JP6033626B2 - LED module - Google Patents

Description

  The present invention relates to an LED module that drives an LED with a full-wave rectified waveform.

  Lighting fixtures using LEDs have become widespread. When driving an LED by obtaining power from a commercial AC power source, by driving a LED with a direct current obtained by rectifying and smoothing the commercial AC power source, and by a full-wave rectification type obtained by rectifying the commercial AC power source. Sometimes the LED is driven. In the former case, a high withstand voltage and large capacity electrolytic capacitor is required. This electrolytic capacitor is not only large, but also tends to reach a high temperature in the lighting device due to the heat generated by the LED, and thus often limits the life of the lighting device. On the other hand, the latter driving method does not require an electrolytic capacitor having a high withstand voltage and a large capacity, and thus can enjoy a long life of the LED.

  Since LEDs take various forms, a single light emitting diode is referred to as an LED element, and an LED array in which a number of LED elements are connected in series so as to withstand a high voltage. For example, when driving an LED with a full-wave rectified waveform, if the effective value of the commercial AC power supply is 240 V, about 80 LED elements are connected in series as the LED array. The threshold value of the LED element is about 3V. At this time, the LED row is lit only for a short period when the full-wave rectified waveform exceeds 240V.

  However, in the method of driving the LED element with the full-wave rectified waveform, the light emission period may be shortened with respect to one cycle of the full-wave rectified waveform as described above. That is, various problems arise because each LED element does not emit light unless the voltage of the full-wave rectified waveform exceeds the threshold of the LED array. For example, a flicker or a motion break in which an object moving at high speed appears to fly out is noticeable, or a power factor is lowered or a high distortion factor (also called total harmonic distortion factor, THD) is caused. Therefore, the LED string may be disassembled into a plurality of blocks, the number of LED elements to be lit is adjusted according to the voltage of the full-wave rectified waveform, and the lighting period may be extended. Among these driving methods, one that simplifies the circuit configuration and that controls the number of LED elements that are lit by measuring the current flowing in the LED array is known (for example, Patent Document 1).

  26 will be described again in FIG. FIG. 6 is a circuit diagram of an LED module 2600 shown as a conventional example. The LED module 2600 includes a diode bridge circuit 2605, an LED group 1 (LED array), an LED group 2 (LED array), an LED group 3 (LED array), resistors R1, R2, and R3, field effect transistors (hereinafter referred to as FETs). Q1 and a bipolar transistor (hereinafter referred to as a transistor) Q2.

  The commercial AC power supply is connected to the input terminal of the diode bridge circuit 2605, and the diode bridge circuit 2605 outputs a full-wave rectified waveform. LED group 1 and LED group 2 are LED rows in which the same number of LED elements are connected in series, and are equivalent to one LED row by connecting them in parallel. The LED group 3 is an LED array in which a plurality of LED elements are connected in series. The resistor R1 is a current limiting resistor that limits the current flowing through the LED groups 1, 2, and 3. A circuit composed of the resistors R2 and R3, the FET Q1, and the transistor Q2 constitutes a bypass circuit 2610.

Next, the operation of the LED module 2600 shown in FIG. 6 will be described with reference to FIG. 7A and 7B are waveform diagrams relating to the LED module 2600. FIG. 7A shows one cycle of the full-wave rectification waveform, and FIG. 7B shows a current flowing through the LED module 2600. In FIG. 7, (a) and (
The time axis of b) is the same.

  There is no circuit current in the period t6 when the voltage of the full-wave rectified waveform is lower than the threshold values of the LED groups 1 and 2. When the voltage of the full-wave rectified waveform becomes higher than the threshold value of the LED groups 1 and 2, the circuit current flows from the LED groups 1 and 2 via the bypass circuit 2610 (period t7). At this time, the bypass circuit 2610 operates at a constant current with feedback applied so that the base-emitter voltage of the transistor Q2 is maintained at 0.6V. When the voltage of the full-wave rectified waveform reaches the vicinity of the sum of the threshold values of LED groups 1 and 2 and LED group 3 (the last part of period t7), the circuit current passes from LED groups 1 and 2 via bypass circuit 2610. And flows to the LED group 3 as well. At this time, the bypass circuit 2610 operates so that the sum of the current flowing through the FET Q1 and the current flowing through the LED group 3 becomes constant. When the voltage of the full-wave rectified waveform becomes sufficiently larger than the sum of the threshold values of LED groups 1 and 2 and LED group 3 (period t8), FET Q1 included in bypass circuit 2610 is cut off, and almost all circuit currents are Flows through LED group 3 and is limited by resistor R1. In the period in which the voltage of the full-wave rectified waveform decreases, the process reverse to the period in which the voltage of the full-wave rectified waveform increases.

