Patent Publication Number: US-2009236990-A1

Title: Electric discharge light-regulation matching...

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a gas discharge fluorescence lamp, and more particularly to a electric discharge light regulation matching circuit that operates with filaments. 
     2. Description of the Related Art 
     Typically, a conventional light-regulation type gas discharge fluorescent lamp or a conventional light-regulation type electronic ballast for fluorescent lamps utilizes IC chips and conventional standard light regulator having electric control switch, such as TRIAC, for light regulation. In a circuit thereof, there usually are a plurality of capacities, resistors and inductances. Typically, the gas discharge fluorescent lamp includes a lamp tube and a plastic case, in which the lamp tube is received. 
     However, in the process of light regulation, when the electric control switch is turned on, a pulse current of a few amperes is generated in charge of capacities. The pulse current is acted with inductances to generate a greater ringing wave, and its negative value usually exceeds the voltage of input power that causes turn-on and turn-off of the electric control switch and the flicker of the gas discharge fluorescent lamp. Therefore, there must be a damping resistor in the circuit to reduce the flicker caused by the ringing wave. However, this damping resistor will generate a great heat in operation that consumes the power and raises the temperature in the plastic case of the gas discharge fluorescent lamp. 
     SUMMARY OF THE INVENTION 
     The primary objective of the present invention is to provide an electronic circuit that matches hot cathode fluorescent lamps to prevent the flicker problem of the electric control switch connecting light regulation lamp. The circuit includes an end of a filament connecting an end of a charge capacity to heat the filament directly. The circuit further has functions of reusing power and preventing temperature rising. 
     The secondary objective of the present invention is to provide a matching circuit for light regulation of a gas discharge fluorescent lamp, which may prevent the temperature rising in the plastic case. 
     To achieve the objectives of the present invention, a electric discharge light regulation matching circuit that operates with filaments includes a resonance unit, a converter unit, a charge circuit, a half-bridge output unit and a lamp. The resonance unit includes a first capacity and a second capacity in series connection, and including a first inductance in parallel connection with the first capacity and in series connection with the second capacity. The converter unit is connected to the resonance unit to convert an AC current to a DC current. The charge circuit includes at least a charge capacity connected to the converter unit. The half-bridge output unit includes two electric control switches in series connection, each of which has a control terminal connected to an oscillation unit respectively. The lamp, which is connected to the charge circuit, includes a first filament and a second filament therein, wherein the first filament has an end connected to the charge capacity to heat the first filament directly that may prevent a flicker problem of the lamp connecting the electric control switch and may provide functions of recycling power and preventing temperature rising. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a circuit diagram of a preferred embodiment of the present invention; and 
         FIG. 2  is a circuit diagram of the standard light regulator of the preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIG. 1 , a matching circuit  10  for light regulation of a hot cathode gas discharge fluorescent lamp which may match a standard light regulator to perform the function of light regulation. The matching circuit  10  includes a resonance unit  11 , a converter unit  21 , a charge circuit  31 , a half-bridge output unit  41 , and a lamp  51 . 
     The resonance unit  11  includes a first capacity C 1  and a second capacity C 2  in series connection, and includes a first inductance L 1  in parallel connection with the first capacity C 1  and in series connection with the second capacity C 2 . 
     The converter unit  21  is connected to the resonance unit  11  to convert an AC current to a DC current. In the present invention, the converter unit  21  is a bridge rectifier. 
     The charge circuit  31  includes a charge capacity Cc connected to the converter unit  21 . 
     The half-bridge output unit  41  includes two electric control switches Q 1 , Q 2  in series connection and connected to the charge circuit  31 . Each of the electric control switches Q 1 , Q 2  has a control terminal G, and each of the control terminals G is connected to an oscillation unit  45 . In the present invention, the electric control switches Q 1 , Q 2  are transistors, and the oscillation units  45  are RL oscillating circuits including a resistor R and an inductance L in series connection. 
     A voltage feedback unit  46 , which is connected to the charge circuit  31 , includes a second inductance L 2  and three capacities C 3 , C 4 , and C 5 . 
     The characters of the present invention are that the lamp  51 , which is connected to the charge circuit  31 , has two filaments  52 ,  53  therein, wherein an end of the first filament  52  is connected to an end of the charge capacity Cc, therefore, the first filament  31  works as a damping resistor of the charge circuit  31 . An end of the second filament  53  is connected to the voltage feedback unit  46 . In the present invention, the lamp  51  is a gas discharge fluorescent lamp having a plastic case (not shown). The matching circuit  10  of the present invention is provided in the plastic case, and the lamp  51  is left out of the plastic case. The plastic case of the gas discharge fluorescent lamp is a conventional element, so we do not describe the detail here. 
     The operation of the present invention is described in following: 
     In operation, the matching circuit  10  of the present invention is connected to a standard light regulator  61 , as shown in  FIG. 2 . The standard light regulator  61  is connected to a power input ends N 1 , N 2  of the resonance unit  11  to adjust the brightness of the lamp via the standard light regulator  61 . The standard light regulator  61  is a conventional device, so we do not describe the detail here. 
     When power inputting, the power go through the resonance unit  11 , the converter unit  21 , the charge circuit  31  and the half-bridge output unit  41  to charge the charge capacity Cc and to light the lamp  51 . 
     In light regulation, to adjust the lamp  51  from dark to bright, the input power is dropping gradually and generates a “ringing” effect that causes a great ringing wave. As a result, the first filament  52  works as the damping resistor to reduce the ringing wave. In the same time, the heat generated by the ringing wave acting on the first filament  52  may heat the filament  52  itself for heat recycling. In addition, the filament, which may replace the damping resistor, may prevent the damping resistor heating in the plastic case that the temperature in the plastic case may be kept in a normal condition. 
     In conclusion, the functions of the present invention are: 
     1. Recycling the waste power: the present invention provides the filament of the lamp working as the damping resistor to fix the problems of connecting the electric control switch. The present invention further recycles the power wasting in the damping resistor to reuse on the filament that provides an efficient use of power. 
     2. Preventing temperature in the plastic case rising of the gas discharge fluorescent lamp: Because the present invention provides the filament replacing the damping resistor, there is no need to provide the damping resistor in the circuit that no heating problem will occur. As a result, the temperature in the plastic case, in which the circuit is received, may be kept in a normal condition. 
     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.