SLUS937C December   2009  – December 2019 BQ24072T , BQ24075T , BQ24079T

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Simplified Circuit
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Device Options
  7. 7 Pin Configuration and Functions
    1.     Pin Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Typical Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  Undervoltage Lockout (UVLO)
      2. 9.3.2  Overvoltage Protection (OVP)
      3. 9.3.3  Dynamic Power-Path Management
      4. 9.3.4  Battery Charging
      5. 9.3.5  Charge Current Translator
      6. 9.3.6  Battery Detection and Recharge
      7. 9.3.7  Termination Disable (TD Input, BQ24072T)
      8. 9.3.8  Battery Disconnect (SYSOFF Input)
      9. 9.3.9  Dynamic Charge Timers (TMR Input)
      10. 9.3.10 Status Indicators (PGOOD, CHG)
      11. 9.3.11 Thermal Regulation and Thermal Shutdown
      12. 9.3.12 Battery Pack Temperature Monitoring
    4. 9.4 Device Functional Modes
      1. 9.4.1 Input Source Connected (Adapter or USB)
        1. 9.4.1.1 Input DPM Mode (VIN-DPM)
        2. 9.4.1.2 DPPM Mode
        3. 9.4.1.3 Battery Supplement Mode
      2. 9.4.2 Input Source Not Connected
  10. 10Applications and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Using the BQ24075T, BQ24079T to Disconnect the Battery from the System
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
          1. 10.2.1.2.1 Program the Fast Charge Current (ISET):
          2. 10.2.1.2.2 Program the Input Current Limit (ILIM):
          3. 10.2.1.2.3 Program 6.25-hour Fast-Charge Safety Timer (TMR):
          4. 10.2.1.2.4 TS Function:
          5. 10.2.1.2.5 CHG and PGOOD LED Status:
          6. 10.2.1.2.6 Processor Monitoring Status:
          7. 10.2.1.2.7 System ON/OFF (SYSOFF):
          8. 10.2.1.2.8 Selecting IN, OUT and BAT Capacitors
        3. 10.2.1.3 Application Curves
      2. 10.2.2 BQ24072T in a Host Controlled Charger Application
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedures
          1. 10.2.2.2.1 Termination Disable:
        3. 10.2.2.3 Application Curves
  11. 11Power Supply Recommendations
    1. 11.1 Power On
      1. 11.1.1 Half-Wave Adapters
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Package
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Related Links
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Support Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

10.2.1 Using the BQ24075T, BQ24079T to Disconnect the Battery from the System

The BQ24075T and BQ24079T are designed for applications that require the input supply to be passed through to the output (OUT). For these devices, the OUT regulation threshold is set to 5.5 V. for applications with a typical regulation on the adapter of 5 V, the main LDO in the BQ24075T and BQ24079T operates in dropout mode so that OUT is as high as possible to supply downstream devices. The input OVP and regulation threshold on OUT protect downstream devices from faulty or incorrect adapters. The BQ24075T and BQ24079T also contain a SYSOFF input that disconnects the OUT output from the battery to prevent standby loads from draining the battery during long storage intervals. See the "System ON/OFF" section for more details.

BQ24072T BQ24075T BQ24079T disconn_bat_lus937.gif

NOTE:

VIN = UVLO to VOVP, IFASTCHG = 800mA, IIN(MAX) = 1.35A, Battery Temperature Charge Range = 0°C to 50°C, 6.25 hour Fastcharge Safety Timer
Figure 23. Using the BQ24075T, BQ24079T to Disconnect the Battery from the System