JP2012252966A - Led light source luminance adjustment device, luminance adjustment method and led lighting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LED light source luminance adjustment device which can avoid the problem associated with multi-stage connections of operational amplifiers and also can adjust luminance and color tone easily and surely.SOLUTION: The LED light source luminance adjustment device comprises: a drive unit 54 which includes drive circuits for driving LEDs in respective colors of an LED light source, and a plurality of individual setting resistors connected to the respective drive circuits so as to control the output current of each drive circuit; a color tone setting unit which includes a plurality of color tone setting variable resistors 53 that are provided correspondingly to the LEDs in respective colors, a plurality of constant current sources 52 which are respectively connected to the plurality of color tone setting variable resistors, and which is configured so as to adjust the luminance of the LEDs for each color; and a general luminance setting unit composed of general luminance setting variable resistors and constant current sources connected to the general luminance setting variable resistors, where the outputs of the constant current sources are respectively connected to the outputs of plural constant current sources in the color tone setting unit, the general luminance setting unit being configured so as to adjust the luminance of the LED light source in a unified manner by adjusting the general luminance setting variable resistors.

Description

  The present invention relates to a luminance adjusting device, a luminance adjusting method, and an LED lighting device for adjusting luminance and color tone of an LED light source.

  Lighting equipment using LEDs is attracting attention as lighting equipment that achieves both energy saving and environmental consideration. However, an LED is a semiconductor element, and is an element different from incandescent bulbs and fluorescent lamps that have been used in conventional lighting. When designing an illumination device using an LED, the allowable range of operating temperature and operating current is instantaneous. In addition, it is necessary to take into account variations in brightness and color tone inherent in individual LEDs. In particular, lighting for exhibits in museums and art galleries, or lighting for cultural properties such as buildings, etc., must be individually adjusted for brightness and color tone, and color reproducibility must be taken into account. And halogen lamps are frequently used, and the transition to LED lighting is not progressing slowly.

  This is because the majority of LED lighting devices once convert AC to DC, the inside is operating with DC, and even if the device that controls the brightness for incandescent lamps is connected to the LED lighting device described above, AC Due to the method of controlling the average power by supplying only a part of the input voltage by phase control, the power supply in the LED lighting device operates normally up to a certain range of AC input voltage. The reason is that dimming cannot be performed originally because it does not operate, and the dimming variation of the LED is due to reasons such as the fact that the LED is sorted and assembled, so that it cannot be adjusted in the field. However, there is a need for a method that can realize brightness, color tone, and color temperature that can be easily and easily realized so as to perform brightness control for incandescent bulbs.

  FIG. 1 shows an example of an LED drive control circuit configured according to the prior art. The LED drive control circuit 30 shown in FIG. 1 has a configuration in which multiplying DACs (DA converters) are connected in three stages in series. In the LED drive control circuit 30, the first-stage DAC 31 is used to adjust the overall luminance, the second-stage DACs 32a to 32d are used to adjust the color tone, and the third-stage DACs 33a to 33d are constant current sources. This is used to set the outputs 34a to 34d (that is, the currents of the white, red, blue, and green LEDs). The control unit 35 includes control software, an MCU, and an interface, and operates to set data in each DAC according to input luminance information.

  Patent Document 1 below shows an example of an LED drive control circuit configured to adjust the luminance and color tone of an LED by connecting a plurality of DACs in series.

JP 2008-135220 A

  In the case of not using pulse modulation in the digital LED drive control circuit as shown in FIG. 1, a multi-stage DA converter is used to DA-convert and output the output value of the previous stage using a DA converter connected in multiple stages. In order to convert the DA converter output into a current value for LED driving, a high-speed and stable constant current circuit is used. This method has a problem that the accuracy of each DA converter cannot be increased to several bits at most. When pulse modulation is used, it is difficult to construct a DA converter connected in multiple stages. Usually, only one stage of DA conversion is performed by pulse modulation, and it is difficult to control items other than luminance simultaneously. is there. When a failure occurs in the circuit block of the DA converter, there may be a problem that the LED drive current value increases significantly depending on the failure location.

  The present invention has been made in view of the above circumstances. That is, the present invention can avoid the problem of the digital LED drive control circuit with the conventional configuration as described above, and can easily and reliably adjust the brightness and color tone of the LED light source. An object is to provide an adjusting device, a luminance adjusting method, and an LED lighting device.

