SLVSES3A February   2021  – March 2021 TPS62903

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 Mode Selection and Device Configuration MODE/S-CONF
      2. 7.3.2 Adjustable VO Operation (External Voltage Divider)
      3. 7.3.3 Setable VO Operation (VSET and Internal Voltage Divider)
      4. 7.3.4 Soft Start / Tracking (SS/TR)
      5. 7.3.5 Smart Enable with Precise Threshold
      6. 7.3.6 Power Good (PG)
      7. 7.3.7 Undervoltage Lockout (UVLO)
      8. 7.3.8 Current Limit And Short Circuit Protection
      9. 7.3.9 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Pulse Width Modulation (PWM) Operation
      2. 7.4.2 AEE (Automatic Efficiency Enhancement)
      3. 7.4.3 Power Save Mode Operation (Auto PFM/PWM)
      4. 7.4.4 100% Duty-Cycle Operation
      5. 7.4.5 Output Discharge Function
      6. 7.4.6 Starting into a Pre-Biased Load
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application with Adjustable Output Voltage
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Programming the Output Voltage
        3. 8.2.2.3 External Component Selection
        4. 8.2.2.4 Inductor Selection
        5. 8.2.2.5 Capacitor Selection
          1. 8.2.2.5.1 Output Capacitor
          2. 8.2.2.5.2 Input Capacitor
          3. 8.2.2.5.3 Soft-Start Capacitor
        6. 8.2.2.6 Tracking Function
        7. 8.2.2.7 Output Filter and Loop Stability
      3. 8.2.3 Application Curves
      4. 8.2.4 Typical Application with Setable VO using VSET
        1. 8.2.4.1 Design Requirements
        2. 8.2.4.2 Detailed Design Procedure
        3. 8.2.4.3 Application Curves
    3. 8.3 System Examples
      1. 8.3.1 LED Power Supply
      2. 8.3.2 Powering Multiple Loads
      3. 8.3.3 Voltage Tracking
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
      1. 10.2.1 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Custom Design With WEBENCH® Tools
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
  • RPJ|9
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.8 Current Limit And Short Circuit Protection

The TPS62903 is protected against overload and short circuit events. If the inductor current exceeds the high-side FET current limit (ILIMH), the high-side switch is turned off and the low-side switch is turned on to ramp down the inductor current. The high-side FET turns on again only if the current in the low-side FET has decreased below the low-side FET current limit threshold.

Due to internal propagation delay, the actual current can exceed the static current limit during that time. The dynamic current limit is given as Equation 1:

Equation 2. GUID-D0ADBE77-2BC6-4D5D-8E08-A1B515085E97-low.gif

where

  • ILIMH is the static high-side FET current limit as specified in the Electrical Characteristics
  • L is the effective inductance at the peak current
  • VL is the voltage across the inductor (VIN - VOUT)
  • tPD is the internal propagation delay of typically 50 ns

The current limit can exceed static values, especially if the input voltage is high and very small inductances are used. The dynamic high-side switch peak current can be calculated as follows:

Equation 2. GUID-3764678D-CCAF-45C8-B77B-7452AA2DC693-low.gif