Abstract: A method for operating a lamp, wherein in the preheating phase a first value of the voltage drop correlated with the reciprocal of the electrical resistance of a coil of the lamp is determined across a resistor at a first instant, and a second value of the voltage drop is determined at a second instant, may include: a) determining the difference between a first and the second value; b) b1) if the difference is greater than a first threshold value: carrying out an algorithm for lamp-type recognition; b2) if the difference is not greater than the first threshold value: c1) if the difference is greater than a second threshold value: d1) if the second value is greater than a third threshold value: determining a coil short circuit; d2) if the second value is not greater than the third threshold value: operating the lamp with the current set of operating parameters.

Abstract: An improved LED traffic signal is provided. The LED traffic signal suitably includes a housing with an opening, a printed circuit board coupled to the housing, and a power supply system coupled to the printed circuit board. The power supply system includes a power supply module that receives an AC input voltage from an AC input line and transforms the AC input voltage into a DC voltage with a regulated current to power the LED load, and a synchronized power pulse circuit connected to the power supply that generates a synchronized power pulse representing a power consumption substantially equivalent to that of a halogen or incandescent traffic signal.

Abstract: A power supply control device for lamp includes a control unit, the control unit receives a forward voltage signal and a reverse voltage signal simultaneously from a zero-crossover sampling circuit and determines if a connected load is an LED lamp, then the control unit turns on a tri-electrode AC switch (TRIAC) after an operating voltage for the LED voltage is reached, thereby outputting the AC power to an outlet for illuminating the LED lamp; since the TRIAC can be turned on with the forward voltage or the reverse voltage, the LED lamp is powered with a stable power supply to prevent the LED lamp from blinking.

Abstract: This invention relates to an LED lamp device which can be applicable to a socket of a general fluorescent lamp, a halogen lamp, an incandescent lamp or the like by embodying an LED illuminating lamp powered by an alternating current (AC) through a simplified rectifier circuit and control of the number of LEDs without a dedicated circuit such as SMPS or the like when constructing the illuminating lamp using the LEDs, and which can reduce manufacturing costs and miniaturize the size of a product.

Abstract: In order to provide open-lamp protection to a backlight module, a pseudo open-lamp voltage is first generated according to the current flowing through a light source. If the backlight module receives a mode signal corresponding to a high contrast mode, a compensation voltage is added to the pseudo open-lamp voltage for generating a reference voltage. If the reference voltage is larger than a feedback voltage received from an input node of the light source, a driving voltage is outputted to the light source.

Abstract: A single-stage integrated circuit drives LED sources in a constant power mode to eliminate the need for LED current sensing, while reshaping the waveform of the inductor current near line zero crossing to achieve high power factor. The integrated circuit achieves substantially constant input power my maintaining a constant voltage at a power factor corrector controller through an input voltage feedforward system. Accordingly, the disclosed circuit provides a high power factor, high efficiency, simple, and cost-effective solution with substantially consistent input power for both isolated and non-isolated offline LED applications.

Abstract: A lighting system has an array (100) of at least one light-emitting solid-state element such as a light-emitting diode (LED) or a laser diode. A voltage source (10), which may supply either alternating or direct current, energizes the array. Array state circuitry (125; Q2, R2), electrically connected in series with the array (100), senses at least one state of the array, such as the amount of current passing through the array, or temperature. Secondary circuitry (127; R1, Q1; 200, 201, 202; 200, R4, Q1; 126, 127) is connected in parallel with the array (100). A switching component (Q1; Q1, Q3; 202) adjusts the current passing through the secondary circuitry in accordance with the sensed state of the array such that current through the array is maintained substantially constant.