  In order to solve the above problems, according to one aspect of the present invention, there is provided an LED brightness adjusting device for adjusting the brightness and color tone of an LED light source having a plurality of LEDs, which drives the LEDs of each color of the LED light source. Each drive circuit, a drive unit having a plurality of individual setting resistors respectively connected to each drive circuit to control the output current of each drive circuit, and a plurality of color tones provided corresponding to the LEDs of each color Each of the LEDs has a setting variable resistor and a plurality of constant current sources connected to the plurality of color tone setting variable resistors, and each of the plurality of LED colors is adjusted by adjusting the plurality of color tone setting variable resistors. A color tone setting unit configured to adjust brightness, a variable resistor for setting overall brightness, and a constant current source connected to the variable resistor for setting overall brightness, the output of the constant current source is color tone Multiple constant current sources in the setting section And an overall brightness setting unit configured to uniformly adjust the brightness of the LED light source by adjusting a variable resistor for overall brightness setting, and each drive circuit of the drive unit includes: There is provided an LED brightness adjusting device that drives each color LED of an LED light source in accordance with an output from a constant current source of an overall brightness setting unit and an output from each constant current source of a color tone setting unit. That is, in this configuration, the output of each constant current source of the color tone setting unit and the output of the constant current source for setting the overall luminance are connected to the individual setting resistor (for example, the input of the variable resistor) of each drive circuit. Each driving circuit drives each color LED in accordance with the combined current of the output of each constant current source of the color tone setting unit and the output of the constant current source for setting the overall luminance.

  According to such a configuration, it is possible to easily and surely adjust the luminance and the color tone while avoiding the problem of the digital LED drive control circuit according to the conventional configuration.

  The plurality of individual setting resistors of the driving unit may be a plurality of individual setting variable resistors provided corresponding to the plurality of colors of the LEDs.

  Each of the plurality of constant current sources of the color tone setting unit, the constant current source of the overall luminance setting unit, and each drive circuit of the driving unit includes an operational amplifier, a constant current output transistor connected to the output of the operational amplifier, and a constant current output It may be configured to have a negative feedback circuit from the unit to the operational amplifier.

  The constant current source of the overall luminance setting unit may be configured by further connecting a plurality of constant current output transistors in parallel to the output of the operational amplifier.

  The constant current source of the overall luminance setting unit may be configured such that a plurality of emitter resistors respectively connected to the emitters of the plurality of constant current output transistors have the same resistance value.

  The constant current source of the overall brightness setting unit may be configured such that at least one of the plurality of emitter resistors connected to the emitters of the plurality of constant current output transistors has a resistance value different from that of the other emitter resistors. good.

  In order to solve the above-described problem, according to another aspect of the present invention, there is provided a method for adjusting the luminance and color tone of an LED light source using the above-described LED luminance adjusting device, wherein a plurality of color tone setting variable resistors of a color setting unit are provided. There is provided a method for adjusting the luminance and color tone of an LED light source, which adjusts the color tone of the LED light source by adjusting, and adjusts the overall luminance of the LED light source by adjusting a variable resistor of the overall luminance setting unit.

  According to such a configuration, it is possible to easily and surely adjust the luminance and the color tone while avoiding the problem of the digital LED drive control circuit according to the conventional configuration.

  According to another aspect of the present invention, there is provided an LED brightness adjusting device for adjusting the brightness and color tone of an LED light source having a plurality of LEDs, and one first-stage DAC for adjusting the overall brightness. Connected to the output of one first-stage DAC, and connected to the outputs of a plurality of second-stage DACs corresponding to a plurality of colors of the LED light source, and to the outputs of the plurality of second-stage DACs, respectively. And a controller that controls the first-stage DAC and the plurality of second-stage DACs.

  According to such a configuration, it is possible to easily and reliably adjust the luminance and the color tone even though the configuration is simple.

  According to another aspect of the present invention, there is provided an LED brightness adjusting device for adjusting brightness and color tone of an LED light source having a plurality of LEDs, the plurality of DACs provided corresponding to the plurality of colors of the LED light source. And an LED brightness adjusting device that is connected to the outputs of the plurality of DACs and that respectively drives a plurality of color LEDs and a control unit that controls the plurality of DACs.

  According to such a configuration, it is possible to easily and reliably adjust the luminance and the color tone even though the configuration is simple.

