TWI641290B - Fluorescent lamp dimmer - Google Patents

Abstract

Disclosed herein is a fluorescent lamp dimmer that can power one or more fluorescent lamps by dimming. The fluorescent lamp dimmer includes a fluorescent lamp power output, at least one fluorescent lamp heater output, a tunable photocurrent source usable to generate a controllable fixed current, and a controllable fixed current pair A fluorescent lamp outputs a current fed inverter, and a heater circuit operable to supply the at least one fluorescent heater output. The heater circuit provides a substantially fixed level of power when the controllable fixed current system is variable.

Description

Fluorescent dimmer

The invention relates to a fluorescent lamp dimmer.

Fluorescent lamps are widely used in a variety of applications, such as general purpose lighting for commercial and residential locations, backlighting for liquid crystal displays for computers and televisions, and the like. Fluorescent lamps generally comprise a glass tube containing a circular, spiral or other shaped bulb of very low pressure gas or mixed gas such as argon, xenon, neon. , or krypton, and low-pressure mercury vapor during operation. A phosphor coating is deposited on the interior of the luminaire. When a current is passed through the luminaire, the mercury atoms are excited and the photons are released, most having a frequency in the ultraviolet spectrum. These photons are absorbed by the fluorescent coating, causing them to emit light at visible frequencies. Some types of fluorescent lamps include a heater in the tube that is heated by an electrical current to provide a source of electrons in the tube. Many power supplies for fluorescent lamps, including ballasts, cannot be used with traditional AC (AC) wall dimmers such as TRIAC (bidirectional AC triode) and SCR (controlled rectifier) .

The present invention provides a fluorescent lamp dimmer that can be used to power one or more fluorescent lamps and that can be dimmed with conventional AC wall dimmers and internal dimming circuits. In some embodiments, the fluorescent dimmer includes a fluorescent lamp power output, at least one fluorescent lamp plus a heater output, a tunable current source operable to generate a controllable fixed current, a current-fed inverter operable to supply the output of the fluorescent lamp from the controllable fixed current, and A heater circuit operable to output the at least one fluorescent lamp heater output. The heater circuit provides a substantially fixed level of power when the controllable fixed current system is variable.

This summary is merely a brief description of some specific embodiments. A variety of other objects, features, advantages and other embodiments will become apparent from the Detailed Description. Nothing in this document should be construed or deemed to be a limitation in any way or form.

