Abstract: A USB charger circuit includes at least a converter, a control circuitry, a first resistor, a second resistor, an error amplifier, a sense resistor and a diode. The converter has a transistor. The control circuitry is coupled to the transistor. The control circuitry is used for producing a drive signal to the transistor. The first resistor is connected between the output node of the converter and a first node. The second resistor is connected between the first node and a second node. The error amplifier is coupled to receive a voltage divided by the first resistor and the second resistor to compare to a reference voltage. The sense resistor is connected between the second node and ground. The diode is connected between the output node of the converter and a first node.

Abstract: A two-terminal current controller regulates a first current flowing through a load, which is coupled in parallel with the two-terminal current controller, according to a voltage established across the two-terminal current controller. When the voltage established across the two-terminal current controller does not exceed a first voltage, the two-terminal current controller conducts a second current related to a rectified AC voltage, thereby limiting the first current to zero and regulating the second current according to the load voltage. When the voltage established across the two-terminal current controller is between the first voltage and a second voltage, the two-terminal current controller conducts the second current, thereby limiting the first current to zero and limiting the second current to a constant value larger than zero. When the voltage established across the two-terminal current controller is greater than second voltage, the two-terminal current controller is turned off.

Abstract: A current distributor that simplifies the architecture and reduces the connecting wires. According to the invention, current distributor can be utilized for distributing the current evenly through a plurality of rows of light-emitting diodes. Each respectively is coupled between a supply pin and a first current pin. The first current pin is coupled to the current distributor. The current distributor is coupled to a total current pin. The current distributor comprises a first resistor, a plurality of first clamp circuitries, a second clamp circuitry and a plurality of first transistors. The first resistor has a first end and a second end. The first end is coupled to the supply pin. Each of the plurality of first clamp circuitries has a first terminal and a second terminal. Each of the first terminal of the first clamp circuitries is coupled to the second end of the first resistor. Each of the second terminal of the first clamp circuitries is coupled to the first current pin.

Abstract: An LED driver circuit that sinks pure DC current through LEDs. According to the invention, a constant current sink circuit is coupled to a full bridge rectifier. The full bridge rectifier includes at least a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm. The first bridge arm and the fourth bridge arm are connected in parallel with the third bridge arm and the second bridge arm in opposite directions, respectively. The connection of the first bridge arm and the third bridge arm and the connection of the second bridge arm and the fourth bridge arm are connected in series. Each of the bridge arms may consist of at least one LED. The constant current sink circuit is used for sinking pure DC current. The LEDs can be driven by pure constant current and can provide desired luminance.

Abstract: Constant current driving circuit includes a latch, an ON timer, and an OFF timer. The latch outputs a switch control signal according to an ON signal and an OFF signal for controlling a power switch. The power switch is coupled between an input voltage source and an inductor. When the switch control signal controls the power switch to turn on/off, the input voltage source is able/unable to couple to the inductor through the power switch. The inductor provides an output current and an output voltage. The ON timer detects if the output current reaches a peak value for accordingly outputting the OFF signal. The OFF timer outputs the ON signal according to the output voltage and the switch control signal for control the interval of the switch control signal representing “OFF”.

Abstract: A driving circuit includes at least one light-emitting device, a voltage regulator circuit, an analysis and decision circuit, and a selecting circuit. The voltage regulator circuit is coupled to the light-emitting device for providing a driving voltage to drive the light-emitting device. The analysis and decision circuit is coupled to the light-emitting device for determining whether the light-emitting device is open-circuited to generate a decision result. The selecting circuit is coupled between the analysis and decision circuit and the voltage regulator circuit for selecting a maximum forward bias voltage corresponding to the light-emitting device to generate a feedback signal according to the decision result and for transmitting the feedback signal to the voltage regulator circuit. The voltage regulator circuit adjusts the driving voltage according to the feedback signal.

Abstract: A current distributor that simplifies the architecture and reduces the connecting wires. According to the invention, current distributor can be utilized for distributing the current evenly through a plurality of rows of light-emitting diodes. Each respectively is coupled between a supply pin and a first current pin. The first current pin is coupled to the current distributor. The current distributor is coupled to a total current pin. The current distributor comprises a first resistor, a plurality of first clamp circuitries, a second clamp circuitry and a plurality of first transistors. The first resistor has a first end and a second end. The first end is coupled to the supply pin. Each of the plurality of first clamp circuitries has a first terminal and a second terminal. Each of the first terminal of the first clamp circuitries is coupled to the second end of the first resistor. Each of the second terminal of the first clamp circuitries is coupled to the first current pin.

