Abstract: An electronic device includes electronic components, including: a power switching unit to output a power switching signal; a first power input unit to receive first power from one of a plurality of external power devices; a second power input unit to receive second power from one of the external power devices; a power converting unit to convert the first power received through the first power input unit into driving power having a voltage level to drive each electronic component, and to supply the driving power to each electronic component; and a power management unit to control the power converting unit to be enabled when the second power is input through the second power input unit, and control whether the power converting unit is enabled corresponding to the power switching signal from the power switching unit, when the second power is not input through the second power input unit.

Abstract: A control circuit for a cooling fan is provided that adjusts input power and drive a cooling fan. The control circuit comprises a temperature detector for detecting temperature; a power controller for controlling driving power to the cooling fan based on the input power and supplying the driving power; a proportional electric power block supplying control power proportional to temperature variation of the detected; and a fixed electric power block supplying control power at a fixed level when the detected temperature is lower than a predetermined level. The control circuit for a cooling fan is configured to detect temperature variation and to operate with less noise by controlling rotational velocity of the cooling fan in proportion to variation in temperature variation to reduce noise generated when operating the cooling fan.

Abstract: An electronic device includes electronic components, including: a power switching unit to output a power switching signal; a first power input unit to receive first power from one of a plurality of external power devices; a second power input unit to receive second power from one of the external power devices; a power converting unit to convert the first power received through the first power input unit into driving power having a voltage level to drive each electronic component, and to supply the driving power to each electronic component; and a power management unit to control the power converting unit to be enabled when the second power is input through the second power input unit, and control whether the power converting unit is enabled corresponding to the power switching signal from the power switching unit, when the second power is not input through the second power input unit.

Abstract: A control circuit for a cooling fan is provided that adjusts input power and drive a cooling fan. The control circuit comprises a temperature detector for detecting temperature; a power controller for controlling driving power to the cooling fan based on the input power and supplying the driving power; a proportional electric power block supplying control power proportional to temperature variation of the detected; and a fixed electric power block supplying control power at a fixed level when the detected temperature is lower than a predetermined level. The control circuit for a cooling fan is configured to detect temperature variation and to operate with less noise by controlling rotational velocity of the cooling fan in proportion to variation in temperature variation to reduce noise generated when operating the cooling fan.