  According to another aspect of the present invention, there is provided a brightness / color tone adjustment method for an LED light source having a plurality of LEDs using an LED brightness adjustment device. Here, the LED brightness adjustment circuit includes a plurality of DACs provided corresponding to a plurality of colors of the LED light source, and a drive unit that is connected to the outputs of the plurality of DACs and drives the LEDs of the plurality of colors, respectively. A control unit that controls a plurality of DACs. In this method, the control unit receives input luminance information, converts the input luminance information into DAC data, and sets the converted DAC data in each DAC.

  According to such a configuration, it is possible to easily and reliably adjust the luminance and the color tone even though the configuration is simple.

Here, the DAC data may be calculated by the following equation.
DAC data = Lm × IL × Lc
However, Lm is luminance information obtained by converting non-linear input luminance information into linearity.
IL is the maximum current that flows in the LED connected to the output of each DAC
Lc is LED brightness correction information

  According to another aspect of the present invention, there is provided an LED illumination device including a power supply unit, any one of the above-described LED brightness adjustment circuits, and an LED light source connected to the LED brightness adjustment circuit.

  According to such a configuration, it is possible to easily and reliably adjust the luminance and the color tone even though the configuration is simple.

It is a figure showing an example of the LED brightness adjustment circuit by the conventional digital system. FIG. 2A is a diagram illustrating the configuration of the LED brightness adjustment circuit according to the embodiment of the present invention, and FIG. 2B illustrates the connection relationship between the LED brightness adjustment circuit of FIG. 2A and the LED light source. FIG. FIG. 3 is a circuit diagram of a constant current source in the LED luminance adjustment circuit of FIG. FIG. 3 is a circuit diagram of a constant current source for overall luminance control in the LED luminance adjusting circuit of FIG. It is a figure showing the structure of the LED illuminating device using the LED brightness adjustment circuit of Fig.2 (a). It is a figure showing the example at the time of comprising a LED brightness adjustment circuit using DAC by 2 steps | paragraphs structure. It is a figure showing the example at the time of comprising an LED brightness adjustment circuit by the all digital system. It is a figure showing the control flow in the LED brightness adjustment circuit of FIG.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 2A is a block diagram showing the configuration of the luminance adjustment circuit 50 according to the present embodiment. At the output end of the brightness adjustment circuit 50, LED light sources (that is, red (R), green (G), blue (B), and white (W) LED arrays) are, for example, as shown in FIG. Connected in a simple configuration. With this configuration, the luminance adjustment circuit 50 functions as an LED lighting device that can adjust luminance and color tone.

  Specifically, in the luminance adjustment circuit 50, the four constant current sources 52a, 52b, 52c, 52d arranged in parallel on the left side are respectively white (W), red (R), green (G), And a circuit for driving the blue (B) LED strings at a constant current. Four variable resistors 51a, 51b, 51c, 51d are connected to these four constant current sources, and the output currents of the constant current sources 52a to 52d are adjusted by adjusting these four variable resistors. Be able to.

  The constant current source 52e connected to the variable resistor 51e has a function of adjusting the overall luminance of the LED light source. The constant current source 52e normally has four output terminals that output the same current value (drawn current value) (see FIG. 4). These four outputs are the constant current sources 52a, 52b, 52c and 52d are respectively connected to the outputs. That is, by adjusting the variable resistor 51e, it is possible to simultaneously adjust the output current for driving the LED arrays of the respective colors with constant current. Therefore, the variable resistor 51e and the constant current source 52e function as a setting unit for adjusting the overall luminance.

  As shown in FIG. 2A, the outputs from the constant current sources 52a, 52b, 52c, and 52d of the respective colors are output from the constant current driving units 54a to 54 on the right side through the rows of variable resistors 53a to 53d. 54d, respectively. The constant current drive units 54a to 54d drive the LED rows of the respective colors according to the current drawn from the left-stage constant current source and the input voltage determined by the setting of the variable resistors 53a to 53d. The variable resistors 53a to 53d have a function of suppressing the output current of the constant current driving units 54a to 54d within the rating of the LED. The variable resistors 53a to 53d may additionally have a function of correcting the color tone.

  Note that it is possible to use various types of variable resistors as described above (those whose output changes with a logarithmic curve, a straight line, or an inverse logarithmic characteristic with respect to the adjusting rotation operation). There is. Therefore, the variable amount of luminance can be controlled for each color. Considering the sensitivity to the brightness of the human eye (when bright, increase the amount of quantization to increase the amount of change, and when dark, reduce the amount of quantization to reduce the amount of change) A variable resistor type may be selected.

