Abstract: A device for reducing jitter of light source in low brightness by a vibration suppression module includes an LED light source, an inductor L, a current control module, a switch K1, a signal control module, a current acquisition module, and the vibration suppression module. The present invention can eliminate a current ripple in a rising process of a current in the LED light source, as well as suppressing current oscillations generated when the current changes suddenly, the current on the LED light source thus can rise steadily, the LED light source can be steadily brightened in a brightness adjusting process of a dark part, and a phenomenon of light flicker and jitter caused by the current oscillation and the current ripple is avoided.

Abstract: A device for controlling the electrical power supply of a pixelated light source comprises a converter having a feedback control loop and a microcontroller element. The microcontroller element is arranged to act on the controlled value in a precise manner as a function of at least one parameter of the pixelated light source powered by the converter.

Abstract: A circuit and a method for reducing interference of power on/off to hardware test. The circuit includes: a power unit, a voltage processing unit, a PSU and a to-be-tested hardware. An input terminal of the voltage processing unit is connected to the power unit, an output terminal of the voltage processing unit is connected to an input terminal of the PSU, and an output terminal of the PSU is connected to the to-be-tested hardware; the power unit is configured to provide an operating voltage; the voltage processing unit is configured to eliminate electric sparks caused by instability of the operating voltage at an instant of power on/off; the PSU is configured to convert a stable operating voltage outputted from the voltage processing unit into a direct current voltage required for the to-be-tested hardware; and the to-be-tested hardware is configured to receive the direct current voltage outputted from the PSU.

Abstract: Provided is an LED system for vehicle lighting, the LED system including: an LED package (10) including a first LED chip (11) and a second LED chip (12); and an external transistor (20) provided outside the LED package (10), and connected to a main current channel of the LED package (10) in series, wherein the driving circuit (13) is configured to drive only the first LED chip (11) with a first constant current when a level of an input voltage is lower than that of a reference voltage, or drive the first LED chip (11), the second LED chip (12), and the external transistor (20) with a second constant current when the level of the input voltage is higher than that of the reference voltage, wherein the driving circuit (13) controls the first constant current and the second constant current such that power of the first LED chip (11) when only the first LED chip (11) is driven is the same as power of the first LED chip (11) and the second LED chip (12) when all the first LED chip (11), the second LED chip (12), an

Abstract: A light fixture can include a lighting circuit comprising at least one light source and at least one discrete component. The light fixture can also include a power supply coupled to the lighting circuit, where the power supply provides a setting current to the at least one light source. The light fixture can further include a sensor that measures the setting current flowing to the at least one light source. The light fixture can also include a controller coupled to the power supply and the sensor, where the controller provides, in real time, a setting current correction signal to the power supply to adjust the setting current delivered to the at least one light source. The setting current correction signal can be calibrated to an actual value of the at least one discrete component of the lighting circuit.

Abstract: Embodiments described herein provide a LED lighting system and method. A transformer has a primary winding and a secondary winding. A plurality of LED strings are coupled to the secondary winding of the transformer. At least one switch is coupled to at least one of the plurality of LED strings. A controller is coupled to the at least one switch and configured to control the operation of the at least one switch such that current flows through the plurality of LED strings in an alternating manner.

Abstract: A LED driver system (1) comprises a current source (4) which supplies a power supply current (i) to a parallel arrangement of a parallel switch (20) and a LED (10). The parallel switch (20) short-circuits the LED (10) when it is closed. A controller (15) generates during use: (i) a first control signal (E) to control the current source (4) to change from a regulating mode wherein the power supply (i) current is regulated to have a non-zero average level into a decaying mode wherein the power supply current (i) decays during a decay period (Td), and (ii) a second control signal (CSO) to control the parallel switch (20) to open during an open period (To) comprising a sub-period of the decay period (Td).