Abstract: A ballast for driving one or more lamps includes a controller and a current reduction circuit for accelerating a controller reset. Upon detecting a fault, the controller disables the ballast for a preset period of time, and resets. The controller additionally resets when the ratio of a supplied second value to a supplied first value falls below a threshold value. The current reduction circuit reduces the supplied second value in less than the preset period of time, such that the ratio falls below the threshold value and the controller resets. An emergency lighting system includes the ballast as a primary ballast, a backup ballast, and a primary power source. The controller detects a fault if the primary power source de-energizes and the backup ballast disconnects the one or more lamps from the primary ballast. The current reduction circuit accelerates the reset of the controller when the primary power source de-energizes.

Abstract: An electronic ballast is capable of inhibiting ballast shutdown caused by erroneously determining a fault condition. The ballast includes a DC power supply circuit for outputting DC power, a power conversion circuit that appropriately converts DC power outputted by the DC power supply circuit and outputs it to a discharge lamp, a DC voltage droop detection circuit for determining existence/absence of a fault condition in the DC power supply circuit 1, a lamp end of life detection circuit for determining existence/absence of a fault condition of the discharge lamp; and a sequence control circuit and a shutdown control circuit that control at least the power conversion circuit according to detection by the DC voltage droop detection circuit the discharge lamp life detection circuit.

Abstract: An electronic ballast powers at least one fluorescent tube or lamp which has a power source; a DC power supply having an input connected to the power source; an oscillator connected to an output of said DC power supply so as to be driven therefrom; a driver means; and a protection means that deactivates the oscillator when the output reaches a predetermined abnormally high voltage. The protection means includes a transformer; a plurality of windings disposed on the transformer, a delegated winding disposed on the transformer. The protection means includes a sample point for sampling voltage. The protection means deactivates the delegated winding disposed on the transformer for the magnetizing the transformer and stopping oscillation when the sample point reaches a predetermined abnormally high voltage.

Abstract: A circuit arrangement for operating a converter, which comprises a bridge circuit having at least a first bridge switch and a second bridge switch and a first bridge center point and a second bridge center point is provided. The circuit arrangement may include a current differential amplifier, the first input of the current differential amplifier being coupled to a first comparison signal input, the second input of the current differential amplifier being coupled to a second comparison signal input, the output of the current differential amplifier being coupled to a control electrode of a first electronic switch.

Abstract: The present invention is an overvoltage protection and automatic re-strike circuit for an electronic ballast. The electronic ballast has an inverter, a shut-down circuit, a safety circuit, a monitoring circuit, and an overvoltage protection circuit. The inverter provides an appropriate alternating current power supply to operate the lamp. The shut-down, safety, monitoring, and overvoltage protection circuits are coupled to the inverter and provide the overvoltage protection and automatic re-striking functions. During an overvoltage condition, the overvoltage protection circuit will temporarily disable the inverter. Subsequent to the overvoltage condition, the overvoltage protection circuit permits the inverter to attempt to re-ignite the lamp. After a predetermined number of unsuccessful re-ignition attempts, the safety circuit will permanently disable the inverter to avoid damage to the ballast.

Abstract: According to one or more embodiments, an inverter provides a light source with an input voltage. A protection circuit shuts down the inverter based on an overvoltage protection level that is detected based on the input voltage. A protection circuit control part shuts down the operation of the protection circuit during a predetermined interval. Abnormal operation of the protection circuit caused by a high voltage provided when the light source is turned on may be prevented. Therefore, a turn-on defect of the light source may be prevented.

Abstract: A network operation center for a light management system having networked intelligent luminaire managers. A plurality of networked luminaire managers, each collocated with a respective luminaire, monitor the status of their respective luminaires. The luminaire managers include transmitters for transmitting status information about their respective luminaires and third-party devices to a network server. The network server forwards the received status information from the networked luminaire managers to a computer of an owner/operator of the plurality of luminaires and/or a third-party user. The luminaire managers communicate with each other, whereby they form a network.

Abstract: An apparatus for driving a backlight includes a controller for driving a lamp; a limiter for preventing the controller from driving the lamp during a contact condition of the lamp; and means for disabling the limiter during a first time of the controller, wherein the controller drives the lamp from a zero condition to the contact condition during the first time of the controller.