  Next, a connection relationship between the constant current driving units 54a to 54d in the output stage of the luminance adjustment circuit 50 and the LED light sources (LED rows of the respective colors) will be described. As shown in FIG. 2A, each color constant current drive unit 54a to 54d has four output ends, and is configured to drive four LED rows. For example, the red LED constant current drive unit 54 a has four output terminals, and four LED strings (red LED strings) can be connected between the four output terminals and the external power supply 57. . In the connection example shown in FIG. 2B, LED substrates 81 on which red, blue, green, and white LED chips are arranged in an orderly manner are connected in series in four stages, and this is used as one LED block. In this case, four LED blocks are configured. The output end groups 61, 62, 63, and 64 shown in FIG. 2A are connected to four LED blocks, respectively. As shown in FIG. 2A, the power supply voltage Vcc may be generated by the local regulator 58 based on an output from the external power supply 57, for example.

  FIG. 3 is a diagram illustrating an example of a detailed configuration of a circuit used in each of the constant current sources 52a to 52d for white (W), red (R), green (G), and blue (B). The constant current source 52e for overall brightness control has a configuration in which four transistors are connected in parallel to the output stage of the operational amplifier (see FIG. 4). As shown in FIG. 3, in the constant current source, negative feedback is applied to the operational amplifier OP1 from the emitter of the transistor TR1 in the current output stage. The negative feedback circuit includes resistors R11 and C11 and R12. The output from the variable resistor in the previous stage of the constant current source is input to the input terminal (+) of the operational amplifier OP1.

  As shown in FIG. 4, the constant current source 52e for overall brightness adjustment has a configuration in which four constant current output transistors TR11 to TR14 are connected in parallel to the output of the operational amplifier OP11. With this configuration, it is possible to simultaneously adjust the drive currents of the red, blue, green, and white LED arrays in accordance with the input voltage set by the variable resistor 51e. In the circuit illustrated in FIG. 4, it is assumed that the values of the emitter resistors R21 to R24 of the constant current output transistors TR11 to TR14 are the same, but these emitter resistors R21 to R24 may be different values. good. When these emitter resistors R21 to R24 have different values, the color tone can be changed according to the degree of restriction of the variable resistor 51e. For example, if the emitter resistance for driving the red LED is set so that the attenuation of the driving current for the red LED is reduced when the variable resistor 51e is squeezed, the emission color as the light source is reduced as the variable resistor 51e is squeezed. It is possible to control such as reddish color. Alternatively, a temperature compensation circuit can be realized by arranging a thermistor in the feedback circuit to the operational amplifier.

  Each of the constant current drive units 54a to 54d may have a configuration equivalent to the circuit shown in FIG. That is, each of the constant current driving units 54a to 54d has a configuration in which four constant current driving transistors are connected in parallel to the output from the constant current circuit. With this configuration, for example, in the constant current driving unit 54a for red LED, each of the four constant current output transistors has an output current (a pull-in current value) corresponding to the input voltage set by the variable resistor 53a. The red LED row is driven.

  As described above, in the luminance adjustment circuit 50 according to the embodiment of the present invention, all circuit blocks are configured by constant current sources, and the output of the constant current source for overall luminance control is supplied to the constant current source for each color control. It is configured to connect to the output. Therefore, according to the luminance adjustment circuit 50 according to the embodiment of the present invention, it is possible to adjust the luminance, the color tone, etc. while having a simple configuration while solving the problems of the conventional luminance adjustment circuit due to the multi-stage connection such as a constant voltage source. Can be performed reliably. Further, in the luminance adjustment circuit 50, the frequency characteristics of the constant current source are corrected as described above. Therefore, it is possible to effectively prevent an oscillation phenomenon or the like due to the routing of the wiring from the output stage of the luminance adjustment circuit 50 to the LED light source, and to suppress the generation of radiation noise.

