TIDUFE2 October   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Fault Detection and Protection
      2. 2.2.2 Theory of Operation - Parallel LDOs Using Op Amps
      3. 2.2.3 Theory of Operation - Parallel LDOs Using Ballast Resistors
    3. 2.3 Highlighted Products
      1. 2.3.1 TPS7B7702-Q1, Automotive, Dual-Channel Antenna Low Dropout (LDO) Regulator With Current Sense
      2. 2.3.2 OPAx388 Automotive, Precision, Zero-Drift, Zero-Crossover, True Rail-to-Rail, Input/Output Operational Amplifiers
      3. 2.3.3 LMV321A-Q1 Automotive Low-Voltage Rail-to-Rail Output Operational Amplifier
  9. 3Hardware, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Test Setup
    3. 3.3 Test Results - Parallel LDOs Using Op Amps
      1. 3.3.1 Short to Battery
      2. 3.3.2 Load Transient Response
      3. 3.3.3 Current Limit
      4. 3.3.4 Start-Up
      5. 3.3.5 Shutdown
      6. 3.3.6 Line Transient
      7. 3.3.7 PSRR
      8. 3.3.8 Thermal Performance
      9. 3.3.9 Thermal Limit Protection
    4. 3.4 Test Results - Parallel LDOs Using Ballast Resistors
      1. 3.4.1 Short to Battery
      2. 3.4.2 Load Transient Response
      3. 3.4.3 Current Limit
      4. 3.4.4 Start-Up
      5. 3.4.5 Line Transient
      6. 3.4.6 Thermal Performance
      7. 3.4.7 Thermal Limit Protection
    5. 3.5 Comparison of Results Between Parallel LDO Techniques
      1. 3.5.1 VLOAD vs ILOAD
      2. 3.5.2 PSRR
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
      3. 4.1.3 Layout Prints
    2. 4.2 Tools
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

Description

This reference design demonstrates two methods for paralleling the TPS7B7702-Q1 linear regulator to achieve higher load currents which can be required in common applications such as phantom power supplies. The first approach uses external operational amplifiers (op amps) to parallel four TPS7B7702-Q1 channels, delivering up to 1.2A to the load. This technique is scalable and more linear regulator channels can be paralleled for additional current. The second approach uses ballast resistors to parallel two TPS7B7702-Q1 channels, providing up to 500mA of output current.