SLVSGB5 August   2022 TPS56C231

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  PWM Operation and D-CAP3 Control Mode
      2. 7.3.2  Eco-mode Control
      3. 7.3.3  4.7-V LDO
      4. 7.3.4  MODE Selection
      5. 7.3.5  Soft Start and Prebiased Soft Start
      6. 7.3.6  Enable and Adjustable UVLO
      7. 7.3.7  Power Good
      8. 7.3.8  Overcurrent Protection and Undervoltage Protection
      9. 7.3.9  UVLO Protection
      10. 7.3.10 Thermal Shutdown
      11. 7.3.11 Output Voltage Discharge
    4. 7.4 Device Functional Modes
      1. 7.4.1 Light Load Operation
      2. 7.4.2 Standby Operation
  8. 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 External Component Selection
          1. 8.2.2.1.1 Output Voltage Set Point
          2. 8.2.2.1.2 Switching Frequency and MODE Selection
          3. 8.2.2.1.3 Inductor Selection
          4. 8.2.2.1.4 Output Capacitor Selection
          5. 8.2.2.1.5 Input Capacitor Selection
      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
  9. 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
  10. 10Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RNN|18
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.2 Eco-mode Control

The TPS56C231x is designed with Eco-mode control to increase efficiency at light loads. This option can be chosen using the MODE pin as shown in Table 7-2. As the output current decreases from heavy load condition, the inductor current is also reduced. If the output current is reduced enough, the valley of the inductor current reaches the zero level, which is the boundary between continuous conduction and discontinuous conduction modes. The low-side MOSFET is turned off when a zero inductor current is detected. As the load current further decreases, the converter runs into discontinuous conduction mode. The on time is kept approximately the same as it is in continuous conduction mode. The off time increases as it takes more time to discharge the output with a smaller load current. Use Equation 2 to calculate the light load current where the transition to Eco-mode operation happens (IOUT(LL)).

Equation 2. GUID-70356BF3-1DD3-4497-8CE1-137DD7D3E2AE-low.gif

After identifying the application requirements, design the output inductance (LOUT) so that the inductor peak-to-peak ripple current is approximately between 20% and 30% of the IOUT(ma×) (peak current in the application). Size the inductor properly so that the valley current does not hit the negative low-side current limit.