WO2018074717A1

WO2018074717A1 - Ad led lighting system

Info

Publication number: WO2018074717A1
Application number: PCT/KR2017/008284
Authority: WO
Inventors: 정동열
Original assignee: 주식회사 웰랑
Priority date: 2016-10-21
Filing date: 2017-08-01
Publication date: 2018-04-26
Also published as: KR20180043961A; KR101872248B1

Abstract

An AC LED lighting system is disclosed. The present invention provides an AC LED driving apparatus which can reduce power consumption of at least one driving current source by controlling a driving voltage supplied to the driving current source such that only a predetermined voltage at which the driving current source can be optimally operated is supplied thereto. Therefore, the AC LED driving apparatus according to the present invention can prevent an IC chip, in which a driving current source is implemented, from locally having an excessively increased surface temperature.

Description

AD LED lighting system

The present invention relates to the driving of a light emitting diode (LED).

The contents described in this section merely provide background information on the present invention and do not constitute a prior art.

Environmentally friendly and energy-efficient LEDs are used in many industries, and one of them is LED lighting, which is being extended to indoor lighting and outdoor lighting. LED lighting has a DC driving method and an AC driving method depending on the driving method for driving the LED. In the DC driving method, the AC rectified AC voltage is first converted into a DC voltage through an AC / DC converter, and the LED driving current is supplied using the converted DC voltage as a power supply voltage of the LED driving system. AC driving method is to supply the LED driving current by using the AC voltage rectified without rectifying DC voltage as the power supply voltage of the LED driving system. The AC driving method does not use a high voltage capacitor, inductor, transformer, etc., compared to the DC driving method, which takes up less space in the driving circuit and has good reliability and design convenience.

AC LED lighting systems are typically implemented with semiconductor ICs and peripheral passive components, which typically include a plurality of current sources and a plurality of switches. While the input full-wave rectified voltage exceeds the forward on voltage of the LED string, the excess voltage drops in the semiconductor IC in which the current source is implemented, and power corresponding to this excess voltage is consumed as thermal energy in the semiconductor IC. To increase the IC's reliability, the temperature of the IC chip must be managed within an appropriate range.

SUMMARY OF THE INVENTION The present invention aims to provide an AC LED lighting system in which the temperature of the IC chip does not locally rise excessively, thereby increasing the IC reliability. SUMMARY OF THE INVENTION An object of the present invention is to provide an AC LED driving circuit which controls a driving voltage supplied to at least one driving current source so that only an optimum constant driving voltage for operating the driving current source is supplied to lower power consumption of the driving current source.

According to an aspect of the present invention, there is provided a plurality of LED groups, a driving circuit including a plurality of driving current sources, and a plurality of power distribution controllers connected to positive ends of the common node and the preceding LED group. Provides a device for driving an LED. Each LED group has a positive end and a negative end, and a pulse current input voltage is input to the positive end of the preceding LED group among the plurality of LED groups. Each drive current source included in the drive circuit has a first end connected to the negative end of the corresponding LED group and a second end connected to the common node. Here, during the rising or falling period of the pulse current input voltage, (a) if the pulse current input voltage exceeds a predetermined threshold voltage, the power distribution controller outputs a power distribution control voltage corresponding to the excess to the common node. Operating in a first mode, and (b) if the pulse current input voltage does not exceed the threshold voltage, the power distribution controller operates in a second mode that outputs a zero voltage to the common node.

Embodiments of the drive device may further include one or more of the following features.

In some embodiments, the driving circuit and the power distribution controller may be implemented in different integrated circuit chips. In another embodiment, the driving circuit and the power distribution controller may be implemented as one integrated circuit chip.

In some embodiments, the threshold voltage is set to a value greater than the sum of the forward on voltages of the plurality of LED groups.

In some embodiments, the power distribution control voltage is the voltage minus the threshold voltage.

In some embodiments, the voltage between the positive end of the preceding LED group and the common node of the plurality of LED groups has a constant voltage in the first mode, regardless of the variation of the pulse current input voltage. .

In some embodiments, the power distribution controller comprises: a reference voltage generation circuit for outputting a reference voltage proportional to the threshold voltage from the pulse current input voltage; A first voltage dividing circuit for dividing the pulse current input voltage to output a first voltage dividing voltage; A feedback circuit including a pair of resistors connected in series between the reference voltage generation circuit and the common node and outputting a feedback voltage; An operational amplifier outputting a control signal according to a difference between the feedback voltage and the first divided voltage; And a transistor that operates according to the control signal. The operational amplifier includes a first input terminal for receiving the feedback voltage, a second input terminal for receiving the first divided voltage, and an output terminal for outputting the control signal. The transistor has a first terminal connected to the common node, a second terminal connected to ground, and a control terminal connected to an output terminal of the operational amplifier.

In some embodiments, the reference voltage generation circuit may include a regulator connected to a positive end of the preceding LED group to receive the pulse current input voltage and output a constant voltage; A second voltage dividing circuit for dividing the constant voltage to output a second voltage dividing voltage; And an analog buffer receiving the second divided voltage and outputting the reference voltage having a magnitude substantially the same as the second divided voltage.

In some embodiments, the second voltage divider circuit includes two voltage divider resistors, and the two voltage divider resistors are located outside the integrated circuit chip in which the regulator and the analog buffer are implemented.

According to another aspect of the invention, a plurality of LED groups, a drive circuit including a plurality of driving current sources connected in series, and a plurality of power distribution controllers connected to positive ends of the common node and the preceding LED group Provides a device for driving an LED. Each LED group has a positive end and a negative end, and a pulse current input voltage is input to the positive end of the preceding LED group among the plurality of LED groups. Each drive current source included in the drive circuit has a first end connected to the negative end of the corresponding LED group and a second end connected to the common node. Here, when the pulse current input voltage is sufficient to turn on the group of the plurality of LEDs, the power distribution controller is configured to (a) if the pulse current input voltage exceeds a predetermined threshold voltage, among the plurality of LED groups. A first outputting a power distribution control voltage to the common node in accordance with the change in the pulse current input voltage such that the voltage between the positive terminal of the preceding LED group and the common node has a constant voltage regardless of the change in the pulse current input voltage. Mode and (b) the second mode outputs a zero voltage to the common node if the pulse current input voltage does not exceed the threshold voltage.

