Abstract: Systems and methods of variably controlling a driver signal to a light emitting device located proximate to a burner assembly of an appliance are provided. The driver signal can be adjusted based on a signal indicative of a temperature in a region proximate the light emitting device. The signal indicative of a temperature of the burner assembly temperature can be generated by a temperature senor or the signal can be based on an anticipated temperature profile of the burner assembly. The driver signal can be adjusted based on the signal indicative of the temperature of the burner assembly temperature using pulse width modulation.

Abstract: In embodiments of the present invention, a method and system is provided for designing improved intelligent, LED-based lighting systems. The LED based lighting systems may include fixtures with one or more of rotatable LED light bars, integrated sensors, onboard intelligence to receive signals from the LED light bars and control the LED light bars, and a mesh network connectivity to other fixtures.

Abstract: A light emitting diode (LED) assembly is provided having a LED and a temperature sensor for monitoring a temperature of the LED. An active cooling circuit receives temperature input from the temperature sensor. The temperature input is indicative of the temperature of the LED. An active cooling system cools the LED. The active cooling system being controlled by the active cooling circuit to control a temperature of the LED.

Abstract: A lighting device capable of generating warm or neutral white light using blue light-emitting diodes (“LEDs”), red LEDs, and/or luminescent material that responds to blue LED emission is disclosed. The lighting device includes multiple first solid-state light-emitting structures (“SLSs”), second SLSs, and balancing resistor element. The first SLS such as a string of blue LED dies connected in series is able to convert electrical energy to blue optical light, which is partially turned into longer wavelength emission by the luminescent material. The second SLS such as a red LED die is configured to convert electrical energy to red optical light, wherein the second SLSs are connected in series. While the first SLSs and second SLSs are coupled in parallel, the balancing resistor element provides load balance for current redistribution between the first and second SLSs in response to fluctuation of operating temperature.

Abstract: Representative embodiments of the disclosure provide a system, apparatus, and method of controlling an intensity and spectrum of light emitted from a solid state lighting system. The solid state lighting system has a first emitted spectrum at full intensity and at a selected temperature, with a first electrical biasing for the solid state lighting system producing a first wavelength shift, and a second electrical biasing for the solid state lighting system producing a second, opposing wavelength shift. Representative embodiments provide for receiving information designating a selected intensity level or a selected temperature and providing a combined first electrical biasing and second electrical biasing to the solid state lighting system to generate emitted light having the selected intensity level and having a second emitted spectrum within a predetermined variance of the first emitted spectrum over a predetermined range of temperatures.

Abstract: A system and method for driving one or more LEDs by regulating their brightness by controlling the LEDs' average current or voltage. The system includes a switching power converter and an integrated digital regulator with at least one of electrical, thermal, and optical feedbacks. The regulator is constructed as a PI or PID controller for continuous mode of operation of the power converter. Current is provided through an inductor and a power switch during an on time of the power switch. The ampseconds of the inductor are measured at an off time and compared with a periodic ramp signal. A set reference signal is also compared with the periodic ramp signal. Based on the comparisons between the ramp signal, the measured ampseconds, and the reference signal, a control signal is generated to regulate the peak current through the power switch.

Abstract: A lighting apparatus (100) includes one or more first LEDs (202) for generating a first spectrum of radiation (503), and one or more second LEDs (204) for generating a second different spectrum radiation (505). The first and second LEDs are electrically connected in series between a first node (516A) and a second node (516B), between which a series current (550) flows with the application of an operating voltage (516) across the nodes. A controllable current path (518) is connected in parallel with one or both of the first and second LEDs so as to at least partially divert the series current, such that a first current (552) through the first LED(s) and a second current (554) through the second LED(s) are different. Such current diversion techniques may be employed to compensate for shifts in color or color temperature of generated light during thermal transients, due to different temperature-dependent current-to-flux relationships for different types of LEDs.

Abstract: The present invention provides an integrated circuit controller for ballast with preheat/repreheat filament and ignition time control. A charge/discharge circuit is connected to a capacitor to provide the charge/discharge path for the capacitor. It charges when integrated circuit controller without errors and discharges when error occurred during lamp operation or power tripped. A control circuit is coupled to the charge/discharge circuit to control the charge/discharge circuit to charge or discharge the capacitor. A compare circuit is coupled to the charge/discharge circuit to compare a voltage signal on the capacitor from the charge/discharge circuit with threshold voltages for timing control and providing a preheat signal and an ignition signal. A control logic circuit is coupled to the control circuit to control the control circuit and coupled to the compare circuit to receive the preheat signal and the ignition signal for preheating the filament and igniting the lamp.

