SLUSDJ8A April   2020  – April 2021 BQ25170

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
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Device Power Up from Input Source
        1. 7.3.1.1 ISET Pin Detection
        2. 7.3.1.2 VSET Pin Detection
        3. 7.3.1.3 Charger Power Up
      2. 7.3.2 Battery Charging Features
        1. 7.3.2.1 Lithium-Ion Battery Charging Profile
        2. 7.3.2.2 Charge Termination and Battery Recharge
        3. 7.3.2.3 Charging Safety Timers
        4. 7.3.2.4 Battery Cold, Hot Temperature Qualification (TS Pin)
      3. 7.3.3 Status Outputs ( PG, STAT)
        1. 7.3.3.1 Power Good Indicator (PG Pin)
        2. 7.3.3.2 Charging Status Indicator (STAT)
      4. 7.3.4 Protection Features
        1. 7.3.4.1 Input Overvoltage Protection (VIN OVP)
        2. 7.3.4.2 Output Overvoltage Protection (BAT OVP)
        3. 7.3.4.3 Output Overcurrent Protection (BAT OCP)
        4. 7.3.4.4 Thermal Regulation and Thermal Shutdown (TREG and TSHUT)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown or Undervoltage Lockout (UVLO)
      2. 7.4.2 Sleep Mode
      3. 7.4.3 Active Mode
        1. 7.4.3.1 Standby Mode
      4. 7.4.4 Fault Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Li-Ion Charger Design Example
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 TS Function
        3. 8.2.1.3 Application Curves
      2. 8.2.2 LiFePO4 Charger Design Example
        1. 8.2.2.1 Design Requirements
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.1.1 ISET Pin Detection

After a valid VIN is plugged in, the device checks the resistor on the ISET pin for a short circuit (RISET < RISET_SHORT). If a short condition is detected, the charger remains in the FAULT state until the input or TS pin is toggled. If the ISET pin is open-circuit, the charger proceeds through pin detection and starts the charger with no charge current. This pin is monitored while charging and changes in RISET while the charger is operating will immediately translate to changes in charge current.

An external pulldown resistor (±1% or better recommended to minimize charge current error) from ISET pin to GND sets the charge current as:

Equation 1. GUID-40D0B89F-0D4F-4D54-ACBF-9D822205B48B-low.gif

where

  • ICHG is the desired fast-charge current
  • KISET is a gain factor found in the electrical specifications
  • RISET is the pulldown resistor from ISET pin to GND

For charge currents below 50 mA, an extra RC circuit is recommended on ISET to achieve more stable current signal. For greater accuracy at lower currents, part of the current-sensing FET is disabled to give better resolution.