In some embodiments, when the pulse current input voltage is sufficient to turn on the k-th LED group from the first LED group of the plurality of LEDs, where j ≦ k ≦ M-1 and 1 ≦ j ≦ M-1 The power distribution controller operates in k-1 mode for outputting a zero voltage to the common node when (c) the pulse current input voltage is less than a predetermined kth threshold voltage, for each k. (d) if the pulse current input voltage is greater than the k th threshold voltage and less than the sum of the forward on voltages from the first LED group to the k + 1 LED group, the positive terminal of the first LED group and the common Operating in a k-2 mode of outputting a k-th power distribution control voltage corresponding to an excess exceeding the k th threshold voltage to the common node such that the voltage between nodes has a constant voltage regardless of the fluctuation of the pulse current input voltage. do.

According to still another aspect of the present invention, there is provided a plurality of LED groups, a driving circuit including a plurality of driving current sources, and a plurality of power distribution controllers connected to positive ends of the common node and the preceding LED group. Provides a device for driving LEDs. Each LED group has a positive end and a negative end, and a pulse current input voltage is input to the positive end of the preceding LED group among the plurality of LED groups. Each drive current source included in the drive circuit has a first end connected to the negative end of the corresponding LED group and a second end connected to the common node. Here, during the rising period or the falling period of the pulse current input voltage, the power distribution controller (a) if the pulse current input voltage exceeds a first predetermined threshold voltage, the power corresponding to the excess exceeding the first threshold voltage; Operating in a first mode for outputting one power distribution control voltage to the common node; and (b) if the pulse current input voltage does not exceed the first threshold voltage but exceeds the sum of the forward on voltages of the plurality of LED groups. And operating in a second mode of outputting a zero voltage to the common node, and (c) does not exceed a sum of forward on voltages of the plurality of LED groups but exceeds a predetermined second threshold voltage lower than the first threshold voltage. The third mode outputs a second power distribution control voltage proportional to an excess exceeding the second threshold voltage to the common node, and (d) the pulse current input voltage is high. The second does not exceed the threshold voltage, and operates in the fourth mode for outputting a zero voltage to the common node.

According to an aspect of the present invention, the power distribution controller controls the driving voltage supplied to the driving current source to supply only the optimum constant driving voltage at which the driving current source can operate, thereby lowering the power consumption of the driving current source, and thus It reduces IC chip heat, increasing the reliability of AC LED lighting systems. The power consumption saved in the drive current source is consumed in the power distribution controller.

According to another aspect of the invention, the power distribution controller, based on the multi-stage power distribution setting voltage, the drive voltages of the other end drive current sources supplied with a lower drive voltage as well as the drive current source supplied with the maximum drive voltage are constant. By controlling the voltage, the chip heat can be further lowered.

Furthermore, according to the present invention, since power consumed by at least one driving current source can be reduced as compared with the prior art, there is a margin to further supply driving power of the driving unit. Therefore, in the high output AC LED lighting system, compared to the prior art, it is possible to implement a driving unit with a smaller number of ICs, thereby enabling a high output AC LED lighting system at a lower cost.

In addition, the driving unit and the output of the power distribution controller PSCon may be connected in series to improve resistance to surge occurring in the AC power line.

Figure 1a is a diagram showing a simplified configuration of a conventional AC LED lighting system.

FIG. 1B illustrates an ideal operating waveform of the conventional AC LED lighting system shown in FIG. 1A.

2A is a simplified schematic diagram of an AC LED lighting system according to an embodiment of the present invention.

2B-2D show operating waveforms of the AC LED lighting system illustrated in FIG. 2A.

3 is a diagram illustrating a configuration of a power distribution controller according to an embodiment of the present invention.

4 is a diagram showing a preferred output waveform of the power distribution controller of the present invention when two power distribution setting voltages are placed.

FIG. 5 is a diagram illustrating a configuration of a power distribution controller according to an embodiment of the present invention when two power distribution setting voltages are provided.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in describing the component of this invention, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to that other component, but there may be another configuration between each component. It is to be understood that the elements may be "connected", "coupled" or "connected".

1A and 1B are schematic diagrams and operational waveforms of a conventional AC LED lighting system.

AC LED lighting system 100 of Figure 1a, which emits light by receiving the full-wave rectifier 110, a pulsating input voltage V _IN to be converted to a pulsating input voltage V _IN of the full-wave rectification of the AC input voltage V _AC light-emitting unit 120 The light emitting unit 120 and the light emitting unit 120 includes a driving unit 130 for supplying a light emission driving current.

The light emitting unit 120 is configured from one stage light emitting stage LED1 to four stage light emitting stage LED4, and each single emitting stage is actually composed of a plurality of LEDs connected in series or mixed in series and parallel connection. It can be a configuration. The driving unit 130 includes a first stage driving current source CS ₁ to a fourth stage driving current source CS _{4. When} the driving current source of each light emitting stage is turned on, the driving unit 130 generates the driving current I ₁ to I ₄ of the corresponding current source. ) To the corresponding luminophore. The driving current sources CS ₁ to CS ₄ operate in an ON state, an OFF state, or a transition state according to the pulse current input voltage V _IN . This will be described in detail as follows.

Except for the transition state, only one driving current source of each stage driving current source is turned on at one time of the pulse current input voltage V _IN , and all other driving current sources operate in an off state (or a small current flows). When the pulse current input voltage V _IN gradually increases in the transition state, the driving current I _n-1 of the (n-1) stage (a natural number of n≥2) driving current source gradually decreases, and the (n) driving current of the driving current source. I _n gradually increases. When the input pulsating flow voltage V _IN decreases gradually in a transition state, (n) drive current I _n of the single driving source it is gradually decreased, and (n-1) of the short driving current source drive current I ₁ _n- is increasing. The circuit configuration for the operation of the driving unit 130 of FIG. 1A may be implemented in various ways, but is not explicitly illustrated for convenience of description.

