The following method to design converter compensation optimizes the load transient response.

1. Calculate the require output impedance to meet transient response goals. This equation assumes the load step transient is faster than the BW of the converter.
   Equation 9. ${\mathrm{Z}}_{\mathrm{O}\mathrm{U}\mathrm{T}\_\mathrm{R}\mathrm{E}\mathrm{Q}\mathrm{U}\mathrm{I}\mathrm{R}\mathrm{E}\mathrm{D}}=\frac{{\mathrm{d}\mathrm{e}\mathrm{l}\mathrm{t}\mathrm{a}\_\mathrm{V}}_{\mathrm{O}\mathrm{U}\mathrm{T}}}{{\mathrm{d}\mathrm{e}\mathrm{l}\mathrm{t}\mathrm{a}\_\mathrm{I}}_{\mathrm{O}\mathrm{U}\mathrm{T}}}$
2. Select a value for output inductance.
   Equation 10. $\mathrm{L}=\frac{\left({\mathrm{V}}_{\mathrm{I}\mathrm{N}}\mathrm{ }\mathrm{}\mathrm{ }-\mathrm{}\mathrm{ }\mathrm{ }{\mathrm{V}}_{\mathrm{O}\mathrm{U}\mathrm{T}}\right)}{\mathrm{∆}\mathrm{I}}\times \frac{{\mathrm{V}}_{\mathrm{O}\mathrm{U}\mathrm{T}}}{{\mathrm{V}}_{\mathrm{I}\mathrm{N}}}\times \frac{1}{{\mathrm{f}}_{\mathrm{S}\mathrm{W}}}$
3. Calculate the required converter output impedance to meet the transient response goal.
   Equation 11. ${\mathrm{Z}}_{\mathrm{O}\mathrm{U}\mathrm{T}\mathrm{\_}\mathrm{C}\mathrm{O}\mathrm{N}\mathrm{V}\mathrm{E}\mathrm{R}\mathrm{T}\mathrm{E}\mathrm{R}}=\frac{\left(0.00135\mathrm{ }\mathrm{ }+\mathrm{ }\mathrm{ }\frac{\mathrm{L}}{{\tau }_{\mathrm{C}\mathrm{R}\mathrm{A}\mathrm{M}\mathrm{P}}}\right)}{34}\times \frac{{\mathrm{V}}_{\mathrm{O}\mathrm{U}\mathrm{T}}}{{\mathrm{V}}_{\mathrm{R}\mathrm{E}\mathrm{F}}}$
   Make sure Z_{OUT_CONVERTER} is less than the Z_{OUT_REQUIRED} found in step 1. Also recheck that the voltage on C_RAMP is within acceptable limits. (see previous section) If the voltage on C_RAMP is too large, use a larger C_RAMP value.
4. Calculate the minimum output capacitance required to meet the impedance requirements.
   Equation 12. ${\mathrm{C}}_{\mathrm{O}\mathrm{U}\mathrm{T}\_\mathrm{M}\mathrm{I}\mathrm{N}}=\frac{1}{\mathrm{ }2\pi \mathrm{ }\times \mathrm{ }{\mathrm{Z}}_{\mathrm{O}\mathrm{U}\mathrm{T}\_\mathrm{C}\mathrm{O}\mathrm{N}\mathrm{V}\mathrm{E}\mathrm{R}\mathrm{T}\mathrm{E}\mathrm{R}}\mathrm{}\mathrm{ }\times \mathrm{ }\mathrm{}\mathrm{}\mathrm{ }{\mathrm{f}}_{\mathrm{C}\mathrm{O}\_\mathrm{D}\mathrm{E}\mathrm{S}\mathrm{I}\mathrm{R}\mathrm{E}\mathrm{D}}}$

   where

   • f_{CO_DESIRED} is the desired converter closed loop crossover frequency, which is usually 1/8 to 1/4 of the converter switching frequency.
5. Calculate the number of output capacitors required. From the previous section, use the guidelines for ESR to select a capacitor type and value, then use the equation here to find the number of capacitors required. Notice that the impedance of the capacitors (ESR plus impedance of the capacitance at the chosen crossover frequency) is used.
   Equation 13. $Z_{\mathrm{C}\mathrm{A}\mathrm{P}\mathrm{A}\mathrm{C}\mathrm{I}\mathrm{T}\mathrm{O}\mathrm{R}}={\mathrm{R}}_{\mathrm{E}\mathrm{S}\mathrm{R}\_\mathrm{C}\mathrm{A}\mathrm{P}\mathrm{A}\mathrm{C}\mathrm{I}\mathrm{T}\mathrm{O}\mathrm{R}}+\frac{1}{2\mathrm{\pi }\mathrm{ }\mathrm{ }\times \mathrm{ }\mathrm{ }{\mathrm{C}}_{\mathrm{C}\mathrm{A}\mathrm{P}\mathrm{A}\mathrm{C}\mathrm{I}\mathrm{T}\mathrm{O}\mathrm{R}}\mathrm{ }\mathrm{ }\times \mathrm{ }\mathrm{ }{\mathrm{F}}_{\mathrm{C}\mathrm{O}}}$
   Equation 14. ${\mathrm{N}}_{\mathrm{C}\mathrm{A}\mathrm{P}\mathrm{A}\mathrm{C}\mathrm{I}\mathrm{T}\mathrm{O}\mathrm{R}\mathrm{S}}=\frac{{\mathrm{Z}}_{\mathrm{C}\mathrm{A}\mathrm{P}\mathrm{A}\mathrm{C}\mathrm{I}\mathrm{T}\mathrm{O}\mathrm{R}}}{{\mathrm{Z}}_{\mathrm{O}\mathrm{U}\mathrm{T}\_\mathrm{C}\mathrm{O}\mathrm{N}\mathrm{V}\mathrm{E}\mathrm{R}\mathrm{T}\mathrm{E}\mathrm{R}}}$
6. Using one of the tools on TI.com, simulate with the values for the design.