Abstract: A luminaire can comprise an electronic circuit, such as an LED driver or electronic ballast. A surge protection device in the current path between a power supply and the luminaire components can be configured to protect the electronic circuitry by absorbing and/or redirecting energy of a surge by switching into a low-impedance state while maintaining the protected circuitry (including its internal protective components, if any) in a high-impedance state. The surge protection device can comprise a MOV stage and a filter stage, for example. The surge protection device can be configured as a replaceable module, with the luminaire including an assembly designed to receive the module and allow for easy replacement over the useful life of the other components. Use of fuses or thermal components may cause the surge protection device to interrupt power flow if protection is lost due to internal failure, indicating when module replacement is needed.

Abstract: A lighting device for a cold-cathode tube includes an inverter that supplies a current through the cold-cathode tube, an operation portion through which a luminance adjustment is performed, an inverter control circuit that controls the inverter in accordance with a luminance adjustment value adjusted through the operation portion so as to change the current flowing through the cold-cathode tube, and a protective circuit that stops operation of the inverter when the current flowing through the cold-cathode tube becomes smaller than a predetermined set value. The protective circuit of the lighting device is controlled in such a way that the protective circuit does not operate when the luminance adjustment value adjusted through the operation portion is smaller than a luminance threshold value.

Abstract: A precision approach path indicator system (PAPI) including multiple LHA indicators and power sources. Each LHA indicator comprises several assembly modules, with each module made up of several red and white LEDs, several collimating lens, one optical combiner, and one projection lens set. From a side view of the module, the red LEDs are placed on top of white LEDs, with a collimating lens in front of each LED. The optical combiner is in front of both the red and white LEDs, slightly above the white LEDs in vertical placement. The optical combiner has a reflective coating on the bottom surface, and a red light filter coating on the projection surface. The combined beam of light is projected out through a projection lens at front of the assembly module.

Abstract: A bypass circuit is provided for each LED in a series to permit continued operation with reduced lighting in the event of an LED failure. The bypass circuit is provided in parallel to the LED and comprises a Zener Diode provided in parallel to a thyristor. Upon LED failure, the voltage across the Zener Diode is increased thereby triggering the thyristor which is maintained in a triggered mode as long as current flows through the series circuit.

Abstract: In a method of detecting arc discharge in a glow-discharge apparatus GD that has a high-frequency power source PS, a cutting pulse is output for time T1 to the high-frequency power source PS to stop a supply of power to the glow-discharge apparatus GD, when dVr/dt-dVf/dt increases over a first level, where Vf and Vr are a traveling-wave voltage and a reflected-wave voltage applied to the glow-discharge apparatus GD, respectively.

Abstract: An electronic ballast is provided for controlled preheating of filaments in a discharge lamp. A power converter has a plurality of switching elements and converts DC power from a DC power source into AC power for the lamp. A starting circuit generates a high voltage for starting the lamp. A half-wave discharge detecting circuit detects an absolute value for each polarity peak of a lamp current, calculates an asymmetrical current value from the detected peaks with respect to a predetermined current threshold, and detects a half-wave discharge of the lamp wherein an absolute value of the asymmetrical current value is equal to or more than the current threshold for a predetermined determination time.

Abstract: An electronic ballast is provided for adjustable filament preheating of a discharge lamp based on output current symmetry. A power converter receives DC power and outputs AC power. A starting circuit generates a high voltage for starting the lamp. A control circuit controls the AC power output from the power converting circuit. A symmetry determining circuit determines a positive-negative symmetrical state of the AC power output to the lamp with respect to ground. After lamp startup, the control circuit enters a filament heating operation in which the output frequency of the power converting circuit is controlled to a first frequency. At one or more predetermined current detection points during the filament heating operation, the control circuit checks the symmetry state.

