SLVAFH1A December   2022  – December 2023 TPS62933 , TPS62933F , TPS62933O , TPS62933P

 

  1.   1
  2.   Create an Inverting Power Supply Using a TPS6293x Buck Converter With Internal Compensation
  3.   Trademarks
  4. 1Configuring the Buck Converter for Inverting Buck-Boost Topology Application
  5. 2Choosing the Correct Buck Converter for Inverting Power Application
    1. 2.1 Output Voltage Range
    2. 2.2 Input Voltage Range
    3. 2.3 Output Current Range
  6. 3Selecting Applicable External Components for Inverting Power Application
    1. 3.1 Resistor Divider
    2. 3.2 Inductor and Output Capacitor Selection
      1. 3.2.1 Inductor Selection
        1. 3.2.1.1 Output Current
        2. 3.2.1.2 Inductor Current Ripple
      2. 3.2.2 Output Capacitor Selection
        1. 3.2.2.1 Large Load Transient
        2. 3.2.2.2 Output Ripple Voltage
    3. 3.3 Input Capacitors
    4. 3.4 Bypass Capacitor
    5. 3.5 Enabling and Adjusting UVLO
  7. 4Experimental Results
  8. 5Summary
  9. 6References
  10. 7Revision History

3.1 Resistor Divider

The output voltage of the TPS62933 device is externally adjustable using a resistor divider network. In this example, this divider network is comprised of R2 and R3. Use Equation 6 to calculate the relationship of the output voltage to the resistor divider.

Equation 6. R4=R3×VrefVOUT-Vref

As previously discussed, due to the increased noise of the inverting buck boost topology, and for a more robust design, use smaller value resistors than what are used for the buck configuration. For this design, Vref = 0.8 V, set R3 = 143 kΩ and R4 = 10.2 kΩ. The 49.9-Ω resistor, R2, is provided as a convenient location to break the control loop for stability testing.