Abstract:
A lighting device includes a power conversion unit, an impedance adjustment unit, a first control unit, and a second control unit. The power conversion unit is configured to convert input power to direct-current power used for a light source. The impedance adjustment unit is formed of a series circuit of a resistor element and a switch element and is coupled to the light source in parallel, relative to the power conversion unit. The second control unit is configured to cause the power conversion unit to operate, for each burst cycle, for an operation period which is not longer than the burst cycle, and increase and reduce the ratio of the operation period to the burst cycle. The first control unit is configured to make the switch element conductive for a predetermined adjustment period which is not longer than the operation period, during the operation period.
Abstract:
A control circuit is configured to convert a DC voltage that is outputted from a DC power supply to a square wave voltage by switching the switching element according to a PWM signal having a duty ratio that corresponds to a light modulation level of the light source unit, and cause the square wave voltage to be outputted to the light source unit. The control circuit includes a voltage controller configured to control an operating voltage for operating the switching element such that at least one of a rising time and a falling time of a current that flows through the switching element is 1 microsecond or more.
Abstract:
A high-frequency transmission device includes first and second resonators as ring-shaped wires each having an opening part at a part thereof, first and second input/output terminals each electrically connected to both resonators, a first ground shield formed on a plane different from planes on which both resonators are arranged, a second ground shield formed on a plane different from the planes on which both resonators and the first ground shield are arranged, and first and second ground wires each formed to surround peripheries of both resonators. The ground shields and the ground wires are respectively connected to each other. A dielectric wire is present between both ground wires, and the ground wires are not electrically connected to each other.
Abstract:
A power semiconductor element includes: a main transistor including a first gate electrode, a first drain electrode, and a first source electrode; a sensor transistor including a second gate electrode, a second drain electrode, and a second source electrode; and a gate switch transistor including a third gate electrode, and a third drain electrode, a third source electrode. The first gate electrode, the second gate electrode, and the third drain electrode are connected, the first drain electrode and the second drain electrode are connected, the first source electrode and the second source electrode are connected via a sensor resistor, the first source electrode and the third source electrode are connected, the second source electrode and the third gate electrode are connected via a switch resistor, and the main transistor, the sensor transistor, and the gate switch transistor are formed with a nitride semiconductor.
Abstract:
A controller circuit is configured to adjust the number of light-emitting diodes that a current flows from a rectifier circuit through so that: the number of light-emitting diodes, which are lit, of the plurality of light-emitting diodes increases according to a value of a pulsating voltage during a time period that the value of the pulsating voltage increases; and the number of light-emitting diodes, which are lit, of the plurality of light-emitting diodes decreases according to the value of the pulsating voltage during a time period that the value of the pulsating voltage decreases. Light-emitting diodes, which start to emit light by a higher voltage value, of the plurality of light-emitting diodes are disposed at a position nearer to an outside of a mounting region of a substrate than light-emitting diodes, which start to emit light by a lower voltage value, of the plurality of light-emitting diodes.
Abstract:
The light source unit includes a light source circuit including N (N≧3) pairs of a light source group including one or more solid light emitting elements and a constant current circuit connected in series with the light source group to keep, constant, current flowing through the light source group, a full-wave rectification circuit for performing full-wave rectification on AC voltage, and a control circuit. The first pair is connected to the full-wave rectification circuit. The k-th (2≦k≦N) pair is connected in parallel with the constant current circuit of the (k−1)-th pair so that the light source groups of the k-th and (k−1)-th pairs are in series. The control circuit terminates operations of the constant current circuits of the N pairs or limits currents flowing through the light source groups of the N pairs in response to detection of light or a signal.
Abstract:
A lighting device includes a rectifier, a constant current regulator and a charge-discharge circuit. The constant current regulator is electrically connected in series with first and second solid-state light-emitting element arrays between a pair of output terminals of the rectifier. The constant current regulator is configured to adjust a current flowing through the second solid-state light-emitting element array to a constant current. The charge-discharge circuit is electrically connected in series with the first solid-state light-emitting element array between the pair of output terminals of the rectifier. The charge-discharge circuit includes a charge storage element, and is configured so that a charge current flows to the charge storage element through the first solid-state light-emitting element array, and so that a discharge current flows from the charge storage element to the second solid-state light-emitting element array.
Abstract:
A control unit of a light source device after activation time is configured to turn on switches respectively connected in series with light sources, in prescribed order. The light source device and a lighting device are configured to transmit characteristics of the light sources, based on a voltage change depending on a pattern of on and off of the switches.
Abstract:
A lighting apparatus includes a light source module and a power supply module. The light source module includes an electrical light source and a transmitter circuit configured to transmit a wireless signal containing information about the light source. The power supply module is connected to the light source module and includes a power supply circuit configured to generate electric power for the light source, a receiver circuit configured to receive the wireless signal transmitted from the transmitter circuit, and a control circuit configured to control the power supply circuit in accordance with the wireless signal received through the receiver circuit.
Abstract:
An illumination device includes a main light source block having a plurality of main light sources and a plurality of current limiters, and an auxiliary light source block having an auxiliary light source and a constant-current unit. A series circuit of the auxiliary light source and the constant-current unit is electrically connected in parallel with the main light source block, between first and second output terminals of a rectifier. A smoothing capacitor is electrically connected in parallel with a specific main light source among the plurality of main light sources. The specific main light source and a corresponding current limiter are electrically connected in parallel with the series circuit of the auxiliary light source and the constant-current unit.