The operating waveform diagram of FIG. 1B illustrates an ideal operating waveform without a transition section in the operation of the driver 130. That is, FIG. 1B assumes a transition from the (n-1) stage driving current source to the (n) stage driving current source or the (n) stage driving current source to the (n-1) stage driving current source without a transition section. . From the first stage light emitting end (LED1), a forward diode turn-on voltage of the four-stage emission stage (LED4) respectively named in V _LED1 to V _LED4, and with reference to the ideal operating waveforms shown in Figure 1b to AC LED lighting system (100) The operation method of the drive unit 130 will be described briefly. In the operating waveform diagram of FIG. 1B, the voltages V _DT1 to V _DT4 represent input voltages required for each light emitting terminal 120 to be turned on and emit light. When this is expressed as a function of the forward diode on voltage, V _DT1 = V _LED1 , V _DT2 = V _LED1 + V _LED2 , V _DT3 = V _LED1 + V _LED2 + V _LED3 , V _DT4 = V _LED1 + V _LED2 + V _LED3 + V _LED4 .

* (1) Although the AC input voltage is gradually increasing, the driving current source CS ₁ of the driving unit 130 of the driving unit 130 in the section where the pulse current input voltage V _IN of the light emitting unit 120 is smaller than V _DT1 (0 ≤ t ≤ t ₁ section). ₄ are all off and the drive currents are all zero. (2) As the AC input voltage increases gradually, only the driving current source CS ₁ is turned on in the section where V _IN is larger than V _DT1 but smaller than V _DT2 (t ₁ ≤ t ≤ t ₂ section), so that the driving current I ₁ is one stage light emitting stage. Supplied only with (LED1). (3) In the section where V _IN is greater than V _DT2 but smaller than V _DT3 (t ₂ ≤ t ≤ t ₃ ), only the driving current source CS ₂ is turned on so that the driving current I ₂ is emitted from the first stage light emitting stage (LED1) and the second stage light emitting. It is supplied to the stage LED2. (4) In the section where V _IN is larger than V _DT3 but smaller than V _DT4 (t ₃ ≤ t ≤ t ₄ section), only the driving current source CS ₃ is turned on, so that the driving current I ₃ is emitted in three stages from the first stage light emitting stage (LED1). It is supplied up to the stage (LED3). (5) In the section where V _IN is greater than V _DT4 (t ₄ ≤ t ≤ t ₅ section), only the driving current source CS ₄ is turned on so that the driving current I ₄ is from the first stage light emitting stage (LED1) to the four stage light emitting stage (LED4). Supplied. (6) The AC input voltage increases to the maximum value and then gradually decreases. Only in the section where V _IN is smaller than V _DT4 but larger than V _DT3 (t ₅ ≤ t ≤ t ₆ section), only the driving current source CS ₃ is turned on and the driving current is I ₃ is supplied from the first stage light emitting stage LED1 to the three stage light emitting stage LED3. (7) In the section where V _IN is smaller than V _DT3 but larger than V _DT2 (t ₆ ≤ t ≤ t ₇ ), only the driving current source CS ₂ is turned on so that the driving current I ₂ is the first stage light emitting stage (LED1). It is supplied up to (LED2). (8) In a section where V _IN is smaller than V _DT2 but larger than V _DT1 (t ₇ ≤ t ≤ t ₈ section), only the driving current source CS ₁ is turned on and the driving current I ₁ is supplied to the first stage light emitting diode LED1. (9) In the section where V _IN is smaller than V _DT1 (t≥t ₈ section), all of the driving current sources CS ₁ to CS ₄ are turned off so that the driving currents are all zero.

In the operation waveform diagram of FIG. 1B, the driving voltages V ₁ to V ₄ supplied to the respective stage driving current sources CS ₁ to CS ₄ are V ₁ = V _IN -V _LDE1 , V ₂ = V _IN -V _LDE1 -V _LDE2 , V ₃ = V _IN- V _LDE1- V _LDE2- V _LDE3 , V ₄ = V _IN- V _LDE1- V _LDE2- V _LDE3- V _LDE4 . Therefore, instantaneous power P _D1 ~ P _D4 consumed by each stage driving current source CS ₁ ~ CS ₄ is P _D1 = V ₁ × I ₁ , P _D2 = V ₂ × I ₂ , P _D3 = V ₃ × I ₃ , P _D4 = V ₄ × I ₄ . The average power is the instant power divided by the period divided by one period.

In the operation waveform diagram of FIG. 1B, the integral value of the instantaneous power, that is, the area of the instantaneous power, is expressed as AREA ₁ to AREA ₇ in each operation section of each stage driving current source CS ₁ to CS ₄ , and each stage driving current source CS ₁ to CS. _If the average power consumed by ₄ is _expressed as P _AV1 to P _AV4 , then P _AV1 = (AREA ₁ + AREA ₇ ) / T, P _AV2 = (AREA ₂ + AREA ₆ ) / T, P _AV3 = (AREA ₃ + AREA ₅ ) / T, P _AV4 = AREA ₄ / T Here, T is a period of the pulse current input voltage V _IN , T = 1/120 for a 60 Hz AC input power supply, and T = 1/100 for a 50 Hz AC input power supply.

In the AC LED lighting system 100, the light emitting unit 120 is not always turned off at any of the light emitting units of the light emitting unit 120 in response to a change in the AC input voltage, for example, a change in the AC input voltage of about 20%. Is designed not to. For example, in the case of 220V AC input power, when the AC input voltage is 20% lower, the maximum voltage of the AC input becomes 249V. Therefore, the total V _DT4 of the LED forward-on voltages of the light emitting unit 120 is set to be lower than 249V so that the AC input is reduced. Even when the voltage is extremely low, the light emitting unit 120 is configured such that the four-stage light emitting stage LED4 is not always turned off. As a result of the system configuration, as shown in the operation waveform diagram of FIG. 1B, a large driving voltage is applied in a section in which the four-stage light emitting diode LED4 is turned on (t ₄ ≤ t ≤ t ₅ section) at a rated AC input voltage. Four stage drive current source CS ₄ is supplied. For example, when the maximum voltage is 311V for the 220V AC input power, when the total V _DT4 of the LEDs 120 onwards of the light emitting unit 120 is 240V, a maximum driving voltage of 71V is supplied to the _fourth driving current source CS ₄ . In general, when a driving voltage of about 10V or more is supplied to the driving current sources CS ₁ to CS ₄ from the driving unit 130 configured as a semiconductor integrated circuit (IC), the preset driving currents I ₁ to I _{4 are applied} to the light emitting unit 120. Can be supplied to the corresponding luminophore LED1 to LED4.

