Abstract: An alternating current-to-direct current (AC-to-DC) power supply has a first stage providing a first DC voltage and a second stage providing a second DC voltage. The AC-to-DC power supply has a first efficiency at the first stage and a second efficiency at the second stage that is less than the first efficiency. The second DC voltage is also less than the first DC voltage. A blower is electrically connected to the first stage of the AC-to-DC power supply to receive the first DC voltage from the AC-to-DC power supply to power the blower. Electrical connection of the blower to the first stage of the AC-to-DC power supply instead of to the second stage of the AC-to-DC power supply wastes less power and is more efficient.

Abstract: An alternating current-to-direct current (AC-to-DC) power supply has a first stage providing a first DC voltage and a second stage providing a second DC voltage. The AC-to-DC power supply has a first efficiency at the first stage and a second efficiency at the second stage that is less than the first efficiency. The second DC voltage is also less than the first DC voltage. A blower is electrically connected to the first stage of the AC-to-DC power supply to receive the first DC voltage from the AC-to-DC power supply to power the blower. Electrical connection of the blower to the first stage of the AC-to-DC power supply instead of to the second stage of the AC-to-DC power supply wastes less power and is more efficient.

Abstract: An apparatus, system, and method are disclosed for determining fan rotation direction. A first temperature detection module detects a first temperature at a first location between a fan and a heat generating device. The fan provides cooling for the heat generating device by drawing air from the heat generating device across the first location to the fan when the fan is rotating in a first direction. A second temperature detection module detects a second temperature at a second location where the heat generating device is between the second location and the fan such that heat from the heat generating device is drawn away from the second location when the fan is rotating in the first direction. A temperature comparison module determines if the second temperature is above the first temperature. A fan rotation error module generates a fan rotation error signal if the second temperature is above the first temperature.

Abstract: An apparatus, system, and method are disclosed for controlling fan speed. A power sensing module senses input voltage and current of a power supply. The power supply includes one or more stages and regulates at least one output bus. A power calculation module calculates input power from the input voltage and the input current. A temperature sensing module senses an ambient temperature and/or a temperature at a component cooled by a fan. A fan speed calculation module calculates a fan speed signal for the fan. The fan speed signal is a function of the input power calculated by the power calculation module and the sensed temperature sensed by the temperature sensing module for at least a portion of a fan speed range. A fan speed transmission module transmits the fan speed signal to the fan and adjusts a fan speed based on the fan speed signal.

Abstract: An apparatus, system, and method are disclosed for determining fan rotation direction. A first temperature detection module detects a first temperature at a first location between a fan and a heat generating device. The fan provides cooling for the heat generating device by drawing air from the heat generating device across the first location to the fan when the fan is rotating in a first direction. A second temperature detection module detects a second temperature at a second location where the heat generating device is between the second location and the fan such that heat from the heat generating device is drawn away from the second location when the fan is rotating in the first direction. A temperature comparison module determines if the second temperature is above the first temperature. A fan rotation error module generates a fan rotation error signal if the second temperature is above the first temperature.

Abstract: An apparatus, system, and method are disclosed for controlling fan speed. A power sensing module senses input voltage and current of a power supply. The power supply includes one or more stages and regulates at least one output bus. A power calculation module calculates input power from the input voltage and the input current. A temperature sensing module senses an ambient temperature and/or a temperature at a component cooled by a fan. A fan speed calculation module calculates a fan speed signal for the fan. The fan speed signal is a function of the input power calculated by the power calculation module and the sensed temperature sensed by the temperature sensing module for at least a portion of a fan speed range. A fan speed transmission module transmits the fan speed signal to the fan and adjusts a fan speed based on the fan speed signal.