Abstract: In a DC power supply circuit (1), when an instantaneous value (Vin) of a voltage from a rectifier circuit (2) is higher than or equal to a voltage (VC2) across terminals of a capacitor (C2), in an ON period of a switching element (Q1), current flows along a first current path, from a high-potential output terminal of the rectifier, through a load (11), an inductor (L2), and the switching element in the stated order, and into a low-potential output terminal of the rectifier, and in an OFF period of the switching element, current flows along a second current path, from the high-potential output terminal of the rectifier, through the load, the inductor, a diode (D1), and the capacitor in the stated order, and into the low-potential output terminal of the rectifier.

Abstract: In a DC power supply circuit, a first period and a second period are alternately repeated a plurality of times during each half cycle of AC supplied to the DC power supply circuit. The first period is a period during which current flows along a first current path extending from an output terminal at a high-potential side of a rectifier circuit to an output terminal at a low-potential side of the rectifier circuit, via an inductor and a switching element. The second period is a period during which current flows along a second current path extending from the output terminal at the high-potential side of the rectifier circuit to the output terminal at the low-potential side of the rectifier circuit, via the inductor, a charging current supply path, and a capacitor.

Abstract: An illumination light source includes: a light-emitting unit; a disturbance detecting unit which detects a specific disturbance; a timer circuit that times a first period and a second period, the first period starting from when the disturbance detecting unit detects the specific disturbance, a second period immediately following after the first period; and a driving circuit that turns ON the light-emitting unit at a start of the first period, causes the light-emitting unit to emit light during the first period, causes the light-emitting unit to emit light that is different from the light emitted during the second period, and turns OFF the light-emitting unit at an end of the second period.

Abstract: A power supply circuit (1) including: rectifying and smoothing circuit (31); transistor (switching element) (37) connected to an output terminal of the rectifying and smoothing circuit (31); transformer (TF1) including primary coil (L36) connected to the transistor (37) and secondary coil (L47) magnetically coupled with the primary coil (L36); current detector circuit (41) detecting current flowing through the transistor (37), and outputting voltage corresponding to the current; voltage output circuit (44) outputting, while the transistor (37) is in a turned-on state, voltage dependent on voltage induced by the secondary coil (L47); and on-off control circuit (57) turning off the transistor (37) when absolute value (Vbe) of a difference between the voltage from the current detector circuit (41) and the voltage from the voltage output circuit (44) is no smaller than threshold voltage (Von), and turning on the transistor (37) when the absolute value (Vbe) is smaller than the threshold voltage (Von).

Abstract: In a DC power supply circuit (1), when an instantaneous value (Vin) of a voltage from a rectifier circuit (2) is higher than or equal to a voltage (VC2) across terminals of a capacitor (C2), in an ON period of a switching element (Q1), current flows along a first current path, from a high-potential output terminal of the rectifier, through a load (11), an inductor (L2), and the switching element in the stated order, and into a low-potential output terminal of the rectifier, and in an OFF period of the switching element, current flows along a second current path, from the high-potential output terminal of the rectifier, through the load, the inductor, a diode (D1), and the capacitor in the stated order, and into the low-potential output terminal of the rectifier.

Abstract: A power supply circuit (1) including: rectifying and smoothing circuit (31); transistor (switching element) (37) connected to an output terminal of the rectifying and smoothing circuit (31); transformer (TF1) including primary coil (L36) connected to the transistor (37) and secondary coil (L47) magnetically coupled with the primary coil (L36); current detector circuit (41) detecting current flowing through the transistor (37), and outputting voltage corresponding to the current; voltage output circuit (44) outputting, while the transistor (37) is in a turned-on state, voltage dependent on voltage induced by the secondary coil (L47); and on-off control circuit (57) turning off the transistor (37) when absolute value (Vbe) of a difference between the voltage from the current detector circuit (41) and the voltage from the voltage output circuit (44) is no smaller than threshold voltage (Von), and turning on the transistor (37) when the absolute value (Vbe) is smaller than the threshold voltage (Von).

