SLUS756D September   2007  – June 2026 BQ24751A

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
    1. 4.1 Terminal Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 Recommended Operating Conditions
    3. 5.3 Package Thermal Data
    4. 5.4 Electrical Characteristics
    5. 5.5 Typical Charateristics
  7. 6 Detailed Description
    1. 6.1  Functional Block Diagram
    2. 6.2  Battery Voltage Regulation
    3. 6.3  Battery Current Regulation
    4. 6.4  Input Adapter Current Regulation
    5. 6.5  Adapter Detect and Power Up
    6. 6.6  Enable and Disable Charging
    7. 6.7  System Power Selector
    8. 6.8  Battery Learn Cycles
    9. 6.9  Automatic Internal Soft-Start Charger Current
    10. 6.10 Converter Operation
    11. 6.11 Synchronous and Non-Synchronous Operation
    12. 6.12 High Accuracy IADAPT Using Current Sense Amplifier (CSA)
    13. 6.13 Input Overvoltage Protection (ACOV)
    14. 6.14 Input Undervoltage Lock Out (UVLO)
    15. 6.15 Battery Overvoltage Protection
    16. 6.16 Battery Shorted (Battery Undervoltage) Protection
    17. 6.17 Charge Overcurrent Protection
    18. 6.18 Thermal Shutdown Protection
    19. 6.19 Adapter Detected Status Register ( ACGOOD Pin)
    20. 6.20 Input Over-Power Protection (ACOP)
      1. 6.20.1 Conditions for ACOP Latch Off:
  8. 7 Application Information
    1. 7.1 Input Capacitance Calculation
    2. 7.2 PCB Layout Design Guideline
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3 Battery Current Regulation

The SRSET input sets the maximum charge current. Battery current is sensed by resistor RSR connected between SRP and SRN. The full-scale differential voltage between SRP and SRN is 100 mV. Thus, for a 0.010-Ω sense resistor, the maximum charging current is 10 A. SRSET is ratiometric with respect to VDAC using Equation 2:

Equation 2. bq24751A

The input voltage range of SRSET is between 0 and VDAC, up to 3.6 V.

The SRP and SRN pins are used to sense across RSR, with a default value of 10 mΩ. However, resistors of other values can also be used. A larger sense-resistor value yields a larger sense voltage, and a higher regulation accuracy. However, this is at the expense of a higher conduction loss.