KR100946093B1 - Power supply for led - Google Patents

Abstract

The present invention relates to a power supply for LED for controlling the brightness of the LED by converting the commercial AC power into a main power supply and an auxiliary power supply, and converts the main power supply to the LED driving power supply using the LED driving power supply and the auxiliary power supply. And a primary coil receiving input power, and a power conversion having a plurality of secondary coils respectively converting input power from the primary coil into a main power supply and a secondary power supply having a predetermined voltage level according to a winding ratio with the primary coil. And a brightness controller for converting the main power from the power converter into a preset LED driving power according to a dimming signal to supply the LED driving power and the auxiliary power to the LED array.

Power Supply, Light Emitting Diode (LED), Brightness Control

Description

Power supply for LED {POWER SUPPLY FOR LED}

The present invention relates to a power supply device, and more particularly, converts commercial AC power into a main power supply and an auxiliary power supply, converts a main power supply into an LED driving power supply, and uses the LED driving power supply and the auxiliary power supply to improve brightness of the LED. It relates to a power supply for LED to regulate.

In general, currently widely used light emitting diodes (LEDs) are widely used for transmitting various signals or emitting light in electronic products such as home appliances, TVs, and monitors.

When the voltage applied to the LED is higher than the threshold voltage, the current starts to flow to the LED and light is generated. For this purpose, a battery, a battery, a power supply, etc. are employed to provide a low voltage DC power source. It is common to be supplied.

As a device for supplying the above-described low voltage DC power supply, a power supply device is mainly employed.

The power supply device receives commercial AC power and converts it into a predetermined DC power supply, and converts it into a LED driving power and supplies the LED to the LED.

At this time, the power supply for driving the LED is controlled according to the dimming (Dimming) signal from the outside, and the brightness of the LED is adjusted accordingly.

Meanwhile, in order to generate light sources of various colors, LEDs of red, green, and blue series, three primary colors of light, have been developed, and arbitrary colors are output by a combination of luminance output from each LED. Research and development on the so-called RGB LED that can be done is in progress.

In particular, RGB LEDs developed for lighting or display require a large amount of current to flow, unlike low-brightness signal transmission LEDs, and in order to obtain the required high brightness, a large number of RGB LEDs are configured in a series or parallel array form. Should be.

1 is a configuration diagram of a conventional power supply for LEDs.

Referring to FIG. 1, a conventional LED power supply device converts commercial AC power into DC power converter 10 and converts DC power into LED driving power to red, green, and blue LED arrays of the LED array 30. DC / DC converters 20 to 31, 32 and 33, respectively.

As described above, the DC / DC converter 20 supplies first, second, and third DC / DC converters 21, 22 to supply power for driving LEDs to the red, green, and blue LED arrays 31, 32, and 33, respectively. , 23). The first to third DC / DC converters 21, 22, and 23 control the supply and blocking of the LED driving power according to the dimming signal from the outside to adjust the brightness of the LEDs.

In the above-described conventional LED power supply device, since the entire DC power from the converter is directly transmitted to the DC / DC converter, the DC / DC converter employs a high breakdown voltage, thus requiring a high manufacturing cost. The DC converter has a problem in that the power change efficiency is lowered since the DC power is converted into the entire LED driving power.

In order to solve the above problems, an object of the present invention is to convert the commercial AC power into a main power supply and an auxiliary power supply, and converts the main power supply to the LED driving power supply to use the LED driving power supply and the auxiliary power supply to improve the brightness of the LED. It is to provide a power supply for the LED to adjust.

In order to achieve the above object, one technical aspect of the present invention is to provide a main coil having an input voltage from a primary coil and an input power from the primary coil in accordance with a turns ratio with the primary coil. A power conversion unit having a plurality of secondary coils respectively converting to a power source and an auxiliary power source; and converting the main power source from the power conversion unit into a preset LED driving power source according to a dimming signal, thereby converting the LED driving power source and the And a brightness controller for supplying auxiliary power to the LED array.

According to one technical aspect of the present invention, the power converter includes a rectifier for rectifying commercial AC power, a power factor corrector for power factor correcting the rectified power from the rectifier, and a power factor corrected power source from the power factor corrector. A transformer having the primary coil received as an input power source, a first secondary coil magnetically coupled to the primary coil to output the main power, and a second secondary coil magnetically coupled to the primary coil to output the auxiliary power source; It may include a switching unit for switching the power factor corrected power input to the primary coil.