Abstract: An optimum regulation method is disclosed for reconfigurable LED arrays used for general illumination applications. This document describes a reconfigurable LED array formed by connecting in series LED lamps and LED pairs capable of being reconfigured in either series or parallel. The performance deficiencies of previous solutions are solved by changing the knee voltage of the array through the reconfiguration of LED pairs. The simplicity of the concept can make practical the implementation of driverless LED lighting fixtures.

Abstract: An apparatus, method and system are disclosed for providing AC line power to lighting devices such as light emitting diodes (“LEDs”). A representative apparatus comprises: a plurality of LEDs coupled in series to form a plurality of segments of LEDs; first and second current regulators; a current sensor; and a controller to monitor a current level through a series LED current path, and to provide for first or second segments of LEDs to be in or out of the series LED current path at different current levels. A voltage regulator is also utilized to provide a voltage during a zero-crossing interval of the AC voltage. In a representative embodiment, first and second segments of LEDs are both in the series LED current path regulated at a lower current level compared to when only the first segment of LEDs is in the series LED current path.

Abstract: The light-emitting device having an equivalent circuit, includes at least four terminals, numbered from first terminal to fourth terminal, for electrical power feeding; a first light-emitting diode, arranged between the first terminal and the second terminal, configured to not emit light when a voltage is applied between the second terminal and one of the third terminal and the fourth terminal, and configured to emit light when a. voltage is applied between the first terminal and one of the third terminal and the four the terminal; and a second light-emitting diode, arranged between the third terminal and the fourth terminal, and configured to not emit light when the voltage is applied between the third terminal and one of the first terminal and the second terminal and configured to emit light when a voltage is applied between the fourth terminal and one of the first terminal and the second terminal.

Abstract: The present invention provides a LED device with voltage-limiting unit and voltage-equalizing and current-limiting resistances, in which a LED is connected in parallel with a voltage-limiting unit, and a current-limiting resistance is connected in series between the LED and the voltage-limiting unit, and two ends of each LED are connected in parallel with an voltage-equalizing resistance for forming a light-emitting unit, so that a light-emitting unit set can be structured through connecting two or more than two of the mentioned light-emitting units in series or in series-parallel in the same polarity; with the two ends of each LED being connected in parallel with the voltage-equalizing resistance, the end voltage of each light-emitting unit can be evenly stabilized; and the current-limiting resistance is connected in series between the connection joints of the LED and the voltage-limiting unit for limiting the shunt current passing through the voltage-limiting unit.

Abstract: A device serves to control an electrical load of at least two single loads connected in series. Each of the at least two single loads is connected in parallel to a controllable switch, so that each of the at least two single loads can be switched independently of one another. In addition, a driver stage that drives a current into the electrical load is present. The controllable switches can be controlled by the control unit. A dummy load is connected in series to the at least two single loads.

Abstract: A circuit is disclosed for driving a plurality of LED strings from an AC supply and arranged to, in use, drive current through a series arrangement of a plurality N of the LED strings when the AC voltage is sufficient to drive the plurality N of the LED strings: the circuit comprising a first current source configured to be switchably connected to a one end of said series arrangement of N LED strings; a series combination of a second current source and a heat dissipater, wherein the series combination of the second current source and the heat dissipater is arranged in parallel with the first current source; and a current balancer for balancing the current through the first current source and the second current source. A driver for such a circuit is also disclosed.

Abstract: An LED array switching apparatus, comprises: a plurality of LED arrays arranged in a serial path; a voltage supply coupled to the plurality of LED arrays; a plurality of current sources selectively coupled to the LED arrays, each of the current sources being switchable between a current regulating state and an open state; and a controller that outputs at least one control signal. The controller, the at least one switch and current sources cooperate together such that: when the voltage of the voltage source is below the at least one reference voltage, and/or when a predetermined level of current passes through the one or more current sources, at least one switch is closed and one or more associated current sources are controlled so as to break the serial path into one or more parallel paths each including less than all of the LED arrays.