  As described above, the lighting period of the LED module 2600 is extended. At this time, since the bypass circuit 2610 is cut off through a constant current operation, the circuit current smoothly changes. As a result, in addition to reducing flicker and motion break, the power factor increases and the distortion rate also decreases.

  Next, the circuit of FIG. 8 obtained by improving the circuit of FIG. 6 will be described. FIG. 8 is a circuit diagram of the LED module 80 in which the number of electronic components is reduced and the influence of fluctuations in the commercial power source is reduced. The LED module 80 includes a diode bridge circuit 801, LED strings 811 and 821, FETs 814 and 824, and resistors 815 and 825. In the drawing, the broken line on the left side indicates that the commercial AC power source 802 is not included in the LED module 80.

  The commercial AC power source 802 is connected to the input terminal of the diode bridge circuit 801, and the diode bridge circuit 801 outputs a full-wave rectified waveform. A bypass circuit 813 including an FET 814 and a resistor 815 is connected to a connection portion between the LED array 811 and the LED array 821, and a constant current circuit 823 including an FET 824 and a resistor 825 is connected to the cathode terminal of the LED array 821. Note that the LED array 811 includes a plurality of LED elements 812 connected in series, and the LED array 821 similarly includes a plurality of LED elements 822 connected in series. The FETs 814 and 824 are depletion type FETs.

  In the bypass circuit 813, the current flowing through the FET 814 and the current flowing from the constant current circuit 823 flow through the current detection resistor 815. When the current flowing from the constant current circuit 823 is 0 or small, the bypass circuit 813 performs a constant current operation by applying feedback from the resistor 815 to the gate of the FET 814. When the current flowing from the constant current circuit 823 to the bypass circuit 813 becomes sufficiently large, the FET 814 is cut off. At this time, the constant current circuit 823 operates at a constant current by feedback from the current detection resistor 825.

  As a result, the LED module 80 operates substantially the same as the LED module 2600 shown in FIG. In the LED module 80, since the current limiting resistor R1 of the LED module 2600 is replaced with the constant current circuit 823, the LED module 80 is less susceptible to fluctuations in the voltage (effective value) of the full-wave rectified waveform.

WO2011 / 020007 (FIG. 26)

  In the LED module circuit 80 illustrated in FIG. 8, a light emitting circuit block 810 including an LED array 811 and a bypass circuit 813 and a light emitting circuit block 820 including an LED array 821 and a constant current circuit 823 are similar. That is, to improve flicker, motion break, power factor, and distortion rate, it can be easily estimated that light emitting circuit blocks including the LED array 811 and the like, the FET 814 and the resistor 815 and the like may be connected in a multi-stage manner like a ladder. However, even if the LED elements and FETs included in the LED rows can be shared in each light emitting circuit block, the current detection resistance must be different. For this reason, as the number of light emitting circuit blocks is increased, the number of types of current detection resistors increases and the management load increases.

  Therefore, the present invention has been made in view of the above problems, and even when an LED element is driven with a full-wave rectified waveform, even if a light emitting circuit block including an LED array and a current detection resistor is connected in multiple stages, the current is An object of the present invention is to provide an LED module with a small management load of a detection resistor.

The LED module of the present invention is an LED module that drives a plurality of LED elements with a full-wave rectified waveform, and the n light-emitting circuit blocks including a LED array in which the LED elements are connected in series and a bypass circuit or a constant current circuit are ladder-shaped. Connected to
1 <m ≦ n,
1 ≦ k <m,
The light emitting circuit block on the side to which the full-wave rectified waveform is input is a first stage ,
When the value of the current detection resistor included in the light emitting circuit block in the m-stage and the reference value R, the current detecting resistor contained in said light emitting circuit block in the (m-k) stages, the resistance of the reference value R There is a (k + 1), wherein der Rukoto those pieces connected in series.

  In the LED module of the present invention, an LED array in which LED elements are connected in series and a light emitting circuit block including a bypass circuit or a constant current circuit are connected in a ladder shape. Here, the number of light emitting circuit blocks is n. In this ladder connection, when the light-emitting circuit block on the side where the full-wave rectified waveform is input is the first stage, the light-emitting circuit blocks from the first stage to the (n−1) -th stage include a bypass circuit together with the LED row. Yes. The n-th light emitting circuit block includes a constant current circuit together with the LED array.