Abstract: In a DC power supply circuit, upon a switching element switching to a turned-on state, a first current path is formed from an output terminal at a high-potential side of a rectifier circuit to an output terminal at a low-potential side of a rectifier circuit, via an inductor and the switching element in respective order, and a second current path is formed between terminals of a capacitor, via a load, another inductor, and the switching element. Upon the switching element switching to a turned-off state, a third current path is formed from the output terminal at the high-potential side of a rectifier circuit to the output terminal at the low-potential side of a rectifier circuit, via the inductor, a diode, and the capacitor in respective order, and a fourth current path is formed between the inductors, via the diode and the load in respective order.

Abstract: An illumination light source includes: a light-emitting unit; a disturbance detecting unit which detects a specific disturbance; a timer circuit that times a first period and a second period, the first period starting from when the disturbance detecting unit detects the specific disturbance, a second period immediately following after the first period; and a driving circuit that turns ON the light-emitting unit at a start of the first period, causes the light-emitting unit to emit light during the first period, causes the light-emitting unit to emit light that is different from the light emitted during the second period, and turns OFF the light-emitting unit at an end of the second period.

Abstract: A lighting system includes: a lighting apparatus including a first human detection sensor unit that detects a person in a first detection area, and a light source that turns ON when the first human detection sensor unit detects the person; and a support apparatus including (i) a second human detection sensor unit that detects a person in a second detection area, and (ii) an emission unit that emits, when the second human detection sensor unit detects the person, infrared rays to cause the first human detection sensor unit to react as if the person is present in the first detection area.

Abstract: In a DC power supply circuit, upon a switching element switching to a turned-on state, a first current path is formed from an output terminal at a high-potential side of a rectifier circuit to an output terminal at a low-potential side of a rectifier circuit, via an inductor and the switching element in respective order, and a second current path is formed between terminals of a capacitor, via a load, another inductor, and the switching element. Upon the switching element switching to a turned-off state, a third current path is formed from the output terminal at the high-potential side of a rectifier circuit to the output terminal at the low-potential side of a rectifier circuit, via the inductor, a diode, and the capacitor in respective order, and a fourth current path is formed between the inductors, via the diode and the load in respective order.

Abstract: In a DC power supply circuit, a first period and a second period are alternately repeated a plurality of times during each half cycle of AC supplied to the DC power supply circuit. The first period is a period during which current flows along a first current path extending from an output terminal at a high-potential side of a rectifier circuit to an output terminal at a low-potential side of the rectifier circuit, via an inductor and a switching element. The second period is a period during which current flows along a second current path extending from the output terminal at the high-potential side of the rectifier circuit to the output terminal at the low-potential side of the rectifier circuit, via the inductor, a charging current supply path, and a capacitor.

Abstract: There is provided a lamp capable of informing a user that the LED lamp is at the end of its productive life and urging the user to replace the lamp reliably with a simple configuration. The lamp includes: a light emitting diode (1) as a light source; and a driving circuit (3) that turns on the light emitting diode (1) by an alternating-current or direct-current power source. The lamp further includes a life detecting element (2) that turns off the light emitting diode (1) following the occurrence of insulation deterioration in a resin material when the light emitting diode (1) has been operated for a predetermined time.

Abstract: An LED light source lamp includes a housing configured to be attached to a lamp holder; an LED module provided in the housing; a drive circuit provided in the housing and configured to drive the LED module to cause the LED module to emit light; an LED installation plate on which the LED module is installed; a cover arranged to block an optical axis of the LED module and configured to transmit light emitted from the LED module; and a separation member configured to separate the drive circuit from a space between the LED module and the cover in the housing. The LED installation plate has a rear surface, opposite the surface on which the LED module is installed. The rear surface is configured to closely contact the lamp holder, and is a part of the housing.

