SLUSCK5 March   2017


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Description (continued)
  6. Pin Configuration and Functions
  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 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Power-On-Reset (POR)
      2. 8.3.2  Device Power Up from Battery without Input Source
      3. 8.3.3  Power Up from Input Source
        1. Power Up REGN Regulation
        2. Poor Source Qualification
        3. Input Source Type Detection
          1. PSEL Pins Sets Input Current Limit in bq25601
        4. Input Voltage Limit Threshold Setting (VINDPM Threshold)
        5. Converter Power-Up
      4. 8.3.4  Boost Mode Operation From Battery
      5. 8.3.5  Host Mode and Standalone Power Management
        1. Host Mode and Default Mode in bq25601
      6. 8.3.6  Power Path Management
      7. 8.3.7  Battery Charging Management
        1.  Autonomous Charging Cycle
        2.  Battery Charging Profile
        3.  Charging Termination
        4.  Thermistor Qualification
        5.  JEITA Guideline Compliance During Charging Mode
        6.  Boost Mode Thermistor Monitor during Battery Discharge Mode
        7.  Charging Safety Timer
        8.  Narrow VDC Architecture
        9.  Dynamic Power management
        10. Supplement Mode
      8. 8.3.8  Shipping Mode and QON Pin
        1. BATFET Disable Mode (Shipping Mode)
        2. BATFET Enable (Exit Shipping Mode)
        3. BATFET Full System Reset
        4. QON Pin Operations
      9. 8.3.9  Status Outputs (PG, STAT, INT)
        1. Power Good indicator (PG Pin and PG_STAT Bit)
        2. Charging Status indicator (STAT)
        3. Interrupt to Host (INT)
      10. 8.3.10 Protections
        1. Voltage and Current Monitoring in Converter Operation
          1. Voltage and Current Monitoring in Buck Mode
            1. Input Overvoltage (ACOV)
            2. System Overvoltage Protection (SYSOVP)
        2. Voltage and Current Monitoring in Boost Mode
          1. VBUS Soft Start
          2. VBUS Output Protection
          3. Boost Mode Overvoltage Protection
        3. Thermal Regulation and Thermal Shutdown
          1. Thermal Protection in Buck Mode
          2. Thermal Protection in Boost Mode
        4. Battery Protection
          1. Battery overvoltage Protection (BATOVP)
          2. Battery Over-Discharge Protection
          3. System Over-Current Protection
      11. 8.3.11 Serial interface
        1. Data Validity
        2. START and STOP Conditions
        3. Byte Format
        4. Acknowledge (ACK) and Not Acknowledge (NACK)
        5. Slave Address and Data Direction Bit
        6. Single Read and Write
        7. Multi-Read and Multi-Write
    4. 8.4 Register Maps
      1. 8.4.1  REG00
      2. 8.4.2  REG01
      3. 8.4.3  REG02
      4. 8.4.4  REG03
      5. 8.4.5  REG04
      6. 8.4.6  REG05
      7. 8.4.7  REG06
      8. 8.4.8  REG07
      9. 8.4.9  REG08
      10. 8.4.10 REG09
      11. 8.4.11 REG0A
      12. 8.4.12 REG0B
  9. Application and Implementation
    1. 9.1 Application information
    2. 9.2 Typical Application Diagram
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. inductor Selection
        2. input Capacitor
        3. Output Capacitor
  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 Links
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

Application and Implementation


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.

Application information

A typical application consists of the device configured as an I2C controlled power path management device and a single cell battery charger for Li-Ion and Li-polymer batteries used in a wide range of smart phones and other portable devices. It integrates an input reverse-block FET (RBFET, Q1), high-side switching FET (HSFET, Q2), low-side switching FET (LSFET, Q3), and battery FET (BATFET Q4) between the system and battery. The device also integrates a bootstrap diode for the high-side gate drive.

Typical Application Diagram

bq25601 AppD_bq25601_SLUSCK5.gif Figure 28. Power Path Management Application

Design Requirements

Detailed Design Procedure

inductor Selection

The 1.5-MHz switching frequency allows the use of small inductor and capacitor values to maintain an inductor saturation current higher than the charging current (ICHG) plus half the ripple current (IRIPPLE):

Equation 3. ISAT ≥ ICHG + (1/2) IRIPPLE

The inductor ripple current depends on the input voltage (VVBUS), the duty cycle (D = VBAT/VVBUS), the switching frequency (fS) and the inductance (L).

Equation 4. bq25601 Equation_04_SLUSCJ4.gif

The maximum inductor ripple current occurs when the duty cycle (D) is 0.5 or approximately 0.5. Usually inductor ripple is designed in the range between 20% and 40% maximum charging current as a trade-off between inductor size and efficiency for a practical design.

input Capacitor

Design input capacitance to provide enough ripple current rating to absorb input switching ripple current. The worst case RMS ripple current is half of the charging current when duty cycle is 0.5. If the converter does not operate at 50% duty cycle, then the worst case capacitor RMS current ICin occurs where the duty cycle is closest to 50% and can be estimated using Equation 5.

Equation 5. bq25601 Equation_05_SLUSCJ4.gif

Low ESR ceramic capacitor such as X7R or X5R is preferred for input decoupling capacitor and should be placed to the drain of the high-side MOSFET and source of the low-side MOSFET as close as possible. Voltage rating of the capacitor must be higher than normal input voltage level. A rating of 25-V or higher capacitor is preferred for 15 V input voltage. Capacitance of 22-μF is suggested for typical of 3A charging current.

Output Capacitor

Ensure that the output capacitance has enough ripple current rating to absorb the output switching ripple current. Equation 6 shows the output capacitor RMS current ICOUT calculation.

Equation 6. bq25601 Equation_06_SLUSCJ4.gif

The output capacitor voltage ripple can be calculated as follows:

Equation 7. bq25601 Equation_07_SLUSCJ4.gif

At certain input and output voltage and switching frequency, the voltage ripple can be reduced by increasing the output filter LC.

The charger device has internal loop compensation optimized for >20μF ceramic output capacitance. The preferred ceramic capacitor is 10V rating, X7R or X5R.