SLUS999A November   2009  – November 2015

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (Continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 SMB Timing Requirements
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Adapter Detect and Power Up
      2. 8.3.2  Enable and Disable Charging
      3. 8.3.3  Automatic Internal Soft-Start Charger Current
      4. 8.3.4  Switching Frequency
      5. 8.3.5  Converter Operation
      6. 8.3.6  Refresh BTST Capacitor
      7. 8.3.7  UCP (Charge Undercurrent): Using Sense Resistor
      8. 8.3.8  Cycle-By-Cycle Charge Overcurrent Protection, Using High-Side Sense-FET
      9. 8.3.9  Average Charge Overcurrent Protection, Using Sense Resistor
      10. 8.3.10 Battery Overvoltage Protection, Using Remote Sensing VFB
      11. 8.3.11 Battery Short Protection
      12. 8.3.12 Battery Trickle Charging
      13. 8.3.13 High Accuracy VICM Using Current Sense Amplifier (CSA)
      14. 8.3.14 VDDSMB Input Supply
      15. 8.3.15 Input Undervoltage Lockout (UVLO)
      16. 8.3.16 VDDP Gate Drive Regulator
      17. 8.3.17 Input Current Comparator Trip Detection
      18. 8.3.18 Open-Drain Status Outputs (ACOK, ICOUT Pins)
      19. 8.3.19 Thermal Shutdown Protection
      20. 8.3.20 Charger Timeout
      21. 8.3.21 Charge Termination For Li-Ion or Li-Polymer
      22. 8.3.22 Remote Sense
    4. 8.4 Device Functional Modes
      1. 8.4.1 Continuous Conduction Mode and Discontinuous Conduction Mode
    5. 8.5 Programming
      1. 8.5.1 Battery-Charger Commands
        1. 8.5.1.1 SMBus Interface
      2. 8.5.2 Battery Voltage Regulation
      3. 8.5.3 Battery Current Regulation
      4. 8.5.4 Input Adapter Current Regulation
    6. 8.6 Register Maps
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
      2. 12.1.2 Device Nomenclature
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

9.1 Application Information

The bq24765EVM-349 evaluation module (EVM) is a complete charger module for evaluating the bq24765. The application curves were taken using the bq24765EVM-349. Refer to the bq24765 EVM (HPA349) User's Guide, SLUU415 for EVM information.

9.2 Typical Application

bq24765 typ_app5_lus999.gif
VIN = 20 V, VBAT = 4-cell Li-Ion, ICHARGE = 4.5 A, Idpm = 5 A
Figure 17. Typical System Schematic, Using Internal Input Current Comparator

9.2.1 Design Requirements

For this design example, use the parameters listed in Table 6.

Table 6. Design Parameters

DESIGN PARAMETER EXAMPLE VALUE
Input Voltage(1) 17.7 V < Adapter Voltage < 24 V
Input Current Limit(1) 3.2 A for 65 W adapter
Battery Charge Voltage(2) 12592 mV for 3s battery
Battery Charge Current(2) 4096 mA for 3s battery
Battery Discharge Current(2) 6144 mA for 3s battery
(1) Refer to adapter specification for Input Voltage and Input Current Limit.
(2) Refer to battery specification for settings.

9.2.2 Detailed Design Procedure

The parameters are configurable using the evaluation software, SLVC309. The simplified application circuit (see Figure 17) shows the minimum capacitance requirements for each pin. Inductor, capacitor, and MOSFET selection are explained in the rest of this section. Refer to the bq24765 EVM (HPA349) User's Guide, SLUU415 for the full application schematic.

