SPVA059 June   2026 BQ21080 , BQ21088 , BQ24070 , BQ24071 , BQ24072 , BQ24073 , BQ24074 , BQ24075 , BQ24076 , BQ24078 , BQ24079 , BQ25150 , BQ25155 , BQ25157 , BQ25170 , BQ25170J , BQ25171-Q1 , BQ25172 , BQ25173 , BQ25173-Q1 , BQ25175 , BQ25176J , BQ25176K , BQ25176M , BQ25180 , BQ25185 , BQ25186 , BQ25188 , BQ25190

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Design Procedure
    1. 2.1 Step-by-Step Calculation Method
  6. 3Design Examples
    1. 3.1 Example 1: BQ25190 with Standard NTC Beta Value, 10°C to 45°C
    2. 3.2 Example 2: BQ25188 with Different NTC Beta Value, 0°C to 45°C
    3. 3.3 Example 3: BQ25170 with Standard NTC Beta Value, -10°C to 60°C
  7. 4Error Analysis
    1. 4.1 Worst-Case Analysis Method
    2. 4.2 Example: Worst-Case Error Analysis for BQ25190, 10°C to 45°C
  8. 5NTC Thermistor Modeling
  9. 6Summary
  10. 7References

Abstract

This application note explains how to design the external TS pin network for battery chargers with current-based battery NTC temperature sensing. It is intended for system designers implementing battery temperature monitoring and applies when a specific charging profile is required for the battery that cannot be achieved through device configuration alone, or when the battery pack NTC thermistor does not match the type of NTC the charger was designed for, a 10kΩ at 25°C with β(25/85°C)=3435K. This application note presents a method to calculate the required series and parallel compensation resistors, verify the resulting temperature thresholds, and evaluate worst-case trip temperatures across component and device tolerances.