Abstract:
The present invention discloses an integrated dimmable compact fluorescence lamp and a circuit used therein. The circuit includes: a dimming module configured to adjust the brightness of the compact fluorescence lamp by controlling the frequency of a voltage to be output to a control module, wherein the dimming module includes the following: a control part configured to receive a first electrical signal from an input module and an electrical feedback signal from a lamp tube of the compact fluorescence lamp, generate an electrical reference signal which represents a part of the first electrical signal or the whole electrical signal, adjust the electrical reference signal as reaction to an external operation and output the electrical reference signal and the electrical feedback signal to a frequency adjustment part to control the frequency of a voltage output from the frequency adjustment part; and the frequency adjustment part configured to receive the first electrical signal from the input module, generate the frequency of the voltage to be output to the control module and adjust the frequency of the voltage as reaction to the electrical reference signal and the electrical feedback signal.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to Chinese Patent Application No. 200810185714.9, which was filed Dec. 8, 2008, and is incorporated herein by reference in its entirety. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to a dimmable compact fluorescence lamp and relates particularly to an integrated dimmable compact fluorescence lamp (CFL) and a circuit used therein. 
       BACKGROUND 
       [0003]    A fluorescence lamp is a low voltage gas discharge lamp and also is a load with negative resistance. Accordingly, the control technology of the fluorescence lamp is more complex than the one of a filament lamp. A traditional compact fluorescence lamp, also referred to as energy-saving lamp, is dimmed by a wall dimmer. The wall dimmer generally is mounted on a position for a switch of the compact fluorescence lamp, and is integrated with a switching function for the compact fluorescence lamp. Generally, different kinds of compact fluorescence lamps each work with a wall dimmer, which is adapted to its kind. For example, the compact fluorescence lamps with different working voltages or working powers work with different wall dimmers. Furthermore, different wall dimmers may lead to different dimming effects at the same compact fluorescence lamp, while the dimming of the same wall dimmer may also lead to different dimming effects at different compact fluorescence lamps. 
         [0004]      FIG. 1  shows a schematic circuit diagram of a wall dimmer in the state of the art. In the circuit diagram of  FIG. 1 , a load  1100  is a compact fluorescence lamp. As shown in  FIG. 1 , a wall dimmer  1200  is connected in parallel to the load  1100  between the input terminals of the alternating current supply (AC) of the load  1100 . The wall dimmer may control the flow angle of a bi-directional silicon rectifier (SCR) by adjusting a control resistance W, whereby the voltage applied to the compact fluorescence lamp is adjusted. 
         [0005]      FIG. 2  is a wave form diagram that shows the working principle of the wall dimmer in the state of the art, as shown in  FIG. 1 . As shown in  FIG. 2 , the working principle of the wall dimmer as shown in  FIG. 1  consists in transforming in fact a complete sinusoidal alternating voltage into an incomplete sinusoidal alternating voltage. In this way, the brightness of the compact fluorescence lamp may be adjusted. 
         [0006]    A normal compact fluorescence lamp, however, cannot work directly with the dimmer. To work with the dimmer, the circuit of the compact fluorescence lamp must be specifically designed so that the normal compact fluorescence lamp becomes a dimmable compact fluorescence lamp. There are different dimmable compact fluorescence lamps, which may work with a will dimmer in the art, and therefore, they are not described in detail herein. 
         [0007]    Because in the state of the art, the dimmable compact fluorescence lamp and the wall dimmer are separated from each other and both of them need a specific circuit for supporting the dimming function, the structure of the circuits is overall complex and the overall production costs are high. 
         [0008]    Because the wall dimmer in the state of the art generally further works as a switch of the dimmable compact fluorescence lamp, furthermore the dimming of the wall dimmer generally has a region from the position forming the highest brightness level. 
       SUMMARY 
       [0009]    An object of the present invention is providing an integrated dimmable compact fluorescence lamp and a circuit used therein. This integrated dimmable compact fluorescence lamp may be dimmed without an additional dimmer. 
