing the same. In one embodiment, the pulse detection circuit includes a charge pump that receives an input signal and varies a charge in a charge storage device based on the input signal. The pulse detection circuit further includes a level detector, coupled to the charge pump, that compares a voltage across the charge storage device with first and second reference voltages, and a signaling circuit, coupled to the level detector, that generates an output signal based on the comparison and indicating an existence of the pulse. The pulse detection circuit may be a part of a fan assembly test circuit adapted to receive an input signal from a cooling fan under test.

Abstract: For use with a power supply having first and second circuit protection devices, a detection circuit, a method of monitoring the protection devices and a power supply employing the circuit or the method. In one embodiment, the detection circuit includes (1) a bridge circuit coupled to the first and second circuit protection devices, (2) a resistor parallel-coupled across one of the first and second circuit protection devices and (3) a sensing circuit, coupled to the bridge circuit and the resistor, that senses an imbalance in the bridge circuit and develops therefrom a failure signal when at least one of the first and second circuit protection devices becomes inoperable.

Abstract: For use with a DC fan, a detection circuit and a method of detecting an operational condition thereof. In one embodiment, the detection circuit includes: (1) a sensor, coupled to the DC fan, that senses a current through the sensorless DC fan and produces an intermediate signal based thereon and (2) an alarm circuit, coupled to the sensor, that compares the intermediate signal to a range defined by an upper limit signal and a lower limit signal and generates an alarm signal when the intermediate signal is outside of the range.

Abstract: A filter for an inrush relay, the relay having a relay coil having first and second leads includes a common-mode inductor connected to the relay coil leads across the relay coil. A first capacitor is connected to the first relay coil lead and a chassis ground potential. A second capacitor is connected to the second relay coil lead and the chassis ground potential. A third capacitor is connected to the relay coil leads across the relay coil. A first resistor is connected to the first relay lead, and a second resistor is connected to the second relay coil lead. The inductor and first and second capacitors form a high frequency common-mode filter. The third capacitor and first and second resistors form a high frequency differential mode filter.

Abstract: A temperature protection circuit, a method of protecting a power converter and a power converter employing the circuit or the method. In one embodiment, the circuit includes: (1) a temperature sensor, located in thermal communication with the power converter, that produces a signal based on a temperature associated with the power converter and (2) a current controller, coupled to the temperature sensor, that reduces an output current of the power converter to an intermediate level based on the signal.