Abstract: The present application discloses an open circuit protecting circuit, an open circuit protecting method and an illuminating apparatus. The open circuit protecting circuit is configured in an apparatus with a LED load being supplied with power by a current source, and comprises: a switch circuit, a timer circuit and a detecting circuit. When the LED load malfunctions, the open circuit protecting circuit carries out the following operations: the detecting circuit sends an enabling signal to the timer circuit, the timer circuit sends a driving signal with a set time to the switch circuit and the switch circuit is in the on-state during the set time, so as to make the LED load be short circuited to protect the circuit from being damaged. The open circuit protecting circuit can also resume to normal work automatically after the open circuited malfunction is cleared, and thus a hot-plugging function can be realized.

Abstract: The present invention provides an LED backlight system and display device. Backlight system includes power source module, LED array, master switch module, current detection module, current equalizer module and current shunt module. LED array is connected to power source module and includes LED strings with common anode. Master switch module includes first switch transistors for receiving switch control PWM signal of LED strings. Current detection module outputs current feedback signals corresponding to currents of LED strings. Current equalizer module is connected to current detection and includes equalizer control unit and equalizer switch unit. Based on current feedback signal, equalizer control unit controls on-and-off of equalizer switch unit. Current shunt module is connected in parallel with current equalizer module and performs current shunt on current equalizer module. As such, the present invention reduces energy-consumption of current equalizer module and temperature of LED drive chip.

Abstract: A lamp driver responsive to a control signal that is variable in a predetermined control range includes a circuit operable in response to a value of the control signal within the predetermined control range to develop a first current and a lamp control voltage dependent upon the value of the control signal. A shutdown interface is operable in response to a value of the control signal outside of the predetermined control range to develop a second current to turn off a lamp.

Abstract: A plurality of light emitting diodes (LEDs) is driven based on the voltage and current requirements of the LEDs at any given time. The driving of the LEDs is adapted to the input voltage provided. A series of switches (e.g. MOSFETS) is used to selectively illuminate the LEDs according to the input voltage and current, with more LEDs being lit as the input voltage or current increases. In one configuration, the switches are driven to provide a light dimming function. The LEDs can be controlled remotely using, e.g. an X10 communication protocol. A direct current implementation is also provided. In an alternate embodiment, the LEDs are used in photo diode mode for communication with a remote controller or other light bulbs.

Abstract: The present invention relates to a LED device with shared voltage-limiting unit and individual voltage-equalizing resistance, wherein two ends of a LED set constituted by a plurality of same-polarity series LEDs are in parallel connected with a shared voltage-limiting unit, and two ends of individual LED are respectively in parallel connected with an voltage-equalizing resistance for providing an overvoltage protection to the LEDs.

Abstract: Embodiments of the present invention disclose a dimming control method and apparatus and a dimming system. The method according to an embodiment of the invention includes: detecting a conduction angle of a dimming apparatus according to an output signal; and controlling a first shunt load according to the conduction angle to disconnect the first shunt load upon detecting a valid conduction angle of the dimming apparatus and to keep the first shunt load conducted upon detecting no valid conduction angle of the dimming apparatus, thereby lowering power consumption.

Abstract: In various embodiments, a device for controlling power supply towards at least one light source comprising a load having a value variable as a result of switching of at least one switch coupled thereto, is provided. The device may include: a power supply set controllable to determine the intensity of the current fed towards said load; a current feedback loop sensitive to the intensity of the current fed towards said load, said current feedback loop connected to said power supply set to maintain the intensity of the current fed towards said load upon variation of said load; and a voltage control sensitive to the voltage across said load, said voltage control likewise connected to said power supply set to maintain the intensity of the current fed towards said load upon variation of said load.