         [0010]    According to an embodiment of the present invention, a circuit for a compact fluorescence lamp is provided. The circuit includes: A dimming module, which is configured to adjust the brightness of the compact fluorescence lamp by controlling the frequency of a voltage to be output to a control module, wherein the dimming module includes the following: a control part, which is configured to receive a first electrical signal from an input module and an electrical feedback signal from a lamp tube of the compact fluorescence lamp, generate an electrical reference signal, which represents a part of the first electrical signal or the whole electrical signal, adjust the electrical reference signal as reaction to an external operation and output the electrical reference signal and the electrical feedback signal to a frequency adjustment part, to control the frequency of a voltage output from the frequency adjustment part; and the frequency adjustment part, which is configured to receive the first electrical signal from the input module, generate the frequency of the voltage to be output to the control module and adjust the frequency of the voltage as a reaction to the electrical reference signal and the electrical feedback signal. 
         [0011]    According to another embodiment of the present invention, an integrated dimmable compact fluorescence lamp including the above circuit is provided. 
         [0012]    In the present invention, the dimming part is integrated in the compact fluorescence lamp and only a single dimming circuit is required. Therefore, the structure of the circuit is overall simple and the production costs are low. 
         [0013]    Because of the integrated design it furthermore is not necessary, that the dimming part of the present invention includes a switching function. Thus, dimming of the dimming part may start from an arbitrary brightness level. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The above and further objects, features and advantages of the present invention will be better understood by referring to the following description given in connection with the attached figures. 
           [0015]      FIG. 1  shows a schematic circuit diagram of a wall dimmer in the state of the art; 
           [0016]      FIG. 2  shows a wave form diagram, that shows the working principle of the wall dimmer in the state of the art, as shown in  FIG. 1 ; 
           [0017]      FIG. 3  shows a diagram of a circuit for a compact fluorescence lamp according to an embodiment of the present invention; 
           [0018]      FIG. 4  shows a diagram of an integrated dimmable compact fluorescence lamp according to an embodiment of the present invention; and 
           [0019]      FIG. 5  shows a diagram of an integrated dimmable compact fluorescence lamp according to another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    The principle of the embodiments of the present invention consists in integrating a dimming module into a compact fluorescence lamp and adjusting the brightness of the compact fluorescence lamp by controlling the frequency of a voltage output from the dimming module to a control module of the compact fluorescence lamp. The change at the frequency of the voltage output to the control module may cause a change of the working frequency of a lamp tube of the compact fluorescence lamp. Accordingly, the working voltage and the working current of the lamp tube change. In this way, the brightness of the compact fluorescence lamp may be dimmed. 
         [0021]      FIG. 3  shows a diagram of a circuit for a compact fluorescence lamp according to an embodiment of the present invention. As shown in  FIG. 3 , a circuit  3000  includes an input module  3100 , a control module  3200  and a dimming module  3300 . The input module  3100  is configured to transform a line alternating voltage (AC) into a direct voltage (DC). For example, as shown in  FIG. 3 , the line alternating voltage is supplied to the terminals S 11  and S 12  to be applied to the input module  3100 , and is then transformed into a direct voltage and output to the output nodes N 1  and N 2  of the input module  3100 . The node N 2  is connected to a reference mass node NGref of the circuit  3000 . The line alternating voltage is for example an alternating voltage of 120 V/50 Hz or 60 Hz. The person skilled in the art will understand that the line alternating voltage may also be an alternating voltage of 220 V/50 Hz or 60 Hz. 
         [0022]    The control module  3200  is configured to supply current to a lamp tube of the compact fluorescence lamp, so that the lamp tube illuminates and so that the lamp tube can work stably. As an example, in  FIG. 3  the two pairs of output terminals (J 1 , J 2 ) and (J 3 , J 4 ) of the control module  3200  each include a fiber connected between them, i.e. a fiber is connected between the output terminal pair (J 1 , J 2 ) and another fiber is connected between the output terminal pair (J 3 , J 4 ). 
         [0023]    Here, the input module  3100  and the control module  3200  are circuits in the state of the art, and different ways for implementing of these two modules are known to the person skilled in the art. Therefore, these two modules are not detailed herein. 
         [0024]    A dimming module  3300  is connected between the input module  3100  and the control module  3200 . In the embodiment of  FIG. 3 , the dimming module  3300  includes a control part  3310  and a frequency adjustment part  3320 . 
