SLUS940D September   2009  – May 2021 BQ24050 , BQ24052

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings (1)
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions (1)
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Typical Characteristics
      1. 6.8.1 Power Up, Down, OVP, Disable and Enable Waveforms
      2. 6.8.2 Protection Circuits Waveforms
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Power Down, or Undervoltage Lockout (UVLO)
      2. 7.3.2  Power Up
      3. 7.3.3  D+, D– Detection
      4. 7.3.4  New Charge Cycle
      5. 7.3.5  Overvoltage Protection (OVP) – Continuously Monitored
      6. 7.3.6  CHG Pin Indication
      7. 7.3.7  CHG LED Pullup Source
      8. 7.3.8  Input DPM Mode (VIN-DPM or IN-DPM)
      9. 7.3.9  OUT
      10. 7.3.10 ISET
      11. 7.3.11 TS
      12. 7.3.12 Termination and Timer Disable Mode (TTDM) -TS Pin High
      13. 7.3.13 Timers
      14. 7.3.14 Termination
      15. 7.3.15 Battery Detect Routine
      16. 7.3.16 Refresh Threshold
      17. 7.3.17 Starting a Charge on a Full Battery
    4. 7.4 Device Functional Modes
      1. 7.4.1 Sleep Mode
    5. 7.5 Programming
      1. 7.5.1 PRE_TERM – Precharge and Termination Programmable Threshold
      2. 7.5.2 ISET2
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 BQ2405x Charger Application Design Example
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Program the Fast Charge Current, ISET
          2. 8.2.1.2.2 Program the Termination Current Threshold, ITERM
          3. 8.2.1.2.3 TS Function
          4. 8.2.1.2.4 CHG
          5. 8.2.1.2.5 Selecting IN and OUT Pin Capacitors
        3. 8.2.1.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
      1. 10.3.1 Leakage Current Effects on Battery Capacity
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.12 Termination and Timer Disable Mode (TTDM) -TS Pin High

The battery charger is in TTDM when the TS pin goes high from removing the thermistor (removing battery pack/floating the TS pin) or by pulling the TS pin up to the TTDM threshold.

When entering TTDM, the 10 hour safety timer is held in reset and termination is disabled. A battery detect routine is run to see if the battery was removed or not. If the battery was removed then the CHG pin will go to its high impedance state if not already there. If a battery is detected the CHG pin does not change states until the current tapers to the termination threshold, where the CHG pin goes to its high impedance state if not already there (the regulated output will remain on).

The charging profile does not change (still has precharge, fast-charge constant current and constant voltage modes). This implies the battery is still charged safely and the current is allowed to taper to zero.

When coming out of TTDM, the battery detect routine is run and if a battery is detected, then a new charge cycle begins and the CHG LED turns on.

If TTDM is not desired upon removing the battery with the thermistor, one can add a 237k resistor between TS and VSS to disable TTDM. This keeps the current source from driving the TS pin into TTDM. This creates ≉0.1°C error at hot and a ≉3°C error at cold.