KR100952941B1 - Apparatus and method for constant power control of ballast for flat panel lamp - Google Patents

Abstract

The present invention is to provide a constant power control device and method of the ballast for driving the surface light source, the power factor correction unit for receiving the AC power to correct the power factor of the AC power, converting the output to DC power; An inverter unit for converting an output of the power factor correction unit into a pulse power source and supplying the surface light source of mercury-free type; A comparator for sensing a current of the inverter and outputting a comparison result; A controller which receives the output of the comparator and outputs a control signal to the power factor correcting unit; And a voltage controller configured to receive a control signal of the controller and perform voltage control on the power factor correcting unit. In order to prevent an arc from occurring due to an increase in power consumption in the mercury-type surface light source, the surface light source It is possible to stably drive the surface light source by preventing the power of the driving ballast from increasing.

Surface light source, ballast, constant power, power supply, mercury free

Description

Apparatus and method for constant power control of ballast for flat panel lamp}

The present invention relates to a ballast for driving a surface light source, and in particular, in order to prevent an arc from occurring due to an increase in power consumption in a surface light source of mercury type, a surface light source is prevented from increasing the power of the ballast for driving a surface light source. The present invention relates to a constant power control device and a method of a ballast for driving a surface light source, which is suitable for driving stably.

Almost all light sources currently used around the world contain harmful substances such as mercury, which are considered to be one of the main causes of global environmental pollution, and are gradually limiting their use. Therefore, he is working on developing a mercury-free surface light source that does not affect environmental pollution.

Among the mercury-free flat fluorescent lamps (MFFLs) that are currently being developed, the type that allows xenon instead of mercury (Hg) is one of the most advanced.

However, xen type (Xe) type surface light source has the disadvantage that the temperature of the surface light source rises and the power consumed also increases with time after starting the light source.

As the power consumption of the surface light source increases, an arc is generated in the surface light source, which has a fatal effect on the life and reliability of the surface light source (["Feedback drive system and driving method for maintaining glow discharge of surface light source"). , Baek Jong-bok, Park Jong-hoo, Cho Bo-hyun, Power Electronics Society Conference 2007.7, Power Electronics Society, pp356 ~ 358], hereinafter referred to as "prior art 1"). However, since the conventional technique 1 adjusts the constant power by using a method of controlling the output of the DC-DC converter according to the current of the inverter by adding a new DC-DC converter in front of the inverter, the hardware has a complicated disadvantage.

1 is a block diagram of a power supply device for a conventional LCD display device, and described in Korean Patent Office Registration No. 10-0782755, "Power Supply Device for LCD Display Device" (hereinafter, referred to as "Prior Art 2"). It is content.

Thus, the prior art 2 includes a converter unit 110 for switching an AC power source to a DC power source according to a switching control signal; An inverter unit 120 for switching the DC power from the converter unit 110 and converting the DC power into a predetermined AC power; A lamp unit 130 which receives AC power from the inverter unit 120 and emits light; The first switching control signal is generated by combining the current detection signal detected from the ramp unit 130 and the digital dimming signal, and generating a second switching control signal according to the voltage detection signal detected from the output terminal of the converter unit 110. A controller 140 for generating; A selection unit 150 for selecting a signal having a high voltage level among the first switching control signal and the second switching control signal from the control unit 140 and transferring the switching control signal to the converter unit 110. It is configured by.

In the related art 2, the power supply device 100 includes a converter unit 110, an inverter unit 120, a lamp unit 130, a control unit 140, and a comparison unit 150.

The converter unit 110 receives the AC power and transfers a predetermined DC power to the inverter unit 120. The converter unit 110 includes a power factor correcting unit 111 for correcting a power factor of the AC power and switching the AC power to a predetermined DC power.

The inverter unit 120 receives a preset DC power from the converter unit 110, switches the DC power, converts the DC power into a preset AC power, and transfers the converted AC power to the lamp unit 130.

