8.2.2.9 Current Slope Compensation

The TPS23751 and TPS23752 provide a fixed internal compensation ramp that suffices for most applications. R_S (see Figure 32) may be used if the internally provided slope compensation is not enough. Most current-mode control papers and application notes define the slope values in terms of V_PP/T_S (peak ramp voltage / switching period). Assuming that the desired slope, V_{SLOPE_D} (in mV/period), as shown in Figure 1, is based on the full period, compute R_S per the following equation where V_PK and I_{CS_RAMP} are from the electrical characteristics table with voltages in mV and current in μA.

Equation 5.

Figure 32. Additional Slope Compensation

C_S may be required if the presence of R_S causes increased noise, due to adjacent signals like the gate drive, to appear at the C_S pin.