  With the nth light emitting circuit block as the uppermost stage, a current detection resistor included in each light emitting circuit block having a bypass circuit measures the bypass current and the current flowing from the upper light emitting circuit block. When the constant current circuit included in the nth stage light emitting circuit block has a current detection resistor, the current detection resistor measures only the current flowing through the light emitting circuit block.

  Further, when the value of the current detection resistor included in the mth light emitting circuit block is set as the reference value R, the value of the current detection resistor included in the light emitting circuit block k steps below the light emitting circuit block is (k + 1) R. Yes. In this way, the current detection resistors included in the light emitting circuit blocks from the first stage to the m-th stage can be managed as the number of resistors of the reference value R.

In addition, in order to increase or decrease the circuit current in accordance with the increase or decrease of the full-wave rectification wave system in order to improve the power factor and distortion factor, the current detection resistor included in the lower light emitting circuit block must be made larger than the upper one. The difference between the current detection resistance values between the adjacent light emitting circuit blocks from the first stage to the m-th stage is set as one resistance based on the reference, so that the type of resistance of the reference value R managed as a whole Can be minimized.

  The bypass circuit may include a depletion type FET.

  The current detection resistors included in the light emitting circuit blocks from the first stage to the m-th stage may be network resistors.

  The network resistor preferably includes a gate protection resistor.

  As described above, the LED module of the present invention that drives the LED element with a full-wave rectified waveform can reduce the management load of the current detection resistor even if the light emitting circuit block including the LED array and the current detection resistor is connected in a multi-stage manner like a ladder. Can be small.

The circuit diagram of the LED module shown as 1st Embodiment of this invention. The circuit diagram of the LED row | line | column shown in FIG. The wave form diagram which concerns on the LED module shown in FIG. The circuit diagram of the LED module shown as 2nd Embodiment of this invention. The top view of the network resistance shown in FIG. The circuit diagram of the LED module shown as a prior art example. The wave form diagram which concerns on the LED module shown in FIG. The circuit diagram of the LED module shown as a prior art example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted. For the sake of explanation, the scale of the members is changed as appropriate. Furthermore, the relationship with the invention specific matter described in the claims is described in parentheses.
(First embodiment)

  The LED module 10 shown as the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a circuit diagram of the LED module 10. FIG. 2 is a circuit diagram of the LED array 111 included in the LED module 10. FIG. 3 is a waveform diagram relating to the LED module 10, where (a) shows one cycle of the full-wave rectification waveform, and (b) shows the current flowing through the LED module 10. In FIG. 3, the time axes of (a) and (b) coincide.

  As shown in FIG. 1, the LED module 10 includes a diode bridge circuit 101, LED rows 111, 121, 131, 141, 151, bypass circuits 113, 123, 133, 143, and a constant current circuit 153. The commercial AC power supply 102 is connected to the input terminal of the diode bridge circuit 101, and the diode bridge circuit 101 outputs a full-wave rectified waveform. The LED strings 111, 121, 131, 141, 151 are connected in series, and bypass circuits 113, 123, 133, 143 are connected to the connection portions of the LED strings 111, 121, 131, 141, 151. A constant current circuit 153 is connected to the cathode of the LED array 151. In the drawing, the broken line on the left side indicates that the commercial AC power supply 102 is not included in the LED module 10.

  In the LED array 111, a plurality of LED elements 112 are connected in series. More specifically, as shown in FIG. 2, the LED array 111 is obtained by connecting two LED arrays in parallel with 20 LED elements 112 connected in series. An LED array in which 20 LED elements 112 are connected in series and an LED array 111 in which two LED arrays are connected in parallel can be said to have the same basic characteristics such as threshold values and are functionally equivalent. However, since the luminous efficiency decreases as the current flowing through the LED element 112 increases, the LED array 111 in which two identical LED arrays are arranged in parallel is better than one LED array. Further, since the number of elements is large, the heat dissipation efficiency is improved in the LED array 111 in which two LEDs are arranged in parallel.

  Similarly, the LED rows 121 and 131 are two LED rows in which 20 LED elements 122 and 132 are connected in series, and are connected in parallel. The LED array 141 includes two LED arrays in which 17 LED elements 142 are connected in series, and two LED arrays connected in parallel. The LED array 151 includes two LED arrays in which 13 LED elements 152 are connected in series.