10‧‧‧Fluorescent dimmer

12‧‧‧ fluorescent light

14‧‧‧AC main power input / AC main power line input

16‧‧‧Electromagnetic interference filter

20‧‧‧Constant current dimming control circuit

22‧‧‧ Current Feeding Inverter

24‧‧‧heater/filament cathode circuit

30‧‧‧Fluorescent dimmer

32‧‧‧Wall dimmer

40‧‧‧Fluorescent light dimmer

42‧‧‧Power factor control and constant current dimming control circuit

44‧‧‧Power factor control circuit

50‧‧‧Fluorescent dimmer

52‧‧‧heater/filament cathode circuit

60‧‧‧Fluorescent light dimmer

62‧‧‧Power factor control circuit

70‧‧‧Fluorescent dimmer

72‧‧‧Lights

74‧‧‧Lights

76‧‧‧ Output

80‧‧‧ output

82‧‧‧ Output

84‧‧‧ Output

86‧‧‧ Output

90‧‧‧ Output

92‧‧‧ Output

94‧‧‧ Output

100‧‧‧Fluorescent dimmer

120‧‧‧current feeding inverter

122‧‧‧Fixed current signal

124‧‧‧Transformers

126‧‧‧Optoelectronics

130‧‧‧Optoelectronics

132‧‧‧ Non-overlapping inverted clock signals

134‧‧‧ Grounding

136‧‧‧ output

140‧‧‧ Capacitance

200‧‧‧ circuit

202‧‧‧load

204‧‧‧Output driver

206‧‧‧AC input

210‧‧‧Fuse

212‧‧‧Electromagnetic interference (EMI) filter

214‧‧‧Rectifier

216‧‧‧Load current detector

220‧‧‧Variable Pulse Generator

222‧‧‧ position shifter

224‧‧‧Control signal

226‧‧‧Power output/input voltage

230‧‧‧resistance

232‧‧‧resistance

234‧‧‧Circuit grounding

236‧‧‧Area grounding

240‧‧‧Reference current source

242‧‧‧Reference current signal

244‧‧‧resistance

246‧‧‧Load current signal

250‧‧‧ pulse output

252‧‧‧bit shift control signal

254‧‧‧Switch

256‧‧‧Load path

260‧‧‧ Capacitance

262‧‧‧Inductance

264‧‧‧ Current sense resistor

266‧‧ ‧ diode

270‧‧‧ Current overload protection

272‧‧‧Current measurement signal

300‧‧‧Draw lines

302‧‧‧Shoulder waveform

A further understanding of the various exemplary embodiments can be achieved by reference to the example drawings, which are described in the remainder of the specification. In the drawings, like reference numerals may be used to refer to the

1 depicts a fluorescent lamp dimmer suitable for dimming power to one or more fluorescent lamps in accordance with one of many embodiments of the present invention.

2 depicts a fluorescent lamp dimmer including an AC wall dimmer in accordance with many embodiments of the present invention.

3 through 5 depict a fluorescent lamp dimmer including a plurality of power factor control devices in accordance with many embodiments of the present invention.

Figure 6 depicts a fluorescent lamp dimmer connected in parallel to one of the two fluorescent lamps in accordance with many embodiments of the present invention.

Figure 7 depicts a series connection to two fluorescent lamps in a series connection in accordance with many embodiments of the present invention. Light dimmer.

Figure 8 depicts an example of a current fed inverter suitable for use in some embodiments of a fluorescent lamp in accordance with one of many embodiments of the present invention.

9 depicts an example circuit that can be used in place of the dimmable current source and/or heater source circuit of FIG. 1 in accordance with many embodiments of the present invention.

10 depicts a plot of an example output current versus input voltage setting in a dimmable current source in accordance with some embodiments.

11 depicts a plot of example output current versus input voltage setting in a heater source circuit in accordance with some embodiments.

The following is a brief definition of the terms used in this document. The statement "in an embodiment", "in accordance with an embodiment", and similar terms are used to mean that a particular form, structure, or characteristic that follows the statement is included in at least one embodiment of the invention, and It may be included in one or more embodiments of the present invention. It is important that the statements not necessarily refer to the same embodiment.

If a component or feature is "may" or "capable" is included or has a characteristic, this means that the particular component or feature does not necessarily have to be included or have the characteristic.

The fluorescent dimmers disclosed herein can be used to power one or more fluorescent lamps and, if necessary, dimming with various types of external dimmers or internal dimming circuits. The fluorescent dimmer allows it to control the voltage and current of the fluorescent lamp to control the brightness or intensity while maintaining a substantially constant voltage through the heater. Therefore, the input voltage can be It is controlled and limited externally or internally to dim the fluorescent lamp while maintaining the heater voltage for proper illumination of the luminaire. It is important to note that the term "fluorescent dimmer" in some embodiments refers to a power supply or driver circuit that does not itself contain a dimmer or dimming control input, but is modulated Properly function with an external dimmer and allow the illumination of the fluorescent lamp to be controlled by the external dimmer. In other embodiments, the fluorescent dimmer may include an internal dimming circuit and/or a dimming control input. Still other embodiments may include a combination of internal and external dimmers.

The present invention thus describes a device for controlling dimming of a fluorescent lamp, which can include all types and tubular fluorescent lamps (FL) of all shapes such as linear, curved, U-shaped, compact fluorescent lamps (compact Fluorescent lamp; CFL), high-performance lamps, cold cathode fluorescent lamps (CCFL), and so on.

Some embodiments include the use of a dimming to constant current transfer function that allows the degree of dimming to be converted to a fixed current proportional to the degree of dimming. In particular, the proportionality may be linear but not necessarily linear, and almost any function can be used and/or can be designed/programmed into the invention, including but not limited to, quadratic, offset functions ( Offset), sub-linear, super-linear, cubic, power law or power series function, logarithmic, etc. Wait. The present invention takes a fixed current provided by a constant current dimming transfer function and applies this current to a circuit such as a current fed inverter, including a current fed inverter based on a resonant current fed inverter design And convert the output to a suitable waveform to drive the fluorescent light. In addition, a fixed output heater/filament/cathode circuit is incorporated that allows voltage, current, and power to be maintained over the heater/filament/cathode during operation, including dimming Hold roughly fixed. One feature of the present invention is the modulation of the performance, transfer curve, and custom design (including input voltage versus output heater/filament/cathode voltage) to achieve predetermined performance, characteristics, transfer characteristics, and the like.