The lamp unit 130 receives AC power from the inverter unit 120 and emits light.

The controller 140 receives the current detection signal Vs1 from the lamp unit 130, generates a first switching control signal Veao1, and receives the voltage detection signal Vs2 from the converter 110. Two switching control signals Veao2 are generated and transmitted to the selector 150.

Accordingly, the control unit 140 combines the current detection signal Vs1 and the digital dimming signal Vd to generate a first switching control signal Veao1 by comparing with the preset current signal V1. ) And the second comparator 142 and the inverter unit 120 generating the second switching control signal Veao2 by comparing the voltage detection signal Vs2 with a preset voltage signal V2. It may include a first controller 143 to control the switching.

The first controller 143 may control the switching of the inverter unit 120 according to the digital dimming signal Vd. That is, when the digital dimming signal Vd is high, the switching of the inverter unit 120 is disabled. When the digital dimming signal vd is low, the switching of the inverter unit 120 is performed. By enabling switching, the inverter unit 120 may be switched at a preset rate.

The selector 150 receives the first switching control signal Veao1 and the second switching control signal Veao2 and selects one control signal from the first switching control signal Veao1 and the second switching control signal Veao2. To the converter 110. The selector 150 includes first and second diodes D1 and D2 that receive the first switching control signal Veao1 and the second switching control signal Veao2, respectively.

However, this prior art 2 is a case in which the DC-DC converter plays a role of the constant power control, which is a limitation that can not be used in the surface light source of mercury type.

2 is a block diagram of a conventional dimming control ballast, which is described in Korean Patent Office Registration No. 10-0672028, "Dimming Control Ballast" (hereinafter, referred to as "prior art 3").

Thus, the related art 3 is a fluorescent lamp ballast for dimming control that maintains a constant illuminance of a lamp, including: a bridge rectifier 2 for converting a commercial AC voltage input through the AC input unit 1 to generate a pulse voltage; Control current harmonics according to the phase difference between the current and voltage of the input (AC) generated in the process of converting the pulse current voltage input from the bridge rectifier 2 into a direct current (DC) voltage, and the output voltage even when the input voltage changes A constant power supply unit 3 for maintaining a constant; An inverter unit 5 for receiving an operating voltage from the constant power supply unit 3 and performing high frequency switching; A frequency generator (4) for controlling a lamp current by adjusting the switching frequency of the inverter (5); A frequency controller 6 for adjusting the oscillation frequency of the frequency generator 4; A current detector 7 which senses the inverter unit 5 and the lamp current and keeps the lamp current constant; A resonator unit 8 for resonating the high speed switching voltage by the inverter unit 5 to light a lamp; An inverter current comparison section 9 for generating a control signal of the frequency control section 6 by comparing the currents of the inverter section 5 and the current detection section 7; And a dimming control unit 11 for generating an operating current according to the control voltages 10V to 0V from the outside to control the inverter current comparison unit 9.

However, the prior art 3 is a method of controlling the frequency to make the power flowing to the light source constant, but there is a limit that cannot be used in the mercury-free surface light ballast.

Therefore, in the present invention, it is intended to stably drive the surface light source by preventing the characteristic of increasing power in the mercury-free surface light source ballast.

Accordingly, the present invention has been proposed to solve the above conventional problems, the object of the present invention is to stabilize the surface light source driving ballast in order to prevent the occurrence of an arc in accordance with the rise of power consumption in the surface light source of mercury type The present invention provides a constant power control apparatus and method of a ballast for driving a surface light source that can stably drive a surface light source by preventing a power increase.

3 is a block diagram of an apparatus for controlling a constant power of a ballast for driving a surface light source according to an embodiment of the present invention.