Abstract: Digital Control Ready (DCR) is a two-way open standard for controlling and managing next-generation fixtures. A DCR-enabled lighting fixture responds to digital control signals from a separate digital light agent (DLA) instead of analog dimming signals, eliminating the need for digital-to-analog signal conditioning, fixture-to-fixture variations in response, and calibration specific to each fixture. In addition, a DCR-enabled lighting fixture may also report its power consumption, measured light output, measured color temperature, temperature, and/or other operating parameters to the DLA via the same bidirectional data link that carries the digital control signals to the fixture. The DLA processes these signals in a feedback loop to implement more precise lighting control. The DCR-enabled lighting fixture also transforms AC power to DC power and supplies (and measures) DC power to the DLA via a DCR interface.

Abstract: A lamp assembly provides both instant light through use of an incandescent/halogen light/lamp source and an energy saving type light provided by a compact fluorescent light/lamp source. Both light sources are enclosed within a common envelope or outer bulb. First and second thermal sensors are provided in the lamp envelope at spaced locations to monitor the temperature of the lamp. When the sum of these two temperatures reaches a preselected value, power to the incandescent lamp source is terminated. Alternatively, when the difference these two temperatures reaches a preselected value, power to the incandescent lamp source is terminated.

Abstract: A ballast for driving a gas discharge lamp includes an inverter configured to generate a lamp supply voltage signal, and a voltage regulator coupled to the inverter and configured to generate a regulation signal. The regulation signal is used by the inverter to maintain the lamp voltage signal at a substantially constant voltage. A thermistor circuit is coupled between the lamp supply voltage signal and the voltage regulator and configured to detect a temperature of the ballast. The lamp supply voltage signal is varied by the regulation signal in accordance with the detected temperature of the ballast.

Abstract: An amount of filament voltage supplied by a reconfigurable ballast may be adjusted based on a lamp type with which the ballast is operating. The filament voltage may be reconfigured dynamically and/or may be reconfigured via a user-provided value. An electronic dimming ballast may include a control circuit configured to control generation of the AC filament voltage in accordance with a reconfigurable AC filament voltage value. Reconfiguring an electronic dimming ballast may include reconfiguring an AC filament voltage applied by the electronic dimming ballast to a filament of a lamp installed in the electronic dimming ballast. Reconfiguring the AC filament voltage may include computing a hot-to-cold cathode resistance ratio associated with the filament. Reconfiguring the AC filament voltage may include determining whether the computed hot-to-cold cathode resistance ratio is within a range specified for the electronic dimming ballast.

Abstract: A temperature control method for light emitting diode (LED) is disclosed, and the method comprises the following steps: acquiring the present temperature of the LED during the light emission of the LED; obtaining a driving electric current corresponding to the present temperature based on the present temperature of the LED; and driving the LED based on the driving electric current. This invention further discloses a temperature control device for the LED and a liquid crystal display.

Abstract: A light emitting system includes: first, second, and reference light emitting components having first, second, and reference forward voltages when driven under constant current, respectively; an instrumentation amplifier for generating a temperature detection voltage with a magnitude dependent on the reference forward voltage of the reference light emitting component; first and second compensation voltage modules each generating a respective one of first and second compensation voltages based at least on the temperature detection voltage; and first and second power control modules providing first and second driving currents through the first and second light emitting components according to the first and second compensation voltages and the first and second forward voltages, respectively.

Abstract: A vehicle lighting device according to the present invention is configured in such a manner that a current that is supplied to a light emitting element that serves as a light source can be controlled with low power consumption in accordance with either of a voltage change in input power supply and a change in ambient temperature. This vehicle lighting device is configured in such a manner as to take out a reference voltage that is input to a switching controller 5 from a voltage dividing resistor R2 that is connected between a constant voltage source Vcc and a ground terminal GND. A current control circuit 10C for voltage change is provided to between an input power supply Vin and the ground terminal GND. Further, a current control circuit 10A for temperature change is provided to between the constant voltage source Vcc and the ground terminal GND.