         [0025]    The control part  3310  receives the direct voltage output from the input module  3100  and an alternating feedback voltage from the lamp tube. The control part  3310  generates a reference direct voltage, which forms a part of the direct voltage output from the input module  3100  or the whole direct voltage. The control part  3310  adjusts the reference direct voltage as reaction to the external operation and outputs the adjusted reference direct voltage and the feedback alternating voltage from the lamp tube to the frequency adjustment part  3320 . The frequency adjustment part  3320  receives the direct voltage from the input module  3100  and generates the frequency of a voltage to be output to the control module  3200 . The frequency adjustment part  3320  adjusts the frequency of the voltage to be output to the control module  3200  as reaction to the reference direct voltage from the control part  3310  and the feedback alternating voltage. 
         [0026]    The frequency adjustment part  3320  may be implemented with an electronic apparatus available on the market like for example an IC chip, which has the function of outputting a voltage with a corresponding frequency as a reaction to a change at the input voltage. The periphery circuit for such an electronic apparatus is also well known to the person skilled in the art. 
         [0027]    As an example, in  FIG. 3  an IC chip U 1  and a periphery circuit of it are used to implement the frequency adjustment part  3320 , wherein the IC chip U 1  has the function to output a voltage with a corresponding frequency as a reaction to a change at the input voltage. A working voltage input node Vcc of the frequency adjustment part  3320  is connected to a first output node N 1  of the input module  3100 , and a reference mass input node NGref of the frequency adjustment part  3320 , which is also the reference mass input node of the circuit  3000 , is connected to a second output node N 2  of the input module  3100 . In  FIG. 3 , pin  1  of the chip U 1  is connected to the working voltage input node Vcc of the frequency adjustment part  3320  by a resistor R 13 , and a pin  2  of the chip U 1  is connected to the reference mass voltage input node NGref of the frequency adjustment part  3320 . The chip U 1  receives the reference direct voltage and the alternating voltage from the control part  3310  at its input terminal  3 . The chip U 1  permanently adjusts the switching frequency at the pins  5  and  7  by checking the voltage at pin  3 , whereby the working frequency of the lamp tube is adjusted, the working current of the lamp tube is changed and thus the brightness of the compact fluorescence lamp is adjusted. In an embodiment of the present invention, the switching frequency at the pins  5  and  7  varies between 40 kHz and 80 kHz. 
         [0028]    The circuit of the frequency adjustment part  3320 , like shown in  FIG. 3 , is just an example. The person skilled in the art understands a lot of other circuits for implementing the frequency adjustment part  3320  and may conceive them. Therefore, the structure of the frequency adjustment part  3320  will not be further detailed here. 
         [0029]    In the embodiment of  FIG. 3 , the control part  3310  includes a slide resistor VR 1 . The two ends of VR 1  each are connected to the output nodes N 1  and N 2  of the input module  3100 , whereby the direct voltage is received from the input module. The sliding contact P of VR 1  is connected to pin  3  of the chip U 1  of the frequency adjustment part  3320  and may be displaced by an external operation. With the displacement of the sliding contact P the reference direct voltage to be input from U 1  in pin  3  in the region of the received direct voltage. 
         [0030]    The control part  3310  further includes a feedback resistor R 12 . The feedback resistor R 12  is connected between the reference mass node NGref of the circuit  3000  and the position of the lamp tube. The end of the feedback resistor R 12  connected to the position of the lamp tube is also connected to the input terminal  3  of the frequency adjustment part  3320 , i.e. pin  3  of U 1 . The feedback resistor R 12  is a resistor for feeding back the lamp tube current. When the lamp tube current flows through R 12 , this means that the feedback current flows from the lamp tube through R 12 . Then, the voltage at R 12  may be supplied to the input terminal  3  of the frequency adjustment part  3320 . In one embodiment of the present invention the voltage at R 12  is an alternating voltage. The alternating voltage supplied from R 12  and the reference direct voltage output from VR 1  are superimposed with each other at the input terminal  3  of the frequency adjustment part  3320 , whereby a sinusoidal voltage to be supplied to pin  3  from U 1  is formed. 
         [0031]    In the above embodiment, the chip U 1  permanently adjusts the switching frequency at the pins  5  and  7  by checking the voltage at pin  3 , whereby the working frequency of the lamp tube is adjusted, the working current of the lamp tube is changed and finally the minimum value of the sinusoidal voltage at pin  3  is made zero. When the minimum value of the sinusoidal voltage at pin  3  is zero, an adjustment at the compact fluorescence lamp is completed and the light of the compact fluorescence lamp is stabilized. 
         [0032]    In an embodiment of the present invention the control part  3310  may further include a capacitor C 8  and a resistor R 7 . 