From the point of view of power consumption, as shown in an operational waveform chart of Figure 1b, four-speed drive current source CS ₄ is pre-set driving is further supplied to a four-stage drive current source CS ₄ drive voltage to a voltage above that can supply a current I ₄ normally The power consumption will be larger than necessary. As a result, the chip temperature of the part where the four-stage current source CS ₄ is located in the IC increases significantly, which may damage the IC package reliability.

The present invention is to provide an AC LED lighting system that can solve the above problems, and in more detail by controlling the driving voltage supplied to the driving current source so that only a constant driving voltage of a suitable size to operate the driving current source is supplied. It provides an AC LED lighting system that lowers the power consumption of the drive current source. Accordingly, the AC LED lighting system of the present invention provides an AC LED lighting system that controls the IC chip temperature so as not to rise very locally, thereby increasing IC reliability.

Hereinafter, an AC LED lighting system 200 according to an embodiment of the present invention will be described with reference to FIGS. 2A to 2D.

Figure 2a is a diagram showing the configuration of the AC LED lighting system according to an embodiment of the present invention.

The AC LED lighting system 200 illustrated in FIG. 2A receives a full-wave rectifier 210 and a pulse current input voltage V _IN for full-wave rectifying the AC input voltage V _AC to convert the pulse current input voltage V _IN of the light emitting unit 220. The power distribution control voltage V _PS to the common node of the light emitting unit 220 to emit light, the driving unit 230 to supply the light emission driving current to the light emitting unit 220, and the driving current sources CS ₁ to CS ₄ of the driving unit 230. It includes a power distribution controller (PSCon) 240 for supplying.

The light emitting unit 220 is configured from the first stage light emitting stage LED1 to the four stage light emitting stage LED4, and each single emitting stage is actually composed of a plurality of LEDs connected in series, or a series and parallel connection are mixed. It can be a configuration.

* The driving unit 230 is composed of four driving current sources CS ₁ to CS ₄ , and when each stage driving current source is turned on, the predetermined driving current I ₁ to I ₄ of the corresponding current source is supplied to the corresponding light emitting stage of the light emitting unit 220. do.

The power distribution controller 240 receives the pulse current input voltage V _IN , and the power distribution control voltage V for controlling the driving voltage supplied to the driving current source of the driving unit 230 so that only the proper driving voltage in which the driving current source operates normally is supplied. Output _PS Pulse current input voltage V _IN This power distribution setting voltage V _SHARE If smaller, the power distribution control voltage V _PS becomes zero, and the electromotive force distribution setting voltage V _SHARE If larger, the remaining voltage minus the electromotive force distribution setting voltage V _SHARE from the pulse current input voltage V _IN is output as the power distribution control voltage V _PS .

2B is a view showing an operating waveform diagram when the power distribution controller 240 is configured to control only the driving voltage of the fourth stage driving current source CS ₄ of the driving unit to a constant driving voltage. The operation of the power distribution controller 240 will be described in more detail with reference to FIG. 2B.

In FIG. 2B, V _{AC, max} is the maximum value of the pulse current input voltage V _IN , and V _DT4 is the sum of the forward-on voltages of the LEDs of the light emitting units 220, V _DT4 = V _LED1 + V _LED2 + V _LED3 + V _LED4 . . V _SHARE is a power budget set voltage, V _DROP is a four-stage driving a drive voltage of an appropriate value that can be supplied to the four-stage emission stage (LED4) of the current source CS ₄ a preset drive current I ₄ to the light-emitting part 220. In the AC LED lighting system 100 of the prior art shown in FIG. 1A and the AC LED lighting system 200 according to the embodiment of the present invention shown in FIG. 2A, the driving voltage V supplied to the fourth stage driving current source CS ₄ . To distinguish between ₄ and instantaneous power consumption P _D4 and the integral value of instantaneous power consumption AREA ₄ , V _{4, old} , V _{4, new} , P _{D4, old} , P _{D4, new} , AREA _{4, old} and AREA _{4, new} is shown. To better understand the explanation, say V _IN = 220Vrms, V _DT4 = 240V, and V _SHARE = 255V, V _{AC, max} = 311V.

In the AC LED lighting system 100 of the related art, in a section in which the pulse current input voltage V _IN is greater than V _DT4 (t ₄ ≤ t ≤ t ₅ section), the fourth stage driving current source CS ₄ is turned on to emit light 120. Supply drive current I ₄ to. At this time, the driving voltage waveform supplied to the four-stage driving current source is the same as V _{4, old} and the maximum voltage is V _{AC, max} -V _DT4 = 71V, and the most suitable driving voltage for operating the four-stage driving current source in most operating sections. The large driving voltage is supplied, and accordingly _, as shown in the waveforms of the instantaneous power consumption and the instantaneous power consumption _, the waveforms of P _{D4, old} and AREA _{4, old,} the power consumption is large. Will be higher.