The invention can be used for alternating current (AC) 50 or 60 Hz line voltage, direct current (DC) input voltage, 400 Hz, and almost any other type of waveform and frequency including multiple frequencies. The invention can be dimmed by any conventional method and method, including TRIAC dimmer, thyristor dimmer, silicon controlled rectifier (SCR) dimmer, transistor dimmer, capacitive Dimmers, contact variacs, DC dimmers, phase dimmers, forward and reverse dimmers, and more. The invention can be used for all types of low voltage dimming signals, including DALI, 0 to 10V dimming, RS 232, USB, Ethernet, I2C, SPI, SPC, etc., any other type of wired dimming, Includes power line wired dimming, wireless dimming, including Bluetooth, Zigbee, WiFi, IEEE 802 standard, 25MHz, 49MHz, any allowed MHz and GHz radio frequency, infrared (IR) transmission, and essentially any wired or Wireless mode. The invention can be designed and implemented to match, for example, wall (i.e., two-way alternating current triode) dimming and remote (i.e., wired or wireless) dimming.

Certain embodiments of the invention may also use current limiting at the input or output circuitry to limit the maximum current through the luminaire. In one example, this is not intended to limit the invention in any way or form, limiting the maximum fixed current that a constant current dimming transfer function can provide in terms of current. By doing so, this will limit the amount of power and current to the luminaire. Other embodiments may sense the current in the output circuit and provide feedback to the constant current dimming transfer function. Still other embodiments may incorporate combinations of such items and/or also limit AC input current. Any combination of dimming of walls, wires, wireless, etc. (meaning one or more of them) All may be incorporated into individual embodiments and examples of the invention. Likewise, the invention is not limited herein by any means or form.

The implementation of the constant current dimming transfer function can utilize several circuit configurations, including independent and non-independent modes and structures, buck, boost, buck-boost, boost-buck, and cook ( Cuk), flyback, etc., and may utilize discontinuous conduction mode (DCM), continuous conduction mode (CCM), critical conduction mode, resonant conduction ( Resonant conduction), and so on. An example of such a constant current dimming transfer function circuit includes any of the U.S. patent application "Universal Dimmer" numbered 12/776,435, issued May 10, 2010, which is incorporated herein by reference. The form of reference is included in this specification.

The invention can also be designed, constructed, and fabricated to have a high power factor and have passive or active power factor correction (PFC).

The present invention can also be designed using an integrated circuit (IC) designed and manufactured for the present invention. Such ICs can reduce the number of components, combine functions, allow an IC to control more than one function or action, reduce the size and cost of the present invention, combine blocks, provide common overall and local functionality, and the like.

Turning now to Figure 1, an example of a fluorescent lamp dimmer 10 is illustrated in which one or more fluorescent lamps 12 are input from an AC mains power source 14 or from any other suitable power input such as a DC or other input waveform. powered by. The input can be filtered into an EMI filter 16 to reduce EMI as needed. A dimming to constant current control circuit 20, also referred to herein as a dimmable current source, can be used to invert a current based on an AC mains input 14 or other power input. The device 22 produces a fixed but controllable power flow. A heater/filament cathode circuit 24, also referred to herein as a heater source, can be used to provide a substantially fixed low current or voltage to the fluorescent lamp 12 or other load even when the input voltage is reduced by an external dimmer Also.

For example, circuitry disclosed in the aforementioned "Universal Dimmer" file can be used for each constant current dimming control circuit 20 and heater/filament cathode circuit 24 such that the circuit is adjusted to a current pair The voltage relationship (see Figure 10) has a current slope starting at approximately 30 VAC (or any other predetermined starting voltage below 30 VAC) and is incremented over the input voltage range, as provided by the same dimmer for use as The constant current dimming control circuit 20, and having the elbow waveform 302, is lowered to provide a substantially constant current throughout the dimming range as the heater/filament cathode circuit 24 (see, for example, Figure 11). Thus, with respect to constant current dimming control circuit 20, the output current provided to current feed inverter 22 will be proportional to the input voltage from AC mains input 14, which in some embodiments may be externally The dimmer is adjusted. For the heater/filament cathode circuit 24, the output current and/or voltage will remain substantially fixed regardless of the input voltage level from the AC main power input 14, as such, in some embodiments, An external dimmer is adjusted.

