Abstract: A detection circuit configured to detect a short in a plurality of LED arrays is provided. The detection circuit includes a voltage measuring unit, a short detecting unit, and a detection control unit. The voltage measuring unit is configured to measure respective feedback voltages of the plurality of LED arrays and output a lowest measured feedback voltage as a first feedback voltage. The short detecting unit is configured to detect the short in the LED arrays using the measured feedback voltages. The detection control unit is configured to control the short detecting unit to stop short detection operation, when the first feedback voltage exceeds a first preset reference voltage.

Abstract: A level shifting circuit includes a transistor output unit that receives a first power supply signal and convert the first power supply signal to a second power supply signal having a different level from the first power supply signal and a current provision unit that provides a current to an output terminal of the transistor output unit when the first power supply signal of the transistor output unit is inputted to shorten a prolonged portion of the second power supply signal. Therefore, the level shifting circuit may provide an additional current to the output terminal of the transistor output unit to shorten a prolonged portion of the output voltage.

Abstract: A power factor correction controlling circuit includes a control signal providing circuit configured to provide a control signal associated with a feedback signal, the feedback signal being controlled based on a bias signal, a pulse width modulation signal controlling circuit configured to control a pulse width modulation signal based on one of first and second bias signals and a power factor controlling circuit configured to provide a power factor control signal when an amplitude of the pulse width modulation signal reaches that of the power factor control signal. Such a circuit Is able to operate stably, regardless of a load condition and an input voltage condition.

Abstract: Disclosed is a circuit for compensating a bipolar junction transistor (BJT) base current that mirrors the BJT base current to induce a mirror current that is coupled to an emitter of the BJT to decrease an emitter current by a size of the mirror current. Also disclosed is a light-emitting diode (LED) driving apparatus including an LED array, a BJT series-coupled to the LED array, a measuring unit coupled to an emitter of the BJT to measure a current flowing into the LED array, a differential amplifier configured to differentially amplify a reference voltage and the measured current to supply a base current to a base of the BJT, and a BJT base current compensation circuit as disclosed to accurately control an LED current.

Abstract: A detecting circuit and method thereof are configured to detect whether an LED array is open is described. The detecting circuit includes a resistance unit, a first switching unit, and an output unit. The resistance unit is operatively connected in series to the LED array. The switching unit is configured to be turned on when a voltage of the resistance unit is greater than or equal to a predetermined voltage level. The output unit is configured to produce an output indicative of whether the LED array is open, based whether the first switching unit is turned on.

Abstract: A level shifting circuit includes a transistor output unit that receives a first power supply signal and convert the first power supply signal to a second power supply signal having a different level from the first power supply signal and a current provision unit that provides a current to an output terminal of the transistor output unit when the first power supply signal of the transistor output unit is inputted to shorten a prolonged portion of the second power supply signal. Therefore, the level shifting circuit may provide an additional current to the output terminal of the transistor output unit to shorten a prolonged portion of the output voltage.

Abstract: There is provided a current controlling mode DC-DC converter that operates in a PWM mode or a PFM mode by adjusting a turned-on time of a gate depending on power consumption of a load. The DC-DC converter includes a first comparator that receives a first input voltage and a second input voltage and outputs a first output signal, a second comparator that receives a reference voltage for mode switching and the second input voltage and outputs a second output signal, and a first logic element that outputs a reset signal for turning off a gate at a point of time when both the first output signal and the second output signal are applied. Examples may also include additional elements to facilitate mode switching.

Abstract: A power factor correction controlling circuit includes a control signal providing circuit configured to provide a control signal associated with a feedback signal, the feedback signal being controlled based on a bias signal, a pulse width modulation signal controlling circuit configured to control a pulse width modulation signal based on one of first and second bias signals and a power factor controlling circuit configured to provide a power factor control signal when an amplitude of the pulse width modulation signal reaches that of the power factor control signal. Such a circuit Is able to operate stably, regardless of a load condition and an input voltage condition.

Abstract: Provided are a ramp circuit and a DC-DC converter. The ramp circuit generates a current flowing in a resistor using voltages affected by an output voltage and an input voltage of a DC-DC converter, and generates a ramp signal through copying of the current and charging and discharging of a capacitor using a current mirror unit. The ramp signal is generated by considering the input voltage and the output voltage, and thus the ramp signal has an optimal slope to provide an adaptive response to state change in the input voltage and the output voltage. The DC-DC converter uses such a ramp circuit to facilitate its operation.

Abstract: Disclosed is a circuit for compensating a bipolar junction transistor (BJT) base current that mirrors the BJT base current to induce a mirror current that is coupled to an emitter of the BJT to decrease an emitter current by a size of the mirror current. Also disclosed is a light-emitting diode (LED) driving apparatus including an LED array, a BJT series-coupled to the LED array, a measuring unit coupled to an emitter of the BJT to measure a current flowing into the LED array, a differential amplifier configured to differentially amplify a reference voltage and the measured current to supply a base current to a base of the BJT, and a BJT base current compensation circuit as disclosed to accurately control an LED current.

Abstract: There is provided a current controlling mode DC-DC converter that operates in a PWM mode or a PFM mode by adjusting a turned-on time of a gate depending on power consumption of a load. The DC-DC converter includes a first comparator that receives a first input voltage and a second input voltage and outputs a first output signal, a second comparator that receives a reference voltage for mode switching and the second input voltage and outputs a second output signal, and a first logic element that outputs a reset signal for turning off a gate at a point of time when both the first output signal and the second output signal are applied. Examples may also include additional elements to facilitate mode switching.

Abstract: Provided are a ramp circuit and a DC-DC converter. The ramp circuit generates a current flowing in a resistor using voltages affected by an output voltage and an input voltage of a DC-DC converter, and generates a ramp signal through copying of the current and charging and discharging of a capacitor using a current mirror unit. The ramp signal is generated by considering the input voltage and the output voltage, and thus the ramp signal has an optimal slope to provide an adaptive response to state change in the input voltage and the output voltage. The DC-DC converter uses such a ramp circuit to facilitate its operation.

Abstract: A detecting circuit and method thereof are configured to detect whether an LED array is open is described. The detecting circuit includes a resistance unit, a first switching unit, and an output unit. The resistance unit is operatively connected in series to the LED array. The switching unit is configured to be turned on when a voltage of the resistance unit is greater than or equal to a predetermined voltage level. The output unit is configured to produce an output indicative of whether the LED array is open, based whether the first switching unit is turned on.

Abstract: A detection circuit configured to detect a short in a plurality of LED arrays is provided. The detection circuit includes a voltage measuring unit, a short detecting unit, and a detection control unit. The voltage measuring unit is configured to measure respective feedback voltages of the plurality of LED arrays and output a lowest measured feedback voltage as a first feedback voltage. The short detecting unit is configured to detect the short in the LED arrays using the measured feedback voltages. The detection control unit is configured to control the short detecting unit to stop short detection operation, when the first feedback voltage exceeds a first preset reference voltage.