ZHCU578 October 2018
For this reference design, a maximum peak-to-peak LED ripple current (ΔILED(PP)) of 50 mA or less is desired. Using the inductor current ripple and the LED string dynamic resistance, the minimum output capacitance can be calculated. For this example, the LED string designed for has a total dynamic resistance (RD) of 4.2 Ω at 1.25 A of current.
A total output capacitance (C10, C11, C24, C32, C33) of 23.5 µF is used.