SLUSCM1A October   2017  – December 2017

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
    1. 7.1 EN1/EN2 Settings
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Dissipation Ratings
    6. 8.6 Electrical Characteristics
    7. 8.7 Typical Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Undervoltage Lockout (UVLO)
      2. 9.3.2 Power On
      3. 9.3.3 Overvoltage Protection (OVP)
      4. 9.3.4 Dynamic Power-Path Management
        1. 9.3.4.1 Input Source Connected (ADAPTER or USB)
          1. 9.3.4.1.1 Input DPM Mode (VIN-DPM)
          2. 9.3.4.1.2 DPPM Mode
          3. 9.3.4.1.3 Battery Supplement Mode
        2. 9.3.4.2 Input Source Not Connected
      5. 9.3.5 Battery Charging
        1. 9.3.5.1 Charge Current Translator
        2. 9.3.5.2 Battery Detection and Recharge
        3. 9.3.5.3 Battery Disconnect (SYSOFF Input, bq24076, bq24078)
        4. 9.3.5.4 Dynamic Charge Timers (TMR Input)
        5. 9.3.5.5 Status Indicators (PGOOD, CHG)
        6. 9.3.5.6 Thermal Regulation and Thermal Shutdown
      6. 9.3.6 Battery Pack Temperature Monitoring
    4. 9.4 Device Functional Modes
      1. 9.4.1 Sleep Mode
      2. 9.4.2 Explanation of Deglitch Times and Comparator Hysteresis
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 bq2407x Charger Design Example
          1. 10.2.2.1.1 System ON/OFF (SYSOFF) (bq24076 or bq24078 only)
        2. 10.2.2.2 Calculations
          1. 10.2.2.2.1 Program the Fast Charge Current (ISET):
          2. 10.2.2.2.2 Program the Input Current Limit (ILIM)
          3. 10.2.2.2.3 Program 6.25-hour Fast-Charge Safety Timer (TMR)
        3. 10.2.2.3 TS Function
        4. 10.2.2.4 CHG and PGOOD
        5. 10.2.2.5 Selecting IN, OUT, and BAT Pin Capacitors
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Considerations
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Related Links
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Community Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

10 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.

10.1 Application Information

The bq2407x devices power the system while simultaneously and independently charging the battery. The input power source for charging the battery and running the system can be an AC adapter or a USB port. The devices feature dynamic power-path management (DPPM), which shares the source current between the system and battery charging and automatically reduces the charging current if the system load increases. When charging from a USB port, the input dynamic power management (VIN-DPM) circuit reduces the input current limit if the input voltage falls below a threshold, preventing the USB port from crashing. The power-path architecture also permits the battery to supplement the system current requirements when the adapter cannot deliver the peak system currents.

The bq2407x is configurable to be host controlled for selecting different input current limits based on the input source connected, or a fully stand alone device for applications that do not support multiple types of input sources.

10.2 Typical Application

VIN = UVLO to VOVP, IFASTCHG = 800 mA, IIN(MAX) = 1.3 A, Battery Temperature Charge Range = 0°C to 50°C, 6.25-hour Fastcharge Safety Timer

bq24076 bq24078 typ_app_cir_luscm1.gif Figure 26. Using bq24076/bq24078 in a Host-Controlled Charger Application

10.2.1 Design Requirements

  • Supply voltage = 5 V
  • Fast charge current of approximately 800 mA; ISET - pin 16
  • Input current limit = 1.3 A; ILIM - pin 12
  • Termination current threshold = 110 mA; ITERM – pin 15 (bq24074 only)
  • Safety timer duration, Fast-Charge = 6.25 hours; TMR – pin 14
  • TS – Battery Temperature Sense = 10 kΩ NTC (103AT-2)

10.2.2 Detailed Design Procedure

10.2.2.1 bq2407x Charger Design Example

See Figure 26 for a schematic of the design example.

10.2.2.1.1 System ON/OFF (SYSOFF) (bq24076 or bq24078 only)

Connect SYSOFF high to disconnect the battery from the system load. Connect SYSOFF low for normal operation

10.2.2.2 Calculations

10.2.2.2.1 Program the Fast Charge Current (ISET):

RISET = KISET / ICHG

KISET = 890 AΩ from the electrical characteristics table.