Meanwhile, in the AC LED lighting system 200 of the present invention, the power distribution controller 240 outputs the power distribution control voltage V _PS according to the magnitude of the pulse current input voltage V _IN , where V _IN is smaller than the power distribution setting voltage V _SHARE. period, the remainder obtained by subtracting the voltage V in, the _SHARE V _iN output V _PS is zero (zero), and, V _iN is greater than the power budget period setting voltage V _SHARE (t _s1 _s2 ≤t≤t interval) (V _iN - V _SHARE ) Since the power distribution control voltage V _PS is connected to the common nodes of the driving current sources of the driving unit 230 to control the common node voltage, a period in which V _IN is greater than the power distribution setting voltage V _SHARE (t _s1 ≤ t≤ t _s2 interval) The driving voltage supplied to the four-stage driving current source is controlled by the constant voltage V _DROP = V _SHARE -V _DT4 = 15V. Therefore, unlike the AC LED driving system 100 of the related art, the driving voltage is not supplied to the four-stage driving current source CS ₄ more than the required voltage at which the driving current source can operate, and the appropriate voltage at which the driving current source can operate. Only V _DROP is controlled to be supplied. Accordingly, the power consumed by the four-stage current source can be significantly lowered, and as a result, the heat generated locally high in the four-stage current source can be reduced. In the AC LED lighting system 200 of the present invention, as shown in the waveform diagram of the instantaneous power and the instantaneous power integral value P _{D4, new} and AREA _{4, new} consumed in the four-stage drive current source (AC LED lighting system 100) It can be seen that the power consumption of the four-stage driving current source is much lower than that of.

The instantaneous power consumption, the integrated value of the instantaneous power consumption of the power distribution controller 240 in Figure 2b is inde each P _SHARE and AREA _SHARE, as can be seen from the operation waveform of Figure 2b also _{_{AREA 4, old = AREA 4,}} new + AREA It can be seen that the _SHARE , which means that the power consumption saved in the four-stage drive current source CS ₄ of the AC LED system 100 of the prior art is distributed to the power distribution controller 240 of the present invention and consumed.

In the AC LED lighting system 200 of the present invention, the driver 230 and the power distribution controller 240 may be implemented as one IC chip or may be implemented as separate IC chips.

When the driver 230 IC and the power distribution controller 240 IC are implemented in one chip and packaged, the power consumption of the four-stage driving current source of the driver 230 IC in which maximum power consumption occurs is generated. By dividing the power with the power distribution controller 240, the heat generation of the chip surface is controlled to be evenly generated without being concentrated in one place, thereby increasing chip reliability.

In the case where the driver 230 IC and the power distribution controller 240 IC are each implemented with two chips, an appropriate power distribution setting voltage is set so that the power consumption is reduced so that the chip temperature due to the power consumed by the two chips becomes an appropriate value. Can be distributed. In addition, the power distribution setting voltage may be set to allow a margin in each chip temperature to set a larger output power of the driver 230 IC. Accordingly, the number of ICs used in the high output AC LED lighting system may be reduced, thereby making it simpler. AC LED lighting systems can be implemented.

2C and 2D show the operation of the power distribution controller 240 when the AC power supply voltage in the AC LED lighting system 200 of FIG. 2A is lowered or raised by varying in the rated voltage.

As shown in FIG. 2C, when the maximum value V _{AC, max} of the AC power supply voltage is smaller than the power distribution setting voltage V _SHARE , the power distribution control voltage V _PS of the power distribution controller 240 is always output as zero. On the other hand, as shown in FIG. 2D, when the AC power supply voltage is significantly higher than the rated voltage, when the pulse current input voltage V _IN is smaller than the power distribution setting voltage V _SHARE , the power distribution control voltage V _PS of the power distribution controller 240 is zero. Output, if V _IN is greater than V _SHARE , then V _PS = V _IN -V _SHARE Is output. Therefore, even if the AC power supply voltage is considerably higher than the rated voltage, the voltage supplied to the four-stage drive current source of the driver 230 IC is the same as when the AC power supply voltage is the rated voltage. According to the prior art illustrated in FIG. 1A, as the AC power supply voltage is higher than the rated voltage, the power consumed by the four-stage driving current source of the driver increases, whereas according to the present invention illustrated in FIG. 2A, the AC power supply voltage Even if it increases above this rated voltage, the power consumed by the 4th stage drive current source of a drive part does not increase.

Outdoor lighting systems such as street lamps and tunnels usually require high power lighting systems of 100W or more, which are implemented using multiple drive ICs to lower the IC chip temperature. The AC LED lighting system according to the present invention may be set to further increase the output power of the driving IC when the IC LED temperature is sufficiently controlled to be within a temperature capable of managing the IC chip. The required AC LED lighting system can be implemented with fewer ICs.

FIG. 3 is a diagram illustrating an implementation of a power distribution controller 240 of the AC LED lighting system 200 illustrated in FIG. 2A. In particular, FIG. 3 illustrates a configuration that can be most efficiently implemented when the power distribution controller 240 is implemented with an IC.

The power distribution controller 240 of FIG. 3 includes a bias and regulator 310, a buffer 320, a differential amplifier 330, a MOSFET 340 and resistors R ₁₁ , R ₂₁ , R ₁₂ , R ₂₂ , R _SREF1 , R _SREF2 ).

The bias and regulator 310 receives a pulse current input voltage V _IN as an input and outputs a bias required for the power distribution controller 240 circuit, and also outputs a constant voltage V _REG . The reference voltage V _SREF is a voltage for setting the power distribution setting voltage V _SHARE , and is obtained by dividing the _voltage through R _SREF1 and R _SREF2 from the output V _REG of the bias and regulator 310. The buffer 320 is configured as an amplifier having a _unity gain and is an analog buffer for eliminating a loading effect caused by the resistances of R _SREF1 and R _SREF2 . The differential amplifier 330 and the MOSFET 340 together constitute an amplifier circuit for outputting the power distribution control voltage V _PS , and the gain of the amplifier circuit is determined by the resistors R ₁₁ , R ₂₁ , R ₁₂ , and R ₂₂ .

Referring to the configuration of the power distribution controller 240 shown in FIG. 3 in more detail, the constant voltage output V _REG of the bias and regulator 310 is connected to one end of R _SREF1 . The other end of R is connected to one end of _SREF1 and _SREF2 R V is a reference voltage _SREF, the other end of R _SREF2 is connected to ground (G _ND). The voltage V _SREF is input to the positive input of the buffer 320, so that the voltage at the output node 351 of the buffer 320 also becomes V _SREF . The reference voltage V _SREF divided by the resistors R _SREF1 and R _SREF2 is _expressed by Equation 1 below.