According to one technical aspect of the present invention, the transformer may be electrically insulated from the primary coil and the first and second secondary coils.

According to one technical aspect of the invention, the switching unit is a fly-back, forward, push-pull, half-bridge and full-bridge (Full-Bridge) can be configured in one way.

According to one technical aspect of the present invention, the LED array may include a red LED array emitting red light, a green LED array emitting green light, and a blue LED array emitting blue light,

The luminance controller converts the main power into a red LED driving power and transfers the sum of the voltages of the red LED driving power and the auxiliary power to the red LED array, and the main power to drive the green LED. A second switching circuit converting the green power supply driving voltage and the sum of the voltages of the green LED driving power supply and the auxiliary power supply to the green LED array, and converting the main power supply to the blue LED driving power supply, and the blue LED driving power supply. And a third switching circuit configured to transfer the sum of the voltages of the auxiliary power supplies to the blue LED array.

According to one technical aspect of the present invention, the first switching circuit includes a first controller controlling switching according to the feedback voltage and the dimming signal from the red LED array, and the main controller according to the control of the first controller. A second switch configured to control a switching according to a feedback voltage and the dimming signal from the green LED array and the second switching circuit; And a second switch for switching the main power supply, wherein the third switching circuit comprises: a third controller controlling switching according to the feedback voltage and the dimming signal from the blue LED array, and the control of the third controller According to the present invention, a third switch for switching the main power source may be included.

According to one technical aspect of the present invention, each of the first to third switching circuits includes a boost, a buck, a buck-boost, a cook, and a single ended primary. It may be configured in one of Inductor Converter (SEPIC).

According to the present invention, the LED power supply device of the present invention converts commercial AC power into a main power supply and an auxiliary power supply, and converts the main power supply to an LED driving power supply to use a LED driving power supply and an auxiliary power supply, thereby reducing the breakdown voltage. Employing an element can reduce manufacturing costs and increase power conversion efficiency.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of a power supply for LED of the present invention.

Referring to FIG. 2, the LED power supply device 100 according to the present invention uses a power converter 110 for converting commercial AC power into a main power supply and an auxiliary power source, and a main power source from the power converter 110. It includes a brightness control unit 120 to convert the driving power to the LED array 130.

The power converter 110 corrects the power factor by adjusting the voltage and current phases of the rectifier 111 rectifying the commercial AC power source and the rectifier 111. And a power factor corrector 112 for outputting a DC power of a degree.

In addition, the first secondary coil S1 and the primary coil P that output the main power according to a preset winding ratio between the primary coil P receiving the DC power from the power factor corrector 112 and the primary coil P. ) Is electrically connected to a transformer 113 having a second secondary coil S2 for outputting an auxiliary power source having a predetermined voltage level according to a predetermined turns ratio between the first and second coils P of the transformer 113. It comprises a switching unit 114 for switching the direct current power from the primary coil (P).

The transformer 113 includes a primary coil P and a secondary coil S as described above.

The primary coil P is formed of one conductor so that one end is electrically connected to the power factor corrector 112 and the other end is electrically connected to the switching unit 114.

The first secondary coil S1 is formed of one conductor to transfer the main power supply Vo1 having a voltage level set in advance according to a preset winding ratio with the primary coil P to the brightness controller 120. The second secondary coil S2 is formed of one conductor to transfer the auxiliary power Vo2 having the voltage level set in advance according to the preset winding ratio with the primary coil P to the brightness controller 120.

The primary coil P and the first and second secondary coils S1 and S2 are magnetically coupled and electrically insulated.

The brightness controller 120 may include first to third switching circuits for supplying power for driving LEDs to the red LED array 131, the green LED array 132, and the blue LED array 133 of the LED array 130, respectively. 121,122,123).

The first switching circuit 121 controls the switching according to the voltage detected from the resistor R1 of the red LED array 131 and the dimming signal S1 from the outside, and the first controller 121a. The first switch 121b converts the main power Vo1 to a red LED driving power VoR according to the control of FIG.

