SLVSFL2A May 2021 – August 2021 TPS7H4002-SP
There are several industry techniques used to compensate DC-DC regulators. For this design, type 2B compensation is used as shown in Small Signal Model for Frequency Compensation.
A good starting rule of thumb is to set the crossover frequency fco to roughly one-tenth of the converter switching frequency. This will generally provide good transient response and ensure that the modulator poles do not degrade phase margin. For this particular design, the target crossover frequency was set to be slightly lower than the rule of thumb at 30 kHz in order to optimize the phase margin of the frequency response.
An additional high frequency pole can be used if necessary by adding a capacitor in parallel with the series combination of R3 and C1. The pole frequency is given by Equation 17.