Meanwhile, one end of the resistor R ₂₁ is connected to the pulse current input voltage V _IN , the other end of the R ₂₁ is connected to one end of the resistor R ₁₁ , and the other end of the R ₁₁ is connected to the ground G _ND . Common node 353 of resistors R ₁₁ and R ₂₁ is connected to the negative input of differential amplifier 330. Output node 351 is connected to one end of resistor R ₁₂ and the other end of R ₁₂ is connected to one end of the resistor R ₂₂ common node of R ₁₂ and R ₂₂ 352 of the buffer 320 to the positive input terminal of the differential amplifier 330 Connected. The other end of the resistor R ₂₂ is connected to the drain of the MOSFET 340 to output the power distribution control voltage V _PS . The output node 354 of the differential amplifier 330 is connected to the gate of the MOSFET 340 and the source of the MOSFET 340 is connected to the ground G _ND .

In the circuit of FIG. 3, the power distribution control voltage V _PS becomes as follows.

When R ₁₁ = R ₁₂ = R ₁ and R ₂₁ = R ₂₂ = R ₂ , Equation 2 becomes as follows.

Here, as in the following Equation 4, when the last term is the power distribution setting voltage V _SHARE , the power distribution control voltage V _PS becomes as in Equation 5.

When the pulse current input voltage V _IN is smaller than the power distribution setting voltage V _SHARE , V _PS of Equation 5 becomes negative. Since the lowest voltage in the actual power distribution controller 240 circuit is ground (G _ND ), , V _PS is ground, that is, a zero voltage is output. On the other hand, when the input pulsating flow voltage V _IN power distribution set voltage V is greater than the _SHARE is to output a voltage obtained by subtracting the remaining electric power distribution setting voltage V from the _SHARE pulsating input voltage V _IN as shown in equation (5) by voltage V _PS.

As can be seen from the equations (1) and (4), by adjusting the resistance values of R _SREF1 and R _SREF2 , a desired power distribution setting voltage V _SHARE can be set. For example, if V _REG = 5V and R ₂ = 100 · R ₁ = 100kΩ, the design is such that V _SHARE = 250V. From Equation 4, V _SREF = 2.5V. Therefore, the equation of R _SREF1 = R _SREF2 can be obtained from Equation 1, and if it is set to an arbitrary value (for example, R _SREF1 = R _SREF2 = 50kΩ), the power distribution controller 240 having V _SHARE = 250V can be designed. have.

In the power distribution controller 240 of FIG. 3, the MOSFET 340 must withstand the withstand voltage above the maximum voltage of V _IN -V _SHARE , and thus a MOSFET having a high breakdown voltage should be used. Instead of the MOSFET 340 of FIG. 3, similar high voltage devices, such as high voltage Bipolar Junction Transistors (BJTs), may also be used.

The power distribution controller 240 of FIG. 3 may implement the entire circuit of FIG. 3 in one chip (eg, using a 700V high voltage process), or alternatively, may be implemented in one chip with only the power distribution control IC 300. This allows the user to change the R _SREF1 and R _SREF2 located outside the chip to set the power distribution set voltage V _SHARE to the desired value. In this case, when the MOSFET 340 is implemented using a MOSFET device having a maximum withstand voltage, for example, a 700V MOSFET device, the power connected in series with the driver 230 in the AC LED lighting system 200 according to the present invention. The higher withstand voltage of the MOSFET 340 of the distribution controller 240 makes it possible to significantly increase the resistance to surge voltages occurring in the AC power lines of the entire AC LED lighting system 200. Accordingly, the AC breakdown voltage, such as metal oxide varistor (MOV) and transient voltage suppression (TVS) diodes, required to absorb the surge voltage generated on the AC power line in the AC LED lighting system 200, may be used with a lower rated voltage. This allows for lower volume and cost of the overall AC LED lighting system.

In the above description, only the driving voltage supplied to the fourth stage driving current source CS ₄ (that is, the last driving current source) included in the driving unit 230 by the power distribution controller 240 in the AC LED lighting system 200 of FIG. 2A is a constant voltage. Although the embodiment configured to control has been described, the power distribution setting voltage of multiple stages may be set, and the power distribution controller 240 may be configured to control each driving voltage supplied to the plurality of driving current sources to a constant voltage.

4 is a driving voltage supplied to the third stage driving current source CS ₃ and the fourth stage driving current source CS ₄ of the driving unit 230 by setting two power distribution setting voltages V _SHARE1 and V _SHARE2 in the AC LED lighting system 200 of the present invention. Is a diagram showing an example of a preferable output waveform of the power distribution control voltage V _PS of the power distribution controller 240 when controlling to each constant driving voltage. At this time, the power distribution control voltage V _PS is represented by Equation 6 below, and the driving voltage supplied to the third stage driving current source CS ₃ is V _SHARE1 -V _DT3 , and the driving voltage supplied to the fourth stage driving current source CS4 is V _SHARE2 −. V _DT4 is set to each constant drive voltage.

As shown in FIG. 4, the power distribution controller controls the driving voltage of the three-stage driving current source as well as the four-stage driving current source to a constant voltage, thereby lowering the chip temperature of the driving unit 230.

Conceptually, the power distribution controller may be designed such that even the driving voltages of the two-stage driving current source and the first-stage driving current source are controlled by a constant driving voltage. In this case, when the power distribution controller is implemented as a chip, the circuit implementation becomes complicated and the power consumption of the power distribution controller increases, thereby increasing the chip temperature of the power distribution controller. Therefore, an appropriate power distribution controller suitable for the requirements and operating conditions of the AC LED lighting system is required. Must be configured.

5 is a diagram illustrating an example of an implementation of a multi-stage power distribution controller 400 that constantly controls driving voltages of a three-stage driving current source CS ₃ and a four-stage driving current source CS ₄ of the driving unit 230 as shown in the operation waveform diagram of FIG. 4. .