Abstract: An LED device with voltage-limiting unit and voltage-equalizing and current-limiting resistances includes an LED connected in parallel with a voltage-limiting unit, and a current-limiting resistance connected in series between the LED and the voltage-limiting unit. Two ends of each LED are connected in parallel with a voltage-equalizing resistance for forming a light-emitting unit, so that a light-emitting unit set can be structured through connecting two or more than two of the mentioned light-emitting units in series or in series-parallel in the same polarity. With the two ends of each LED being connected in parallel with the voltage-equalizing resistance, the end voltage of each light-emitting unit can be evenly stabilized; and the current-limiting resistance connected in series between the connection joints of the LED and the voltage-limiting unit for limiting the shunt current passing through the voltage-limiting unit.

Abstract: A feedback circuit for a power converter (e.g., a non-isolated converter) is disclosed. The feedback circuit may include a sense circuit coupled to receive an output current of the converter. A sense voltage may be generated across the sense circuit and a voltage-to-current converter may be used to convert the sensed voltage into a feedback signal representative of the output current. The voltage-to-current converter may include a variable shunt regulator, resistor, and transistor. A voltage across the shunt regulator may change in response to a change in voltage across the sense circuit, and the feedback signal may change in response to a change in the voltage across the shunt regulator. A controller may be coupled to receive the feedback signal from the feedback circuit and may control switching of a power switch to regulate the output current based at least in part on the feedback signal.

Abstract: The present invention provides a LED device with the voltage-limiting unit and the shunt current-limiting resistance wherein a voltage-limiting unit is connected in series with a current-limiting resistance then connected in parallel with two ends of a LED, so that to constitute the light-emitting unit, thereby when plural of the light-emitting units are connected in series (including connected in series and parallel), the current of LED loaded with higher end voltage passing through the voltage-limiting unit is prevented to be overly high when subject to abnormal high voltage.

Abstract: A controller for controlling power to a light source includes a first sensing pin, a second sensing pin, a third sensing pin, and a driving pin. The first sensing pin receives a first signal indicating an instant current flowing through an energy storage element. The second sensing pin receives a second signal indicating an average current flowing through the energy storage element. The third sensing pin receives a third signal indicating whether the instant current decreases to a predetermined current level. The driving pin provides a driving signal to a switch to control an average current flowing through the light source to a target current level. The driving signal is generated based on one or more signals selected from the first signal, the second signal and the third signal.

Abstract: A method for controlling an electrical load of at least two single loads includes activating and deactivating the single loads in switching cycles of predefined duration sequentially following one another. In one switching cycle, the single loads are activated and deactivated alternately with respect to one another.

Abstract: Ballasts and LED drivers are presented for powering at least one light source, in which a shunt circuit provides a high impedance to allow operation of the light source when the AC input power exceeds a power threshold value, and provides a low impedance when the AC input power is below the power threshold value to prevent an output power stage from providing power to the light source.

Abstract: Disclosed is a driving device for driving a plurality of lighting fixtures, including a power converter for converting an input voltage into a DC output voltage; a plurality of lighting fixture bases connected in series with each other and each connected to a corresponding lighting fixture for outputting an operating voltage and an operating current to the lighting fixture. The operating voltage is derived by dividing the DC output voltage, and each operating current is identical with each other. The driving device further includes a plurality of output protection circuits respectively connected in parallel with a lighting fixture base for selectively bypass the lighting fixture base to stop the lighting fixture base from outputting current, and a control circuit connected to the output protection circuits for manipulating the output protection circuit to bypass the lighting fixture bases, thereby regulating the number of the lighting fixtures that illuminate.

Abstract: A circuit arrangement for operating discharge lamps is provided with an input, to which an AC system voltage from a power supply system can be connected, an output, to which at least one discharge lamp can be connected, a backup capacitance, which is arranged between the input and the output, and a switch, which is in a charging current path of the backup capacitance. The circuit arrangement may include a driver configured to clock the switch for a predetermined period of time when the circuit arrangement is switched on for periodically interrupting the charging current path of the backup capacitance.