  Compared with the conventional configuration for performing dimming by digital control as shown in FIG. 1, the configuration like the luminance adjustment circuit 50 of the present embodiment has the following advantages. As a problem with digital control, when digital control is performed, it is necessary to write a digital value for control to a DA converter or the like in a predetermined procedure. When a failure occurs, there is a disadvantage that adjustment of luminance and the like cannot be performed at all. However, according to the configuration of the present embodiment, such a problem does not occur. Regarding digital control, non-linear DA conversion is very difficult, and it is possible to realize non-linearization by changing the size of the apparent gradation using a high-precision DA converter, but the original DA conversion However, according to the configuration of the present embodiment, such a problem does not occur.

  FIG. 5 is a block diagram illustrating an example of a configuration when the LED lighting device 90 is configured using the brightness adjustment circuit 50 of the present embodiment. As shown in FIG. 5, the power supply unit 91 generates a predetermined DC voltage from an alternating current (commercial AC input) from an alternating current power supply, and supplies it to the luminance adjustment circuit 50. The brightness adjustment circuit 50 drives the LED light source 92. The power supply unit 91 supplies the voltage of 60 v / 700 mA and the voltage of Vcc (5 V) in the above-described embodiment.

  The above is the embodiment of the present invention. It should be noted that the above-described embodiment specifically described with reference to the drawings can be modified from various viewpoints. For example, the variable resistors 53a to 53d on the right side shown in FIG. 2A may be replaced with fixed resistors as long as the LED drive current is set to be within the rating. In this case, the number of variable resistors can be further reduced. Moreover, the values of resistance and capacitance shown in each figure are merely examples, and various values can be used within the scope of the present invention. The constant current circuit shown in FIG. 3 can also be modified from various viewpoints.

  In the above-described embodiment, the LED light source is configured to realize white light using white (W), red (R), green (G), and blue (B) LEDs. Therefore, the luminance adjustment circuit 50 has a configuration including four constant current sources for color tone adjustment and a driving unit. When the LED light source is composed of LEDs of other combinations as LEDs for realizing white light, the number of constant current sources and driving units for color tone adjustment of the luminance adjustment circuit 50 is the number of the LEDs. It should be understood that the number may vary depending on the type. For example, when the LED light source is composed of three types of LEDs of red (R), green (G), and blue (B), the constant current source for color tone adjustment of the luminance adjustment circuit 50 and the drive unit The number may be three.

  Next, two examples in which a luminance adjustment circuit is configured using a DA converter will be described. These brightness adjusting circuits are also configured to eliminate the problems in the conventional digital LED driving circuit.

  FIG. 6 shows an example in which a luminance adjustment circuit is realized by connecting DA converters in a two-stage configuration. The luminance adjustment circuit 100 shown in FIG. 6 has a configuration that can be referred to as a mixed analog / digital type. The first-stage DAC 101, four second-stage DACs 102a to 102d, variable resistors 103a to 103d, constant current Sources 104 a to 104 d and a control unit 105 are included. The control unit 105 includes control software, an MCU (Micro Controller Unit), and an interface, and is connected to the first-stage DAC 101 and the second-stage DACs 102a to 102d via the interface. The four second-stage DACs 102a to 102d are provided corresponding to white (W), red (R), green (G), and blue (B) LEDs. In the luminance adjustment circuit 100, the first-stage DAC 101 is used to adjust the overall luminance, and the four second-stage DACs 102a to 102d are used to adjust the luminance of each color, that is, the color tone. The output of the first-stage DAC 101 is connected to the Vref (reference voltage) input terminals of the respective second-stage DACs 102a to 102d through resistors.

  For the application of the brightness adjustment circuit 100 as shown in FIG. 6 (that is, an application for performing further DA conversion on the DAC output at the first stage), a multiplication type DA converter is generally used. In view of various circumstances, a normal type high-precision DA converter is used here. As the DA converter, a type that performs linear conversion is used. That is, it is necessary to treat the output of the first-stage DAC as inputs of a large number of DACs, and the sensitivity to human light is non-linear (similar to a logarithmic curve) and is low when bright, and high when dark. This is because the DA converter also needs to increase the size of quantization when the luminance is high and decrease the size of quantization when the luminance is low, while the multiplying DAC is about 8 bits even if it is high accuracy.