The current and/or voltage levels provided by the constant current dimming control circuit 20 and the heater/filament cathode circuit 24 can be configured to match a predetermined load, such as the number of fluorescent lamps, their voltage ratings, and The structure connected to it. For example, given that four 100V fluorescent lamps are connected in series as the load 12, the output voltage of the constant current dimming control circuit 20 can be set at about 400V when it is not dimmed, and is adjusted. The time of light decreases from this point. The current and/or voltage levels provided by the heater/filament cathode circuit 24 are similarly set according to the requirements of the fluorescent lamp 12, such as a heater that provides a fixed 5V to fluorescent lamp 12, or a fluorescent lamp 12 Any voltage and / or current required according to its breakdown voltage, etc. By adjusting the supply circuit in the heater/filament cathode circuit 24, the heater/filament cathode circuit 24 is configured to reach the desired heater voltage even at a slight dimming angle, such as the elbow waveform 302. (Fig. 11) is set to a low input voltage due to the small dimming angle. Certain embodiments of the present invention may use a heater circuit that reduces or even cuts off output voltage, current, and power when the dimming level approaches the fully open state.

In some embodiments as illustrated in FIG. 2, a fluorescent dimmer 30 can include a wall dimmer 32 coupled to the AC main power source 14 to adjust the input voltage under control. Wall dimmer 32 may comprise a TRIAC, a transistor, a contact voltage regulator, an SCR, or other type of dimmer as described above. In some embodiments of a fluorescent dimmer 40 (see FIG. 3), the constant current dimming control circuit 20 can be replaced with a power factor control and constant current dimming control circuit 42. A power factor control circuit 44 can also be coupled to the heater/filament cathode circuit 24 to maximize the power factor of the heater. In still other embodiments of a fluorescent dimmer 50 (see Figure 4), power factor control can be integrated into the heater/filament cathode circuit 52. In other embodiments of a fluorescent dimmer 60 (see FIG. 5), a power factor control circuit 62 can be provided to both the constant current dimming control circuit 20 and the heater/filament cathode circuit 24. At the input end to maximize the power factor of the overall fluorescent dimmer 60. In other embodiments, the power factor correction can be designed, incorporated, fabricated, embedded in the circuit, or as an integral part thereof, and the like.

Referring to Figures 6 and 7, the connection from the fluorescent lamp dimmers 70 and 100 to the two fluorescent lamps 12 is illustrated as a connection in parallel and in series. In FIG. 6, current fed inverter 22 has two output terminals 76 and 80 connected to each end of each of the lamps 72 and 74. A heater connector. The heater/filament cathode circuit 24 has two common outputs 82 and 84, each connected to a heater connector on the two lamps 72 and 74, and having independent outputs 86 and 90, 92 and 94, with outputs 86 and 90 at the lamp 72. One end bridges the heater connector and outputs 92 and 94 bridge the heater connector at one end of the luminaire 74. In this embodiment, the heater voltage is the same for the heater at one of the lamps 72 and 74 and can be independently controlled at the other end of the lamps 72 and 74 as desired. This is merely an example and illustration of several ways in which the heater connection can be configured in various embodiments, and the fluorescent lamp dimmer 70 is not limited to such particular heater connections.

In Figure 7, the heater connections to the heater/filament cathode circuit 24 remain the same as in Figure 6, but the lamps 72 and 74 are connected in series across the current feed inverter 22. In this embodiment, the outputs 76 and 80 of the current feed inverter 22 are each coupled to a heater connector at the distal end of the series combination of the lamps 72 and 74, wherein a heater connection 82 and/or 84 causes the lamp A series connection between 72 and 74 is constructed.

In this configuration, the current through the two lamps is the same as when the lamps are connected in series. It should be noted that although two fluorescent lamps are shown in Figures 6 and 7, the present invention is not limited to two fluorescent lamps; any number of fluorescent lamps, from 1 to N (where N is usually 2, 3) Or 4 or more, can be used in the present invention. As previously stated, the present invention is capable of powering and driving any type of single fluorescent lamp to any type of fluorescent lamp of any type.