Abstract: A lighting arrangement comprises a checking device and a method for the control thereof, with a sensor device containing at least one light source, where the at least one light source radiates light with high radiant power which represents a danger to the eyes of operators or service personnel. A housing, which contains the at least one light source and prevents an emergence of light of the light source, is monitored as to whether the housing is open, where the at least one light source with high radiant power is switched off if there is detected upon the monitoring an opening of the housing, which permits an emergence of light of the light source. It is provided here that a lighting arrangement is switched on at the same time or later which has a radiant power not representing any danger to the eyes of operators or service personnel.

Abstract: A controller for controlling power to a light source includes a first sensing pin, a second sensing pin, a third sensing pin, and a driving pin. The first sensing pin receives a first signal indicating an instant current flowing through an energy storage element. The second sensing pin receives a second signal indicating an average current flowing through the energy storage element. The third sensing pin receives a third signal indicating whether the instant current decreases to a predetermined current level. The driving pin provides a driving signal to a switch to control an average current flowing through the light source to a target current level. The driving signal is generated based on one or more signals selected from the first signal, the second signal and the third signal.

Abstract: In a converter of a motor drive control device, one of a first switching element and a second switching element is selected in accordance with a current command value of a current flowing through a reactor. The converter is then controlled so that a drive command for the selected switching element is generated. In this way, the efficiency of the converter is improved while a voltage step-up or step-down operation is performed by the converter.

Abstract: A light emitting diode (LED) driving system comprises a plurality of current limitation circuits and a plurality of over-voltage protection circuits to driving a plurality of LED strings. Each of the current limitation circuits comprises a first switch comprising a control pole receiving a reference voltage, a first pole correspondingly connected to a LED string, and a second pole connected to the ground via a first resistor and a second switch comprising a control pole connected to the second pole of the first switch via a second resistor, a first pole receiving the reference voltage, and a second pole grounded. Each of the over-voltage protection circuits comprises a zener diode, a third switch and a first capacitor.

Abstract: A driving circuit for an LED lamp including no more than 4 strings each having an input and an output terminals outputs a DC voltage of no more than 70V to the input terminals. The driving circuit includes constant current circuits each coupled between the output terminal of a corresponding string and ground. An on-off control signal controls whether the constant current circuits work to control whether the LED lamp works. A dimming control signal controls a duty cycle of working of to the constant current circuits to control a brightness of the LED lamp. The driving circuit further includes an overvoltage protection circuit and a switch. When a voltage at one input terminal is too high or a short circuit occurs in one string, the overvoltage protection circuit outputs an overvoltage control signal and accordingly the switch forces the on-off control signal to control the constant current circuits not to work.

Abstract: A discrete dimming luminance control circuit for light emitting diode illumination includes first and second control inputs, a first supply circuit between the first control input and an output, a second supply circuit between the second control input and the output, a first shunt circuit between the second control input and the output, and a second shunt circuit between the first control input and the output. The luminance control circuit delivers a first voltage to the output when a supply voltage is applied to the first control input and the second control input is left open, a second voltage when the supply voltage is applied to the second control input and the first control input is left open, a third voltage when the supply voltage is applied to the first control input and the second control input is grounded, and a fourth voltage when the supply voltage is applied to the second control input and the first control input is grounded.

Abstract: A dimmable light-emitting diode (LED) lamp and a dimmable LED lighting apparatus thereof are provided. The dimmable LED lamp includes a bridge rectifier, a toggle detector, a sustain voltage supply circuit, a counter, an LED light source, and an LED lighting driver. The bridge rectifier receives a source alternating current (AC) voltage through a wall switch and provides a rectified direct current (DC) voltage. The toggle detector monitors a toggle action of the wall switch. The sustain voltage supply circuit provides a sustain voltage. The counter receives the sustain voltage for operation. Moreover, the counter stores and provides an counting value that changes when the toggle detector detects the toggle action. The LED lighting driver converts the rectified DC voltage to a constant current to drive the LED light source. The LED lighting driver also provides multi-level dimming to the LED light source according to the counting value.

