JAJSLS3 December   2022 OPT4048

PRODUCTION DATA  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  4. 4 Revision History
  5. 5 概要 (続き)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Spectral Matching to CIE
      2. 8.3.2 Automatic Full-Scale Range Setting
      3. 8.3.3 Output Register CRC and Counter
        1. 8.3.3.1 Output Sample Counter
        2. 8.3.3.2 Output CRC
        3. 8.3.3.3 Threshold Detection
      4. 8.3.4 Device Functional Modes
        1. 8.3.4.1 Modes of Operation
        2. 8.3.4.2 Interrupt Modes of Operation
        3. 8.3.4.3 Light Range Selection
        4. 8.3.4.4 Selecting Conversion Time
        5. 8.3.4.5 Light and Color Measurement
        6. 8.3.4.6 Light Resolution
        7. 8.3.4.7 Programming
          1. 8.3.4.7.1 I2C Bus Overview
            1. 8.3.4.7.1.1 Serial Bus Address
            2. 8.3.4.7.1.2 Serial Interface
          2. 8.3.4.7.2 Writing and Reading
            1. 8.3.4.7.2.1 High-Speed I2C Mode
            2. 8.3.4.7.2.2 Burst Read Mode
            3. 8.3.4.7.2.3 General-Call Reset Command
            4. 8.3.4.7.2.4 SMBus Alert Response
    4. 8.4 Register Maps
      1. 8.4.1 ALL Register Map
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Electrical Interface
      2. 9.2.2 Design Requirements
        1. 9.2.2.1 Optical Interface
      3. 9.2.3 Detailed Design Procedure
        1. 9.2.3.1 Optomechanical Design
      4. 9.2.4 Application Curves
    3. 9.3 Do's and Don'ts
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
      3. 9.5.3 Soldering and Handling Recommendations
  10. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 ドキュメントの更新通知を受け取る方法
    3. 10.3 サポート・リソース
    4. 10.4 Trademarks
    5. 10.5 静電気放電に関する注意事項
    6. 10.6 用語集
  11. 11Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

9.2.4 Application Curves

Matrix values for Color determination

ADC measurements from OPT4048 channels can be used to determine the intensity (lux) and the color (CIE X,Y coordinates) as per specified in Section 8.3.4.5. Here is an example of such measurements performed an RGB LED source TI LP5036EVM. The intensity of the Red, Green and Blue LEDs were varied independently and the corresponding color coordinates detected by OPT4048 (CIEx,CIEy) are plotted on the CIE XY and CIE UV color space.

Figure 9-3 CIE XY and CIE UV space plots of color coordinates

Value of matrix used for this calculation is as shown below

Equation 16. 2 . 34892992 e - 04   - 1.89652390 e - 05   1.20811684 e - 05   0 4.07467441 e - 05   1.98958202 e - 04   - 1.58848115 e - 05 2.15 e - 3 9.28619404 e - 05   - 1.69739553 e - 05   6.74021520 e - 04   0 0 0 0 0

Correlated Color Temperature

The CIE XY and CIE UV color spaces shown in Figure 9-3 and Figure 9-4 has been annotated with the ideal black body curve and intersecting iso-thermal lines. The ideal black body curve represents the color perceived by human eye in CIE YX and CIE UV spaces when an ideal black body of certain Kelvins emit radiation. The intersecting lines with various kelvin markings are iso-thermal lines which represent the same color temperature and is commonly referred to as Correlated Color Temperature (CCT). CCT is a representation of how warm or cool a color source is which is a common terminology used in classifying light bulbs. CCT is often valid only around the ideal black body curve and does not make sense when there is too much deviation. Any color coordinate close to the ideal black body curve can be represented as having a particular CCT by using the formula below:

Equation 17. C C T = 437 n 3 + 3601 n 2 + 6861 n + 5517

where n is defined as

Equation 18. n = C I E x - 0.3320 0.1858 - C I E y

These are highly non-linear functions and the estimation of the CCT is very sensitive to the CIE X and CIE Y coordinates. Small errors due to non-ideality in the system can cause an amplified error in CCT estimation.

Set of off the shelf lamp sources were taken and the CCT values measured by OPT4048 is shown below.

Figure 9-4 CIE XY and CIE UV Space Plots of Color Coordinates

The CIE color space plots have been zoomed-in to see the points more clearly. The annotation in the plot specify the color temperature of the lamps as specified by the manufacturer. While the lamp manufacturers approximate the CCT in Kelvins to nearest 1000 s, 500 s or 100 s, OPT4048 estimates the CCT high resolution using the equations specified above.

Color accuracy and the CCT accuracy can be further optimized based on the cavity design, cover glass and target application. More information is available at OPT4048.