SLVAE22A July   2018  – March 2019 TPS54334 , TPS65251 , TPS65251-1 , TPS65251-2 , TPS65251-3 , TPS652510 , TPS65261 , TPS65263 , TPS65263-1Q1 , TPS65263-Q1 , TPS65265 , TPS65266 , TPS65266-1 , TPS65270 , TPS65273V , TPS65276V , TPS65279 , TPS65279V

 

  1.   Power Stage Gain and Slope Compensation Measurement in PCM (Peak Current Mode) BUCK Converter
    1.     Trademarks
    2. 1 Introduction
    3. 2 Unified PCM BUCK Converter
    4. 3 Power Stage Gain Measurement
      1. 3.1 Simplified Small Signal Model for Power Stage Gain
      2. 3.2 Power Stage Gain Measurement Method
    5. 4 Slope Compensation Measurement
      1. 4.1 Relationship Between VCOMP and Se
      2. 4.2 Slope Compensation Measurement Method
    6. 5 Measurement Results Verification
      1. 5.1 TPS65261 Measured GM-PS and Se
      2. 5.2 Measured Bode Plot vs. Calculated Bode Plot
    7. 6 Summary
    8. 7 References
  2.   Revision History

3.2 Power Stage Gain Measurement Method

GM-PS is the AC small signal parameter. It must be measured by differentiated method. Table 1 shows step-by-step GM-PS calculation guidelines.

  1. Measure VCOMP at different loads in CCM from low current to high current.
  2. Subtract VCOMP and load current with next data.
  3. Equation 3 calculates GM-PS for each condition.

Table 1. GM-PS Calculation Guidelines

STEP 1 STEP 2 STEP 3
VCOMP iLoad Delta VCOMP Delta iLoad GM-PS
VCOMP1 iLoad1
VCOMP2 iLoad2 VCOMP2 - VCOMP1 iLoad2 - iLoad1 (iLoad2 - iLoad1) / (VCOMP2 - VCOMP1)
VCOMP3 iLoad3 VCOMP3 - VCOMP2 iLoad3 - iLoad2 (iLoad3 - iLoad2) / (VCOMP3 - VCOMP2)
... ... ... ... ...
VCOMP(N) iLoad(N) VCOMP(N) - VCOMP(N-1) iLoad(N) - iLoad(N-1) (iLoad(N) - iLoad(N-1)) / (VCOMP(N) - VCOMP(N-1))