  The bypass circuit 113 includes an FET 114 and resistors 115, 116, 117, 118, and 119. The FET 114 is a depletion type FET, and the drain serves as a bypass current input terminal. The resistor 115 is a protective resistor for protecting the gate of the FET 114 from surge and noise, and may be about 10 kΩ. The resistors 116 to 119 are current detection resistors, each having a resistance value of a reference value R (Ω) and a combined resistance of 4 R (Ω). In this embodiment, the reference value R is 11.8Ω, and the power consumption of the LED module 10 is 30W. A connection portion between the source of the FET 114 and the resistor 119 serves as an external current input terminal. Similarly, a connection portion between the resistor 115 and the resistor 116 serves as a current output terminal.

  Similarly, the bypass circuits 123, 133, and 143 include depletion type FETs 124, 134, and 144, and gate protection resistors 125, 135, and 145, and include a bypass current input terminal, an external current input terminal, and a current output terminal. . The bypass current input terminal is a drain of the FETs 124, 134, and 144, and the external current input terminal is a portion connected to the sources of the FETs 124, 134, and 144. The current output terminal is a connection portion between the protective resistors 125, 135, and 145 and the current detecting resistors 126, 136, and 146.

  The values of the current detection resistors 126, 127, and 128 included in the bypass circuit 123 are each a reference value R (Ω), and the combined resistance is 3R (Ω) (in this embodiment, as described above, R Is 11.8Ω, and so on). The values of the current detection resistors 136 and 137 included in the bypass circuit 133 are also the reference value R (Ω), and the combined resistance is 2R (Ω). The value of the current detection resistor 146 included in the bypass circuit 143 is also the reference value R (Ω). That is, the current detection resistor of the circuit block 140 including the bypass circuit 143 is one resistor of the reference value R (Ω), and the current detection resistors of the circuit blocks 130, 120, and 110 including the bypass circuits 133, 123, and 113 are In this order, there are 2, 3 and 4 resistors of the reference value R (Ω).

  The constant current circuit 153 includes a depletion type FET 154, a gate protection resistor 155, and a current detection resistor 156. The drain of the FET 154 is a current input terminal, and a connection portion between the resistor 155 and the resistor 156 is a current output terminal. In this embodiment, the resistor 156 is set to 5.6Ω.

When the LED module 10 connects the light emitting circuit blocks 110, 120, 130, 140, and 150 in a ladder shape, the current output terminal of the constant current circuit 153 included in the light emitting circuit block 150 is bypassed in the light emitting circuit block 140. The external current input terminal of the circuit 143 is connected. Similarly, between the adjacent light emitting circuit blocks 110, 120, 130, and 140, the current output terminal and the external current are bypassed among the bypass circuits 113, 123, 133, and 143 included in each light emitting circuit block 110, 120, 130, and 140. The input terminal is connected.

  Next, the operation of the LED module 10 will be described with reference to FIG. In the period t0 until the full-wave rectified waveform shown in (a) starts to rise from 0V and reaches the threshold value of the LED array 111, no circuit current flows as shown in (b).

  When the voltage of the full-wave rectified waveform becomes higher than the threshold value of the LED string 111 in the period t1, the circuit current flows from the LED string 111 via the bypass circuit 113. At this time, the bypass circuit 113 operates at a constant current with feedback from the current detection resistors 116 to 119 to the gate of the FET 114. When the voltage of the full-wave rectified waveform reaches the vicinity of the sum of the threshold value of the LED string 111 and the threshold value of the LED string 121 (the last part of the period t1), the circuit current flows from the LED string 111 via the bypass circuit 113. Then, it flows into the bypass circuit 113 via the LED row 121 and the bypass circuit 123. At this time, the bypass circuit 113 operates so that the sum of the current flowing through the FET 114 and the current flowing through the LED array 121 becomes constant.

  When the voltage of the full-wave rectified waveform becomes sufficiently larger than the sum of the threshold value of the LED string 111 and the threshold value of the LED string 121 in the period t2, the FET 114 included in the bypass circuit 113 is cut off, and almost all the circuit current is supplied to the LED string. It flows through the bypass circuit 123 via 121. At this time, the bypass circuit 123 operates at a constant current. When the voltage of the full-wave rectified waveform reaches the vicinity of the sum of the threshold values of the LED strings 111, 121, and 131 (the last part of the period t2), the circuit current flows through the bypass circuit 123 and bypasses with the LED string 131. It flows into the bypass circuit 123 via the circuit 133. At this time, the bypass circuit 123 operates so that the sum of the current flowing through the FET 124 and the current flowing through the LED array 131 becomes constant.