The second switching circuit 122 controls the switching according to the voltage detected from the resistor R2 of the green LED array 132 and the dimming signal S2 from the outside, and the second controller 122a. And a second switch 122b for switching the main power Vo1 to a green LED driving power VoG according to the control.

The third switching circuit 123 controls the switching according to the voltage detected from the resistor R3 of the blue LED array 133 and the dimming signal S3 from the outside, and the third controller 123a. And a third switch 123b for switching the main power Vo1 to a blue LED driving power VoB.

3A to 3D show various embodiments of a power conversion unit employed in the LED power supply device of the present invention.

Referring to FIG. 1, the switching unit 114 of the power conversion unit 110 employed in the LED power supply device 100 of the present invention is switched in a pulse width modulation (PWM) manner, as shown in FIG. 1. A flyback comprising a main switch 114b connected to the other end of the switching controller 114a and the primary coil P for controlling the switch and switching the DC power from the primary coil P under the control of the switching controller 114a ( Fly-Back) can be configured.

The power conversion unit 110 described above may be configured in various embodiments as shown in FIGS. 3A, 3B, and 4A, 4B.

Referring to FIG. 3A, the switching unit 114 of the power converter 110 may configure a forward method. Accordingly, the transformer 113 may include first and second primary coils P1 and P2 connected in parallel to each other, and a transmission path of electric power may be provided between one end of the first and second primary coils P1 and P2. The diode Da is provided, and the main switch 114b for switching the DC power from the second primary coil P2 under the control of the switching controller 114a is connected to the other end of the first primary coil P1. It is electrically connected between the other end of the 2nd primary coil P2.

Referring to FIG. 3B, the switching unit 114 of the power converter 110 may be configured as a push-pull scheme. Accordingly, the transformer 113 may include a primary coil P having an intermediate tap, and similarly, the first and second secondary coils S1 and S2 may be formed to have an intermediate tap. At one end and the other end of the primary coil P, the first main switch 114b and the second main switch 114c, which switch DC power from the primary coil P under the control of the switching controller 114a, are electrically connected. DC power is introduced into the middle tap of the primary coil P.

Referring to FIG. 4A, the switching unit 114 of the power converter 110 may be configured in a half-bridge scheme. Accordingly, the primary coil P is electrically connected between the first main switch 114b and the second main switch 114c that complementarily switch the DC power source under the control of the switching controller 114a.

Referring to FIG. 4B, the switching unit 114 of the power conversion unit 110 may be configured in a full-bridge manner. Accordingly, the first to fourth main switches 114b, 114c, 114d, and 114e which complementarily switch the DC power supply under the control of the switching controller 114a may operate the first and third main switches 114b and 114d. Receives a DC power supply through, one end of the primary coil (P) is connected to the connection point of the third and fourth main switch (114d, 114e), the other end of the primary coil (P) is the first and second main switch (114b) , 114c).

5A, 5B, and 6A, 6B are various embodiments of the brightness adjusting unit employed in the LED power supply device of the present invention.

Referring to FIG. 2, the first to third switching circuits 121, 122, and 123 included in the brightness controller 120 employed in the power supply device 100 according to the present invention may respectively use the boost method to boost the main power source Vo1. The step-up is converted to red, green and blue LED driving power (VoR, VoG, VoB) and transferred to the red, green and blue LED arrays (131, 132, 133) together with the auxiliary power (Vo2). To this end, the first, second and third controllers 121a, 122a, and 123a are respectively configured according to the voltage detected from the detection resistors R1, R2, and R3 and the dimming signals S1, S2, and S3 from the outside. The switching of the first, second and third switches 121b, 122b and 123b is controlled.

Referring to FIG. 5A, the first to third switching circuits 121, 122, and 123 included in the brightness adjusting unit 120 employed in the power supply device 100 of the present invention may be buck type, respectively. The power source Vo1 is reduced in pressure to be converted into red, green, and blue LED driving power sources VoR, VoG, and VoB, and transferred to the red, green, and blue LED arrays 131, 132, and 133 together with the auxiliary power source Vo2. To this end, the first, second and third switches 121b, 122b, 123b are electrically connected in series with the power transmission paths, and thus the first, second and third switches 121b, 122b, 123b At the rear end, diodes D1, D2 and D3 are connected in parallel and inductors L1, L2 and L3 are connected in series.