Abstract: A lighting circuit (1) includes a controller integrated circuit (U1) for on and off control of a switching element (Q1), a transformer (T1) having a primary coil (T11) that is connected in series to the switching element and a secondary coil (T12), a first voltage supply circuit supplying a voltage that occurs across both ends of the primary coil to an LED module (2), and a second voltage supply circuit supplying a voltage induced in the secondary coil to a power source terminal (Vcc) when the switching element is on. A turns ratio N of the primary coil to the secondary coil satisfies Equation 1, where X1 V denotes a voltage that an AC power source supplies, Y V denotes the maximum value of a power source voltage of the control unit at which normal operation is guaranteed, and Z V denotes the minimum value of the power source voltage.

Abstract: A lighting circuit that is for a lamp including an LED as a light source and that includes a resonant circuit that can be designed with ease. A lighting circuit 11 is for a lamp including a light-emitter 39 composed of an LED as a light source. The lighting circuit comprises: a rectifier circuit 31 that rectifies power supplied from an alternating current power supply via a base 28; an inverter circuit 33 connected to an output side of the rectifier circuit 31 and outputting alternating power to the LED; and a resonant circuit 35 connected to an output side of the inverter circuit 33, wherein the resonant circuit 35 includes an inductor L and a capacitor C1 and is connected in series with the light-emitter 39, the inductor L and the capacitor C1 being connected in series.

Abstract: An LED light source lamp includes a housing configured to be attached to a lamp holder; an LED module provided in the housing; a drive circuit provided in the housing and configured to drive the LED module to cause the LED module to emit light; an LED installation plate on which the LED module is installed; a cover arranged to block an optical axis of the LED module and configured to transmit light emitted from the LED module; and a separation member configured to separate the drive circuit from a space between the LED module and the cover in the housing. The LED installation plate has a rear surface, opposite the surface on which the LED module is installed. The rear surface is configured to closely contact the lamp holder, and is a part of the housing.

Abstract: An LED light source lamp has built-in drive circuits in a housing, and is used by being attached to a lamp holder. An LED installation plate is arranged, in a main space of the housing, on an attachment side to the lamp holder. An LED module on a surface, of the LED installation plate, opposite to the lamp holder, is a collection of LEDs driven by the drive circuit. A light diffusion member is arranged so as to block the optical axis of light emitted by each LED of the LED module. Here, the drive circuits are arranged in an outer peripheral space, between the LED module and the light diffusion member, so as not to block the optical axis of light emitted by each LED of the LED module.

Abstract: A lamp light source comprises: a light-emitting unit having a plurality of semiconductor light-emitting elements arranged as a ring on a front face of a mount so as to principally emit light in a frontal direction; and a circuit unit converting externally-supplied electrical power to cause the semiconductor light-emitting elements to emit the light, wherein a through-hole passes vertically through the light-emitting unit at a point inside the ring of semiconductor light-emitting elements, the circuit unit is at least partly arranged within the through-hole, and a space is provided between the circuit unit and the light-emitting unit.

Abstract: A light source device is provided such that light emerges mainly from the axially central section of an outer tube and is configured to minimize the risk of thermal damage to electronic components of a circuit unit. The device includes: a semiconductor light-emitting element as a light source; a circuit unit driving the semiconductor light-emitting element to emit light; and an envelope formed from an outer tube and a power connector, the envelope housing the semiconductor light-emitting element and the circuit unit. A light diffuser having a reflective outer surface to diffuse incident light is disposed at least partially in the axially central section of the outer tube. The semiconductor light-emitting element is disposed on a side of the light diffuser at which the power connector is located and in an orientation that its main emission direction points toward the light diffuser.

Abstract: A lamp comprises: a primary reflective mirror being funnel-shaped and having an opening at one end; LEDs disposed within the primary reflective mirror; a base attached to another end of the primary reflective mirror; and a circuit configured to receive power via the base and cause the LEDs to emit light. The circuit unit is housed in a circuit case and disposed within the primary reflective mirror close to the opening in a direction in which the LEDs emit light. The circuit case has a secondary reflective surface configured to reflect light emitted from the LEDs to a reflective surface of the primary reflective mirror.