  The above operation is repeated in the periods t3, t4, and t5, and the FETs 124, 134, and 144 are sequentially cut off. In the period t5, the constant current circuit 153 limits the upper limit value of the circuit current. In addition, since the largest current flows in the period t5, the current detection resistor 156 is set to the smallest value with respect to the other current detection resistors 116 to 119, 126 to 128, 136 to 137, and 146 (each combined value). . In the period in which the voltage of the full-wave rectified waveform decreases, the process reverse to the period in which the voltage of the full-wave rectified waveform increases.

  As shown in FIG. 3, the circuit current increases as the full-wave rectified waveform increases, and the power factor improves as the circuit current decreases as the full-wave rectified waveform decreases. Further, the distortion is improved by changing the current in small increments (five steps in FIG. 3). In particular, in the case of the LED module 10 of the present embodiment, the harmonic component is small because the transition is smoothly made from the constant current operation state to the next constant current operation state. At this time, the current detection resistors included in the bypass circuits 113, 123, 133, and 143 and the constant current circuit 153 must be sequentially increased from the constant current circuit 153 side toward the bypass circuit 113 side. In addition, the current detection resistors 146, 136 to 137, 126 to 128, and 116 to 119 sequentially increase in calorific value. However, since the number of resistors increases according to the calorific value, the resistance heat resistance design and the heat radiation design are improved. It becomes easy.

In the LED module 10 of the present embodiment, the number of the light emitting circuit blocks 110, 120, 130, 140, 150 is five (see FIG. 1). However, the number of light emitting circuit blocks is not limited to five. When there are n light emitting circuit blocks including LED rows and bypass circuits or constant current circuits, n light emitting circuit blocks are connected in a ladder shape, and the input side of the full-wave rectified waveform is the first stage, 1 <m If ≦ n and the value of the current detection resistor included in the mth light emitting circuit block can be set as the reference value R, the value of the (m−k) th current detection resistor may be (k + 1) R. . Note that k, m, and n are integers, and 1 ≦ k <m. At this time, each LED row included in the light emitting circuit block is connected in series, and the current output terminal and the external current input terminal of the adjacent light emitting circuit block are connected so as to match the current direction. In the LED module 10, n = 5 and m = 4.

  Further, as an example of n = m, when a constant current circuit included in the nth stage light emitting circuit block includes a current detection resistor, the current detection resistor may be a resistor having a reference value R. At this time, the value of the current detection resistor included in the (n−1) th light emitting circuit block is 2R. Similarly, the values of the current detection resistors included in the (n-2) th, (n-3),..., 2nd stage light emitting blocks are 3R, 4R,. nR.

  In the LED module 10 of this embodiment, the constant current circuit 153 included in the light emitting circuit block 150 is configured by a depletion type FET 154 and resistors 155 and 156 so as to be similar to the bypass circuit 143 and the like. However, the constant current circuit is not limited to this type as long as it has a current input terminal and a current output terminal. The constant current circuit may be a circuit using a constant current diode or a well-known bipolar transistor, and a simple circuit may be a resistor.

Similarly, in the LED module 10, the bypass circuit 113 and the like are configured by a depletion type FET 114 and the resistor 116, but the bypass circuit is not limited to this type. For example, as in the bypass circuit 2610 illustrated in FIG. 6, a current limiting circuit including an enhancement type FET, a bipolar transistor, a pull-up resistor, and a current detection resistor may be used. In this case, the base terminal of the bipolar transistor serves as an external current input terminal, and the constant current operation is performed so that the base voltage is maintained at 0.6V. When a large amount of current is input from the external current input terminal, the enhancement type FET is cut off.
(Second Embodiment)

  In general, when there are a plurality of resistors, the products may be reduced in size by replacing them with network resistors. As shown in FIG. 1, the LED module 10 also has resistors 115 to 119 around the FET 114, for example, so that these can be networked. Therefore, an LED module 40 using network resistors 401, 402, 403, 404, 405, and 406 will be described as a second embodiment of the present invention with reference to FIGS.

  FIG. 4 is a circuit diagram of the LED module 40. Among the components and light emitting circuit blocks shown in FIG. 4, the components and light emitting circuit blocks having the same numbers as the components and light emitting circuit blocks included in the circuit of the LED module 10 shown in FIG. Is omitted.

