Fairchild Korea Semiconductor Ltd.

Kwang-Il Lee

Jin-Tae Kim

Gwan-Bon Koo

Hyun-Chul Eom

Hojae Lee

Sang Cheol Moon

Shanmei Li

The present invention relates to a hold-up time expansion circuit and a converter including the same. The hold-up time expansion circuit controls switching frequency of at least one switch according to the input voltage of the converter. The converter is dependent on the switching frequency that is controlled by the hold-up time expansion circuit, and controls the duty of at least one switch according to the feedback signal of the output voltage.

Hold-up time extending circuit and converter including the same

A converter supplies output power according to a first output current and a second output current generated according to each switching operation of a first switch and a second switch. A duty adjuster circuit generates an adjuster current to compensate the difference between the peak of the first output current and the peak of the second output current to adjust duty of the first and second switches.

Duty adjuster circuit and converter including the same

The present invention relates to a switch control device, a power supply device, and a switch control method. A switch control device controls a switching operation of a power switch by using a feedback voltage of an output voltage. In detail, the switch control device generates the feedback current according to the feedback voltage and the feedback signal corresponding to the feedback voltage by using the feedback current. The switch control device compares the sensing signal corresponding to the drain current flowing to the power switch and the feedback signal, and turns off the power switch according to the comparison result. The switch control device increases the feedback gain rather than the feedback current during the gain compensation period after a predetermined gain compensation period, and the gain compensation period is longer than a soft start period in which the output voltage is gradually increased.

Switch control device, power supply device including the same, and switch control method

A switched-mode power supply includes a soft-burst circuit to minimize or prevent distracting audible noise. The power supply includes a control circuit for controlling switching of an output transistor to deliver a regulated output voltage to a load. The control circuit adjusts the operating frequency of the power supply based on a control signal. The soft-burst circuit discharges a storage device to minimize or prevent audible noise when the control signal reaches a particular level.

Soft-burst circuit for switched-mode power supplies

Ripple of an input voltage is used to modulate a switching operation frequency of a switch mode power supply. A sensing voltage corresponding to the input voltage is received, a current ripple that is proportional to a difference between a peak value of the sensing voltage and the sensing voltage is generated, and a modulation control signal that is variable by the current ripple is generated. A switching frequency is modulated using an oscillator signal that is variable by the modulation control signal, and reduces the output voltage ripple.

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Bucheon, South Korea

Kwang-Il Lee