An electronic driver circuit for LEDs and LASERs is provided for use in time-of-flight applications featuring a high efficiency of energy-conversion and a high precision of distance-measurements based on a dual conversion circuit. A voltage to voltage DC-DC conversion is hereby merged with a DC-voltage to pulsed-current booster, this booster operating at a time-of-flight modulation frequency. At the start of a new measurement cycle, the PWM signal for driving the DC-DC conversion is updated in response to currents observed during previous illumination periods.

A bicycle light that is constructed and arranged to be supplied with input electrical power. The power can be supplied by multiple power sources, or not. When there are multiple power sources, the bicycle light includes a circuit that is adapted to deliver power to the light source from any of the power sources. The bicycle light can have an electrical power output, and a circuit that is adapted to deliver power to the light source and the power output.

A light source lighting circuit comprises a first lighting circuit for receiving current from the electric power supply line and supplying drive current to a first light source and a second lighting circuit for receiving the current from the electric power supply line and supplying drive current to a second light source. When a state of the drive current flowing to the first light source shows an abnormality, or when state of the drive current flowing to the second light source shows an abnormality, the first lighting circuit stops operation. When a state of the drive current flowing to the second light source shows an abnormality, or when a state of the drive current flowing to the first light source shows an abnormality, the second lighting circuit stops operation.

An ac-dc power supply includes a dc-dc converter coupled to an input of the ac-dc power supply. The input of the ac-dc power supply is coupled to receive an ac input voltage and an ac input current. The dc-dc converter includes a regulated output and a reservoir output. A controller is coupled to receive sense signals from the dc-dc converter. The controller is coupled to control the dc-dc converter to regulate the regulated output in response to the sense signals. The controller is further coupled to control a waveform of the ac input current to have a substantially same shape as a waveform of the ac input voltage. A regulator circuit is coupled to the regulated output and the reservoir output. The controller is coupled to the regulator circuit to control a transfer of energy from the reservoir output to the regulated output through the regulator circuit.

Driver circuitry is coupled between a power supply and at least one LED in a solid-state lighting fixture, such that a non-isolated direct current (DC) path exists between the power supply and the at least one LED. The driver circuitry is configured to receive an AC input voltage and generate a driver output current for driving the at least one LED from the AC input voltage. By using driver circuitry that is non-isolated from the at least one LED in the solid-state lighting fixture, the efficiency of the driver circuitry may be increased, while simultaneously reducing the cost and complexity of the driver circuitry compared to conventional driver circuitry.

The present invention addresses the problem of detecting the timing at which an inductor current becomes zero, turning on a switching element at the optimal timing, and enhancing power efficiency without increasing part quantity or external terminal quantity. A control circuit is configured from a semiconductor integrated circuit; is provided with a first external terminal to which a voltage produced by the conversion of the current flowing through a switching element by a current-to-voltage conversion element is input, a second external terminal to which the voltage of a point of contact of an inductor and rectification element or a voltage proportional thereto is input, a filter for smoothing the voltage input into the second external terminal, and a voltage comparison circuit for comparing the voltage smoothed by the filter and the voltage input into the second external terminal; and performs control such that the switching element is switched from off to on near the point where the inductor current becomes zero on the basis of the voltage comparison circuit output and the switching element is switched from on to off in response to the voltage applied to the first external terminal reaching a prescribed voltage.

A digital power supply system including a microcontroller, a driver, a step down circuit, and a buck and boost circuit is disclosed. The microcontroller circuit provides a first and second plurality of pulse width modulated signals and receives signals indicative of an input current, input voltage, output current, output voltage, and a 3.3 volt supply. The driver receives the first plurality of pulse width modulated signals and a 12 volt supply and provides a DC power signal and the signal indicative of the output current. The step down circuit receives a positive input voltage and provides the 3.3 volt supply. The boost circuit receives the 3.3 volt supply and provides the 12 volt supply. The buck and boost circuit receives the second plurality of pulse width modulated signals and provide the signals indicative of the output voltage, the input current, the input voltage, and the positive input voltage.

An LED lighting device using a ballast may be provided that includes: an LED unit which includes at least one LED device; a rectifier which rectifies a current power signal output from the ballast; and a current driving unit which receives an output current of the rectifier and controls the power which is transmitted from the ballast to the LED unit. The current driving unit transmits current which has a magnitude greater than that of the output current of the rectifier to the LED unit.

A DC-DC converter has a pulse width control circuit producing a sequence of pulses, with an on time, an off time and a switching frequency. The on time as well as the switching frequency are both varied in dependence on a dimming setting.

A driving circuit includes a control circuit and a boost converter circuit. The control circuit receives a sense voltage associated with a direct-current (DC) source voltage, and generates a control signal with a duty cycle that varies with the sense voltage in a monotonically increasing manner. The boost converter circuit receives the DC source voltage and the control signal, thereby providing a driving current for driving light emission of a light emitting component. The driving current has a magnitude positively correlated to the duty cycle of the control signal.