Referring to FIG. 5B, the first to third switching circuits 121, 122, and 123 included in the luminance adjusting unit 120 employed in the power supply device 100 of the present invention are buck-boost, respectively. Can be configured in such a way. Accordingly, the main power supply Vo1 is decompressed or stepped up and converted into red, green, and blue LED driving power sources VoR, VoG, and VoB, and is connected to the red, green, and blue LED arrays 131, 132, and 133 together with the auxiliary power source Vo2. Delivered. To this end, the first, second and third switches 121b, 122b, 123b are electrically connected in series with the power transmission paths, and thus the first, second and third switches 121b, 122b, 123b At the rear end, the inductors L1, L2, L3 are connected in parallel, and the diodes D1, D2, D3 are connected in series in the reverse direction of the transmission path.

Referring to FIG. 6A, the first to third switching circuits 121, 122, and 123 included in the brightness controller 120 employed in the power supply device 100 of the present invention are configured in a cook method. Can be. Accordingly, the main power Vo1 is converted to the red, green, and blue LED driving powers VoR, VoG, and VoB, and is transferred to the red, green, and blue LED arrays 131, 132, and 133 together with the auxiliary power Vo2. To this end, the first, second and third switches 121b, 122b, 123b are electrically connected in parallel to the transmission path of power, and thus the first, second and third switches 121b, 122b, 123b A plurality of inductors L1, L1 ', L2, L2', L3, and L3 'are connected in series at the front and rear ends thereof, and diodes D1, D2, and D3 are connected in parallel.

Referring to FIG. 6B, the first to third switching circuits 121, 122, and 123 included in the brightness controller 120 employed in the power supply device 100 of the present invention may each have a single ended primary inductor converter. ; SEPIC) scheme. Accordingly, the main power Vo1 is converted to the red, green, and blue LED driving powers VoR, VoG, and VoB, and is transferred to the red, green, and blue LED arrays 131, 132, and 133 together with the auxiliary power Vo2. To this end, the first, second and third switches 121b, 122b, 123b are electrically connected in parallel to the transmission path of power, and thus the first, second and third switches 121b, 122b, 123b A plurality of inductors L1, L1 ', L2, L2', L3, and L3 'are connected in series and in parallel, respectively, and diodes D1, D2, and D3 are connected in series.

Figure 7 is a graph of the output voltage of the power supply for LED of the present invention.

Referring to FIG. 7 together with FIG. 2, the commercial AC power is rectified and smoothed through the rectifier 111 and then the power factor is adjusted by adjusting the phase of the voltage and current of the rectified power through the power factor corrector 112. The correction is transmitted to the transformer 113.

The power delivered to the primary coil P of the transformer 113 is delivered to the secondary coils S1 and S2 by the main switch 114b which switches according to the PWM control of the switching controller 114a. The transmitted power is transferred to the brightness controller 120 as the main power supply Vo1 and the auxiliary power source Vo2 having a voltage level preset according to the turns ratio between the primary coil P and the secondary coils S1 and S2.

The main power supply Vo1 is transmitted to the first to third switching circuits 121, 122, and 123 of the luminance controller 120, and the first to third controllers 121a, 122a, 123a controls the switching of the main power supply Vo1 according to the dimming signals S1, S2, S3 from the outside and the detected voltages detected from the red, green, and blue LED arrays 131, 132, and 133, respectively. Converts to driving power sources (VoR, VoG, VoB).

The red, green, and blue LED driving power supplies VoR, VoG, and VoB are delivered to the red, green, and blue LED arrays 131, 132, and 133, respectively, along with the auxiliary power source Vo2. That is, when the dimming signals S1, S2, and S3 are switched off, only the auxiliary power source Vo2 is transmitted to each of the LED arrays 131, 132, and 133 so that the LED arrays 131, 132, 133 do not light up, and the dimming signals S1, S2, S3 are not turned on. ) Is switched on, the auxiliary power source Vo2 and the LED driving power sources Vo (, VoG, and VoB are transmitted to the LED arrays 131, 132, and 133, and the LED arrays 131, 132, and 133 are turned on.