As shown therein, the power factor correction unit 20 receives the AC power, corrects the power factor of the AC power, converts the power to DC power, and outputs the output V _dc ; An inverter unit 30 converting the output V _dc of the power factor correcting unit 20 into a pulse power supply and supplying the surface light source 40 of mercury-free type; A comparator 50 for sensing a current I _sense of the inverter unit 30 and outputting a comparison result V _b ; A controller 60 which receives the output V _b of the comparator 50 and outputs a control signal to the power factor correcting unit 20; And a voltage controller 70 that receives the control signal of the controller 60 and performs voltage control on the power factor correcting unit 20.

When the comparison unit 50 is notified that the current I _sense of the inverter unit 30 is increased, the comparison unit 50 reduces the output voltage V _b and transmits it to the control unit 60.

The controller 60 includes a transistor Q _{1 that} operates by receiving the output V _b of the comparator 50, and receives the output V _dc of the power factor correcting unit 20. A control signal of the power factor correcting unit 20 is output by controlling the collect-emitter equivalent resistance R _equ of the transistor Q ₁ .

The controller 60 receives the output voltage V _b of the comparison unit 50, and when notified that the current I _sense of the inverter unit 30 is increased, the control unit 60 of the transistor Q ₁ . It is characterized in that for outputting the control signal to reduce the output (V _dc ) of the power factor correction unit 20 by increasing the _collector- emitter equivalent resistance (R _equ ).

The constant power control device of the ballast for driving the surface light source, EMI filter 80 for performing EMI (electromagnetic interference) filtering on the AC power input to the power factor correction unit 20; do.

4 is a flowchart illustrating a method for controlling electrostatic force of a ballast for driving a surface light source according to an embodiment of the present invention.

As shown therein, the power factor correction unit 20, the inverter unit 30, the comparison unit 50, the control unit 60, and the voltage control unit 70 are provided, and the mercury-free surface light source 40 is provided. In the control method for the constant power control device of the ballast for driving the surface light source for performing the constant power control for the first, the first (I _sense ) sensed by the inverter unit 30 to compare with the reference current (I _ref ) Steps ST1 and ST2; When it is determined that the current I _sense of the inverter unit 30 is changed as a result of the comparison in the first step, the voltage control unit 70 controls the power factor correcting unit 20 so that the surface light source 40 is changed. And a second step ST3 to ST7 to maintain the constant power.

In the second step, the control unit 60 outputs a control signal to the power factor correcting unit 20 by controlling the collect-emitter equivalent resistance R _equ of the transistor Q ₁ . .

In the second step, if it is determined that the current I _sense of the inverter unit 30 is increased, the output voltage V _b of the comparison unit 50 is decreased (ST3); The reduced output voltage V _b of the comparator 50 is transmitted to the controller 60 to increase the _collector- emitter equivalent resistance R _equ of the transistor Q _{1 in} the controller 60. It characterized in that it comprises a; step (ST4 ~ ST7) to reduce the output (V _dc ) of the power factor correction unit 20.

The electrostatic power control device and method of the ballast for driving surface light source according to the present invention prevent the arc from occurring due to the increase of power consumption in the surface light source of mercury type to prevent the power of the ballast for driving the surface light source from increasing. It is effective to drive surface light source stably.

Referring to the accompanying drawings, preferred embodiments of the electrostatic force control device and method of the ballast for driving a surface light source according to the present invention configured as described above will be described in detail as follows. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to intention or precedent of a user or an operator, and thus, the meaning of each term should be interpreted based on the contents throughout the present specification. will be.

First, the present invention is intended to stably drive the surface light source by preventing the characteristic of increasing the power of the surface light source driving ballast in order to prevent the generation of arc in accordance with the increase in power consumption in the mercury-type surface light source.

3 is a block diagram of an apparatus for controlling a constant power of a ballast for driving a surface light source according to an embodiment of the present invention.

First, the EMI filter 80 performs EMI filtering on the AC power so that the AC power is input to the power factor correcting unit 20.

The power factor correction unit 20 receives the EMI filtered AC power, corrects the power factor of the AC power, converts the AC power to DC power, and outputs the output V _dc to the inverter unit 30.