The

differential amplifiers

430 and 530 operate on or off depending on the states of the bias control transistors 630 and 640. For example, when the gate voltage 552 of the bias control transistor 630 is high, the differential amplifier 430 is turned on and is turned off when it is low. In addition, it buffers 420 and 520 is any one of an output of the pass (Pass)

transistors

610 and 620 is turned on or in accordance with which the off-

state buffers

420 and 520,

outputs

451 and 551 of the connection to the node 452 to produce a power distribution control voltage V _PS Contribute. For example, the output 451 of the buffer 420 is connected to the node 452 when the gate of the pass transistor 610 is high, and the output 551 of the buffer 520 is connected to the node 452 when the gate of the pass transistor 620 is high. Connected.

According to the state of the output 553 of the comparator 660, only one of the

buffers

420 and 520 and the

differential amplifiers

430 and 530 plays a role in determining the power distribution control voltage V _PS value. For example, when the output 553 of the comparator 660 is high, the

transistors

620 and 640 are turned on to operate the buffer 520 and the differential amplifier 530, and the transistor 610 when the output 553 of the comparator 660 is low. And 630 are turned on to operate buffer 420 and differential amplifier 430. The buffer 420 and the differential amplifier 430 control the drive voltage of the three-stage drive current source CS ₃ together with the associated element, and the buffer 520 and the differential amplifier 530 control the drive voltage of the four-stage drive current source CS ₄ together with the associated element.

Pulsating input voltage V _IN is V is smaller than _DT4 voltage is a three-stage driving current source CS when the circuit for controlling the driving voltage of the _third operation, and conversely V _IN is greater than V _DT4 voltage, the four-stage drive current source CS ₄ drive voltage It can be seen that when the circuit is configured to operate the circuit for controlling the operation, the operation is performed as shown in the operation waveform diagram of FIG. 4.

In the multi-stage power distribution controller 400 circuit of FIG. 5, the operation control of the three-stage driving current source and the four-stage driving current source is determined by the operation of the comparator 660, so that the values of the resistors R _X1 and R _X2 may be expressed by Equation 7 below. You can set it.

When V _IN is smaller than the V _DT4 voltage and the output 553 of the comparator 660 becomes low, the output 552 of the inverter 650 becomes high and the transistors 610 and 630 are turned on. Therefore, the buffer 420 and the differential amplifier 430 operate to control the driving voltage of the three-stage driving current source CS ₃ , which corresponds to the section of t≤t ₄ and the section of t≥t ₅ of FIG. 4. Since the operation of the three circuits is exactly the same, the following equations can be obtained.

R _SREF11 and R _SREF12 resistance values may be set to be a desired first power distribution setting voltage V _SHARE1 for V _REG , R ₁ , and R ₂ given from Equations 8 and 10 above.

When V _IN is greater than V _DT4, the output 553 of the comparator 660 becomes high and the

transistors

620 and 640 are turned on. The buffer 520 and the differential amplifier 530 operate to control the driving voltage of the four-stage driving current source CS ₄ . . This case corresponds to a section in which t ₄ ≤ t ≤ t ₅ of FIG. 4 and the operation thereof are also the same as in the circuit of FIG. 3, and thus the following equations may be obtained.

R _SREF21 and R _SREF22 resistance values may be set to be a desired second power distribution setting voltage V _SHARE2 for V _REG , R ₁ , and R ₂ given from Equations 11 and 13 above.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may various modifications and variations of the component without departing from the essential characteristics of the present invention. will be. For example, although FIG. 2 illustrates that the driving unit is configured in four stages, the driving unit may be configured in more or less stages. In addition, the power distribution controller of FIG. 2 is also not limited to the exemplary configurations of FIGS. 3 and 5, and may be implemented in various configurations that perform substantially the same functions.

Therefore, the present embodiments are not intended to limit the technical idea of the present embodiment but to describe the present invention, and the scope of the technical idea of the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present embodiment.

100, 200: AC LED lighting system 110, 210: full wave rectifier

120, 220: light emitting unit 130, 230: driving unit

240: power distribution controller 400: multi-stage power distribution controller

300: power distribution control IC

310, 410: bias and

regulator

320, 420, 520: buffer

330, 430, 530: Differential Amplifiers 340, 440: MOSFET

610, 620: pass transistor 630, 640: bias control transistor

650: inverter 660: comparator

LED1 ~ LED4: Single Stage Luminosity ~ Four Stage Luminosity

VLED1 ~ VLED4: 1 stage light emitting part forward on voltage ~ 4 stage light emitting group forward on voltage

CS ₁ ~ CS ₄ : 1st stage driving current source ~ 4th stage driving current source

V _AC : AC input voltage V _IN : Pulse current input voltage

I _IN : light emitting unit input current V _PS : power distribution control voltage

V _SHARE , V _SHARE1 , V _SHARE2 : Power Distribution Setting Voltage

V _SREF , V _SREF1 , V _SREF2 : Reference Voltage

CROSS-REFERENCE TO RELATED APPLICATION

This patent application claims priority pursuant to United States Patent Act section 119 (a) (35 USC § 119 (a)) for patent application No. 10-2016-0137433, filed in Korea on October 21, 2016. All content is incorporated by reference in this patent application. In addition, this patent application claims priority to countries other than the United States for the same reasons, all of which are incorporated herein by reference.

Claims

In a device for driving a plurality of LEDs,

A plurality of LEDs divided into a plurality of LED groups connected in series, each LED group has a positive end (negative end) and a negative end (negative end), the positive end of the preceding LED group of the plurality of LED groups Pulse current input voltage is input;

A drive circuit comprising a plurality of drive current sources, each drive current source having a first end connected to a negative end of a corresponding LED group and a second end connected to a common node;

A power distribution controller connected to both ends of the common node and the preceding LED group;

During the rising or falling period of the pulse current input voltage,

(a) when the pulse current input voltage exceeds a preset threshold voltage, the power distribution controller operates in a first mode to output a power distribution control voltage corresponding to the excess to the common node,

(b) the power distribution controller operates in a second mode outputting a zero voltage to the common node if the pulse current input voltage does not exceed the threshold voltage.