Abstract: An electrical connector is provided for connecting a light emitting diode (LED) to a driver. The electrical connector includes a housing, a driver input contact held by the housing and configured to be electrically connected to a power output of the driver, and an LED output contact held by the housing and configured to be electrically connected to a power input of the LED. An electrical path is defined between the driver input contact and the LED output contact for supplying electrical power from the driver to the power input of the LED. The electrical connector includes a temperature monitor and control (TMC) module operatively connected to a temperature sensor for receiving a temperature associated with the LED. The TMC module is configured to control the flow of electrical power from the driver input contact to the LED output contact based on the temperature received from the temperature sensor.

Abstract: Disclosed herein are embodiments of failure alerting systems for LED lamps and LED lamps having the same. An illustrative failure alerting system comprises a photodetector configured to detect an actual light output from the at least one LED, a regulator configured to receive a signal from the photodetector when the actual light output is below a target light output and to increase a current to the at least one LED to maintain the target light output, and a low light output indicator configured to receive a signal from the photodetector when the actual light output remains below the target light output and to produce a low light output signal. A thermal sensor can also be included and configured to sense an operating temperature of the LED and to control the regulator to increase the current and the target light output to ensure the operating temperature does not exceed the target temperature.

Abstract: A light-emitting system includes first and second solid-state light-emitting components, a current source providing a constant current through the second solid-state light-emitting component, a first instrumentation amplifier detecting a second forward voltage across the second solid-state light-emitting component so as to generate a first detection voltage having a magnitude dependent on the second forward voltage, a compensation voltage module operable to generate a compensation voltage having a magnitude related to the second forward voltage according to the first detection voltage and two reference voltages, and a power control module detecting a first forward voltage across the first solid-state light-emitting component and providing a driving current therethrough that is dependent on the compensation voltage and the first forward voltage and that varies according to ambient temperature.

Abstract: A lighting device may include a substrate attached to one edge side of a radiator and a cover may be attached to cover the substrate. Heat-radiating fins may be provided on the other edge side of the radiator and an air-cooling unit may be rotatably provided inside the heat-radiating fins, thereby enabling freely rotation. In one or more examples, a case storing a circuit part is attached to the other edge side of the radiator and a cap is provided to the case. By the air flow from the air-cooling unit, the heat-radiating fins are caused to be a part of the ventilation path to allow for ventilation of the inside of the radiator.

Abstract: A DC-DC converter for driving one or more LED (38), which converter comprises an integrated circuit (12) having a switch mode power circuit (24) and a 5 temperature sensing circuit (40) for providing an output indicating a temperature of said integrated circuit (12), the arrangement being such that, in use, said integrated circuit consumes power, some of which power is dissipated in said integrated circuit as heat causing a rise in said internal temperature, and wherein a change in said output from said temperature sensing circuit (40) is used by said integrated circuit to 10 adjust said consumed power whereby said internal temperature may be controlled.

Abstract: In a circuit (1) for sensing a property of light there are provided a first circuit element (7) that is sensitive to light and that is realized to generate an output signal (I1) during a measurement time period (?tM), wherein the output signal (I1) is generated according to light to which the first circuit element (7) is exposed and the temperature (T) of the first circuit element (7), and a second circuit element (8) that is realized to increase the temperature (T) of the first circuit element (7) during a warming time period (?tW) that precedes the measurement time period (?tM).

Abstract: After discharge has begun in a high pressure discharge lamp, constant current control is performed so a lamp current becomes 4 [A]. Then, the current supplied to a pair of electrodes in the lamp is controlled so an electrode tip temperature t [degrees C.] at this time and an electrode tip temperature T [degrees C.] during stable lighting satisfy the relationship t [degrees C.]<=1.1 T [degrees C.]. When a power of the lamp reaches a rated power value, power control is changed to constant power control. This method enables suppressing an excessive rise in the temperature of the electrode tips in an initial lighting interval from lighting commencement until stable lighting, thereby preventing an increase in arc length due to melting of the electrode tips. Accordingly, illuminance does not readily decrease, particularly in a lamp unit including a high pressure discharge lamp mounted to a reflecting mirror.

Abstract: Embodiments disclosed herein describe the use of a power supply to provide power to an LED load. The power supply provides a present output current to the LED, and receives a temperature signal representing the operating temperature of the LED. A target output current is determined, for instance based on the temperature signal. An output current rate of change is determined, and the power supply adjusts the output current to the LED at the determined rate of change until the output current is substantially equal to the target current.