Table 7. Component List For Typical System Circuit of bq24765

PART DESIGNATOR Qty DESCRIPTION
Q1, Q2, Q6 3 P-channel MOSFET, –30 V, –7.5 A, SO-8, Vishay-Siliconix, Si4835
RAC, RSR 2 Sense Resistor, 10 mΩ, 1 W, 2010, Vishay-Dale, WSL2010R0100F
L1 1 Inductor, 2.2 µH, 8 A, 20 mΩ, Vishay, IHLP2525CZ01-2R2
4xC2, 2xC9, 3xC13 9 Capacitor, Ceramic, 10 µF, 35 V, 20%, X5R, 1206, Panasonic, ECJ-3YB1E106M
C1 1 Capacitor, Ceramic, 2.2 µF, 25 V, 1210
C3, C7, C11 3 Capacitor, Ceramic, 1 µF, 25 V, 10%, X7R, 2012, TDK, C2012X7R1E105K
C6 1 Capacitor, Ceramic, 0.47 µF, 25 V, 0805
C4, C5, C10, C11, C12, C13, C15 7 Capacitor, Ceramic, 0.1 µF, 50 V, 10%, X7R, 0805, Kemet, C0805C104K5RACTU
C8 1 Capacitor, Ceramic, 100 pF, 25 V, 10%, X7R, 0805, Kemet
C16 1 Capacitor, Ceramic, 51 pF, 25 V, 10%, X7R, 0805, Kemet
C17 1 Capacitor, Ceramic, 2000 pF, 25 V, 10%, X7R, 0805, Kemet
C18 1 Capacitor, Ceramic, 130 pF, 25 V, 10%, X7R, 0805, Kemet
RC1 1 Resistor, thick film chip paralleling, 2x3.9 Ω, 25 V, 1210
RC6 1 Resistor, thick film chip, 20 Ω, 0805
R3, R4, R5, R6, R7 5 Resistor, Chip, 10 kΩ, 1/16 W, 5%, 0402
R1 1 Resistor, Chip, 309 kΩ, 1/16 W, 1%, 0402
R2 1 Resistor, Chip, 49.9 kΩ, 1/16 W, 1%, 0402
R8 1 Resistor, Chip, 51.1 kΩ, 1/16 W, 1%, 0402
R9 1 Resistor, Chip, 17.4 kΩ, 1/16 W, 1%, 0402
R10 1 Resistor, Chip, 7.5 kΩ, 1/16 W, 5%, 0402
R11 1 Resistor, Chip, 4.7 kΩ, 1/16 W, 5%, 0402
R12 1 Resistor, Chip, 200 kΩ, 1/16 W, 5%, 0402
R13 1 Resistor, Chip, 1.4 MegΩ, 1/16 W, 1%, 0402

9.2.3 Application Curves

bq24765 G12_lus999.gif Figure 18. Transient System Load (DPM) Response: Charge Current Dropped From 4A to 2A
bq24765 G14_lus999.gif Figure 20. Charger When Adapter Inserted
bq24765 G16_lus999.gif Figure 22. Inductor Current and Battery Current Soft-Start
bq24765 G18_lus999.gif Figure 24. Discontinuous Conduction Mode (DCM) Switching Waveforms
bq24765 G20_lus999.gif Figure 26. Battery Removal (From Constant Current Mode)
bq24765 G22_lus999.gif Figure 28. Power FET Overcurrent Protection
bq24765 G24_lus999.gif Figure 30. Thermal Regulation at TA = 40°C
bq24765 G13_lus999.gif Figure 19. Transient System Load (DPM) Response: Charge Current Dropped From 4A to 0A
bq24765 G15_lus999.gif Figure 21. Charger When Adapter Removed
bq24765 G17_lus999.gif Figure 23. Continuous Conduction Mode (CCM) Switching Waveforms
bq24765 G19_lus999.gif Figure 25. Near 100% Duty Cycle Bootstrap Recharge Pulse
bq24765 G21_lus999.gif Figure 27. Battery Shorted Charger Response, Reset Charger
bq24765 G23_lus999.gif Figure 29. Charge Overcurrent Protection
bq24765 G25_lus999.gif Figure 31. Charge Current vs Free-Air Temperature