Abstract: An electronic device operable from one of an external power supply and a battery. The electronic device includes a display part, a power converter, an inverter generating an operating voltage for the display part, a system part generating information to be displayed on the display part and operable from an output of the power converter, a battery, an input power detector, and a switching controller. The switching controller controls power to the inverter so that where the input power detector detects availability of an external power, the switching controller supplies the external power to the power converter and the power converter supplies power to the inverter to generate the operating voltage for the display part; and where the input power detector detects the external power is not available, the switching system supplies battery power to the power converter and the inverter independently.

Abstract: A computer includes a system unit which has a plurality of electronic components, a battery unit which supplies auxiliary electric power to the system unit, an adapter which receives a first alternating current (AC) electric power and outputs a second AC electric power; a rectifying unit which rectifies the second AC electric power and supplies a direct current (DC) electric power having a level higher than a minimum electric power level required to operate the system unit and lower than a charging electric power level required to charge the battery unit, to the system unit, a battery charging unit which charges the battery unit, and an electric power amplifying unit which amplifies the DC electric power that branches off from a point of an electric power supplying path between the rectifying unit and the system unit, and supplies a charging electric power to the battery charging unit.

Abstract: A synchronous buck DC/DC converter to perform an improved switching operation by adjusting a variable resistor is provided. The synchronous buck DC/DC converter includes a switching unit for switching two PWM signals inverted with a dead time and outputting the PWM signals, a smoothing circuit for outputting DC power using a waveform output from the switching unit as an input, a variable resistor connected to the switching unit and adjusting a switching time of the waveform output from the switching unit, and a variable resistor controller for sensing a current from an output terminal of the smoothing circuit and setting the resistance of the variable resistor to a resistance corresponding to the sensed current.

Abstract: A DC-DC converter to convert DC power input from an external source into a predetermined DC power required for an electric load. A switch part in which each of a pair of switches that cuts or supplies the input DC power is connected in parallel with at least one other switch. A current sensor senses a load current flowing through the electric load and a controller controls the switch part to enable a number of the switches according to an intensity of the load current sensed by the current sensor. The enabled switches are driven by a PWM signal to cut or supply the input DC power to the load. By changing the number of enabled switches, unnecessary switching is prevented for lower load currents.

Abstract: A power supply device comprises: a battery; a charging part charging the battery; a power input to receive one of adapter power from an adapter supplied with external power, or power output from a similarly configured power supply device; a power output part to output one of the adapter power, the power output of a similarly configured power supply device, or the battery power of the battery; and a controller to control the input power to apply power to the charging part and the power output part when the input power is supplied to the power input part, and to control the battery to apply power to the power output part when the input power is not supplied to the power input part. Thus, the present invention provides a power supply device, which is capable of applying power from an adapter to a portable electronic device while charging an internal battery with the adapter power, and a power supplying method for the power supply device.

Abstract: A power supplying apparatus to supply DC power for driving an electronic device, and an electronic device using the same that includes an AC/DC converter which converts input AC power into the DC power; and an AC switch which switches the AC power input to the AC/DC converter, based on a switching signal supplied from the electronic device. Thus, the power supplying apparatus receives information on an operation state of the electronic device from the electronic device to control an input of AC (alternating current) power according to the operation state of the electronic device.

Abstract: An electronic device operable from one of an external power supply and a battery. The electronic device includes a display part, a power converter, an inverter generating an operating voltage for the display part, a system part generating information to be displayed on the display part and operable from an output of the power converter, a battery, an input power detector, and a switching controller. The switching controller controls power to the inverter so that where the input power detector detects availability of an external power, the switching controller supplies the external power to the power converter and the power converter supplies power to the inverter to generate the operating voltage for the display part; and where the input power detector detects the external power is not available, the switching system supplies battery power to the power converter and the inverter independently.

Abstract: A synchronous buck DC/DC converter to perform an improved switching operation by adjusting a variable resistor is provided. The synchronous buck DC/DC converter includes a switching unit for switching two PWM signals inverted with a dead time and outputting the PWM signals, a smoothing circuit for outputting DC power using a waveform output from the switching unit as an input, a variable resistor connected to the switching unit and adjusting a switching time of the waveform output from the switching unit, and a variable resistor controller for sensing a current from an output terminal of the smoothing circuit and setting the resistance of the variable resistor to a resistance corresponding to the sensed current.

Abstract: An electronic device operable from one of a battery and a converter and having a plurality of electronic components. A battery supplies electric power having a predetermined voltage level range. An adapter supplies electric power having a voltage level included within the voltage level range of the electric power output from the battery. A converter converts the voltage level of electric power from either the battery or the adapter to have a voltage level adequate to drive the electronic components, thereby decreasing generation of internal heat improving conversion efficiency of the DC/DC converter, and increasing a running time of the battery.