Abstract: An oscillator circuit includes an oscillator having a source node and a sink node, the oscillator being configured to generate a pulse signal having an output voltage that corresponds to a charging or discharging operation of a capacitor, a first bias current generating circuit coupled to the source and the sink nodes of the oscillator and configured to supply a first bias current to the oscillator, the first bias current being adjustable, and a second bias current generating circuit coupled to the source and the sink nodes of the oscillator and configured to supply a second bias current to the oscillator, the second bias current being adjustable. The first bias current and the second bias current are used to tune a frequency range of the oscillator.

Abstract: An oscillator circuit includes an oscillator having a source node and a sink node, the oscillator being configured to generate a pulse signal having an output voltage that corresponds to a charging or discharging operation of a capacitor, a first bias current generating circuit coupled to the source and the sink nodes of the oscillator and configured to supply a first bias current to the oscillator, the first bias current being adjustable, and a second bias current generating circuit coupled to the source and the sink nodes of the oscillator and configured to supply a second bias current to the oscillator, the second bias current being adjustable. The first bias current and the second bias current are used to tune a frequency range of the oscillator.

Abstract: The present invention relates to an LED emitting device and a driving method thereof. The LED emitting device receives an input voltage and supplies a power supply voltage needed for operating an LED channel according to a switching operation of a power switch. The LED emitting device controls the power supply and also controls a load switch between the LED channel and an output voltage. The LED emitting device determines the LED channel to be short circuited when the output voltage is reduced to a predetermined threshold voltage during a predetermined short circuit sense period starting from the time when the output voltage reaches a regulated voltage before the LED channel is dimmed. During the short circuit sense period, the power supply is stopped and the load switch is turned on.

Abstract: A driving apparatus of an LED device is provided. The LED device includes a plurality of LED channels, and each LED channel includes a plurality of LEDs connected in series. A power converter has an output terminal connected to a first terminal of each LED channel, and converts an input voltage into an output voltage to output the output voltage to the output terminal. A plurality of current controllers correspond to the plurality of LED channels, respectively. Each current controller is connected to a second terminal of a corresponding LED channel, and controls a current of the corresponding LED channel. The voltage sensor outputs a sensed voltage corresponding to the output voltage of the output terminal. The fault controller determines whether to stop operation of the power converter by comparing the sensed voltage with a reference voltage.

Abstract: The present invention relates to an LED emitting device and a driving method thereof. The LED emitting device receives an input voltage and supplies a power supply voltage needed for operating an LED channel according to a switching operation of a power switch. The LED emitting device controls the power supply and also controls a load switch between the LED channel and an output voltage. The LED emitting device determines the LED channel to be short circuited when the output voltage is reduced to a predetermined threshold voltage during a predetermined short circuit sense period starting from the time when the output voltage reaches a regulated voltage before the LED channel is dimmed. During the short circuit sense period, the power supply is stopped and the load switch is turned on.

Abstract: The present invention relates to an LED light emitting device and a driving method, and discloses a technology that may improve a slew rate of a channel current flowing through an LED channel when driving with a pulse width modulation method. For this, the present invention includes an LED channel consisting of a plurality of LED elements that are consecutively and serially connected, a current control switch that is connected to the end of the LED channel and performs a switching operation, and an operational amplifier that controls the switching operation of the current control switch according to a pulse width modulation signal. The LED driver samples an output voltage at the operational amplifier when the pulse width modulation signal is in an on state, and maintains the output voltage of the operational amplifier when the pulse width modulation signal is in an off state.

Abstract: A driving apparatus of an LED device is provided. The LED device includes a plurality of LED channels, and each LED channel includes a plurality of LEDs connected in series. A power converter has an output terminal connected to a first terminal of each LED channel, and converts an input voltage into an output voltage to output the output voltage to the output terminal. A plurality of current controllers correspond to the plurality of LED channels, respectively. Each current controller is connected to a second terminal of a corresponding LED channel, and controls a current of the corresponding LED channel. The voltage sensor outputs a sensed voltage corresponding to the output voltage of the output terminal. The fault controller determines whether to stop operation of the power converter by comparing the sensed voltage with a reference voltage.

Abstract: A load driver includes an inverter and an inverter driver. The inverter converts an input voltage into a driving voltage of a discharge lamp using at least one first switch for switching according to a duty ratio, and the inverter driver controls the inverter. The inverter driver controls the duty ratio using a voltage of a capacitor and a control signal having a waveform that is repeated with a predetermined frequency. The capacitor is charged and discharged by a current corresponding to a difference between a feedback voltage corresponding to a current flow to the discharge lamp and a reference voltage. Such inverter driver controls to gradually increase the output voltage of the inverter in the soft start period by setting the voltage of the capacitor as a voltage corresponding to the control signal.

Abstract: The present invention relates to an LED light emitting device and a driving method, and discloses a technology that may improve a slew rate of a channel current flowing through an LED channel when driving with a pulse width modulation method. For this, the present invention includes an LED channel consisting of a plurality of LED elements that are consecutively and serially connected, a current control switch that is connected to the end of the LED channel and performs a switching operation, and an operational amplifier that controls the switching operation of the current control switch according to a pulse width modulation signal. The LED driver samples an output voltage at the operational amplifier when the pulse width modulation signal is in an on state, and maintains the output voltage of the operational amplifier when the pulse width modulation signal is in an off state.

Abstract: A load driver includes an inverter and an inverter driver. The inverter converts an input voltage into a driving voltage of a discharge lamp using at least one first switch for switching according to a duty ratio, and the inverter driver controls the inverter. The inverter driver controls the duty ratio using a voltage of a capacitor and a control signal having a waveform that is repeated with a predetermined frequency. The capacitor is charged and discharged by a current corresponding to a difference between a feedback voltage corresponding to a current flow to the discharge lamp and a reference voltage. Such inverter driver controls to gradually increase the output voltage of the inverter in the soft start period by setting the voltage of the capacitor as a voltage corresponding to the control signal.

Abstract: An information search system that enables efficient collection of information and support of formation of groups which people who share a same interest can join over a network. This system includes an intermediate server and a central server, wherein the intermediate server retains indexes for searching the content database on the central server. Users issue a search request to the intermediate server and search results are returned and recorded on the intermediate server as a search history. The search history is shared by users and used as references from which retrievable content can be selected.