7.4.10.5 Peak Current Limit

The peak current threshold of the OPP curve is used to initiate the 160-ms timer, while the peak current limit (PCL) determines the highest controllable peak current of the peak current loop, V_CST(MAX) = 0.8 V. In other words, this feature provides the highest “short duration” peak power (P_O(MAX)) that the converter can reach. For example, to supply a highest peak power of 150%, R_CS should be chosen to ensure that the peak current at 150% load and V_BULK(MIN) must not be above V_CST(MAX). Then, the threshold of the OPP power (P_O(OPP)) can be programmed to around 112% to support 150% peak power design, based on the following equation. Additionally, before V_O reaches steady state during a V_O soft-start, the highest V_CST can also reach to V_CST(MAX). The transformer must have enough design margin separating its maximum flux density from the saturation limit of the core material under the peak current level in PCL.

Equation 17.