Abstract: A bypass protection circuit connected to a light emitting diode (LED) group in parallel, comprises a switch circuit and a capacitor. The switch circuit comprises a plurality of switch components, an abnormal detection module and a switch control module. The abnormal detection module detects voltage of the LEDs respectively, and determines which one is broken and outputs an abnormal signal. The switch control module controls a switch component connected to the broken LED in parallel on/off according to the abnormal signal. The capacitor is charged by driving signals of the LEDs when the LEDs are operated according to a normal working mode or a first status of a burst dimming mode, and is discharged to maintain an operating power of the switch circuit when the LEDs are operated according to a second status of the burst dimming mode.

Abstract: A LED control circuit and method generate a high frequency clock signal with a fixed duty for a LED driver, to supply a switching current to drive a LED to emit light flashing at a modulated high frequency and with a fixed duty. By controlling the flashing LED light within certain flashing frequency range, the circuit and method allow a LED light source for expelling, confusing or trapping insects but serving only an illuminative or decorative purpose to human eyes, due to the difference between human beings and insects in visual perception of flashing frequencies.

Abstract: The invention relates to a driver device for a load (11), particularly an LED/OLED unit (12; 20, 22), comprising a shunting switch (30) parallel to the load, a control unit (14, 26) for controlling the shunting switch (30), an energy storage element (40) adapted to supply energy to at least the control unit (14, 26), and a recharge control circuitry (46) arranged in series with the energy storage element (40), the series connection of energy storage element (40) and recharge control circuitry (46) being provided parallel to the shunting switch (30), wherein said control unit (14, 26) is adapted to activate said recharge control circuitry (46) and to switch said shunting switch (30) off, when said energy storage element (40) is to be recharged. The invention also relates to a method of driving a load (11).

Abstract: An LED lighting device including a DC power source circuit, a high frequency generation circuit which includes an inverter circuit having switching elements and a resonance circuit having a series-connected inductor and condenser, in which the switching elements are on-off controlled by a no-load resonance frequency of the resonance circuit, and DC voltage input from the DC power source circuit is converted into a high frequency AC voltage, a rectification smoothing circuit having an input side which is connected between both edges of the condenser or both edges of the inductor; and a light emitting diode series connected to an output side of the rectification smoothing circuit.

Abstract: The present invention provides a light emitting diode (LED) device. The LED device include a driver, a first LED coupled in series with the driver, and an impedance-providing component coupled in parallel with the first LED and in series with the driver. The impedance-providing component provides a shunt impedance having a value that varies in positive proportion with a variation in an ambient temperature. The driver is respectively coupled in series with the first LED and the at least one impedance-providing component. The driver provides a drive current divided to flow through the first LED and the at least one impedance-providing component according to the shunt impedance and the internal impedance.

Abstract: A method is provided for driving at least one lamp unit, which is connected to an AC voltage power supply system. The method comprises modulating a control information item for the operation of the lamp unit onto the supplied AC voltage, decoding of the modulation received on the lamp unit side for reading the control information item and driving the light-emitting device in accordance with the control information item. Provision is made for a shunt to be produced in the line used for transmitting the control information item prior to or at the beginning of the modulation of the control information item. The disclosure also provides a lamp unit and a control device for implementing the method. The disclosure also provides a lighting system.

Abstract: The LED driver of the present invention comprises multiple LED arrays, at least one dividing diode, a power module, a driving module, at least one switch pair and a voltage sensing module. Each LED array comprises multiple LEDs connected in series. The dividing diode is mounted between adjacent LED arrays. The power module is connected to an external power source and forms a pulsating direct current (DC) voltage. The driving module receives the pulsating DC voltage outputs a constant current to the LED arrays. The voltage sensing module closes and opens the switch pairs that changes electrical configuration of the LED arrays. The LED driving method of the present invention comprises setting multiple voltage drops and at least one reference voltage; sensing an incoming voltage to compare with the reference voltage; and changing ways of connections of LED arrays based on the reference voltage and the incoming voltage.