Abstract: A USB charger circuit includes at least a converter, a control circuitry, a first resistor, a second resistor, an error amplifier, a sense resistor and a diode. The converter has a transistor. The control circuitry is coupled to the transistor. The control circuitry is used for producing a drive signal to the transistor. The first resistor is connected between the output node of the converter and a first node. The second resistor is connected between the first node and a second node. The error amplifier is coupled to receive a voltage divided by the first resistor and the second resistor to compare to a reference voltage. The sense resistor is connected between the second node and ground. The diode is connected between the output node of the converter and a first node.

Abstract: An LED driver circuit that sinks pure DC current through LEDs. According to the invention, a constant current sink circuit is coupled to a full bridge rectifier. The full bridge rectifier includes at least a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm. The first bridge arm and the fourth bridge arm are connected in parallel with the third bridge arm and the second bridge arm in opposite directions, respectively. The connection of the first bridge arm and the third bridge arm and the connection of the second bridge arm and the fourth bridge arm are connected in series. Each of the bridge arms may consist of at least one LED. The constant current sink circuit is used for sinking pure DC current. The LEDs can be driven by pure constant current and can provide desired luminance.

Abstract: A driving circuit includes a first light-emitting device, a first constant-current supplier, a voltage regulator circuit, an analysis and decision circuit, and a first switch. The first constant-current supplier provides a constant current to the first light-emitting device. The voltage regulator circuit provides a driving voltage to the first light-emitting device and adjusts driving voltage according to a feedback signal. The analysis and decision circuit is coupled to the voltage regulator circuit and the first light-emitting device. The analysis and decision circuit generates a first switch control signal. The first switch is coupled to the first light-emitting device, the analysis and decision circuit, and the voltage regulator circuit. The first switch is turned on and off according to the first switch control signal.

Abstract: An integrated circuit provides a load with back-flow and open-circuit protection and includes a load, a trigger circuit, and a shunt circuit. The integrated circuit provides large-size LED displays having series LED connection with back-flow and open-circuit protection. The shunt circuit of the integrated circuit shunts the back-flow current from the LED when an ESD is applied, and offers an alternative current path when an LED fails so that other functioning LEDs can still emit light.

Abstract: An integrated circuit includes a light emitting device and a light emitting device driver coupled to the light emitting device. The light emitting device driver is for generating a drive signal to drive the light emitting device to emit light. A light emitting device driver includes a transistor having a first terminal coupled to a light emitting device; a resistor having a first terminal coupled to a second terminal of the transistor, and a second terminal coupled to a supply node; and a comparator having a first input terminal coupled to a reference voltage, a second input terminal coupled to the second terminal of the transistor, and an output terminal coupled to a control terminal of the transistor. The light emitting device driver controls an electrical current flowing through the transistor for driving the light emitting device to emit light.

Abstract: An integrated circuit provides a load with back-flow and open-circuit protection and includes a load, a trigger circuit, and a shunt circuit. The integrated circuit provides large-size LED displays having series LED connection with back-flow and open-circuit protection. The shunt circuit of the integrated circuit shunts the back-flow current from the LED when an ESD is applied, and offers an alternative current path when an LED fails so that other functioning LEDs can still emit light.

Abstract: A driving circuit and method for driving a light-emitting device. The driver circuit includes a first bias circuit coupled to an output node of a first light-emitting device for providing a bias current to the first light-emitting device; and a voltage regulator coupled to an input node of the first light-emitting device and the output node of the first light-emitting device for providing a driving voltage to the first light-emitting device and adjusting the driving voltage according to a voltage level of the output node.

Abstract: An integrated circuit includes a light emitting device and a light emitting device driver coupled to the light emitting device. The light emitting device driver is for generating a drive signal to drive the light emitting device to emit light. A light emitting device driver includes a transistor having a first terminal coupled to a light emitting device; a resistor having a first terminal coupled to a second terminal of the transistor, and a second terminal coupled to a supply node; and a comparator having a first input terminal coupled to a reference voltage, a second input terminal coupled to the second terminal of the transistor, and an output terminal coupled to a control terminal of the transistor. The light emitting device driver controls an electrical current flowing through the transistor for driving the light emitting device to emit light.