The operation of the power supply of the present invention described above will be described in comparison with the conventional power supply shown in FIG. 1 in terms of power conversion efficiency.

Referring to FIG. 1, power supplied to each of the LED arrays 31, 32, and 33 of a conventional power supply is first to third DC / DC converters 21, 22, and 23 having a power conversion efficiency η ₂ . (Where the power conversion efficiencies of each DC / DC converter are the same) and the power required by the first to third DC / DC converters 21, 22, and 23 is a converter having a power conversion efficiency η ₁ . Supply from 10). That is, the total power conversion efficiency of the conventional power supply is η ₁ ㆍ η ₂ . Since the output voltages of the first to third DC / DC converters 21, 22, and 23 are the same as the driving voltages of the LED arrays 31, 32, and 33, the first to third DC / DC converters 21, 22. The switching elements, diodes, and capacitors employed in (23) should use elements having a breakdown voltage higher than the driving voltage of each of the LED arrays 31, 32, and 33.

On the contrary, referring to FIG. 2, the power supply device 100 according to the present invention separates and supplies the entire power to the main power Vo1 and the auxiliary power Vo2 from the power converter 110. For example, when the entire power supply pin from the power converter 110 is '1', the main power supply Vo1 and the auxiliary power supply Vo2 may be set to 1-K percent and K percent, respectively. Since the main power Vo1 is converted to LED driving power (VoR, VoG, VoB) and supplied to the LED arrays 131, 132, 133 together with the auxiliary power supply Vo2, the power supplied to the LED arrays 131, 132, 133 is calculated. Pin η ₁ k + Pin η ₁ η ₂ (1-k), and the total power conversion efficiency is η ₁ ㆍ η ₂ + k (1-η ₂ ) η ₁ . Here, since η ₁ ㆍ η ₂ is the same as the power conversion efficiency in the conventional power supply shown in FIG. 1, the power conversion efficiency of the power supply of the present invention increases by k (1-η ₂ ) η ₁ . .

In addition, as described above, since the power supplied to each of the LED arrays 131, 132, 133 is the sum of the LED driving powers VoR, VoG, VoB and auxiliary power Vo2 converted from the main power Vo1, the brightness controller ( The voltage levels of the voltages and output voltages applied to the switching circuits 121, 122, 123 of the 120 are lower than those of the conventional DC / DC converters 21, 22, and 23. Accordingly, switching elements, capacitors, and diodes employed in the switching circuits 121, 122, and 123 of the luminance adjusting unit 120 may be employed as elements having a small breakdown voltage, thereby reducing manufacturing costs.

The above increase in power conversion efficiency is shown in the following table.

<Table>

Conventional The present invention Remarks Breakdown voltage applied to the first switching circuit 42 V 17V 60% pressure reduction (25V breakdown) Breakdown voltage applied to the second switching circuit 62 V 37 V 40% pressure reduction (25V breakdown) Breakdown voltage applied to the third switching circuit 65 V 40 V 35.4% pressure reduction (25V breakdown) Total power loss 76.5% 78.8% 2.3% efficiency improvement

In the power supply apparatus of the present invention applied to the above table, the main power supply Vo1 and the auxiliary power supply Vo2 of the power converter are set to have voltage levels of 13 V and 25 V, respectively, and the efficiency is assumed to be 85%. The conventional power supply converter of FIG. 1 compared to the table assumes that the output voltage is 25V and the efficiency is 85%. The conventional DC / DC converter and the first to third switching circuits of the present invention employ a boost method. And the efficiency is assumed to be 90%.

As described above, when the conventional power supply shown in FIG. 1 is compared with the power supply of the present invention shown in FIG. 2, the switching elements, diodes, and capacitors employed in the first to third switching circuits 121, 122, and 123 may be compared. The breakdown voltage is reduced to 60%, 40% and 35.4%, respectively, compared to the conventional power supply, and the RGB drive circuit total efficiency is improved by 2.3% from 76.5% to 78.8%. Accordingly, since the breakdown voltage and the inductor capacity of the main elements used in the first to third switching circuits 121, 122, and 123 are reduced, the component price can be reduced and the component size can be reduced.

