SLVUCE3 april   2023 TPS54KB20

 

  1.    TPS54KB20EVM 25-A, Regulator Evaluation Module
  2.   Trademarks
  3. 1Introduction
    1. 1.1 Background
    2. 1.2 Before You Begin
    3. 1.3 Performance Characteristics Summary
  4. 2Configurations and Modifications
    1. 2.1 Output Voltage
    2. 2.2 Frequency and Operation Mode Setting (MSEL Pin)
  5. 3Test Setup and Results
    1. 3.1 Input/Output Connections
    2. 3.2 Efficiency
    3. 3.3 Output Voltage Regulation
    4. 3.4 Load Transient and Loop Response
    5. 3.5 Output Voltage Ripple
    6. 3.6 Start-up and Shutdown with EN
    7. 3.7 Thermal Performance
  6. 4Board Layout
    1. 4.1 Layout
  7. 5Schematic and Bill of Materials
    1. 5.1 Schematic
    2. 5.2 Bill of Materials

2.1 Output Voltage

In the U1 design, the output voltage is set by the resistor divider network of R2 (RFBT) and R6 (RFBB). R6 is fixed at 10.0 kΩ to set the FB divider current at approximately 90 µA. The output voltage is set to 3.3V as default. To change the output voltage of the EVM, the value of resistor R2 must change. Changing the value of R2 can change the output voltage above the 0.9-V reference voltage (VREF). The value of R2 for a specific output voltage can be calculated using Equation 1.

In the U2 design, the output voltage is set by the resistor divider network of R12 (RFBT) and R15 (RFBB). R15 is fixed at 3.01 kΩ to set the FB divider current at approximately 299 µA. The output voltage is set to 3.3V as default. To change the output voltage of the EVM, the value of resistor R12 must change. Changing the value of R12 can change the output voltage above the 0.9-V reference voltage (VREF). The value of R12 for a specific output voltage can be calculated using Equation 1. After changing R12, the feed forward capacitor (C51) also needs to be changed.

Equation 1. RFBT=RFBB×(VOUTVREF-1)