SLUSA76B December   2010  – January 2015

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Typical Application Schematic
  5. 5 Revision History
  6. 6 Pin Configuration and 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 Input Voltage-Based Dynamic Power Management (VBUS-DPM)
      2. 8.3.2 CHG Pin Indication
      3. 8.3.3 CHG and PG LED Pull-Up Source
      4. 8.3.4 Power Good Indication (PG)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Power-Down or Undervoltage Lockout (UVLO)
      2. 8.4.2 Operation Mode Detection and Transition
      3. 8.4.3 Sleep Mode
      4. 8.4.4 Load Mode
      5. 8.4.5 Charge Mode
        1. 8.4.5.1  Overvoltage Protection (OVP) - Continuously Monitored
        2. 8.4.5.2  Power Up
        3. 8.4.5.3  Battery Detect Routine
        4. 8.4.5.4  New Charge Cycle
        5. 8.4.5.5  BAT Output
        6. 8.4.5.6  Fast Charge Current (IOUT)
        7. 8.4.5.7  Termination
        8. 8.4.5.8  Timers
        9. 8.4.5.9  Battery Temperature Monitoring
        10. 8.4.5.10 Limited Power Charge Mode - TS Pin High
      6. 8.4.6 Suspend Mode
  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
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Trademarks
    3. 12.3 Electrostatic Discharge Caution
    4. 12.4 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

9.1 Application Information

Although it can be powered from low impedance sources like a USB port or wall adapter, this IC's VBUS-DPM feature makes it ideal to be powered from high impedance sources like solar panels or inductor charging pads.

9.2 Typical Application

sys_sch_lusa76.gifFigure 13. Typical System Schematic

9.2.1 Design Requirements

A solar panel with VOC = 6 V in direct sunlight and capable of up to 1 W of output power is available to charge a 500 mAHr LiIon battery at a 1C rate. Because the light itensity will vary over time, this application uses the IC in battery tracking mode. The IC will never use load mode so EN is tied to PG.

9.2.2 Detailed Design Procedure

The minimum recommend capacitors of 1 µF for VBUS and BAT are used. The pullup resistors for CHG and PG are 2 kΩ.

Using RISET = KISET / IOUT and set IOUT = IC = 500mA gives RISET = 390 AΩ / 500 mA = 780 Ω → 787 Ω closest 1% resistor.

Using Equation 3 and finding RTH(45) from the 103AT-4 thermistor datasheet as 4911 Ω, RT1 = 1 / (0.186) * 4911 Ω - 4911 Ω = 21.492 kΩ → 21.5 kΩ closest 1% resistor.

For battery tracking mode, we leave VDPM floating. If we decided to power the charger using a 5-V wall adapter that a minimum output voltage of 4.6 V, we would size a resistor VDPM to ground using RVDPM = (VBUS_DPM – VBUS_DPM_1)/KVBUS_DPM= (4.6 V - 3.5 V) / ( 0.15 V/kΩ) = 7.333 kΩ → 7.32 kΩ closest 1% resistor.

9.2.3 Application Curves

bq24210-pg=en-tracking-ramp-2p7v-solar.pngFigure 14. Accelerated Charge Cycle Using Solar Panel Input Source
bq24210-pg-vtsb-5Vtriagramp-10ohm-series.png
Figure 15. Power Up / Power Down