Apparatus for driving a plurality of LEDs, characterized in that.
The method of claim 1,

The driving circuit and the power distribution controller,

Apparatus for driving a plurality of LEDs, characterized in that implemented in different integrated circuit chips.
The method of claim 1,

The driving circuit and the power distribution controller,

Apparatus for driving a plurality of LEDs, characterized in that implemented in one integrated circuit chip.
The method of claim 1,

The threshold voltage is

And a greater than the sum of the forward on voltages of the plurality of LED groups.
The method of claim 1,

The power distribution control voltage is,

And a voltage obtained by subtracting the threshold voltage from the pulse current input voltage.
The method of claim 1,

The voltage between the positive terminal and the common node of the preceding LED group of the plurality of LED groups,

And in the first mode, has a constant voltage regardless of the variation of the pulse current input voltage.
The method of claim 1,

The power distribution controller,

A reference voltage generation circuit for outputting a reference voltage proportional to the threshold voltage from the pulse current input voltage;

A first voltage dividing circuit for dividing the pulse current input voltage to output a first voltage dividing voltage;

A feedback circuit including a pair of resistors connected in series between the reference voltage generation circuit and the common node and outputting a feedback voltage;

An operational amplifier for outputting a control signal according to a difference between the feedback voltage and the first divided voltage, the operational amplifier includes a first input terminal for receiving the feedback voltage, a second input terminal for receiving the first divided voltage, and An output stage for outputting a control signal; And

A transistor operating according to the control signal, the transistor having a first end connected to the common node, a second end connected to ground, and a control end connected to an output terminal of the operational amplifier;

Apparatus for driving a plurality of LEDs, comprising a.
The method of claim 7, wherein

The reference voltage generation circuit,

A regulator connected to the positive terminal of the preceding LED group to receive the pulse current input voltage and output a constant voltage;

A second voltage dividing circuit for dividing the constant voltage to output a second voltage dividing voltage; And

An analog buffer receiving the second divided voltage and outputting the reference voltage having substantially the same magnitude as the second divided voltage

Apparatus for driving a plurality of LEDs, comprising a.
The method of claim 8,

The second voltage divider circuit,

And two divider resistors, wherein the two divider resistors are located outside of the integrated circuit chip in which the regulator and the analog buffer are implemented.
In a device for driving a plurality of LEDs,

A plurality of LEDs divided into a plurality of LED groups connected in series (M), each LED group has a positive end and a negative end, a pulse current input voltage is input to the positive end of the preceding LED group of the plurality of LED groups being;

A drive circuit comprising a plurality of drive current sources, each drive current source having a first end connected to a negative end of a corresponding LED group and a second end connected to a common node;

A power distribution controller connected to both ends of the common node and the preceding LED group;

When the pulse current input voltage is sufficient to turn on the plurality of M LEDs, the power distribution controller

(a) when the pulse current input voltage exceeds a predetermined threshold voltage, the voltage between the positive terminal of the preceding LED group and the common node of the plurality of LED groups has a constant voltage regardless of the fluctuation of the pulse current input voltage. And operating in a first mode of outputting a power distribution control voltage to the common node in response to a change in the pulse current input voltage.

(b) operating in a second mode outputting zero voltage to the common node if the pulse current input voltage does not exceed the threshold voltage;

Apparatus for driving a plurality of LEDs, characterized in that.
The method of claim 10,

When the pulse current input voltage is sufficient to turn on the k-th LED group from the first LED group of the plurality of LEDs, where j ≦ k ≦ M-1 and 1 ≦ j ≦ M-1,

The power distribution controller, for each k,

(c) when the pulse current input voltage is less than a predetermined kth threshold voltage, the controller operates in a k-1 mode outputting a zero voltage to the common node,

(d) if the pulse current input voltage is greater than the k th threshold voltage and less than the sum of the forward on voltages from the first LED group to the k + 1 LED group, the positive terminal of the first LED group and the common Operating in a k-2 mode of outputting a k-th power distribution control voltage corresponding to an excess exceeding the k th threshold voltage to the common node such that the voltage between nodes has a constant voltage regardless of the fluctuation of the pulse current input voltage. To do

Apparatus for driving a plurality of LEDs, characterized in that.
The method of claim 10,

The driving circuit and the power distribution controller,

Apparatus for driving a plurality of LEDs, characterized in that implemented in different integrated circuit chips.
The method of claim 10,

The driving circuit and the power distribution controller,

Apparatus for driving a plurality of LEDs, characterized in that implemented in one integrated circuit chip.
The method of claim 10,

The power distribution control voltage is,

And a voltage obtained by subtracting the threshold voltage from the pulse current input voltage.
In a device for driving a plurality of LEDs,

A plurality of LEDs divided into a plurality of LED groups connected in series, each LED group having a positive end and a negative end, and a pulse current input voltage is input to a positive end of the preceding LED group among the plurality of LED groups;

A drive circuit comprising a plurality of drive current sources, each drive current source having a first end connected to a negative end of a corresponding LED group and a second end connected to a common node;

A power distribution controller connected to both ends of the common node and the preceding LED group;

During the rising or falling period of the pulse current input voltage, the power distribution controller,

(a) when the pulse current input voltage exceeds a predetermined first threshold voltage, operating in a first mode of outputting a first power distribution control voltage corresponding to an excess exceeding the first threshold voltage to the common node,

(b) when the pulse current input voltage does not exceed the first threshold voltage but exceeds the sum of the forward on voltages of the plurality of LED groups, the second mode outputs a zero voltage to the common node,

(c) a second power that is proportional to an excess exceeding the second threshold voltage if the sum of the forward on voltages of the plurality of LED groups does not exceed the predetermined second threshold voltage lower than the first threshold voltage; Operate in a third mode of outputting a distribution control voltage to the common node,

(d) operating in a fourth mode for outputting zero voltage to the common node if the pulse current input voltage does not exceed the second threshold voltage;

Apparatus for driving a plurality of LEDs, characterized in that.