Abstract: A scanning apparatus having a cold cathode fluorescent lamp includes a central processing unit (CPU) controlling a scan unit to be in one of the stand-by mode, a scan mode and a sleep mode and outputting a PWM signal having a variable duty ratio based on an operation mode of the scan unit; a filter unit receiving the PWM signal from the CPU, filtering the PWM signal, and outputting the filtered signal; a feedback unit detecting the voltage applied to the fluorescent lamp and outputting a feedback signal; a controlling unit controlling the illumination of the fluorescent lamp based on the voltage input from the feedback unit, the controlling unit outputting a control signal variably controlling the voltage applied to the fluorescent lamp depending on the filtered signal; and a lamp drive unit applying variable AC voltage to the fluorescent lamp based on the control signal, thereby driving the fluorescent lamp.

Abstract: A power supplying apparatus having a power saving function and a method of supplying power with a power saving function. An auxiliary power generator generates auxiliary power in response to a cutoff signal. A main power generator senses the generation of the auxiliary power and generates main power in response to the sensed result and a first state of a control signal supplied by a set which performs an intrinsic function. Absent the power cutoff signal, the set performs the intrinsic function in response to the main power and stands by to perform the intrinsic function in response to the auxiliary power. A second state of the control signal places the power supplying apparatus in a power saving mode during which the set may communicate with another circuit. If the cutoff signal is supplied during performance of the intrinsic function, main power is sustained until the intrinsic function is completed.

Abstract: An apparatus for and a method of controlling a power supply for a printer. A power on signal is automatically provided to turn on the printer power supply in accordance with a predetermined printing command, and a power off signal to turn off the printer power supply is automatically provided when the printer has not performed a printing operation for a predetermined time period. A low voltage and current switch is provided for manual on/off control of the printer power supply in accordance with an operation of a user. If the printer power supply in off, operation of the switch generates the power on signal. If the printer power supply is on, operation of the switch causes the controller to generate the power off signal to turn off the printer power supply.

Abstract: A voltage converting method and a voltage converting apparatus using a large electrolytic condenser are provided. In the method according to an embodiment of the invention, when the level of an input alternating voltage is equal to or greater than a first predetermined level and smaller than a second predetermined level that is smaller than the first predetermined level, the input alternating voltage is rectified to produce an output direct voltage. When the level of the input alternating voltage is equal to or greater than the second predetermined level, the rectification of the input alternating voltage is stopped. Thereafter, if the provision of the input alternating voltage is stopped and then resumed, the production of the output direct voltage is resumed.

Abstract: A power supply for a portable printer, including an apparatus generating a main driving voltage and a driving voltage for driving a portable printer using the external alternating current voltage if an external alternating current voltage is applied, and which generates a main driving voltage and a driving voltage for driving the portable printer using an internal battery in the portable printer if no external alternating current voltage is applied. The power supply includes the reference DC voltage being lower than the first voltage. By lowering the reference DC voltage of the power supply, it is possible to substitute various circuit devices included in the power supply with low-cost components, thereby reducing a cost of the power supply.

Abstract: A power supply for image-forming apparatuses having a power management function. The power supply comprises a power supply unit for rectifying and converting AC power into DC power, and then applying the DC power to at least one or more function modules comprising the image-forming apparatus. A switching unit is provided between an output terminal of the power supply unit and an input terminal of each of the function modules, and a control unit is provided for turning on and off the switching unit when the image-forming apparatus enters a power management mode. A power-saving switch is also provided for applying a signal to the control unit for selectively setting the power management mode. Such a power supply enables users to effectively manage power consumption by preventing voltage application to the function modules when no longer required or safe to do so.

Abstract: A scanning apparatus having a cold cathode fluorescent lamp includes a central processing unit (CPU) controlling a scan unit to be in one of the stand-by mode, a scan mode and a sleep mode and outputting a PWM signal having a variable duty ratio based on an operation mode of the scan unit; a filter unit receiving the PWM signal from the CPU, filtering the PWM signal, and outputting the filtered signal; a feedback unit detecting the voltage applied to the fluorescent lamp and outputting a feedback signal; a controlling unit controlling the illumination of the fluorescent lamp based on the voltage input from the feedback unit, the controlling unit outputting a control signal variably controlling the voltage applied to the fluorescent lamp depending on the filtered signal; and a lamp drive unit applying variable AC voltage to the fluorescent lamp based on the control signal, thereby driving the fluorescent lamp.

