Abstract:
A lighting device includes a thermal sensor, power converter circuits and a control circuit. The thermal sensor is configured to measure an internal temperature of a case. The power converter circuits are housed in the case and configured to be connected with different types of light sources, respectively. The control circuit is housed in the case and has priorities that are provided with respect to the different types of light sources according to their respective types. The control circuit is configured to, when the internal temperature is greater than a threshold, control the respective outputs of the power converter circuits so as to preferentially decrease an output for a light source corresponding to a first priority.
Abstract:
The lighting device includes a control circuit performing dimming control of dimming a light source device according to a desired dimming level. In the dimming control, the control circuit sets a desired current value of amplitude control to a value corresponding to the desired dimming level, and set a desired duty cycle of pulse width modulation control to a predetermined value associated with a dimming subrange containing the desired dimming level, of multiple different dimming subranges of a total dimming range of the light source device. The predetermined value is a duty cycle allowing luminance of the light source device to be equal to upper limit luminance of the associated dimming subrange under a condition where the current value of the current of the light source device is a maximum value.
Abstract:
An impedance adjustment circuit varies an impedance of a transistor, thereby adjusting an impedance of a current path. A second control circuit controls a drive circuit to turn on or off at least one switch device of the switch devices while the impedance adjustment circuit is increasing the impedance of the current path. The impedance adjustment circuit adjusts the impedance of the current path to the minimum value after the drive circuit switches the at least one switch device from off to on or from on to off.
Abstract:
A power supply device includes a DC power supply circuit configured to output DC power, and a ground-fault determining circuit configured to determine presence or absence of a ground fault at a post-stage of the DC power supply circuit. The ground-fault determining circuit includes a capacitor having an end that is connected with ground, and a diode including an anode and a cathode. The anode is connected with another end of the capacitor, and the cathode is connected with an output end on a high voltage side of the DC power supply circuit. The ground-fault determining circuit further includes a constant voltage source configured to charge the capacitor with a prescribed charging voltage, and a comparator as a determining portion configured to determine presence of the ground fault when a voltage across the capacitor falls below a prescribed determination reference voltage lower than the prescribed charging voltage.
Abstract:
In a lighting device, when determining that both of a first measuring value and a second measuring value are not an abnormal value, a controller is configured to control an output of a power converter based on the first and second measuring values. The first measuring value is a temperature inside a main body of the lighting device, sensed by a first temperature sensor. The second measuring value is a temperature of a light source, sensed by a second temperature sensor. When determining that at least one of the first and second measuring values is the abnormal value, the controller is configured to control the output of the power converter to another value that is different from a value of the output set based on the first and second measuring values.
Abstract:
A power supply device includes converters, a command circuit, and a setter. The converters correspond to loads. The command circuit controls the converters. The setter sets a magnitude of an output of at least one target converter of the converters in accordance with an output characteristic representing a relationship between an input voltage of the at least one target converter and an output limit value which is an upper limit value of the output from the at least one target converter. The output characteristic is a characteristic that the output limit value decreases as the input voltage lowers when the input voltage is lower than a threshold. The setter varies the threshold of the output characteristic in accordance with an operation status of the converters and sets the magnitude of the output from the at least one target converter in accordance with the output characteristic whose threshold has been varied.
Abstract:
The lighting control device includes a controller, a diagnosis circuit, a latch circuit, and a logic circuit. The controller outputs a control signal. The diagnosis circuit outputs an irregular signal. The latch circuit decides a state of a forcibly lighting signal. The logic circuit controls a light source in accordance with an ignition signal, the control signal, and the forcibly lighting signal. The logic circuit turns on the light source in accordance with the ignition signal while receiving the forcibly lighting signal, and turns on the light source in accordance with the control signal while not receiving the forcibly lighting signal.
Abstract:
The lighting device of one aspect according to the present disclosure calculates, based on a voltage value of an AC voltage applied to a discharge lamp and a current value of AC current flowing through the discharge lamp, a first power value defined as a value of power supplied to the discharge lamp in a first half period of the AC voltage and a second power value defined as a value of power supplied to the discharge lamp in a second half period of the AC voltage. The lighting device determines that a ground fault has occurred, when an imbalance state in which a difference between the first power value and the second power value is equal to or greater than a threshold value continues for a predetermined time period.