The inverter unit 30 converts the output V _dc of the power factor correcting unit 20 into a pulse power supply and supplies it to the surface light source 40 of the mercury type. In addition, the current I _sense sensed by the inverter unit 30 is transmitted to the comparator 50.

The comparison unit 50 senses the current I _sense of the inverter unit 30 and outputs the comparison result to the control unit 50 (V _b ). Thus, when the comparison unit 50 is notified that the current I _sense of the inverter unit 30 increases, the comparison unit 50 decreases the output voltage V _b and transmits it to the control unit 60. That is, when the current I _sense and the reference current I _{ref of the} inverter unit 30 are received and compared, and the current I _sense of the inverter unit 30 is determined to be greater than the reference current I _ref , The output voltage V _b is reduced and transmitted to the controller 60.

The controller 60 receives the output V _b of the comparator 50 and outputs a control signal for the power factor correcting unit 20. The control unit 60 receives the output (V _dc) of the comparator having a transistor (Q ₁₎ operated by receiving the output (V _b) of 50, and the power factor correction unit (20) transistor (Q ₁ ) _Collects a control signal of the power factor corrector 20 to the voltage controller 70 by controlling the collect-emitter equivalent resistance R _equ . Thus, when the output voltage V _b of the comparator 50 is input and the current I _sense of the inverter unit 30 is notified to increase, the collector-emitter equivalent resistance R of the transistor Q ₁ is increased. _equ ) is increased to output a control signal to the voltage controller 70 so that the output (V _dc ) of the power factor corrector 20 decreases.

The voltage controller 70 receives a control signal from the controller 60 and performs voltage control on the power factor correcting unit 20.

On the other hand if more by the characteristics of the surface light source 40 of a mercury-free type over time, the light source current that flows in the 40 to increase, so when the current is increased the product of the size and current of the need to reduce the size of the V _dc V _dc It becomes constant.

So the present invention is configured as follows for this purpose.

Was an increase in yimi teo equivalent resistance - first, by sensing the current (I _sense) of the inverter unit 30, which increases as to make V _b is reduced and decreases the base current of Q _1, curl collected in Q ₁ . Therefore, R _f2 and R _c and Q ₁ Curl of the select-emitter equivalent resistance (R _ce) R _equ consisting of the sum of and _parallel. Is increased to decrease V _dc , which is determined as in Equations 1 and 2, so that the power entering the surface light source is kept constant.

The output voltage (V _dc ) of power factor correction (PFC) is R _f1 and R _equ. Is determined as in Equations 1 and 2 below.

Where generally R _f1 is R _equ. Since it is 10 or more than, Equation 1 above holds. R _equ. Is the sum of R _f2 , R _{c, and} R _ce and the parallel connection equivalent resistance as in Equation 2.

Looking at the limitations of the constant power circuit, V _b is the smallest and cannot flow the base current of Q ₁ , so R _ce appears to be infinite _. When that is the limit is represented only by R _f2 V _dc is the lowest.

Looking at the time when the surface light source 40 is the brightest, R _equ. Is the smallest. In other words, the curl V _b of the base current sufficiently flows Q ₁ Q ₁ of the select-an emitter becomes saturated as small as negligible for R _ce R _equ. V _dc becomes the highest when R _f2 and R _c can only be seen in parallel connection, where the surface light source 40 is the brightest.

4 is a flowchart illustrating a method for controlling electrostatic force of a ballast for driving a surface light source according to an embodiment of the present invention.

First, the current I _sense of the inverter unit 30 is sensed (ST1) and compared with the reference current I _ref (ST2).

Thus, if it is determined that the current I _sense of the inverter unit 30 is increased, the output voltage V _b of the comparing unit 50 is decreased (ST3).

Then, the reduced output voltage V _b of the comparator 50 is transferred to the controller 60 to reduce the base current of the transistor Q _{1 in} the controller 60 (ST4).

Then, the collector-emitter equivalent resistance R _equ of the transistor Q ₁ is increased (ST5).