Referring now to Figure 8, an exemplary embodiment of a current fed inverter 120 is illustrated which may be used as the current fed inverter 22 of the embodiment of Figures 1 through 7. However, current feed inverter 22 is not limited to the embodiment of FIG. Current feed inverter 120 receives fixed current signal 122 from input from constant current dimming control circuit 20. For example, fixed electricity Stream signal 122 is coupled to a central tap point on a primary winding of transformer 124. The current through the two segments of the primary coil is controlled by a non-overlapping inverted clock signal 132, for example, alternately by transistors 126 and 130, which are non-overlapping inverted clock signals 132. For example, a PWM signal and its complementary signal are suitably processed to prevent the signal from overlapping its complementary signal. For example, the non-overlapping inverted clock signal 132 can operate at a relatively high frequency, such as under thousands or tens of thousands of kilohertz, for example, to increase the efficiency of the fluorescent lamp.

The transistors 126 and 130 are not limited to the illustrated field effect transistors (FETs), but may comprise any suitable type of transistor or other switching element, such as a bipolar transistor or field effect transistor of any type and material, including But not limited to MOSFETs, MOSFETs, insulated gate bipolar transistors (IGBTs), enhanced or depleted transistors, etc., and can be any suitable Made of materials, including silicon, gallium arsenide, gallium nitride, silicon carbide, silicon on insulator, etc. High rated voltage. The transistors or switches 126 and 130 thus allow current from the fixed current signal 122 to alternately flow through each segment of the primary winding of the transformer 124 and to the ground terminal 134, and an alternating current path is generated in the secondary winding of the transformer 124. Output 136 and fluorescent lamp 12. One or more capacitors 140 can be connected across the primary coil of transformer 124 to condition the signal as needed and to support resonant operation.

Referring next to Fig. 9, an example circuit 200 is illustrated that can replace one or both of constant current dimming control circuit 20 and heater/filament cathode circuit 24. In the schematic of FIG. 9, load 202 is shown as being located inside output driver 204 to facilitate the description of the connections in the schematic. An AC input 206 is shown in the figure, and in this embodiment The fuse 210 and an electromagnetic interference (EMI) filter 212 are coupled to the circuit 200. Fuse 210 may be any device suitable for protecting circuit 200 from overvoltage or overcurrent conditions, such as a conventional fusible fuse or other device (eg, a small low power surface carrying resistor), including a solid state circuit breaker (solid state) Circuit breakers, etc. EMI filter 212 may be any device suitable for preventing EMI from entering or leaving circuit 200, such as a coil, inductor, capacitor, and/or other components and/or any combination of such elements, or, in general, a filter ,and many more. As described above, the AC input 206 is rectified in a rectifier 214. In other embodiments, circuit 200 can use a DC input. In this embodiment, circuit 200 can be broadly divided into a high side portion including a load current detector 216 and a low side portion including a variable pulse generator 220, and output driver 204 is coupled or includes the high side. Side and low side sections. In this example, a level shifter 222 can be used between the high side load current detector 216 and the low side variable pulse generator 220 to transmit the control signal 224 to the variable pulse. Generator 220. Both variable pulse generator 220 and load current detector 216 are powered by power output 226 of rectifier 214, for example, through resistors 230 and 232, respectively. The high side including load current detector 216 is floated at a high potential that is lower than the voltage of input voltage 206 and higher than circuit ground 234. An area ground 236 is thus established and used by load current detector 216 as a reference voltage.

A reference current source 240 supplies a reference current signal 242 to the load current detector 216, and a current sensor such as a resistor 244 provides a load current signal 246 to the load current detector 216. The reference current source 240 can use circuit ground 234, or region ground 236, or both, or some other reference voltage level as illustrated in FIG. 9, as desired. Load current detector 216 compares reference current signal 242 with load current signal 246, selectively using one or more The time constants are effective to remove and omits the current fluctuations from any of the waveforms at input voltage 206 and the pulses from variable pulse generator 220, and generate control signal 224 to variable pulse generator 220. The variable pulse generator 220 adjusts the pulse width of a series of pulses at the pulse output 250 of the variable pulse generator 220 based on the level offset control signal 252 from the load current detector 216, which arrives at the current through the load 202. It is activated when the maximum level is reached. When the voltage level of the AC input 206 changes, such as when dimming by an external bidirectional AC trimmer dimmer, the reference current signal 242 will thus change and cause the current through the load 202 to change. In other embodiments, the reference current source 240 can be adjusted by an internal dimmer to vary the current through the load 202.

