S4120MB is a CCT control chip with memory cellsinternal, which can store the state after power downfor long time. lt sets a state-switching-window timeTsw (Typ 6.4S) timed by internal clock. If the OFF timeexceeds the TSW time, the chip will display the last CCTstate before power down when turn on the light nexttime, or it will switch to the next CCT state.