SNVAA33 December   2021 LM61460 , LM61460-Q1 , LM61495 , LM61495-Q1

 

  1.   Trademarks
  2. 1USB Type-C Specifications
  3. 2Popular AC Adapter Design
  4. 3Dynamic Output Voltage Control Methods
    1. 3.1 Method 1: Feedback Resistor Switch Network
    2. 3.2 Method 2: Feedback Current Injection Network
  5. 4Schematic
  6. 5Lab Measurements
    1. 5.1 Bench Measurement (VOUT = 5 V)
    2. 5.2 Bench Measurement (VOUT = 9 V)
    3. 5.3 Bench Measurement (VOUT = 15 V)
    4. 5.4 Bench Measurement (VOUT = 20 V)
  7. 6Summary
  8. 7References

6 Summary

This application note details the design considerations when using a buck converter in an USB Type-C application. Two design examples using the highly efficient buck converters, the LM61460-Q1 and LM61495-Q1 buck converters, step down a typical 21 V input supply voltage to a lower dynamically controllable output voltage set between 5 V to 20 V following USB Type-C PD specifications. The modified EVM schematics, efficiency curve comparisons, and side-by-side thermal image comparisons of the two converters showcase the strengths of each device. While the LM61460-Q1 device optimized particularly for output currents lower than 5 A, the higher current rated LM61495-Q1 device is thermally cooler because of its larger package size and lower internal RDS-ON.