JAJSBJ1B July   2010  – January 2020 BQ24650

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      代表的なアプリケーション
  4. 4 改訂履歴
  5. 5 概要（続き）
  6. 6 Pin Configuration and Functions
    1.     Pin 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  Battery Voltage Regulation
      2. 8.3.2  Input Voltage Regulation
      3. 8.3.3  Battery Current Regulation
      4. 8.3.4  Battery Precharge
      5. 8.3.5  Charge Termination and Recharge
      6. 8.3.6  Power Up
      7. 8.3.7  Enable and Disable Charging
      8. 8.3.8  Automatic Internal Soft-Start Charger Current
      9. 8.3.9  Converter Operation
      10. 8.3.10 Synchronous and Non-Synchronous Operation
      11. 8.3.11 Cycle-by-Cycle Charge Undercurrent
      12. 8.3.12 Input Overvoltage Protection (ACOV)
      13. 8.3.13 Input Undervoltage Lockout (UVLO)
      14. 8.3.14 Battery Overvoltage Protection
      15. 8.3.15 Cycle-by-Cycle Charge Overcurrent Protection
      16. 8.3.16 Thermal Shutdown Protection
      17. 8.3.17 Temperature Qualification
      18. 8.3.18 Charge Enable
      19. 8.3.19 Inductor, Capacitor, and Sense Resistor Selection Guidelines
      20. 8.3.20 Charge Status Outputs
      21. 8.3.21 Battery Detection
        1. 8.3.21.1 Example
    4. 8.4 Device Functional Modes
      1. 8.4.1 Converter Operation
      2. 8.4.2 Synchronous and Non-Synchronous Operation
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Inductor Selection
        2. 9.2.2.2 Input Capacitor
        3. 9.2.2.3 Output Capacitor
        4. 9.2.2.4 Power MOSFETs Selection
        5. 9.2.2.5 Input Filter Design
        6. 9.2.2.6 MPPT Temperature Compensation
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 デバイス・サポート
      1. 12.1.1 デベロッパー・ネットワークの製品に関する免責事項
    2. 12.2 ドキュメントの更新通知を受け取る方法
    3. 12.3 サポート・リソース
    4. 12.4 商標
    5. 12.5 静電気放電に関する注意事項
    6. 12.6 Glossary
  13. 13メカニカル、パッケージ、および注文情報

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

9.2.2.6 MPPT Temperature Compensation

A typical solar panel comprises of a lot of cells in a series connection, and each cell is a forward-biased p-n junction. So, the open-circuit voltage (VOC) of a solar cell has a temperature coefficient that is similar to a common p-n diode, or about –2 mV/°C. A crystalline solar panel specification always provides both open-circuit voltage VOC and peak power point voltage VMP. The difference between VOC and VMP can be approximated as fixed and temperature-independent, so the temperature coefficient for the peak power point is similar to that of VOC. Normally, panel manufacturers specify the 25°C values for VOC and VMP, and the temperature coefficient for VOC, as shown in Figure 17.

BQ24650 tc14_lusa75.gifFigure 17. Solar Panel Output Voltage Temperature Characteristics

The BQ24650 employs a feedback network to the MPPSET pin to program the input regulation voltage. Because the temperature characteristic for a typical solar panel VMP voltage is almost linear, a simple solution for tracking this characteristic can be implemented by using an LM234 3-terminal current source, which can create an easily programmable, linear temperature dependent current to compensate the negative temperature coefficient of the solar panel output voltage.

BQ24650 feedback_lusa75.gifFigure 18. Feedback Network

In the circuit shown in Figure 18, for the LM234 temperature sensor,

Equation 24. BQ24650 EQ23_iset_lusa75.gif

Thus,

Equation 25. BQ24650 EQ24_iset_lusa75.gif

The current node equation is Equation 26:

Equation 26. BQ24650 EQ25_i2_lusa75.gif

To have a zero temperature coefficient on VREG,

Equation 27. BQ24650 EQ26_dIdT_lusa75.gif
Equation 28. BQ24650 EQ27_R3_lusa75.gif
Equation 29. BQ24650 EQ28_R4_lusa75.gif

For example, given a common 18-cell solar panel that has the following specified characteristics:

Open-circuit voltage (VOC) = 10.3 V
Maximum power voltage (VMP) = 9V
Open-circuit voltage temperature coefficient (VOC) = –38 mV/°C

Applying the following parameters into the equations of R3 and R4:

  1. Temperature coefficient for VMP (same as that of VOC) of –38 mV/°C
  2. Peak power voltage of 9 V
  3. MPPSET regulation voltage of 1.2 V
And choosing RSET = 1000 Ω.

The resistor values are RSET = 1 kΩ, R3 = 167.4 kΩ, and R4=10.6 kΩ. Selecting standard 1% accuracy resistors and RSET = 1 kΩ, R3 = 169 kΩ, and R4=10.7 kΩ.