Abstract: A voltage converting method and a voltage converting apparatus using a large electrolytic condenser are provided. In the method according to an embodiment of the invention, when the level of an input alternating voltage is equal to or greater than a first predetermined level and smaller than a second predetermined level that is smaller than the first predetermined level, the input alternating voltage is rectified to produce an output direct voltage. When the level of the input alternating voltage is equal to or greater than the second predetermined level, the rectification of the input alternating voltage is stopped. Thereafter, if the provision of the input alternating voltage is stopped and then resumed, the production of the output direct voltage is resumed.

Abstract: A method and apparatus for controlling a power supply, having a power switching unit, in an electronic machine using a host connected to the electronic machine. Received alternating current (AC) power is transmitted to the power switching unit and simultaneously transformed into direct current (DC) power. Next, it is determined whether the host requests provision of the DC power to the electronic machine. Then, the power switching unit is driven using the AC power when it is determined that provision of the DC power to the electronic machine is requested. Thus, even when a power switching unit is not supplied with power immediately after interruption of power from an AC power supply source, charges stored in an electrolytic capacitor are not discharged so that incorrect operation of the electronic machine is prevented.

Abstract: An apparatus for and a method of controlling a power supply for a printer. A power on signal is automatically provided to turn on the printer power supply in accordance with a predetermined printing command, and a power off signal to turn off the printer power supply is automatically provided when the printer has not performed a printing operation for a predetermined time period. A low voltage and current switch is provided for manual on/off control of the printer power supply in accordance with an operation of a user. If the printer power supply in off, operation of the switch generates the power on signal. If the printer power supply is on, operation of the switch causes the controller to generate the power off signal to turn off the printer power supply.

Abstract: An apparatus controlling a cold cathode fluorescent lamp and a scanning apparatus having the same are disclosed.

Abstract: An apparatus for controlling power and reducing power consumption in a system including a switching mode power supply. (SMPS), and a method thereof. The apparatus includes a switch that is set to an ON state when a user contacts the switch, a detection portion connected in parallel with the switch and detecting whether a signal for requiring a predetermined operation is applied to the system from outside, and a power supply portion supplying the power to each part in a system when the switch is set to the ON state or the signal is input from the detection portion. The power supply portion terminates the power to each part in the system including the system controller when a power off signal is applied from the system controller when the switch is set to an OFF state and when signal is not input from the detection portion.

Abstract: A power supplying apparatus having a power saving function and a method of supplying power with a power saving function. An auxiliary power generator generates auxiliary power in response to a cutoff signal. A main power generator senses the generation of the auxiliary power and generates main power in response to the sensed result and a first state of a control signal supplied by a set which performs an intrinsic function. Absent the power cutoff signal, the set performs the intrinsic function in response to the main power and stands by to perform the intrinsic function in response to the auxiliary power. A second state of the control signal places the power supplying apparatus in a power saving mode during which the set may communicate with another circuit. If the cutoff signal is supplied during performance of the intrinsic function, main power is sustained until the intrinsic function is completed.

Abstract: An apparatus for controlling power so that] and reducing power consumption in a system including a switching mode power supply (SMPS), and a method thereof . The apparatus includes a switch that is set to an ON state when a user contacts the switch, a detection portion connected in parallel with the switch and detecting whether a signal for requiring a predetermined operation is applied to the system from outside, and a power supply portion supplying the power to each part in a system when the switch is set to the ON state or the signal is input from the detection portion. The power supply portion terminates the power to each part in the system including the system controller when a power off signal is applied from the system controller when the switch is set to an OFF state and when signal is not input from the detection portion. the system to which power is supplied using the SMPS can be reduced.