Abstract: The present invention contemplates a variety of improved techniques for the fast switching of current through, among others, LED loads. A current shunting device is utilized to divert current away from a load at high speed when activated, thus enabling the control of the amount current that flows through the load.

Abstract: A driving arrangement for a plurality of light emitting diodes (LEDs), the driving arrangement constituted of: a plurality of serially connected first LEDs coupled to a source voltage; a plurality of first electronically controlled switches, each associated with a particular one of the plurality of serially connected first LEDs and arranged to provide, when closed, a bypass current path for the associated first LED; and a control circuitry coupled to a control terminal of each of the plurality of first electronically controlled switches, the control circuitry operative to close a number of the plurality of first electronic switches, the number responsive to a voltage level of the source voltage.

Abstract: An offline LED driving circuit includes a controller, a shunt regulator, an opto-coupler, and a dimming circuit. The controller generates a switching signal to switch a transformer for providing an output voltage and an output current. The shunt regulator is coupled to an output terminal of the LED driving circuit for providing a feedback signal to the controller via the opto-coupler. The dimming circuit coupled to the shunt regulator modulates the feedback signal at a first feedback level and a second feedback level in response to a dimming signal. The output voltage is respectively regulated at a first output level and a second output level in response to the first feedback level and the second feedback level of the feedback signal. The duty cycle of the switching signal will be varied in a soft-start manner when the feedback signal changes from the second feedback level to the first feedback level.

Abstract: A driving circuit includes a signal generator, a resonant circuit, a control circuit and an adjusting circuit. The signal generator is utilized for generating an alternating current (AC) signal having a fixed frequency. The resonant circuit is coupled to the signal generator, and is utilized for generating an oscillation signal to drive a backlight source according to the alternating current signal. The control circuit is utilized for providing a control signal. The adjusting circuit is coupled to the control circuit, the resonant circuit and the backlight source, and is utilized for providing an impedance according to the control signal to thereby adjust a current value of the backlight source.

Abstract: A novel LED driver circuit, including: a current regulation circuit, having a first end and a second end, wherein a first current is flowing into the second end, and a voltage difference between the first end and the second end is generated in response to the first current; a transistor, coupled with the first end and second end of the current regulation circuit; a bias network, having a first end and a second end, the second end being coupled with the transistor; and a LED module, having at least two connection nodes, wherein the connection node at one end of the LED module is coupled to a line voltage, the connection node at the other end of the LED module is coupled to the transistor, and one of the at least two connection nodes is coupled with the first end of the bias network.

Abstract: A VFD drive apparatus in which the filament of a VFD is coupled at a first terminal to an input voltage derived from a voltage source, and at a second terminal to a shunt voltage regulator that establishes a regulated filament current and a regulated cutoff voltage with respect to ground potential. Other electrical loads such as drive circuitry for the anodes and grid of the display are coupled between the second terminal of the filament and ground potential so that at least a portion of the filament current is supplied to such other electrical loads. Power dissipated by the shunt voltage regulator is thereby reduced, and the cost associated with providing additional voltage regulators for the other electrical loads is avoided.

Abstract: A light source and method for making the same are disclosed. The light source includes a plurality of Segmented LEDs connected in parallel to a power bus and a controller. The power bus accepts a variable number of Segmented LEDs. The controller receives AC power and provides a power signal on the power bus. Each Segmented LED is characterized by a driving voltage that is greater than 3 times the driving voltage of a conventional LED fabricated in the same material system as the Segmented LED. The number of Segmented LEDs in the light source is chosen to compensate for variations in the light output of individual Segmented LEDs introduced by the manufacturing process. In another aspect of the invention, the number of Segmented LEDs connected to the power bus can be altered after the light source is assembled.