SLUUCR0A September   2023  – December 2023

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specifications
    4. 1.4 Device Information
  8. 2Hardware
    1. 2.1 I/O Information
    2. 2.2 Jumper Information
    3. 2.3 Equipment
    4. 2.4 Hardware Setup
  9. 3Software
    1. 3.1 Software Setup
    2. 3.2 Test Procedure
      1. 3.2.1 Initial Power Up
      2. 3.2.2 I2C Register Communication Verification
      3. 3.2.3 Charger Mode Verification
      4. 3.2.4 Boost Mode Verification
      5. 3.2.5 Helpful Tips
  10. 4Hardware Design Files
    1. 4.1 Schematic
    2. 4.2 PCB Layout
      1. 4.2.1 PCB Layout Guidelines
    3. 4.3 Bill of Materials (BOM)
  11. 5Additional Information
    1.     Trademarks
  12. 6Revision History

3.2.5 Helpful Tips

  1. The leads and cables to the various power supplies, batteries and loads have resistance. The current meters also have series resistance. The charger dynamically reduces charge current depending on the voltage sensed at the VBUS pin (using the VINDPM feature), BAT pin (as part of normal termination), and TS pin (through the battery temperature monitoring feature via battery thermistor). Therefore, voltmeters must be used to measure the voltage as close to the IC pins as possible instead of relying on the digital readouts of the power supply. If a battery thermistor is not available, then that shunts JP11 and JP13 in place.
  2. When using a source meter that can source and sink current as your battery simulator, TI highly recommends adding a large (>=1000+ μF) capacitor at the EVM BATTERY and GND connector to prevent oscillations at the BAT pin due to mismatched impedances of the charger output and source meter input within their respective regulation loop bandwidths. Configuring the source meter for 4-wire sensing eliminates the need for a separate voltmeter to measure the voltage at the BAT pin. When using 4-wire sensing, always make sure that the sensing leads are properly connected to prevent accidental overvoltage by the power leads.
  3. For precise measurements of input and output current, especially near termination, the current meter in series with the battery or battery simulator must not be set to auto-range and needs to be removed entirely. An alternate method for measuring charge current is to either use an oscilloscope with hall effect current probe or by a differential voltage measurement across the relevant sensing resistors populated on the BQ25638xEVM.