RISET = 890 AΩ / 0.8 A = 1.1125 kΩ

Select the closest standard value, which for this case is 1.13 kΩ. Connect this resistor between ISET (pin 16) and VSS.

10.2.2.2.2 Program the Input Current Limit (ILIM)

RILIM = KILIM / II_MAX

KILIM = 1550 AΩ from the electrical characteristics table.

RISET = 1550 AΩ / 1.3 A = 1.192 kΩ

Select the closest standard value, which for this case is 1.18 kΩ. Connect this resistor between ILIM (pin 12) and VSS.

10.2.2.2.3 Program 6.25-hour Fast-Charge Safety Timer (TMR)

RTMR = tMAXCHG / (10 × KTMR )

KTMR = 48 s/kΩ from the electrical characteristics table.

RTMR = (6.25 hr × 3600 s/hr) / (10 × 48 s/kΩ) = 46.8 kΩ

Select the closest standard value, which for this case is 46.4 kΩ. Connect this resistor between TMR (pin 2) and VSS.

10.2.2.3 TS Function

Use a 10-kΩ NTC thermistor in the battery pack (103AT-2). For applications that do not require the TS monitoring function, connect a 10-kΩ resistor from TS to VSS to set the TS voltage at a valid level and maintain charging.

10.2.2.4 CHG and PGOOD

LED Status: Connect a 1.5-kΩ resistor in series with a LED between OUT and CHG to indicate charging status. Connect a 1.5-kΩ resistor in series with a LED between OUT and PGOOD to indicate when a valid input source is connected.

Processor Monitoring Status: Connect a pullup resistor (on the order of 100 kΩ) between the power rail of the processor and CHG and PGOOD.

10.2.2.5 Selecting IN, OUT, and BAT Pin Capacitors

In most applications, all that is needed is a high-frequency decoupling capacitor (ceramic) on the power pin, input, output and battery pins. Using the values shown on the application diagram, is recommended. After evaluation of these voltage signals with real system operational conditions, one can determine if capacitance values can be adjusted toward the minimum recommended values (DC load application) or higher values for fast high amplitude pulsed load applications. Note if designed high input voltage sources (bad adaptors or wrong adaptors), the capacitor needs to be rated appropriately. Ceramic capacitors are tested to 2x their rated values so a 16-V capacitor may be adequate for a 30-V transient (verify tested rating with capacitor manufacturer).

10.2.3 Application Curves

bq24076 bq24078 bat_conn_lus810.gif
RLOAD = 10 Ω
Figure 27. Adapter Plug-In
Battery Connected
bq24076 bq24078 hot_plug2_lus810.gif
Figure 29. Battery Detection
Battery Removed
bq24076 bq24078 batt_mode_lus810.gif
RLOAD = 25 Ω to 4.5 Ω
Figure 31. Entering and Exiting Battery Supplement Mode
bq24076 bq24078 on_off_chgr_lus810.gif
Figure 33. Charger ON/OFF Using CE
bq24076 bq24078 system_of6v_lus810.gif
VIN = 6 V
Figure 35. System ON/OFF With Input Connected
bq24076, bq24078
bq24076 bq24078 hot_plug_lus810.gif
Figure 28. Battery Detection
Battery Inserted
bq24076 bq24078 dppm_mode_lus810.gif
RLOAD = 20 Ω to 9 Ω
Figure 30. Entering and Exiting DPPM Mode
bq24076 bq24078 supp_mode_luscm1.gif
RLOAD = 20 Ω to 4.5 Ω
Figure 32. Entering and Exiting Battery Supplement Mode
bq24076 bq24078 ovp_fault_lus810.gif
VIN = 6 V to 15 V RLOAD = 10 Ω
Figure 34. OVP Fault
bq24076 bq24078 system_of0v_lus810.gif
VIN = 0 V
Figure 36. System ON/OFF With Input Not Connected
bq24076, bq24078