Abstract: A converter is disclosed for using at least one switch to convert an input signal to a square wave signal, and using the square wave signal to generate an output voltage. The converter converts the square wave signal by a switching operation of a switch and generates the output voltage, and includes a switch controller for controlling the switching operation. The switch controller generates a first signal VCT having a first period that varies according to an output voltage, controls the switching operation of the switch by using the first signal, detects the output voltage, a first current Ids2 flowing through the switch, and a level of the first signal, and controls a burst mode according to the detection results.

Abstract: In one embodiment, an SMPS includes a rectifier for generating an input DC voltage from an input AC voltage. A switching transistor is coupled to a primary coil of a transformer for generating power which is transferred to a second side of the transformer according to an operation of the switching transistor. A switching controller receives a feedback voltage corresponding to an output voltage, a sensing signal corresponding to a current flowing through the switching transistor, and a first signal corresponding to a voltage difference between a first electrode and a second electrode of the switching transistor. The switching controller controls an on/off operation of the switching transistor. The switching controller sets a threshold period whenever the first signal has a value greater than a reference value, thereby setting a plurality of threshold periods during operation of the switching mode power supply.

Abstract: The present invention relates to a switch mode power supply and a driving method for reducing switching loss and audible noise in the burst mode. The switch mode power supply includes a main switch, a power supply, an output unit, and a switch controller. The power supply includes a transformer having a primary coil connected to the main switch, and supplies power to a secondary coil of the transformer according to the operation of the main switch. The output unit is connected to the secondary coil of the transformer and outputs power supplied to the secondary coil of the transformer.

Abstract: The present invention relates to a quasi-resonant converter. In the quasi-resonant converter according to the present invention, a predetermined first period and a second period following to the first period are set. In the second period, a switch is turned on at a time point where voltages at both ends of the switch fall to the minimum if the second period includes the time point, and the switch is turned on at the end of the second period if the second period does not include the time point. Therefore, the switching frequency of the switch can be restricted within a predetermined range.

Abstract: A switching mode power supply (SMPS) and a driving method thereof are provided. The SMPS includes a power supply block that includes a first switch coupled to a first coil of a primary side of a transformer for converting an input voltage, wherein the power supply block supplies power to a second coil and a third coil of a secondary side of the transformer according to operation of the first switch; and a PWM signal generator determines a turn-on time of the first switch according to the input voltage, and the turn-on time is determined regardless of a power magnitude of an output terminal connected to the second coil. Accordingly, screen noise due to a ripple can be eliminated and stress on the switch breakdown due to excessive power input can be reduced to enable an SMPS with stable driving.

Abstract: A converter is disclosed for using at least one switch to convert an input signal to a square wave signal, and using the square wave signal to generate an output voltage. The converter converts the square wave signal by a switching operation of a switch and generates the output voltage, and includes a switch controller for controlling the switching operation. The switch controller generates a first signal VCT having a first period that varies according to an output voltage, controls the switching operation of the switch by using the first signal, detects the output voltage, a first current Ids2 flowing through the switch, and a level of the first signal, and controls a burst mode according to the detection results.

Abstract: A switching mode power supply (SMPS) and a driving method thereof are provided. The SMPS includes a power supply block that includes a first switch coupled to a first coil of a primary side of a transformer for converting an input voltage, wherein the power supply block supplies power to a second coil and a third coil of a secondary side of the transformer according to operation of the first switch; and a PWM signal generator determines a turn-on time of the first switch according to the input voltage, and the turn-on time is determined regardless of a power magnitude of an output terminal connected to the second coil. Accordingly, screen noise due to a ripple can be eliminated and stress on the switch breakdown due to excessive power input can be reduced to enable an SMPS with stable driving.

Abstract: The present invention relates to a switch mode power supply and a driving method for reducing switching loss and audible noise in the burst mode. The switch mode power supply includes a main switch, a power supply, an output unit, and a switch controller. The power supply includes a transformer having a primary coil connected to the main switch, and supplies power to a secondary coil of the transformer according to the operation of the main switch. The output unit is connected to the secondary coil of the transformer and outputs power supplied to the secondary coil of the transformer.

Abstract: In one embodiment, an SMPS includes a rectifier for generating an input DC voltage from an input AC voltage. A switching transistor is coupled to a primary coil of a transformer for generating power which is transferred to a second side of the transformer according to an operation of the switching transistor. A switching controller receives a feedback voltage corresponding to an output voltage, a sensing signal corresponding to a current flowing through the switching transistor, and a first signal corresponding to a voltage difference between a first electrode and a second electrode of the switching transistor. The switching controller controls an on/off operation of the switching transistor. The switching controller sets a threshold period whenever the first signal has a value greater than a reference value, thereby setting a plurality of threshold periods during operation of the switching mode power supply.

Abstract: The present invention relates to a quasi-resonant converter. In the quasi-resonant converter according to the present invention, a predetermined first period and a second period following to the first period are set. In the second period, a switch is turned on at a time point where voltages at both ends of the switch fall to the minimum if the second period includes the time point, and the switch is turned on at the end of the second period if the second period does not include the time point. Therefore, the switching frequency of the switch can be restricted within a predetermined range.