  In the brightness adjustment circuit 100, the variable resistors 103a to 103d and the constant current sources 104a to 104d on the right side correspond to the variable resistors 53a to 53d and the constant current driving units 54a to 54d in FIG. This is a circuit for adjusting the drive current to be within the maximum rating. The control unit 105 sets values in the first-stage DAC 101 and / or the second-stage DACs 102a to 102d based on the input luminance information. For example, the control unit 105 controls the value set by the first-stage DAC 101 for input information for adjusting the overall luminance, and the second-stage DAC 102a for input information for changing the color tone. It is comprised so that the value set to -102d may be controlled. Through the above processing, the overall luminance and color tone are adjusted. In view of the above-described sensitivity to human light having non-linearity, each DAC may perform linear-to-nonlinear conversion. In this case, the apparent quantization magnitude can be changed.

  FIG. 7 shows an example in which a brightness adjustment circuit is realized by using four DA converters. The luminance adjustment circuit 110 in FIG. 7 has a configuration that can be referred to as an all-digital system, and includes DACs 111a to 111d, constant current sources 113a to 113d, and a control unit 115. The control unit 115 includes control software, an MCU (Micro Controller Unit), and an interface. The control unit 115 is connected to the DACs 111a to 111d through the interface, and can set values for the DACs 111a to 111d. Also, the constant current sources 113a to 113d on the right side are equivalent to the variable resistors 53a to 53d and the constant current drive units 54a to 54d in FIG. 2, and perform adjustment to keep the LED drive current within the maximum rating. It is a circuit for.

In the luminance adjustment circuit 110 in FIG. 7, a normal DA converter having the same 1 digit size is used as each DA converter. The accuracy of each DA converter may be around 10 to 16 bits, for example. The control unit 115 operates according to the internal processing software provided in the control unit 115, for example, as in the flow shown in FIG. First, input of luminance information is accepted (step S101). When the luminance information is input, the control unit 115 then converts the input luminance information (non-linear) into a straight line and acquires the luminance information Lm (Step S102). In step S113, data (DAC data) to be set in the DAC is obtained according to the following equation.
DAC data = Lm × IL × Lc
Here, IL represents current setting information that flows through the LED. For example, the maximum current that flows through the LED is set in IL. Lc represents LED brightness correction information. Lc is determined in consideration of the non-linearity between the LED current and the luminance. The DAC data may be obtained for each color information. In step S104, the DAC data obtained as described above is written in each of the DACs 111a to 111d. Through the above processing, the overall luminance and color tone are adjusted.

50 Brightness Adjustment Circuits 51a to 51e Variable Resistors 52a to 52e Constant Current Sources 53a to 53d Variable Resistors 54a to 54d Constant Current Drive Unit 81 LED Substrate 90 LED Lighting Device 92 LED Light Source 100 Brightness Adjustment Circuit 101 First Stage DAC
102a-102d 2nd stage DAC
103a to 103d Variable resistors 104a to 104d Constant current source 105 Control unit 110 Brightness adjustment circuits 111a to 111d DAC
113a to 113d constant current source 115 control unit

Claims (14)