         [0033]    In the above embodiment, the voltage at pin  3  is influenced by two factors, i.e. the reference direct voltage of VR 1  and the alternating voltage of R 12 . The change at the reference direct voltage of VR 1  may finally change the alternating voltage of R 12 , i.e. may change the working current of the lamp tube. This is a negative feedback procedure, and such a negative feedback procedure may allow that the current of the lamp tube is more stable. 
         [0034]    In an embodiment of the present invention, the control part  3310  further includes resistors R 2  and R 3 . The resistor R 2  is connected between the slide resistor VR 1  and the node N 1 , and the resistance R 3  is connected between the slide resistor VR 1  and the node N 2 . The resistors R 2  and R 3  are configured to define the voltage adjustment region of the slide resistor VR 1 , whereby the highest and the lowest working power of the whole compact fluorescence lamp are defined. 
         [0035]    In an embodiment of the present invention, the dimming module  3300  may further include series resistors R 4  and R 5 . The resistors R 4  and R 5  are connected in series between the working voltage input node Vcc of the frequency adjustment part  3320  and the output node N 1  of the input module  3100 , and are also connected in series between the output node N 1  of the input module  3100  and the end of the slide resistor VR 1 , which is connected with the first input node N 1  of the input module. The series resistors R 4  and R 5  are also configured so that voltage output at node N 1  falls, so that a lower voltage than the voltage output at node N 1  is supplied to the frequency adjustment module  3320  and the voltage adjustment module  3310 . 
         [0036]      FIG. 4  shows a diagram of an integrated dimmable compact fluorescence lamp according to an embodiment of the present invention. The compact fluorescence lamp, as shown in  FIG. 4 , includes a circuit for a compact fluorescence lamp according to an embodiment of the present invention. In  FIG. 4 , the compact fluorescence lamp  4000  includes a spiraliform fluorescence lamp tube  4100  and a lamp tube mounting  4200 . In another embodiment, the lamp tube  4100  may also show another suitable form, such as for example a U-shape or an H-shape. Although it is not shown, the circuit may be arranged in the lamp tube mounting  4200 . 
         [0037]    Furthermore, the compact fluorescence lamp  4000  may also include a slide resistor  4300 . In  FIG. 4 , the slide resistor  4300  is arranged outside the lamp tube mounting  4200  and connected to the lamp tube mounting  4200  and finally to the circuit in the lamp tube mounting  4200  by a conducting wire  4400 . The slide resistor  4300  is the slide resistor VR 1  in the circuit of the integrated dimmable compact fluorescence lamp according to the embodiment of the present invention. 
         [0038]    Furthermore, the conducting wire  4400  may be provided with a fixation apparatus  4500 . The fixation apparatus  4500  is configured to fix the conducting wire  4400  at an object like for example a wall, to prevent the conducting wire  4400  from touching the lamp tube  4100 . 
         [0039]      FIG. 5  shows a diagram of an integrated dimmable compact fluorescence lamp according to another embodiment of the present invention. The compact fluorescence lamp  5000 , as shown in  FIG. 5 , also includes a circuit for a compact fluorescence lamp according to an embodiment of the present invention. The integrated dimmable compact fluorescence lamp  5000  in  FIG. 5  is different from the one in  FIG. 4  in that the slide resistor  5300  in the compact fluorescence lamp  5000  is arranged directly at the outer surface of the lamp tube mounting  5200 , whereby the space is reduced. Furthermore, the slide resistor  5300  in the embodiment of  FIG. 5  possesses the form of a rotary knob. 
         [0040]    It is to be noted that the expressions “comprise”, “include” and any other variations thereof shall cover a non-exclusive inclusion, so that a process, a method, an article or an apparatus, which includes a list of elements, is not necessarily constrained to those elements, but may include other elements, which are not explicitly listed or are inherent in this process, this method, this article or this apparatus. Furthermore, without explicit limitation, the element defined by a sentence “comprises a . . . ” does not exclude an other identical element in the process, the method, in the article or in the apparatus, which comprises the list of the elements. 
         [0041]    Although the embodiments of the present invention have been described in connection with the attached drawings, it will be understood, that the above-described embodiments are provided for illustrative purposes only, but do not form the limit of the present invention. A person skilled in the art may perform various modifications and amendments to the embodiments, without departing from the scope of protection of the present invention. Therefore, the scope of protection of the present invention is only defined by the attached claims and their equivalents.