Abstract: A method and apparatus for derating current and for derating current for a camera flash. The method comprises monitoring a local junction temperature of a module. The local junction temperature is converted into a local junction current. The local junction current is then compared with a reference current, which is independent of temperature. After the current comparison and subtraction is made, a derate control current is obtained to generate the LED reference current. After the temperature crosses the temperature threshold, the derate control current is derated. Both the temperature threshold and current derate slope are programmable and precisely controlled. The LED output current is regulated and proportional to the LED reference current. If the local junction temperature is greater than the temperature threshold, the LED output current is derated at the moment of the camera flash to avoid thermal overload.

Abstract: In accordance with an example embodiment, there is disclosed herein a LED PAPI (10) with condensation protection. The condensation protection may suitably comprise passive components, such as gaskets and seals (26, 36) and a desiccant (48), and/or active components, such as a defroster (39) and/or a heater (50).

Abstract: In embodiments of the present invention, a method and system is provided for designing improved intelligent, LED-based lighting systems. The LED based lighting systems may include fixtures with one or more of rotatable LED light bars, integrated sensors, onboard intelligence to receive signals from the LED light bars and control the LED light bars, and a mesh network connectivity to other fixtures.

Abstract: An LED drive circuit that sufficiently exhibits the performance of an LED element to obtain a favorable luminance at room temperature, includes a constant-current circuit including an LED element, a constant-current output unit, and a temperature sensing element having a negative resistance-temperature coefficient. The LED element is connected to the constant-current output unit in series. The constant-current output unit is connected to the LED element in parallel. Due to changes in the resistance value of the constant-current output unit caused by changes in temperature, the value of a current passing through the LED element is increased at room temperature and the value of a current passing through the temperature sensing element is reduced at high temperature.

Abstract: An inductive LED lamp bulb comprising a male connector, casing, LED, lamp panel and PIR sensor, of which the male connector is set at upper part of the casing, both LED and lamp panel are set at lower part of the casing; moreover, the lamp panel covers said LED, while a controller is embedded into said casing, which is also equipped with a timing switch and a contrast switch; said PIR sensor of a removable structure is mounted at the lower part of the casing, and protruded from said lamp panel; said controller is electrically connected with LED, PIR sensor, timing switch and contrast switch; thus, the utility model can be used as a common LED lamp bulb with more control functions and broader range of applications by disassembling easily the PIR sensor.

Abstract: An appliance and method for variably controlling a drive signal to a light emitting device of the appliance based on a temperature value indicative of a temperature within a chamber of the appliance is provided. The light emitting device can be included in a display or disposed within a chamber of the appliance to provide illumination. The light intensity level of the light emitting device can be controlled based on the temperature value indicative of a temperature within the chamber. The temperature value indicative of a temperature within the chamber can be a value detected within the chamber, a value detected on a surface of the chamber, or a value that anticipates the temperature within the chamber. The light intensity can be controlled with a driving signal to the light emitting device. For instance, the light intensity can be controlled using pulse width modulation of the driving signal.

Abstract: A dimmable driver comprising a dimming control signal.

Abstract: Exemplary embodiments are directed to lamp ballast systems, generally including a lamp, at least one temperature sensor, a ballast and a processor. The at least one temperature sensor can be positioned proximate to the lamp or incorporated into the lamp. The ballast provides an electrical current to the lamp. The processor receives a sensed temperature from the at least one temperature sensor and, in response to the sensed temperature, directs a control signal to the ballast to regulate the electrical current provided to the lamp to maintain the lamp at an optimal operating temperature. Exemplary embodiments are also directed to methods of maintaining a lamp at an optimal operating temperature, generally including providing a lamp ballast system, receiving a sensed temperature, and directing a control signal to the ballast to regulate the electrical current provided to the lamp to maintain the lamp at the optimal operating temperature.

Abstract: In a lighting device, sets of LEDs are employed using the natural characteristics of the LEDs to resemble incandescent lamp behavior when dimmed, thereby obviating the need for sophisticated controls. A first set of at least one LED produces light with a first color temperature, and a second set of at least one LED produces light with a second color temperature. The first set and the second set are connected in series, or the first set and the second set are connected in parallel, possibly with a resistive element in series with the first or the second set. The first set and the second set differ in temperature behavior, or have different dynamic electrical resistance. The light device produces light with a color point parallel and close to a blackbody curve.