Abstract: A electronic ballast according includes a DC power source circuit for generating a DC voltage from an AC power source, a pair of switching elements, an LC series resonance circuit, an inverter circuit for converting the DC voltage into a high frequency voltage to supply to a fluorescent lamp FL, and means such as a current transformer for detecting a current flowing into the fluorescent lamp FL, wherein oscillation of the inverter circuit is stopped when a value of a current flowing into the fluorescent lamp exceeds a predetermined value

Abstract: A control circuit for an operating device for lighting devices, wherein a return signal is supplied to an input of the control circuit by the lighting device, and the control circuit has an error detection block that recognizes at least two different types of lighting device errors by means of the return signal applied at said input.

Abstract: An LED drive circuit is an LED dive circuit that receives an alternating voltage to drive an LED, and includes a current remove portion that removes a current from a current supply line that supplies an LED drive current to the LED. If an input current to the LED drive circuit is an unnecessary current, the LED does not light because of current removal by the current remove portion. If the input current to the LED drive circuit turns into the LED drive current from the unnecessary current, the current remove portion decreases the amount of current removed.

Abstract: A signal is described herein that provides light output for automotive, rail, ship traffic and/or illumination control that includes a light emitting diode (LED) array, wherein the LED array includes three groups of disparate colored LEDs. A power supply unit provides independent power to each of the three LED groups. Each LED group power supply unit includes an input controlled switch connected to a power line to provide power to the LED array. An input under voltage/over voltage circuit monitors the voltage level of the power line and for enabling and/or disables the input controlled switch according to the voltage level of the power line. A flyback transformer converts the power received from the power line from an alternating or a continuous current signal to a direct current signal output to the LED array.

Abstract: A driver (1) for driving a gas discharge lamp (2) comprises: -a current source (3) generating lamp current, having a setpoint input (4) for receiving a setpoint signal; -a controller (10) generating a current setpoint signal (SM); -a controllable noise signal source (20) generating a pseudo random noise signal (SPRNS); -an adder (22) adding the current setpoint signal (SM) from the controller and the pseudo random noise signal (SPRNS) from the noise signal source, and providing the result to the setpoint input of the current source; -measuring means (40) measuring a characteristic lamp response of the lamp in response to the pseudo random noise signal (SPRNS), and providing to the controller a sense signal; -a memory (30) associated with the controller, having stored therein at least one reference signal. The controller compares the measured lamp response with said predetermined reference signal in the memory, and may switch off the lamp.

Abstract: One embodiment of the present invention relates to a lamp abnormality detecting device that detects an abnormality in a lamp. A maximum/minimum extraction circuit outputs, as a maximum current, a current having a maximum current value among currents supplied thereto from lamp drive circuits and outputs, as a minimum current, a current having a minimum current value. A subtraction circuit calculates a difference between the maximum current and the minimum current and outputs an amplified difference as a differential voltage. A comparison circuit compares the differential voltage with a predetermined threshold voltage and outputs a result of the comparison as a control signal. A control circuit stops the operation of the lamp drive circuit when the control signal indicates that the differential voltage is higher than the threshold voltage.

Abstract: A lamp connector allows for checking of a connection between an external electrode of an external electrode tubular lamp and a terminal fitting into which the external electrode is fitted. Because the lamp connector into which an external electrode provided on the outer surface of an end portion of a tubular lamp is fitted includes a terminal fitting which includes a terminal piece and a terminal piece insulated from each other which are to be individually brought into contact with the external electrode, it is possible to easily check conduction between the external electrode and the terminal fitting using a tester. Accordingly, any poor fitting of the lamp into the connector can be readily found and corrected.

Abstract: In order to enhance stability of a discharge lamp at the time of dimming lighting even in the case where a light output is lowered, a direct current superimposing circuit superimposes a direct current voltage on an alternating current voltage applied to a fluorescent lamp, and a dimming signal correction circuit receives a detection value of a direct current voltage detection circuit and a dimming signal that is from an outside, outputs a dimming signal higher in level than the dimming signal in the case where the detection value of the direct current voltage detection circuit exceeds a first threshold value, and decreases the level of the outputted dimming signal to the level of the inputted dimming signal in the case where the detection value of the direct current voltage detection circuit falls down below a second threshold value that is equal to or less than the first threshold value.

