SLUSBC1B September   2013  – December 2016

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 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 Device Power Up
        1. 8.3.1.1 Power-On-Reset (POR)
        2. 8.3.1.2 Power Up from Battery without DC Source
          1. 8.3.1.2.1 BATFET Turn Off
          2. 8.3.1.2.2 Shipping Mode
        3. 8.3.1.3 Boost Mode Operation from Battery
          1. 8.3.1.3.1 Integrated Control to Switch Between USB Charge Mode and Boost Mode
        4. 8.3.1.4 Power Up from DC Source
          1. 8.3.1.4.1 REGN LDO
          2. 8.3.1.4.2 Input Source Qualification
          3. 8.3.1.4.3 Input Current Limit Detection
          4. 8.3.1.4.4 D+/D- Detection Sets Input Current Limit
          5. 8.3.1.4.5 Force Input Current Limit Detection
        5. 8.3.1.5 Converter Power-Up
        6. 8.3.1.6 Low Power HIZ State
      2. 8.3.2 Power Path Management
        1. 8.3.2.1 Narrow VDC Architecture
        2. 8.3.2.2 Dynamic Power Management
        3. 8.3.2.3 Supplement Mode
      3. 8.3.3 Battery Charging Management
        1. 8.3.3.1 Autonomous Charging Cycle
        2. 8.3.3.2 Battery Charging Profile
        3. 8.3.3.3 Thermistor Qualification
          1. 8.3.3.3.1 Cold/Hot Temperature Window
        4. 8.3.3.4 Charging Termination
          1. 8.3.3.4.1 Termination When REG02[0] = 1
        5. 8.3.3.5 Charging Safety Timer
          1. 8.3.3.5.1 Safety Timer Configuration Change
      4. 8.3.4 Status Outputs (STAT, and INT)
        1. 8.3.4.1 Charging Status Indicator (STAT)
        2. 8.3.4.2 Interrupt to Host (INT)
      5. 8.3.5 Protections
        1. 8.3.5.1 Input Current Limit on ILIM
        2. 8.3.5.2 Thermal Regulation and Thermal Shutdown
        3. 8.3.5.3 Voltage and Current Monitoring in Buck Mode
          1. 8.3.5.3.1 Input Over-Voltage (ACOV)
          2. 8.3.5.3.2 System Over-Voltage Protection (SYSOVP)
        4. 8.3.5.4 Current Monitoring in Boost Mode
        5. 8.3.5.5 Battery Protection
          1. 8.3.5.5.1 Battery Over-Voltage Protection (BATOVP)
          2. 8.3.5.5.2 Battery Short Protection
          3. 8.3.5.5.3 System Over-Current Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Host Mode and Default Mode
    5. 8.5 Programming
      1. 8.5.1 Serial Interface
        1. 8.5.1.1 Data Validity
        2. 8.5.1.2 START and STOP Conditions
        3. 8.5.1.3 Byte Format
        4. 8.5.1.4 Acknowledge (ACK) and Not Acknowledge (NACK)
        5. 8.5.1.5 Slave Address and Data Direction Bit
          1. 8.5.1.5.1 Single Read and Write
          2. 8.5.1.5.2 Multi-Read and Multi-Write
    6. 8.6 Register Map
      1. 8.6.1 I2C Registers
        1. 8.6.1.1  Input Source Control Register REG00 [reset = 01011000, or 0x58]58 to 0x58 in heading
        2. 8.6.1.2  Power-On Configuration Register REG01 [reset = 0011101100011011 to 00111011 and 0x1B to 0x3B in heading, or 0x3B]
        3. 8.6.1.3  Charge Current Control Register REG02 [reset = 00100000, or 0x20]
        4. 8.6.1.4  Pre-Charge/Termination Current Control Register REG03 [reset = 00010001, or 0x11]
        5. 8.6.1.5  Charge Voltage Control Register REG04 [reset = 10110010, or 0xB2]
        6. 8.6.1.6  Charge Termination/Timer Control Register REG05 [reset = 10011100, or 0x9C]
        7. 8.6.1.7  Boost Voltage/Thermal Regulation Control Register REG06 [reset = 10010011, or 0x93]
        8. 8.6.1.8  Misc Operation Control Register REG07 [reset = 01001011, or 0x4B4B to 0x4B in heading ]
        9. 8.6.1.9  System Status Register REG08
        10. 8.6.1.10 New Fault Register REG09
        11. 8.6.1.11 Vender / Part / Revision Status Register REG0A
  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
        1. 9.2.2.1 Inductor Selection
        2. 9.2.2.2 Input Capacitor
        3. 9.2.2.3 Output Capacitor
      3. 9.2.3 Application Performance Plots
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    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

5 Description (Continued)

Its low impedance power path optimizes switch-mode operation efficiency, reduces battery charging time and extends battery life during discharging phase. The I2C serial interface with charging and system settings makes the device a truly flexible solution.

The device supports 3.9V – 6.2V USB input sources, including standard USB host port and USB charging port with 6.4V over-voltage protection. The bq24295 is compliant with USB 2.0 and USB 3.0 power specifications with input current and voltage regulation. To set the default input current limit, the bq24295 detects the input source through D+/D- detection following the USB battery charging spec 1.2. In addition, the bq24295 detects non-standard 2A/1A adapters. The bq24295 supports battery boost operation by supplying adjustable voltage 4.55 – 5.5V (default 5.1V) on PMID pin with minimum current of 1.5A.

The power path management regulates the system slightly above battery voltage but does not drop below 3.5V minimum system voltage (programmable). With this feature, the system maintains operation even when the battery is completely depleted or removed. When the input current limit or voltage limit is reached, the power path management automatically reduces the charge current to zero. As the system load continues to increase, the power path discharges the battery until the system power requirement is met. This supplement mode operation prevents overloading the input source.

The devices initiate and complete a charging cycle without software control. It automatically detects the battery voltage and charges the battery in three phases: pre-conditioning, constant current and constant voltage. At the end of the charging cycle, the charger automatically terminates when the charge current is below a preset limit in the constant voltage phase. When the full battery falls below the recharge threshold, the charger will automatically start another charging cycle.

The devices provide various safety features for battery charging and system operation, including negative thermistor monitoring, charging safety timer and over-voltage/over-current protections. The thermal regulation reduces charge current when the junction temperature exceeds 120°C (programmable).

The STAT output reports the charging status and any fault conditions. The INT immediately notifies the host when a fault occurs.

The bq24295 is available in a 24-pin, 4x4 mm2 thin VQFN package.