SLUSCM2B October   2017  – November 2018

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Typical Application Circuit
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Device Comparison Table
  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 Power On
      3. 9.3.3 Overvoltage Protection (OVP)
      4. 9.3.4 Dynamic Power-path Management
        1. 9.3.4.1 Input Source Connected (Adapter or USB)
          1. 9.3.4.1.1 Input DPM Mode (VIN-DPM)
          2. 9.3.4.1.2 DPPM Mode
          3. 9.3.4.1.3 Battery Supplement Mode
        2. 9.3.4.2 Input Source Not Connected
      5. 9.3.5 Battery Charging
        1. 9.3.5.1 Charge Current Translator
        2. 9.3.5.2 Battery Detection And Recharge
        3. 9.3.5.3 Battery Disconnect (SYSOFF Input)
        4. 9.3.5.4 Dynamic Charge Timers (TMR Input)
        5. 9.3.5.5 Status Indicators (PGOOD, CHG)
        6. 9.3.5.6 Thermal Regulation And Thermal Shutdown
      6. 9.3.6 Battery Pack Temperature Monitoring
      7. 9.3.7 Half-Wave Adaptors
    4. 9.4 Device Functional Modes
      1. 9.4.1 Sleep Mode
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application – bq24079QW-Q1 Charger Design Example
      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 Input Current Limit (ILIM)
          3. 10.2.2.1.3 Program 6.25-hour Fast-Charge Safety Timer (TMR)
        2. 10.2.2.2 TS Function
        3. 10.2.2.3 CHG and PGOOD
        4. 10.2.2.4 System ON/OFF (SYSOFF)
        5. 10.2.2.5 Selecting In, Out And Bat Pin Capacitors
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
  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 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Community Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RGT|16
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.3.6 Battery Pack Temperature Monitoring

The bq24079QW-Q1 features an external battery pack temperature monitoring input. The TS input connects to the NTC thermistor in the battery pack to monitor battery temperature and prevent dangerous over-temperature conditions. During charging, INTC is sourced to TS and the voltage at TS is continuously monitored. If, at any time, the voltage at TS is outside of the operating range (VCOLD to VHOT), charging is suspended. The timers maintain their values but suspend counting. When the voltage measured at TS returns to within the operation window, charging is resumed and the timers continue counting. When charging is suspended due to a battery pack temperature fault, the CHG pin remains low and continues to indicate charging.

For applications that do not require the TS monitoring function, connect a 10 kΩ resistor from TS to VSS to set the TS voltage at a valid level and maintain charging.

The allowed temperature range for 103AT-2 type thermistor is 0°C to 50°C. However, the user may increase the range by adding two external resistors. See Figure 25 for the circuit details. The values for Rs and Rp are calculated using the following equations:

Equation 6. bq24079QW-Q1 EQ2_rs_lus810.gif
Equation 7. bq24079QW-Q1 EQ3_rp_lus810.gif

Where:

RTH: Thermistor Hot Trip Value found in thermistor data sheet
RTC: Thermistor Cold Trip Value found in thermistor data sheet
VH: IC's Hot Trip Threshold = 0.3 V nominal
VC: IC's Cold Trip Threshold = 2.1 V nominal
ITS: IC's Output Current Bias = 75 µA nominal
NTC Thermsitor Semitec 103AT-4

Rs and Rp 1% values were chosen closest to calculated values

COLD TEMP RESISTANCE AND TRIP THRESHOLD, Ω (°C) HOT TEMP RESISTANCE AND TRIP THRESHOLD, Ω (°C) EXTERNAL BIAS RESISTOR, Rs (Ω) EXTERNAL BIAS RESISTOR, Rp (Ω)
28000 (–0.6) 4000 (51) 0 ∞
28480 (–1) 3536 (55) 487 845000
28480 (–1) 3021 (60) 1000 549000
33890 (–5) 4026 (51) 76.8 158000
33890 (–5) 3536 (55) 576 150000
33890 (–5) 3021 (60) 1100 140000

RHOT and RCOLD are the thermistor resistance at the desired hot and cold temperatures, respectively.

NOTE

Note that the temperature window cannot be tightened more than using only the thermistor connected to TS, it can only be extended.
bq24079QW-Q1 ts_circuit_luscm2.gifFigure 25. Extended TS Pin Thresholds