SLVAEX2 September   2020  – MONTH  TPS55288 , TPS55288-Q1 , TPS552882 , TPS552882-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2Design Process
    1. 2.1 Radiation Theory
    2. 2.2 Root Cause of the Broad Band EMI in a Buck-Boost Converter
    3. 2.3 How to Achieve Low EMI with TPS55288 Buck-Boost Converter
      1. 2.3.1 Adding Ground Planes under the Critical Loops
      2. 2.3.2 Using Symmetrical Layout Configuration
      3. 2.3.3 Using Frequency Dithering Function
      4. 2.3.4 Adding RC Snubbers at the Switching Node
      5. 2.3.5 Adding Filters at the Input and Output Side
  4. 3Schematic and Test Result
    1. 3.1 Test Result
  5. 4Summary
  6. 5References

3.1 Test Result

Figure 3-2 shows the EMI test result under buck mode. Figure 3-3 shows the EMI test result under boost mode. It is clearly illustrated that both the conduction EMI and the radiation EMI passed the CISPR25 level 5 limit with more than 6-dB margin.

GUID-20200826-CA0I-CN9G-NTKH-JBJL2JDKKGD5-low.pngFigure 3-2 Buck Mode EMI Result (VIN = 12 V, VOUT = 5V / IOUT = 3A)
GUID-20200826-CA0I-XFV7-4PK4-XL5NCLTK1CGM-low.pngFigure 3-3 Boost Mode EMI Result (VIN = 12 V, VOUT = 20V / IOUT = 3A)