TPS54260-Q1: TPS54260-Q1 about slope compensation question.

Fsw vs VSENSE as shown in figure 14 is not related to slope compensation. It is frequency fold back which aids in over current conditions. During over current conditions, the output voltage tends to fall below the normal regulated output. During the on time, the switch current will rise up to the current limit. During the off time the switch current decreases. In extreme cases, the switch current may theoretically be above the limit at the start of the switching cycle and increase higher during the on time. The high side switch will always be on for at least the minimum blanking time before current limit can turn the high side switch off. At high switching frequencies, there may not be enough off time for the switch current to ramp back below the limit. Frequency fold back is a feature the lowers the frequency (and increases the off time) so that the current cannot increase too much under extreme fault conditions.