Abstract: An electronic ballast A includes an inverter circuit for converting a DC voltage into a high-frequency voltage, a resonant circuit which is connected between outputs of the inverter circuit and lights a discharge lamp at a high frequency by a resonant action, a dimming circuit for changing an output voltage to the discharge lamp by changing an operating frequency of the inverter circuit, a DC component detecting circuit for detecting a DC voltage component of the discharge lamp and a control operating circuit which detects an output signal of the DC component detecting circuit for every predetermined period to reduce or stop an output to the discharge lamp in the case where the output signal exceeds a predetermined reference value and to prohibit the protection operation when periodic change amount in the output signal reaches a predetermined value or higher.

Abstract: A electronic ballast includes an inverter circuit for converting a DC voltage into a high-frequency voltage, a resonant circuit connected between outputs of the inverter circuit so as to light a discharge lamp by a resonant action, a control circuit for controlling the inverter circuit, a dimming circuit for continuously changing an output voltage to the discharge lamp by changing an operation frequency in the inverter circuit, a DC component detection circuit and a voltage comparator for detecting whether or not the discharge lamp is at the end of the life at predetermined intervals and outputting an end of life detection signal upon detection of the end of the life state, and a frequency control circuit and a driving circuit for reducing or stopping an output to the discharge lamp by controlling switching elements in response to a life end detection signal inputted from the voltage comparator.

Abstract: A power supply for an insulation detector having a heating element and a temperature sensitive switch thermally coupled to the heating element, the power supply including a power circuit 120 operable to provide heating element power 102 to the heating element 32; a short protector 108 operably connected to the power circuit 120 to monitor current flow through the heating element 32; and an insulation detector sensor 110 operably connected to the power circuit 120 to monitor presence of the heating element 32.

Abstract: A voltage detection circuit includes a voltage obtaining circuit for transforming an AC signal into a voltage signal, an over-voltage detection circuit connected to the voltage obtaining circuit, and an under-voltage detection circuit connected to the voltage obtaining circuit. The over-voltage detection circuit is for determining whether the AC signal is over-voltage, and generating an over-voltage signal if the voltage signal is over-voltage. The over-voltage detection circuit includes a first transistor. The first transistor includes a first control electrode electrically connected to the voltage obtaining circuit, a first electrode, and a second electrode. The under-voltage detection circuit is for determining whether the AC signal is under-voltage, and generating an under-voltage signal if the voltage signal is under-voltage. The under-voltage detection circuit includes a second transistor.

Abstract: A method of electronic ballast protection including providing an electronic ballast having an AC/DC converter 104 with an electronic ballast input and a mains voltage connection 103 connectable to a mains voltage 102, an inverter 120 operably connected to the AC/DC converter 104 and having an electronic ballast output 125 connectable to a lamp 124, a control circuit 116 controlling the inverter 120, and a low voltage power supply 114 providing low voltage power to the control circuit 116; supplying power to the low voltage power supply 114 from the electronic ballast input when the mains voltage connection 103 is wired to mains voltage 102; and disconnecting the power to the low voltage power supply 114 when the electronic ballast output 125 is wired to the mains voltage 102.

Abstract: A lighting control device includes a current driving portion for DC-controlling or PWM-controlling an LED unit, and a disconnection detection portion for detecting disconnection of the LED unit. The disconnection detection portion has a latch circuit and a reset portion. The latch circuit provides a disconnection detection signal after it is detected that disconnection has occurred for a prescribed time. The reset portion resets the disconnection detection signal based on prescribed conditions.

Abstract: A monitoring device for monitoring at least one fluorescent lamp, particularly in areas at risk of explosion, which fluorescent lamp has a lamp tube with electrodes arranged on the ends thereof in the form of coils, and lamp sockets assigned to said electrodes, is improved for preventing large temperature increases in a corresponding fluorescent lamp, particularly in areas at risk of explosion, by complying with the appropriate explosion safety measure, in that the monitoring device has at least one temperature measuring device assigned to a coil, and one electro-mechanical interruption device with which the energy supply to the fluorescent lamp can be interrupted upon reaching a preset critical temperature value.

