TPS54227 Current Protection

TPS54427 uses valley detect current limit. The current is sensed during the low side FET on time. During this time, the current is decreasing. If the current is near the limit it will be positive, that is flowing out of the SW node, but decreasing. If the current is above the limit at the end of the off time, the low side switch will remain on until the current is below the limit, then a new switching cycle begins. If this occurs for 7 consecutive cycles, on the 8th cycle a new lower current limit is established. Current is still flowing. It is positive and increasing during the high side on time and positive, decreasing during the low side on time. The nominal current limit is 5.3 A. The current will range above an below that by 1/2 ILp-p (which depends on the application Vin, Vout and Lout).

It is not specified. If memory serves it is reduced to 80% of the nominal value.