The level shifter 222 shifts the control signal 224 from the load current detector 216 to a one-bit offset control signal 252, wherein the control signal 224 is relative to the region ground 236 in the load current detector 216. The quasi-offset control signal 252 is relative to the circuit ground 234 used in the variable pulse generator 220. The level shifter 222 can include any suitable means for shifting the voltage of the control signal 224, such as an opto-isolator or opto-coupler, a resistor, a transformer, a transistor, etc. Wait. The use of isolated level shifters such as optocouplers or opto-isolators or transformers may be desirable, necessary, and/or beneficial for a particular application.

Pulse output 250 from variable pulse generator 220 drives one of switches 254, such as a field effect transistor (FET), in output driver 204. When a pulse from variable pulse generator 220 is active, switch 254 is turned "on" and draws current from input voltage 206 through load path 256 (and a selective capacitor 260 of parallel load 202) through load current sensing. The resistor 244, one of the output driver 204, the inductor 262, the switch 254, and a current sensing resistor 264, and then to circuit ground 234. When the pulse from variable pulse generator 220 disappears, switch 254 is turned off, blocking current from input voltage 206 to circuit ground 234. The inductor 262 opposes the current change and causes the current to reflow back through one of the diodes 266 in the output driver 204, through the load path 256 and the load current sense resistor 244 and back to the inductor 262. Thus, the load path 256 is alternately supplied with current through the switch 254 when the pulse is emitted from the variable pulse generator 220, and is supplied with the current driven by the inductor 262 when the pulse disappears. The pulse of variable pulse generator 220 has a much higher frequency than the variation of input voltage 206, such as, for example, 30 kHz or 100 kHz, compared to 100 Hz that may occur on input voltage 226 from rectified AC input 206. Or 120Hz.

In the embodiment of FIG. 9, current overload protection 270 is included in variable pulse generator 220 and is based on current measurement signal 272 of one of current sense resistors 264 in series with switch 254. If the current through switch 254 and current sense resistor 264 exceeds a threshold set in current overload protection 270, the pulse width at pulse output 250 of variable pulse generator 220 will be reduced or removed. The example circuit 200 of Figure 9 is shown as being implemented in a discontinuous mode; however, with appropriate modification actions, continuous or critical conduction or resonant modes and other modes are also possible.

The operation of circuit 200 as a constant current dimming control circuit 20 is schematically illustrated in the current relationship diagram of FIG. The input voltage is above the X-axis, the output current is above the Y-axis, and the line 300 depicted represents the load current. In the example of FIG. 10, circuit 200 is configured to limit the load current to approximately 0.243A, while variable pulse generator 220 is set to a range of approximately 0 VAC to 120 VAC as required by the fluorescent tubes in the example load. Among the input voltage ranges. As the input voltage increases, the output current increases until the input voltage The pressure reaches approximately 120 VAC, at which point the load current level hits a shoulder 302 and is confined.

The shoulder waveform 302 can be shifted, for example, by scaling the reference current signal 242. The operation of the circuit 200 as a heater/filament cathode circuit 24 is schematically illustrated in the current diagram of Figure 11, wherein the shoulder waveform 302 is shifted to approximately 35V to produce a minimum dimming angle. A fixed voltage or current 302 is maintained to maintain power to the heater circuit in the fluorescent tube while the fluorescent dimmer 10 is dimming. It should be noted that the voltage and current levels shown in Figures 10 and 11 are merely examples and should not be considered limiting in any way. For example, it can take the form of a flyback transformer in the form of a circuit such as described above, as well as other types of flyback and other independent circuits, structures, and modes. Likewise, nothing shown or described in the exemplary embodiments should be construed as limiting in any manner or form.

The present invention may also include anti-striation circuitry including other similar electrodes that pass through the gate (base) or drain (collector) of the FET (BJT) or other types of components (eg, IGBT). And the principle of the circuit. Other embodiments may employ other forms, methods, types of anti-stripe circuits for use in the present invention.