Abstract: A system for current and/or temperature control of light fixtures includes a sensor in communication with a light fixture, sense a current flow or a temperature of the light fixture, and communicate an input signal relative to the current flow or the temperature; a variable switch in communication with the light fixture to regulate the current flow of the light fixture in response to a control signal; and a controller in communication with the sensor and the variable switch to monitor the input signal, compare the input signal to a condition, and communicate the control signal to the variable switch to control its operation. A bypass circuit applies a normal current directly to the light fixture should a failure occur with the sensor, the variable switch or the controller.

Abstract: A discharge lamp lighting apparatus includes a first inverter, a second inverter to output a voltage whose phase is opposite to that of a voltage provided by the first inverter, a discharge lamp connected between a first output terminal of the first inverter and a first output terminal of the second inverter, a first current detection circuit arranged between a second output terminal of the first inverter and a common potential and having a first current detection element and a second current detection element that are connected in series, a second current detection circuit arranged between a second output terminal of the second inverter and the common potential and having a third current detection element and a fourth current detection element that are connected in series, and a protection circuit to detect a current abnormality according to a composite signal of outputs of the second and fourth current detection elements and stop the operation of the first and second inverters.

Abstract: A DC/AC inverter substrate includes a voltage abnormality detector circuit. All of a high voltage side detection sensor, a low voltage side detection sensor, and a high-voltage and low-voltage detection sensor in the voltage abnormality detector circuit are disposed without being electrically connected to a secondary side of a transformer or to a connection point. Those detection sensors are not damaged since overvoltage is not applied to the voltage abnormality detector circuit when abnormal discharge occurs because the detection sensors are not electrically connected.

Abstract: A safety starter circuit for a gas discharge lamp is described, comprising a series arrangement of: a glow switch starter (5); at least one resistive element (9); a thermally controlled switching element (8). The thermally controlled switching element (8) is in a heat transfer relationship with the resistive element (9) so that the thermally controlled switching element (8) is effectively heated by heat generated in the resistive element (9). The thermally controlled switching element (8) is designed to make a transition from a conductive state to a non-conductive state when its temperature exceeds a predetermined cut-off temperature. According to the invention, the thermally controlled switching element (8) is arranged in a gas-tight casing (7a).

Abstract: According to the invention, a state automaton is used when operating a high-pressure discharge lamp on a ballast operated by means of a microprocessor in order to prevent certain malfunctions.

Abstract: An electrostatic discharge (ESD) protection circuit electrically connected to a first conductive line and a second conductive line is provided. The ESD protection circuit has a first ESD protection circuit unit, wherein the first ESD circuit unit includes a first coupled capacitor and a first active device. The first coupled capacitor includes a first electrode and a second electrode, wherein the first electrode is electrically connected to the first conductive line. The first active device includes a first gate, a first source and a first drain, wherein the first gate is electrically connected to the second electrode. In addition, the first source and the first electrode are electrically connected to the first conductive line, and the first drain is electrically connected to the second conductive line. Therefore, the conduction efficiency of the ESD protection circuit is improved.

Abstract: A light emitting diode driving device and light system are provided. The light emitting diode driving device drives a light source by a received alternating current voltage. The light emitting diode driving device includes a rectifier, a feedback unit, a protection unit, a switch unit, a timing unit, and a control unit. The rectifier is electrically coupled to an alternating current voltage source and the light source for providing the alternating current voltage to the light source. The feedback unit is used to detect a loading state and generate a feedback signal according the loading state for outputting the feedback signal. The protection unit is used to receive the feedback signal and compare the feedback signal with a reference voltage built in the protection unit for outputting a switch signal. The switch unit is used to receive the switch signal and connect or disconnect the alternating current voltage source and the light source.