Abstract: Provided are a variable field effect transistor (FET) designed to suppress a reduction of current between a source and a drain due to heat while decreasing a temperature of the FET, and an electrical and electronic apparatus including the variable gate FET. The variable gate FET includes a FET and a gate control device that is attached to a surface or a heat-generating portion of the FET and is connected to a gate terminal of the FET so as to vary a voltage of the gate terminal. A channel current between the source and drain is controlled by the gate control device that varies the voltage of the gate terminal when the temperature of the FET increases above a predetermined temperature.

Abstract: A ballast. The ballast includes a lamp driver and a controller. The lamp driver is configured to power a gas discharge lamp, and the controller includes a non-volatile memory configured to save one or more parameters related to operation of the gas discharge lamp in the non-volatile memory. The controller is further configured to control the lamp driver based on the one or more parameters.

Abstract: Systems, methods, and devices are provided for maintaining a target white point on a light emitting diode based backlight. In one embodiment, the backlight may include two or more strings of light emitting diodes, each driven at a respective driving strength. Each string may include light emitting diodes from a different color bin, and the respective driving strengths may be adjusted, for example, through pulse width modulation or amplitude modulation, to maintain the target white point. In certain embodiments, the driving strengths may be adjusted to compensate for shifts in the white point that may occur due to temperature or aging. A controller may adjust the driving strengths based on feedback from a temperature sensor, from an optical sensor, from a user input, or from calibration data included within the backlight or system.

Abstract: A lighting device may include a substrate attached to one edge side of a radiator and a cover may be attached to cover the substrate. Heat-radiating fins may be provided on the other edge side of the radiator and an air-cooling unit may be rotatably provided inside the heat-radiating fins, thereby enabling freely rotation. In one or more examples, a case storing a circuit part is attached to the other edge side of the radiator and a cap is provided to the case. By the air flow from the air-cooling unit, the heat-radiating fins are caused to be a part of the ventilation path to allow for ventilation of the inside of the radiator.

Abstract: In a light emitting device and system providing white light with various color temperatures are provided, a light emitting device includes a light emitting element (LED) that is operated by a driving bias and emits first light, and a phosphor layer including a phosphor that partially wavelength-converts first light and emits second light, thereby emitting white light using the first light and the second light, wherein the phosphor has a maximum conversion efficiency at a first level of the driving bias, and the LED has a maximum conversion efficiency at a second level of the driving bias, the first level being different from the first level.

Abstract: Systems, methods, and devices are provided for maintaining a target white point on a light emitting diode (LED) based backlight. In one embodiment, the backlight may include two or more groups of LEDs, each driven at a respective driving strength. Each group may include LEDs of a different chromaticity, and the respective driving strengths may be adjusted, for example, by varying the duty cycles, to maintain the target white point. To ensure that the white point may be maintained over an operational temperature range of the backlight, the LEDs may be selected so that the chromaticities of each group of LEDs are separated by at least a minimum chromaticity difference. Further, the LEDs may be selected so that at the equilibrium temperature of the backlight, the LEDs may produce the target white point when driven at substantially equal driving strengths.

Abstract: To provide a lighting device in which the luminance of an EL element is maintained even when the EL element deteriorates so that degradation of the lighting device is reduced, the lighting device includes a surface light source portion including an organic EL element, and a control circuit portion provided in a base portion. The control circuit portion counts a lighting time of the organic EL element and controls the luminance of the organic EL element in accordance with the lighting time. Accordingly, the lighting device in which the luminance of an EL element is maintained regardless of degradation of the EL element so that degradation of the lighting device is reduced can be provided.

Abstract: A vehicle multi-energy illuminating system is disclosed.

Abstract: A liquid-cooled LED lighting device can be provided in which a temporal increase in the temperature of the tubing and the circulation pump when the LED light sources are turned off is prevented to ensure high reliability. The liquid-cooled LED lighting device can include an LED light source, a liquid cooling system including a heat receiving jacket and a radiator, an LED light source-driving power supply for supplying power to the LED light source, and a liquid cooling system-driving power supply for supplying power to the liquid cooling system. The LED lighting device can include a control unit, such as a timer circuit. The control unit can maintain supply of the power to the liquid cooling system for a predetermined period of time after supply of the power to the LED light source is stopped.