The increased collector-emitter equivalent resistance R _equ of the transistor Q ₁ is transferred to the power factor correcting unit 20 through the voltage controller 70. As a result, the output V _dc of the power factor correcting unit 20 decreases (ST6).

Through this process, the power entering the surface light source 40 can be maintained in the constant power state (ST7).

That is, the present invention is to control the output voltage (V _dc ) of the power factor correction unit 20 as the current of the inverter unit 30 increases so as to maintain a constant power.

As described above, the present invention is to stably drive the surface light source by preventing the power of the surface light source driving ballast from increasing in order to prevent an arc from occurring due to an increase in power consumption in the surface light source of mercury type.

Although the present invention has been described in more detail with reference to the examples, the present invention is not necessarily limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

1 is a block diagram of a power supply for a conventional LCD display device.

2 is a block diagram of a conventional fluorescent lamp ballast for dimming control.

3 is a block diagram of an apparatus for controlling a constant power of a ballast for driving a surface light source according to an embodiment of the present invention.

4 is a flowchart illustrating a method for controlling electrostatic force of a ballast for driving a surface light source according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

20: power factor correction unit

30: inverter unit

40: surface light source

50: comparison unit

60: control unit

70: voltage control unit

80: EMI filter

Claims (8)

A power factor correction unit which receives the AC power, corrects the power factor of the AC power, converts the power to DC power, and outputs the DC power; An inverter unit for converting an output of the power factor correction unit into a pulse power source and supplying the surface light source of mercury-free type; A comparator for sensing a current of the inverter and outputting a comparison result; A controller which receives the output of the comparator and outputs a control signal to the power factor correcting unit; A voltage controller configured to receive a control signal of the controller and perform voltage control on the power factor correcting unit; It is configured to include, The control unit, And a transistor configured to receive an output of the comparator, and to receive the output of the power factor correcting unit to control a collect-emitter equivalent resistance of the transistor to output a control signal to the power factor correcting unit. Constant power control device of the ballast for driving surface light source. The method according to claim 1, The comparison unit, And receiving a notification that the current of the inverter is increased, reducing the output voltage and transferring the output voltage to the controller. delete The method according to claim 1, The control unit, When the output voltage of the comparator is received and notified that the current of the inverter increases, the control signal outputs a control signal to increase the power of the power factor correction unit by increasing the collector-emitter equivalent resistance of the transistor. Constant power control device for ballasts for driving surface light sources. The method according to any one of claims 1, 2 or 4, The constant power control device of the ballast for driving the surface light source, An EMI filter for performing EMI filtering on the AC power input to the power factor correction unit; Constant power control device for a surface light source driving ballast, characterized in that further comprises. A power factor correction unit which receives the AC power, corrects the power factor of the AC power, converts the power to DC power, and outputs the DC power; An inverter unit for converting an output of the power factor correction unit into a pulse power source and supplying the surface light source of mercury-free type; A comparator for sensing a current of the inverter and outputting a comparison result; A controller which receives the output of the comparator and outputs a control signal to the power factor correcting unit; A voltage controller configured to receive a control signal of the controller and perform voltage control on the power factor correcting unit; and include a constant voltage control of a ballast for driving a surface light source for performing constant power control on a surface light source of mercury type. In the control method for the device, Detecting a current of the inverter unit and comparing the current with a reference current; A second step of causing the voltage control unit to control the power factor correcting unit so that the power entering the surface light source is maintained as a result of the comparison in the first step when the current of the inverter unit is changed; Including, and The second step, And controlling the collector-emitter equivalent resistance of the transistor in the control unit to output a control signal to the power factor correcting unit. delete The method according to claim 6, The second step, If it is determined that the current of the inverter unit is increased, decreasing the output voltage of the comparison unit; Transferring the reduced output voltage of the comparator to the controller to increase the collector-emitter equivalent resistance of the transistor in the controller to reduce the output of the power factor corrector; Constant power control method of the ballast for driving the surface light source, characterized in that performed.

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