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I'm looking for something that can switch on and off a 230 Vac, 26mA LED lamp, under microcontroller control. Would a VO2223A, driven by (say) a PIC or Arduino, work as a low-current SSR? The load isn't inductive, so I'd hope not to have to use any form of snubber (but perhaps for safety's sake...) The power consumption of the lamp is just under 8W.

Since I'm looking to run 70 or so lamps (and assuming that such an opto-coupler can be used as a cheap SSR), are there multi-channel variants of the chip?

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up vote 5 down vote accepted

Yes, the VO2223A can be used as a moderate current SSR for AC loads: It is a power Triac switch.

The VO2223 and VO2223A parts are in fact designed for switching power-line (up to 600 Volts) AC by low-voltage control signals such as from a microcontroller, with 5300 Volt isolation between the control and the output circuits.

The parts are rated for switching a 44 Watt load on 220 Volt mains lines, or a 22 Watt load on 110 Volt mains lines.

If the LED used is in fact rated for 26 mA at 230 Volts (datasheet would help confirm), that is a power rating of just under 6 watts. It would thus be safe to operate up to 7 such lamps in parallel on each VO2223A part.

Note that the datasheet derates the current capacity to approximately 0.3 Amperes at 80 degrees C, from the nominal 1 Ampere at 25 degrees. This is not a problem in the stated application, as 7 of the LED lamps would draw approximately 0.182 Amperes altogether.

Vishay's product introduction video provides an overview of power-line switching applications. VO2223

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Many thanks; I'll give it a try. – Peter Reid Jan 17 '13 at 9:40
A follow-up question! The datasheet I downloaded appears to have incorrect pin numbers, and when comparing two datasheets there seems to be an inconsistency in the pinout diagram... Am I correct in thinking that pin 8 is the live AC input, and pin 6 (7 is missing) connects to the load? (Which begs the question as to what pin 5 is for: surely the power triac is gated by the photodiode/triac current -- yet pin 5 appears to be another gate input... Apologies if this is an obvious question... – Peter Reid Jan 19 '13 at 17:51
Separate question should be asked separately... but yes, datasheet is incorrect in listing Pin 7 in the table, numbering for missing pins in packages is typically skipped over. So pin 5, 6, and 8 exist. About pin 5 function - it deserves a fresh question. – Seemingly So Jan 19 '13 at 17:59
@PeterReid Could you please share the links to the conflicting datasheets? – Anindo Ghosh Jan 19 '13 at 18:00
I'll post the pin 5 question separately -- apologies for not following house rules (newbie). I took a version of the datasheet from AllDataSheets.com -- the correct one (it refers to pin 8 as T2, not pin 7), and the diagram looks correct. The other PDF was sent to me a few weeks ago (when I found out about the IC); I don't know its original source. It's almost identical to the first, but has what looks like an error in the pinout table, and a missing part to the diagram! Here are both files: [link]scifun.ed.ac.uk/VO2223A-1.pdf and [link]scifun.ed.ac.uk/VO2223A-2.pdf – Peter Reid Jan 20 '13 at 17:24

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