SLUSAL0C September   2011  – January 2020 BQ24725A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 SMBus Interface
    4. 8.4 Device Functional Modes
      1. 8.4.1  Adapter Detect and ACOK Output
      2. 8.4.2  Adapter Over Voltage (ACOVP)
      3. 8.4.3  System Power Selection
      4. 8.4.4  Battery LEARN Cycle
      5. 8.4.5  Enable and Disable Charging
      6. 8.4.6  Automatic Internal Soft-Start Charger Current
      7. 8.4.7  High Accuracy Current Sense Amplifier
      8. 8.4.8  Charge Timeout
      9. 8.4.9  Converter Operation
      10. 8.4.10 Continuous Conduction Mode (CCM)
      11. 8.4.11 Discontinuous Conduction Mode (DCM)
      12. 8.4.12 Input Over Current Protection (ACOC)
      13. 8.4.13 Charge Over Current Protection (CHGOCP)
      14. 8.4.14 Battery Over Voltage Protection (BATOVP)
      15. 8.4.15 Battery Shorted to Ground (BATLOWV)
      16. 8.4.16 Thermal Shutdown Protection (TSHUT)
      17. 8.4.17 EMI Switching Frequency Adjust
      18. 8.4.18 Inductor Short, MOSFET Short Protection
    5. 8.5 Register Maps
      1. 8.5.1 Battery-Charger Commands
      2. 8.5.2 Setting Charger Options
        1. Table 3. Charge Options Register (0x12H)
      3. 8.5.3 Setting the Charge Current
        1. Table 4. Charge Current Register (0x14H), Using 10mΩ Sense Resistor
      4. 8.5.4 Setting the Charge Voltage
        1. Table 5. Charge Voltage Register (0x15H)
      5. 8.5.5 Setting Input Current
        1. Table 6. Input Current Register (0x3FH), Using 10mΩ Sense Resistor
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Typical System with Two NMOS Selector
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Negative Output Voltage Protection
          2. 9.2.1.2.2 Reverse Input Voltage Protection
          3. 9.2.1.2.3 Reduce Battery Quiescent Current
          4. 9.2.1.2.4 Inductor Selection
          5. 9.2.1.2.5 Input Capacitor
          6. 9.2.1.2.6 Output Capacitor
          7. 9.2.1.2.7 Power MOSFETs Selection
          8. 9.2.1.2.8 Input Filter Design
          9. 9.2.1.2.9 BQ24725A Design Guideline
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Simplified System without Power Path
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
    3. 9.3 System Examples
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Third-Party Products Disclaimer
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

8.5.4 Setting the Charge Voltage

To set the output charge regulation voltage, write a 16bit ChargeVoltage() command (0x15H or 0b00010101) using the data format listed in Table 5. The BQ24725A provides charge voltage range from 1.024V to 19.200V, with 16mV step resolution. Sending ChargeVoltage() below 1.024V or above 19.2V clears the register and terminates charging. Upon POR, charge voltage limit is 0V.

The SRN pin is used to sense the battery voltage for voltage regulation and should be connected as close to the battery as possible, and place a decoupling capacitor (0.1µF recommended) as close to the IC as possible to decouple high frequency noise.

Figure 16. Charge Voltage Register (0x15H)
15 14 13 12 11 10 9 8
Not in use Charge Voltage, DACV 10 Charge Voltage, DACV 9 Charge Voltage, DACV 8 Charge Voltage, DACV 7 Charge Voltage, DACV 6 Charge Voltage, DACV 5 Charge Voltage, DACV 4
R/W R/W R/W R/W R/W R/W R/W
7 6 5 4 3 2 1 0
Charge Voltage, DACV 3 Charge Voltage, DACV 2 Charge Voltage, DACV 1 Charge Voltage, DACV 0 Not in use Not in use Not in use Not in use
R/W R/W R/W R/W R/W R/W R/W R/W
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset

Table 5. Charge Voltage Register (0x15H)

Bit Field Type Reset Description
[15] Not in use R/W Not used.
[14] Charge Voltage, DACV 10 R/W 0 = Adds 0mV of charger voltage.
1 = Adds 16384mV of charger voltage.
[13] Charge Voltage, DACV 9 R/W 0 = Adds 0mV of charger voltage.
1 = Adds 8192mV of charger voltage.
[12] Charge Voltage, DACV 8 R/W 0 = Adds 0mV of charger voltage.
1 = Adds 4096mV of charger voltage.
[11] Charge Voltage, DACV 7 R/W 0 = Adds 0mV of charger voltage.
1 = Adds 2048mV of charger voltage.
[10] Charge Voltage, DACV 6 R/W 0 = Adds 0mV of charger voltage.
1 = Adds 1024mV of charger voltage.
[9] Charge Voltage, DACV 5 R/W 0 = Adds 0mV of charger voltage.
1 = Adds 512mV of charger voltage.
[8] Charge Voltage, DACV 4 R/W 0 = Adds 0mV of charger voltage.
1 = Adds 256mV of charger voltage.
[7] Charge Voltage, DACV 3 R/W 0 = Adds 0mV of charger voltage.
1 = Adds 128mV of charger voltage.
[6] Charge Voltage, DACV 2 R/W 0 = Adds 0mV of charger voltage.
1 = Adds 64mV of charger voltage.
[5] Charge Voltage, DACV 1 R/W 0 = Adds 0mV of charger voltage.
1 = Adds 32mV of charger voltage
[4] Charge Voltage, DACV 0 R/W 0 = Adds 0mV of charger voltage.
1 = Adds 16mV of charger voltage.
[3] Not in use R/W Not used.
[2] Not in use R/W Not used.
[1] Not in use R/W Not used.
[0] Not in use R/W Not used.