SLVSKU8 July   2026 TPS55285A

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 I2C Timing Requirements
    7. 5.7 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  VCC Power Supply
      2. 6.3.2  Default Output Enable (OE) Bit Status
      3. 6.3.3  Input Undervoltage Lockout
      4. 6.3.4  Enable and Programmable UVLO
      5. 6.3.5  Soft Start
      6. 6.3.6  Shutdown and Load Discharge
      7. 6.3.7  Switching Frequency
      8. 6.3.8  Switching Frequency Dithering
      9. 6.3.9  Inductor Current Limit
      10. 6.3.10 Internal Charge Path
      11. 6.3.11 Output Voltage Setting
      12. 6.3.12 Output Current Limit
      13. 6.3.13 Output Cable Voltage Drop Compensation
      14. 6.3.14 Input Overvoltage Protection
      15. 6.3.15 Output Overvoltage Protection
      16. 6.3.16 Output Short-Circuit Protection
      17. 6.3.17 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 PWM Mode
      2. 6.4.2 Power Save Mode
    5. 6.5 Programming
      1. 6.5.1 Data Validity
      2. 6.5.2 START and STOP Conditions
      3. 6.5.3 Byte Format
      4. 6.5.4 Acknowledge (ACK) and Not Acknowledge (NACK)
      5. 6.5.5 Target Address and Data Direction Bit
      6. 6.5.6 Single Read and Write
      7. 6.5.7 Multi-Read and Multi-Write
  8. 7 Register Maps
    1. 7.1 REF Register (Address = 0h, 1h) [reset = 10100100b, 00000001b]
    2. 7.2 IOUT_LIMIT Register (Address = 2h) [reset = 11100100b]
    3. 7.3 VOUT_SR Register (Address = 3h) [reset = 00000001b]
    4. 7.4 VOUT_FS Register (Address = 4h) [reset = 00000011b]
    5. 7.5 CDC Register (Address = 5h) [reset = 11110000b]
    6. 7.6 MODE Register (Address = 6h) [reset = 00100000b]
    7. 7.7 STATUS Register (Address = 7h) [reset = 00000001b]
    8. 7.8 Register Summary
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Switching Frequency
        2. 8.2.2.2 Output Voltage Setting
        3. 8.2.2.3 Inductor Selection
        4. 8.2.2.4 Input Capacitor
        5. 8.2.2.5 Output Capacitor
        6. 8.2.2.6 Output Current Limit
        7. 8.2.2.7 Loop Stability
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

6.4.2 Power Save Mode

The TPS55285A improves the efficiency at light load condition with PFM mode. By enabling the PFM function in the internal register, the TPS55285A works in PFM mode at light load condition. When the TPS55285A operates at light load condition, the output of the internal error amplifier decreases to make the inductor peak current down to deliver less power to the load. When the output current further reduces, the current through the inductor decreases to zero during the switch-off time. When the TPS55285A works in buck mode, after the inductor current becomes zero, the low-side switch of the buck side is turned off to prevent the reverse current from output to ground. When the TPS55285A works in boost mode, once the inductor current becomes zero, the high side-switch of the boost side is turned off to prevent the reverse current from output to input. The TPS55285A resumes switching until the output voltage drops. Thus, PFM mode reduces switching cycles and eliminates the power loss by the reverse inductor current to get high efficiency in light load condition.