I'm using VO2223A opto-coupler/phototriacs to drive some low-current mains lighting with a PIC controller. All are working fine, but when the (DPST) mains switch is first turned on during system power-up), on 50% of occasions the lamps will briefly flash, even though the PIC control inputs on the chips are being held low. (Even grounding these inputs as a test has no effect on this flash.)
Why are the power triacs being triggered? Is there a voltage surge? And is this potentially damaging to the V02223As?
If it is a potential problem, is there a way of softening the initial power-up, raising the voltage more gently, and preventing this somewhat disconcerting flash (of 35 lamps...)? Many thanks.