As described above, the LED power supply of the present invention performs a unique function of LED brightness control in which the brightness of each LED array (131, 132, 133) is adjusted according to the switching on / off of the dimming signal, of the power delivered from the transformer By transferring a part to the brightness control unit, a device with a small breakdown voltage can be adopted, thereby reducing manufacturing costs and increasing power conversion efficiency.

The electrical operation of the power supply of the present invention is similarly applied to the embodiment shown in Figures 3 to 6 to omit the detailed description, and likewise the embodiments shown in Figures 3 to 6 Form the same output voltage graph as shown.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, but is defined by the claims below, and the configuration of the present invention may be modified in various ways without departing from the technical spirit of the present invention. It will be apparent to those skilled in the art that the present invention may be changed and modified.

1 is a configuration diagram of a conventional power supply for LED.

2 is a block diagram of a power supply for LED of the present invention.

3A, 3B, and 4A, 4B show various embodiments of a power conversion unit employed in the LED power supply device of the present invention.

5 (a), (b) and 6 (a), (b) are various embodiments of the luminance adjusting unit employed in the LED power supply device of the present invention.

Figure 7 is a graph of the output voltage of the power supply for LED of the present invention.

<Detailed Description of Major Symbols in Drawing>

100 ... power supply unit 110 ... power conversion unit

111 ... rectifier 112 ... power factor corrector

113 ... Transformer 114 ... Switching Unit

120 brightness control unit 121 first switching circuit

121a ... first controller 121b ... first switch

122 ... second switching circuit 122a ... second controller

122b ... second switch 123 ... third switching circuit

123a ... 3rd controller 123b ... 3rd switch

130 ... LED Array 131 ... Red LED Array

132 ... Green LED Array 133 ... Blue LED Array

Claims (7)

Power conversion having a primary coil receiving an input power and a plurality of secondary coils for converting the input power from the primary coil into a main power supply and a sub power supply each having a predetermined voltage level according to a winding ratio with the primary coil. part; And A brightness controller for converting the main power from the power converter into a preset LED driving power according to a dimming signal and supplying the LED driving power and the auxiliary power to an LED array Power supply for the LED comprising a. The method of claim 1, wherein the power conversion unit Rectifier for rectifying commercial AC power; A power factor corrector for correcting power factor rectified from the rectifier; A first secondary coil that is magnetically coupled with the primary coil and the primary coil that receives the power factor corrected power from the power factor corrector as the input power, and is magnetically coupled with the primary coil to output the auxiliary power; A transformer having a second secondary coil; And A switching unit for switching the power factor corrected power input to the primary coil Power supply for the LED comprising a. The method of claim 2, The switching unit is configured in one of fly-back, forward, push-pull, half-bridge, and full-bridge. LED power supply, characterized in that the. The method of claim 2, The transformer is a power supply for the LED, characterized in that the primary coil and the first and second secondary coil is electrically insulated. The method of claim 1, The LED array A red LED array emitting red light; Green LED arrays emitting green light; And A blue LED array emitting blue light, The brightness control unit A first switching circuit converting the main power into a red LED driving power and transferring a sum of voltages of the red LED driving power and the auxiliary power to the red LED array; A second switching circuit converting the main power into a green LED driving power and transferring the sum of the voltages of the green LED driving power and the auxiliary power to the green LED array; And And a third switching circuit converting the main power into a blue LED driving power and transferring a sum of the voltages of the blue LED driving power and the auxiliary power to the blue LED array. The method of claim 5, The first switching circuit may include a first controller controlling switching according to a feedback voltage from the red LED array and the dimming signal, and converting the main power source into the red LED driving power source under the control of the first controller. A first switch, The second switching circuit may include a second controller controlling switching according to a feedback voltage from the green LED array and the dimming signal, and converting the main power source into the green LED driving power source under the control of the second controller. A second switch, The third switching circuit may include a third controller for controlling switching according to the feedback voltage and the dimming signal from the blue LED array, and converting the main power source into the blue LED driving power source under the control of the third controller. Power supply for the LED, characterized in that it comprises a third switch. The method of claim 6, Each of the first to third switching circuits is configured by one of a boost, a buck, a buck-boost, a cook, and a single ended primary inductor converter (SEPIC). LED power supply, characterized in that the.

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