Abstract: A lighting apparatus includes a control circuit configured to control a power supply circuit such that a measurement value of an output current measured by a current measuring device approaches a target value. The control circuit is configured to execute a control mode alternatively selected from the plurality of control modes to control the power supply circuit. The plurality of control modes of the control circuit includes at least a first control mode and a second control mode. The first control mode is a control mode of adjusting the target value in accordance with a first direct-current voltage. The second control mode is a control mode which includes adjusting the target value regardless of the first direct-current voltage.

Abstract: A lighting apparatus includes a step-up converter, at least one step-down converter, and a controller. The step-up converter is configured to step up a voltage of a direct-current power supply to obtain an output voltage having a first voltage value and output the output voltage. The at least one step-down converter is configured to step down the output voltage of the step-up converter to have a second voltage value to output a current having a current value according to the second voltage value to a light source. The controller is configured to acquire information about a specification of the light source, control the step-down converter such that the current value becomes a current value according to the specification, and control the step-up converter such that the first voltage value changes in accordance with the specification.

Abstract: A lighting apparatus includes a control circuit configured to control a power supply circuit such that a measurement value of an output current measured by a current measuring device approaches a target value. The control circuit is configured to execute a control mode alternatively selected from the plurality of control modes to control the power supply circuit. The plurality of control modes of the control circuit includes at least a first control mode and a second control mode. The first control mode is a control mode of adjusting the target value in accordance with a first direct-current voltage. The second control mode is a control mode which includes adjusting the target value regardless of the first direct-current voltage.

Abstract: In a power supply, a first output terminal and a second output terminal are electrically connected to each other, and a first common terminal and a second common terminal are electrically connected to each other. When a value of a consumption current of a motor is equal to or smaller than a value of a maximum output current of a second constant voltage circuit, the second constant voltage circuit keeps a second voltage at a steady voltage value. When the value of the consumption current of the motor is larger than the value of the maximum output current, the second constant voltage circuit control the second voltage to have a value smaller than a value of the first voltage, and a first constant voltage circuit supplies a differential current which corresponds to a difference between the consumption current of the motor and the maximum output current of the second constant voltage circuit.

Abstract: A lighting device includes an output adjustment circuit, a smoothing circuit and a control circuit. The smoothing circuit receives a binary rotation detection signal according to the rotation of a fan and smooths the rotation detection signal to produce a smoothed signal. The control circuit detects a rotation malfunction of the fan when the smoothed signal is greater than or equal to an upper limit threshold over first predetermined time or when the smoothed signal is smaller than or equal to a lower limit threshold over second predetermined time.

Abstract: In a power supply, a first output terminal and a second output terminal are electrically connected to each other, and a first common terminal and a second common terminal are electrically connected to each other. When a value of a consumption current of a motor is equal to or smaller than a value of a maximum output current of a second constant voltage circuit, the second constant voltage circuit keeps a second voltage at a steady voltage value. When the value of the consumption current of the motor is larger than the value of the maximum output current, the second constant voltage circuit control the second voltage to have a value smaller than a value of the first voltage, and a first constant voltage circuit supplies a differential current which corresponds to a difference between the consumption current of the motor and the maximum output current of the second constant voltage circuit.

Abstract: A lighting device includes an output adjustment circuit, a smoothing circuit and a control circuit. The smoothing circuit receives a binary rotation detection signal according to the rotation of a fan and smooths the rotation detection signal to produce a smoothed signal. The control circuit detects a rotation malfunction of the fan when the smoothed signal is greater than or equal to an upper limit threshold over first predetermined time or when the smoothed signal is smaller than or equal to a lower limit threshold over second predetermined time.

Abstract: The lighting device lights an illumination load in which a first light source block and a second light source block are coupled in series. The lighting device includes a switch unit coupled in parallel with the second light source block. The switch unit includes a series circuit of a switching element and a resistor. The lighting device keeps the switching element off to set a state of the illumination load to a first state. The lighting device keeps the switching element on to set the state of the illumination load to a second state. The resistor has its resistance allowing a value of a voltage across the switch unit to be smaller than a value of a voltage across the second light source block which causes the second light source block to light while the switching element is on.

Abstract: A driving circuit includes a rectifying and smoothing circuit that rectifies an AC dimming signal, and a voltage conversion circuit including: a switching element having a source connected to a low-potential output terminal of the rectifying and smoothing circuit; a diode having an anode connected to a high-potential output terminal of the rectifying and smoothing circuit; an inductor disposed between the diode and a drain of the switching element; an oscillation controller; a capacitor that is charged by receiving magnetic energy from the inductor when the switching element is OFF, and discharges to a load when the switching element is ON; and a power control circuit that applies a voltage corresponding to a voltage at a high-potential terminal of the capacitor to the oscillation controller as a supply voltage for driving the oscillation controller.

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: 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: A driving circuit includes a rectifying and smoothing circuit that rectifies an AC dimming signal, and a voltage conversion circuit (1A) including: a switching element having a source connected to a low-potential output terminal of the rectifying and smoothing circuit; a diode having an anode connected to a high-potential output terminal of the rectifying and smoothing circuit; an inductor disposed between the diode and a drain of the switching element; an oscillation controller; a capacitor that is charged by receiving magnetic energy from the inductor when the switching element is OFF, and discharges to a load when the switching element is ON; and a power control circuit that applies a voltage corresponding to a voltage at a high-potential terminal of the capacitor to the oscillation controller as a supply voltage for driving the oscillation controller.

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: 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: The orientation of fluorescent lamps is detected in a manufacturing method for a direct backlight unit that alternates orientations of adjacent fluorescent lamps. In a preparation step of the manufacturing method for the backlight unit of the present invention, a plurality of fluorescent lamps are prepared. In each of the fluorescent lamps, a length (a1) from a first sealed portion of a glass bulb (26) to a non-phosphor layer (32) area is shorter than a length (a2) from a second sealed portion to a non-phosphor layer (32) area (a1<a2). In a detection step, the difference between the lengths is detected with use of a sensor. In an installation step, the fluorescent lamps are arranged with use of the detection results so that the first and second ends alternate on a same side of a housing.

Abstract: The orientation of fluorescent lamps is detected in a manufacturing method for a direct backlight unit that alternates orientations of adjacent fluorescent lamps. In a preparation step of the manufacturing method for the backlight unit of the present invention, a plurality of fluorescent lamps are prepared. In each of the fluorescent lamps, a length (a1) from a first sealed portion of a glass bulb (26) to a non-phosphor layer (32) area is shorter than a length (a2) from a second sealed portion to a non-phosphor layer (32) area (a1<a2). In a detection step, the difference between the lengths is detected with use of a sensor. In an installation step, the fluorescent lamps are arranged with use of the detection results so that the first and second ends alternate on a same side of a housing.