Abstract: An LED apparatus includes an LED component and a current-limiting device. The LED component includes at least one LED having a corresponding current-limiting resistance value. The current-limiting device includes a plurality of PTC devices connected in series. The plurality of PTC devices are capable of effectively sensing the temperature of the LED and are electrically coupled to the LED component. The resistance value of the current-limiting device increases with the increment of sensed temperature. The current-limiting device has a resistance close to or equal to the current-limiting resistance value at a temperature at which the LED operates normally. When the temperature of the LED gradually increases to an abnormal temperature, current allowable to be flowed through the current-limiting device gradually decreases to be lower than LED operating current.

Abstract: Circuits and methods for driving an LED from a secondary side of a transformer are disclosed herein. An embodiment of the method includes monitoring an input voltage to determine the power level intended to drive the LED. The current flow through the primary side of the transformer is adjusted to make the power actually driving the LED equal to the power intended to drive the LED.

Abstract: Disclosed is an LED light comprising at least one LED (43) that is arranged on a ceramic support element (32) and is connected thereto in a thermally conducting manner, and an electronic driver (17) that is electrically connected to the LED (43) to supply power and control the power supplied to the LED (43). The driver (17) is connected in a thermally conducting manner to the support element (32) in order to improve the electric control function and performance of the LED (43) in the light.

Abstract: In order to supply power and control the power supplied to an LED (43), in particular an LED (43) comprising a ceramic support element (4, 32), an LED driver circuit (17) is designed to regulate the supply current for the LED (43) in accordance with the temperature of the support element (4, 32).

Abstract: A circuit includes a component connected (i) to a rectifier, and (ii) between electrodes of a lamp. The electrodes include a first electrode and a second electrode. A control module is in communication with the rectifier and is configured to receive a temperature signal from a temperature sensor. The temperature signal is indicative of a temperature of the component. The control module is also configured to decrease current to the electrodes for a predetermined period when the temperature of the component is greater than a first predetermined temperature. The control module is further configured to increase the current to the electrodes when the predetermined period expires and independent of the temperature of the component.

Abstract: A pulsed electric operating current that rises during a pulse duration is generated for operating at least one radiation-emitting semiconductor component. For this purpose, in a method for producing a control device for operating the at least one radiation-emitting semiconductor component, a temporal profile of a thermal impedance representative of the at least one radiation-emitting semiconductor component is determined. A profile of the electric operating current that is to be set is determined depending on the determined temporal profile of the thermal impedance. The control device is furthermore designed such that the profile of the operating current that is to be set is set in each case during the pulse duration.

Abstract: A time-multiplexed thermal sensing circuit is provided for control and sensing of two thermistors over a single line electrical coupling. The circuit may include a first diode that selectively couples or isolates a first thermistor from a sense node based on the polarity of an applied voltage to the sense node. The circuit may further include a second diode that selectively couples or isolates a second thermistor from the sense node based on the polarity of the applied voltage to the sense node such that only of the thermistors is coupled to the sense node at any time.

Abstract: A current regulating circuit is for connection in series between a light emitting diode (LED) and a power source, and includes: a first resistive unit having a first resistance that is proportional to an operation temperature of the LED when the operation temperature is above a predetermined threshold temperature; and a second resistive unit connected in series with said first resistive unit, and having a second resistance that is inversely proportional to the operation temperature of the LED when the operation temperature is above the predetermined threshold temperature. When the operation temperature of the LED is above the predetermined threshold temperature, an effective resistance of said current regulating circuit attributed to said first and second resistive units is proportional to the operation temperature of the LED, and absolute value of a rate of change of the first resistance is larger than that of the second resistance.

Abstract: Provided are a variable field effect transistor (FET) designed to suppress a reduction of current between a source and a drain due to heat while decreasing a temperature of the FET, and an electrical and electronic apparatus including the variable gate FET. The variable gate FET includes a FET and a gate control device that is attached to a surface or a heat-generating portion of the FET and is connected to a gate terminal of the FET so as to vary a voltage of the gate terminal. A channel current between the source and drain is controlled by the gate control device that varies the voltage of the gate terminal when the temperature of the FET increases above a predetermined temperature.