Abstract: The present invention refers to a driving device of a discharge lamp (10) having two cathodes. Said device comprises first means (1, 11) having a supply input voltage (Val) and suitable for providing an alternating voltage at the ends of the cathodes, second means (3) capable of monitoring a condition of each of said cathodes and suitable for measuring a first direct voltage signal (Vdc) of the waveform of the voltage of the lamp that develops when the lamp (10) approaches the ageing condition, third means (40) coupled to the second means (3) and suitable for deactivating the first means (11), fourth means (50) suitable for providing to the third means (40) a second direct voltage signal (Vdca) proportional in value to the supply voltage (Val). The third means (40) are suitable for deactivating the first means (11) when a predetermined variation of the first direct voltage signal (Vdc) occurs in relation to the second direct voltage signal (Vdca).

Abstract: There is provided a discharge clamp lighting apparatus including: a transformer, a transformer driving circuit, a control circuit, in which a primary side of the transformer is driven by the transformer driving circuit lighting a discharge lamp connected at a secondary side of the transformer, a discharge sensing circuit, a signal detecting circuit detecting a voltage signal induced in the discharge sensing circuit, and a protection means stopping supply of electric power to the secondary side of the transformer according to the voltage signal detected at the signal detecting circuit, wherein the signal detecting circuit includes a signal discriminating circuit attenuating a component of a voltage signal inputted from the discharge sensing circuit, the component having a frequency equal to or lower than a predetermined value, to be equal to or greater than a secondary high-frequency pass filter, passing only a high-frequency signal caused by an abnormal discharge.

Abstract: An illuminating device for imaging apparatus includes: a light source; plural batteries that supply power to the light source; plural detection voltage generating units that are provided with respect to each battery and generate detection voltages from output voltages of the batteries; a voltage monitoring unit that is supplied with the plural detection voltages, respectively, and determines whether the output voltages of the batteries are equal to or less than a predetermined specified value or not with respect to each battery; and a control unit that turns on/off the supply of the power to the light source based on a determination result of the voltage monitoring unit, wherein detection switches that turn on/off the supply of the detection voltages from the respective detection voltage generating units to the voltage monitoring unit based on the control by the control unit are provided with respect to each battery.

Abstract: The present invention provides a magnetic low voltage dimmer circuit that reduces DC magnetizing current which may be present in a dimmer system. The dimmer circuit delivers an RMS value of an AC supply voltage to a load while preventing or reducing a DC magnetizing current from damaging the dimmer circuit and/or load. The dimmer circuit includes a shutdown circuit which detects whether a DC voltage, corresponding to the DC current, is present across a circuit component and whether the DC voltage has reached or exceeded a predetermined voltage reference level, rendering the component non-conductive and thus preventing the DC magnetizing current from flowing through a load.

Abstract: A discharge lamp ballast is designed to limit or interrupt its AC output power to the discharge lamp upon occurrence of an abnormal discharge outside of an arc tube. A detector is included to examine a lamp voltage once in each of the positive and negative half-cycles or in each one complete cycle of the AC output power, and identifies the abnormal discharge when there is a particular change in the monitored lamp voltage. The particular change may be defined by a single logic or by combination of several logics each designed to represent specific characteristic for the abnormal discharges of several types.

Abstract: Provided is a lighting unit and a discharge lamp each of which is capable of causing a capacitor to break down by heat generated in a heat generating component, so that circuit operation is safely terminated without any additional cost. A compact self-ballasted fluorescent lamp is provided with a lighting unit (50) housed in a case. The lighting unit (50) causes an arc tube to emit light and is composed of a plurality of electronic components, including a rectifier/smoothing circuit portion, an inverter circuit portion having transistors (Q1 and Q2), a resonant circuit portion, and a preheating circuit portion having a positive temperature coefficient element. Among the plurality of electronic components, the transistors (Q1 and Q2) and the positive temperature coefficient element generate excessive heat when, for example, the lamp is operated at the end of electrode's life.