Abstract: A mixed type frequency compensating circuit is disclosed. The mixed type frequency compensating circuit includes an integral component sub-circuit of a voltage-amplifier-type frequency compensating circuit and a proportional component sub-circuit of a transconductance-amplifier-type frequency compensating circuit. The integral component sub-circuit amplifies an input voltage signal in a voltage mode. The proportional component sub-circuit amplifies the input voltage signal in a current mode. Accordingly, the mixed type frequency compensating circuit may occupy a small area in a semiconductor integrated circuit.

Abstract: The present invention relates to a converter and a driving method thereof. The converter uses an input voltage to generate an output voltage by a main switch's switching and applies power to a load, senses the current flowing to the main switch to generate a sense voltage, uses a first voltage corresponding to the current applied to the load and a sawtooth waveform signal having a first frequency to control a group frequency of the burst mode, controls the main switch's turn-on timing, and uses the first voltage and the sense voltage to determine whether to turn off the main switch, thereby controlling the main switch's switching. The converter determines the start and end of the period for switching according to the result of comparing the first voltage and the sawtooth waveform signal. Therefore, a converter for having a constant group frequency, preventing audible noise, and preventing output voltage ripple, and a driving method thereof, are provided.

Abstract: The present invention relates to a converter and a driving method thereof. The converter uses an input voltage to generate an output voltage by a main switch's switching and applies power to a load, senses the current flowing to the main switch to generate a sense voltage, uses a first voltage corresponding to the current applied to the load and a sawtooth waveform signal having a first frequency to control a group frequency of the burst mode, controls the main switch's turn-on timing, and uses the first voltage and the sense voltage to determine whether to turn off the main switch, thereby controlling the main switch's switching. The converter determines the start and end of the period for switching according to the result of comparing the first voltage and the sawtooth waveform signal. Therefore, a converter for having a constant group frequency, preventing audible noise, and preventing output voltage ripple, and a driving method thereof, are provided.

Abstract: Provided is an apparatus and method for displaying a picture in a portable terminal. The method includes identifying a visibility color quality corresponding to the external brightness upon sensing of generation of a visibility control event, identifying external brightness, identifying a set color quality that is a color quality currently output to a display unit, comparing whether the visibility color quality is equal to the set color quality, and altering the set color quality into the visibility color quality when the comparison result is that the visibility color quality is not equal to the set color quality.

Abstract: A mixed type frequency compensating circuit is disclosed. The mixed type frequency compensating circuit includes an integral component sub-circuit of a voltage-amplifier-type frequency compensating circuit and a proportional component sub-circuit of a transconductance-amplifier-type frequency compensating circuit. The integral component sub-circuit amplifies an input voltage signal in a voltage mode. The proportional component sub-circuit amplifies the input voltage signal in a current mode. Accordingly, the mixed type frequency compensating circuit may occupy a small area in a semiconductor integrated circuit.