JAJSL87H january   2010  – april 2021 BQ24090 , BQ24091 , BQ24092 , BQ24093 , BQ24095

PRODUCTION DATA  

  1.   1
  2. 特長
  3. アプリケーション
  4. 概要
  5. Revision History
  6. 概要 (続き)
  7. Device Options
  8. Pin Configuration and Functions
  9. Specifications
    1. 8.1 Absolute Maximum Ratings #GUID-9FC6FB05-10A6-4323-9A52-EE32AE4C5F67/SLUS9405873
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions #GUID-4D70561B-CB71-403D-B731-8EF5DEBEBDF9/SLUS9401392
    4. 8.4 Thermal Information
    5. 8.5 Dissipation Ratings #GUID-196940BE-C3C2-4CDF-A8A4-7C186292F803/SLUS9404025 #GUID-196940BE-C3C2-4CDF-A8A4-7C186292F803/SLUS9403553
    6. 8.6 Electrical Characteristics
    7. 8.7 Typical Characteristics
      1. 8.7.1 Power Up, Power Down, OVP, Disable and Enable Waveforms
      2. 8.7.2 Protection Circuits Waveforms
  10. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  Power Down or Undervoltage Lockout (UVLO)
      2. 9.3.2  UVLO
      3. 9.3.3  Power Up
      4. 9.3.4  Sleep Mode
      5. 9.3.5  New Charge Cycle
      6. 9.3.6  Overvoltage Protection (OVP) – Continuously Monitored
      7. 9.3.7  Power Good Indication ( PG)
      8. 9.3.8  CHG Pin Indication
      9. 9.3.9  CHG and PG LED Pullup Source
      10. 9.3.10 IN-DPM (VIN-DPM or IN–DPM)
      11. 9.3.11 OUT
      12. 9.3.12 ISET
      13. 9.3.13 PRE_TERM – Precharge and Termination Programmable Threshold
      14. 9.3.14 ISET2
      15. 9.3.15 TS
    4. 9.4 Device Functional Modes
      1. 9.4.1 Termination and Timer Disable Mode (TTDM) - TS Pin High
      2. 9.4.2 Timers
      3. 9.4.3 Termination
      4. 9.4.4 Battery Detect Routine
      5. 9.4.5 Refresh Threshold
      6. 9.4.6 Starting a Charge on a Full Battery
  11. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Calculations
          1. 10.2.2.1.1 Program the Fast Charge Current, ISET:
          2. 10.2.2.1.2 Program the Termination Current Threshold, ITERM:
          3. 10.2.2.1.3 TS Function
          4. 10.2.2.1.4 CHG and PG
        2. 10.2.2.2 Selecting IN and OUT Pin Capacitors
      3. 10.2.3 Application Curves
  12. 11Power Supply Recommendations
  13. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Considerations
      1. 12.3.1 Leakage Current Effects on Battery Capacity
  14. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 サード・パーティ製品に関する免責事項
    2. 13.2 ドキュメントの更新通知を受け取る方法
    3. 13.3 サポート・リソース
    4. 13.4 Trademarks
    5. 13.5 静電気放電に関する注意事項
    6. 13.6 用語集
  15.   Mechanical, 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

Thermal Considerations

The BQ2409x family is packaged in a thermally enhanced MSOP package. The package includes a thermal pad to provide an effective thermal contact between the IC and the printed circuit board (PCB). The power pad should be directly connected to the VSS pin. Full PCB design guidelines for this package are provided in the PowerPAD Thermally Enhanced Package Application Report. The most common measure of package thermal performance is thermal impedance (θJA ) measured (or modeled) from the chip junction to the air surrounding the package surface (ambient). The mathematical expression for θJA is:

Equation 2. θJA = (TJ – T) / P

where

  • TJ = chip junction temperature
  • T = ambient temperature
  • P = device power dissipation

Factors that can influence the measurement and calculation of θJA include:

  • Whether or not the device is board mounted
  • Trace size, composition, thickness, and geometry
  • Orientation of the device (horizontal or vertical)
  • Volume of the ambient air surrounding the device under test and airflow
  • Whether other surfaces are in close proximity to the device being tested

Due to the charge profile of Li-ion and Li-pol batteries the maximum power dissipation is typically seen at the beginning of the charge cycle when the battery voltage is at its lowest. Typically after fast charge begins the pack voltage increases to ≉3.4 V within the first 2 minutes. The thermal time constant of the assembly typically takes a few minutes to heat up so when doing maximum power dissipation calculations, 3.4 V is a good minimum voltage to use. This is verified, with the system and a fully discharged battery, by plotting temperature on the bottom of the PCB under the IC (pad should have multiple vias), the charge current and the battery voltage as a function of time. The fast charge current will start to taper off if the part goes into thermal regulation.

The device power dissipation, P, is a function of the charge rate and the voltage drop across the internal PowerFET. It can be calculated from the following equation when a battery pack is being charged :

P = [V(IN) – V(OUT)] × I(OUT) + [V(OUT) – V(BAT)] × I(BAT)

The thermal loop feature reduces the charge current to limit excessive IC junction temperature. It is recommended that the design not run in thermal regulation for typical operating conditions (nominal input voltage and nominal ambient temperatures) and use the feature for non typical situations such as hot environments or higher than normal input source voltage. With that said, the IC will still perform as described, if the thermal loop is always active.