An LED brightness adjusting device for adjusting the brightness and color tone of an LED light source having a plurality of LEDs,
A drive unit having drive circuits for driving LEDs of each color of the LED light source, and a plurality of individual setting resistors respectively connected to the drive circuits so as to control an output current of the drive circuits;
A plurality of tone setting variable resistors provided corresponding to the LEDs of each color; and a plurality of constant current sources connected to the plurality of tone setting variable resistors, respectively, and the plurality of tone settings A color tone setting unit configured to adjust brightness for each color of the plurality of LEDs by adjusting a variable resistor for use;
It comprises a variable resistor for setting the overall brightness and a constant current source connected to the variable resistor for setting the overall brightness, and the outputs of the constant current sources are respectively output to the plurality of constant current sources of the color tone setting unit. An overall brightness setting unit connected and configured to uniformly adjust the brightness of the LED light source by adjusting the variable resistor for overall brightness setting; and
Each driving circuit of the driving unit drives each color LED of the LED light source according to an output from the constant current source of the overall luminance setting unit and an output from each constant current source of the color tone setting unit; LED brightness adjusting device characterized by this.   The LED brightness adjusting device according to claim 1, wherein the plurality of individual setting resistors of the driving unit are a plurality of individual setting variable resistors provided corresponding to a plurality of colors of the LED. .   Each of the plurality of constant current sources of the color tone setting unit, the constant current source of the overall luminance setting unit, and each driving circuit of the driving unit includes an operational amplifier, a constant current output transistor connected to the output of the operational amplifier, The LED brightness adjusting device according to claim 2, further comprising a negative feedback circuit from a constant current output unit to the operational amplifier.   4. The LED brightness adjusting device according to claim 3, wherein the constant current source of the overall brightness setting unit further includes a plurality of constant current output transistors connected in parallel to the output of the operational amplifier.   The constant current source of the overall brightness setting unit is configured such that a plurality of emitter resistors respectively connected to emitters of the plurality of constant current output transistors have the same resistance value. 4. The LED brightness adjusting device according to 4.   The constant current source of the overall brightness setting unit is configured such that at least one of the plurality of emitter resistors connected to the emitters of the plurality of constant current output transistors has a resistance value different from that of the other emitter resistors. The LED brightness adjusting device according to claim 4, wherein A power supply unit;
LED brightness adjusting circuit according to any one of claims 1 to 6,
An LED light source connected to the LED brightness adjustment circuit;
An LED lighting device comprising: A method for adjusting luminance and color tone of an LED light source using an LED luminance adjusting device,
The LED brightness adjusting device
A drive unit having drive circuits for driving LEDs of each color of the LED light source, and a plurality of individual setting resistors respectively connected to the drive circuits so as to control an output current of the drive circuits;
A plurality of tone setting variable resistors provided corresponding to the LEDs of each color; and a plurality of constant current sources connected to the plurality of tone setting variable resistors, respectively, and the plurality of tone settings A color tone setting unit configured to adjust brightness for each color of the plurality of LEDs by adjusting a variable resistor for use;
A variable resistor for setting the overall brightness and a constant current source connected to the variable resistor for setting the overall brightness, and the output of the constant current source is connected to the outputs of the plurality of constant current sources of the color tone setting unit, respectively. And an overall brightness setting unit configured to uniformly adjust the brightness of the LED light source by adjusting the variable resistor for setting the overall brightness, and
Each driving circuit of the driving unit drives each color LED of the LED light source according to an output from the constant current source of the overall luminance setting unit and an output from each constant current source of the color tone setting unit. Yes,
The method
Adjusting the color tone of the LED light source by adjusting a plurality of color setting variable resistors of the color setting unit;
Adjusting the overall brightness of the LED light source by adjusting a variable resistor of the overall brightness setting unit, and adjusting the brightness and color tone of the LED light source. An LED brightness adjusting device for adjusting the brightness and color tone of an LED light source having a plurality of LEDs,
One first-stage DAC for adjusting the overall brightness;
A second-stage DAC connected to the output of the one first-stage DAC and provided in a plurality corresponding to a plurality of colors of the LED light source;
Driving units connected to the outputs of the plurality of second-stage DACs, respectively, for driving the LEDs of the plurality of colors;
An LED brightness adjusting apparatus comprising: a control unit that controls the first stage DAC and the plurality of second stage DACs. A power supply unit;
LED brightness adjusting circuit according to claim 9,
An LED light source having a plurality of LEDs connected to the LED brightness adjustment circuit;
An LED lighting device comprising: An LED brightness adjusting device for adjusting the brightness and color tone of an LED light source having a plurality of LEDs,
A plurality of DACs provided corresponding to a plurality of colors of the LED light source;
Driving units connected to outputs of the plurality of DACs, respectively, for driving the LEDs of the plurality of colors;
An LED brightness adjusting apparatus comprising: a control unit that controls the plurality of DACs. A power supply unit;
The LED brightness adjustment circuit according to claim 11;
An LED light source having a plurality of LEDs connected to the LED brightness adjustment circuit;
An LED lighting device comprising: A method for adjusting the luminance and color tone of an LED light source having a plurality of LEDs using an LED luminance adjusting device,
The LED brightness adjustment circuit includes:
A plurality of DACs provided corresponding to a plurality of colors of the LED light source;
Driving units connected to outputs of the plurality of DACs, respectively, for driving the LEDs of the plurality of colors;
A controller that controls the plurality of DACs,
The method
The control unit receives input luminance information,
Converting the input luminance information into DAC data;
Setting the converted DAC data in each DAC;
The brightness | luminance and color tone adjustment method of LED light source characterized by these. The DAC data is represented by the following formula:
DAC data = Lm × IL × Lc
However, Lm is luminance information obtained by converting non-linear input luminance information into linearity,
IL is the maximum current flowing through the LED connected to the output of each DAC,
Lc is LED brightness correction information,
The brightness / color tone adjusting method of the LED light source according to claim 13, wherein the brightness / color tone adjusting method is calculated by:

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