In some embodiments, the present invention can be grouped into a universal input dimming ballast capable of operating over a wide range of AC (or DC) input voltages; for example, 100 to 305 VAC, 100 to 400 VDC, and the like. In some embodiments, the present invention may use a microprocessor, a microcontroller, a field programmable gate array (FPGA), a complex logic device (CLD), a specific-purpose integrated circuit. Application specific integrated circuit (ASIC), analog and digital logic, etc., to implement several, specific, many features, attributes, functions, acts, performances, and so forth.

Although the illustrative embodiments have been described in detail, it is to be understood that the concepts disclosed herein may be embodied and utilized in various forms.

Claims (19)

A dimmable fluorescent lamp device comprising: a fluorescent lamp power output; at least one fluorescent lamp heater output; a dimmable current source for generating a controllable fixed current; and a current feeding inverter And a heater circuit for supplying power to the at least one fluorescent lamp heater output, wherein the heater circuit is at the controllable fixed current system When variable, a substantially fixed level of power is provided, wherein the heater circuit includes a variable pulse generator and a load current detector. The dimmable fluorescent lamp device of claim 1, wherein the heater circuit provides a substantially fixed voltage level of power. The dimmable fluorescent lamp device of claim 1, wherein the fluorescent lamp power output is used to supply a plurality of fluorescent lamps, and wherein the at least one fluorescent lamp heater outputs the plurality of fluorescent lamps Each contains a heater output. The dimmable fluorescent lamp device of claim 1, wherein the dimmable current source comprises a variable pulse generator and a load current detector. The dimmable fluorescent lamp device of claim 4, wherein the variable pulse generator comprises a control input and a pulse output, the control input being connected to a control input of the power limit switch, the pulse output being connected to the power One of the limit switches controls the input, wherein the variable pulse generator is configured to effectively change a duty cycle at the pulse output, and wherein the load current detector includes an input and an output connected to the output driver a load path and the output is coupled to the variable pulse generator control input, wherein the variable pulse generator and the load current detector are configured to limit the duty cycle when a load current reaches a maximum current limit The load current is substantially prevented from exceeding the maximum current limit. The dimmable fluorescent lamp device of claim 1, wherein the dimmable current source is dimmable by an external dimmer. The dimmable fluorescent lamp device of claim 6, wherein the dimmable current source is powered from an alternating current input, and wherein the dimmable current source can be used to set the controllable fixed current to be proportional to The level of the AC input. The dimmable fluorescent lamp device of claim 1, wherein the dimmable current source is dimmable by an internal dimmer, wherein one of the controllable fixed current levels is set by the internal dimmer. The dimmable fluorescent lamp device of claim 1, wherein the current feeding inverter is configured to provide an AC signal to the fluorescent lamp power output, wherein an intensity of the alternating current is controlled by the controllable fixed current. The dimmable fluorescent lamp device of claim 9, wherein the current feeding inverter comprises a transformer having a central tapping point, a first input and a second input, wherein the central portion The junction is connected to the controllable fixed current from the dimmable current source. The dimmable fluorescent lamp device of claim 10, wherein the first input is switched by a first switch and the second input is switched by a second switch, and wherein the first switch is in a second open relationship Controlled by a non-overlapping signal. The dimmable fluorescent lamp device of claim 1 of the patent scope further includes a power factor control circuit. The dimmable fluorescent lamp device of claim 1 of the patent scope further includes an electromagnetic interference filter. The dimmable fluorescent lamp device of claim 1, wherein the dimmable current source is configured to set the controllable fixed current to a level suitable for the plurality of fluorescent lamps to be connected in series to the output of the fluorescent lamp. The dimmable fluorescent lamp device of claim 1, wherein the dimmable current source is configured to set the controllable fixed current to a level suitable for the plurality of fluorescent lamps to be connected in parallel to the output of the fluorescent lamp. A method of powering a fluorescent lamp system, comprising: generating a controllable fixed current to power at least one fluorescent lamp in the fluorescent lamp system; and generating a fixed heater power output to drive the fluorescent lamp At least one fluorescent lamp heater in the system, wherein the fixed heater power output is operable to generate a substantially fixed level of power, and wherein the controllable fixed current can be varied to dim the fluorescent lamp system The generating a fixed heater power output is performed via a variable pulse generator and a load current detector. The method of claim 16, wherein the controllable fixed current is dimmable by an external dimmer. The method of claim 16, wherein the controllable fixed current is dimmable by an internal dimmer. The method of claim 16 wherein the fixed heater power output is operable to generate a substantially fixed voltage level of power.