  The only difference between FIG. 4 and FIG. 1 is that the resistors 115 to 119, 125 to 128, 135 to 137, and 145 to 146 shown in FIG. Each of the network resistors 401 to 406 is the same and includes terminals 411, 412, 413, and 414.

First, the network resistor 401 will be described with reference to FIG. Since the other network resistors 402 to 406 are equivalent to the network resistor 401, description thereof is omitted. FIG. 5 is a plan view of the network resistor 401 included in the LED module 40. The network resistor 401 is formed by forming resistors 115, 116, 117 of TaN on a silicon substrate 415, and has a chip size of 0.5 mm square (for the role of the resistors 115, 116, 117 in the LED module 40, see FIG. 1). Terminals 411, 412, 413, and 414 are disposed on the periphery of the silicon substrate 415 (see FIG. 4 for the role of the terminals 411, 412, 413, and 414). Terminals 411 to 414 are pads for wire bonding, and are connected to resistors 115 to 117. Resistor 115 is a protective resistor for surge countermeasures, and only needs to be about 10 kΩ. On the other hand, the resistors 116 and 117 are resistors for detecting current, have a thickness of about several to several hundreds Ω, and generate heat, and thus have a strip shape and a wide shape to increase the rated power. Note that the resistors 116 and 117 are included in a single strip of TaN, and the resistor 116 is a portion between the terminal 414 and the terminal 413, and the resistor 117 is a portion between the terminal 413 and the terminal 412. The resistors 116 and 117 are equal in length in the horizontal direction, and each value is a reference value R.

  By using the network resistors 401 to 406 as described above as shown in FIG. 4, the LED module 40 can be equivalent to the circuit of the LED module 10 shown in FIG. The network resistors 401 to 406 include a gate protection resistor 115 and the like, and two reference values R of the resistor 116 and the like. In this case, when m is an even number (m = 4 in the LED module 40), the use efficiency is slightly better than when m is an odd number. Further, the heat radiation design is facilitated for the same reason as described in the description of the LED module 10.

  As described above, the network resistor 401 includes the resistor 115 for protecting the FET 114 from a surge or the like and the resistors 116 and 117 for current detection (see FIGS. 1 and 5). However, since the resistance taken into the network resistance has a degree of freedom, it is not limited to the combination of resistances as in the present embodiment. However, if the network resistor 401 or the like includes the surge protection resistor 115 or the like and the current detection resistor 116 or the like, the bypass circuit 113 or the constant current circuit 153 or the like using the depletion type FET 114 or the like uses wire bonding. However, in addition to reducing the size of the product, it leads to cost reduction and productivity improvement.

  In addition, a depletion type FET 114 or the like (see FIG. 4) that is expensive and has a long manufacturing period (see FIG. 4) may have a threshold (gate-source voltage for turning off) that varies depending on the manufacturing lot. On the other hand, trimming the network resistor 401, which has a shorter manufacturing period and a lower price than the FET 114, in accordance with the characteristics of the FET 114, improves the use efficiency of the electronic components.

10, 40 ... LED module,
101 ... Diode bridge circuit,
102 ... Commercial AC power supply,
110, 120, 130, 140, 150 ... light emitting circuit block,
111, 121, 131, 141, 151 ... LED row,
112, 122, 132, 142, 152 ... LED elements,
113, 123, 133, 143 ... bypass circuit,
153 ... Constant current circuit,
114,124,134,144,154 ... FET,
115-119, 125-128, 135-137,
145 to 146, 155 to 156 ... resistance,
401-406 ... Network resistance,
411-414 ... terminals.

Claims (4)

In an LED module that drives a plurality of LED elements with a full-wave rectified waveform,
The LED array in which the LED elements are connected in series and n light emitting circuit blocks including a bypass circuit or a constant current circuit are connected in a ladder shape,
1 <m ≦ n,
1 ≦ k <m,
The light emitting circuit block on the side to which the full-wave rectified waveform is input is a first stage ,
The value of the current detection resistor included in the light emitting circuit block of the mth stage is set as a reference value R
When
Current detecting resistor contained in said light emitting circuit block in the (m-k) stages, LED module, characterized in der Rukoto that resistance of the reference value R is connected (k + 1) pieces in series. The LED module according to claim 1, wherein the bypass circuit includes a depletion type FET. LED module according to claim 1 or 2, characterized in that the light-emitting circuit current detecting resistor included in the block up to the m-stage from the first stage is Ru network resistor der. The LED module according to claim 3 , wherein the network resistor includes a gate protection resistor.

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