120 VAC to 6vdc board mount chip

[robyn95]

Hi there, I was looking for a chip that converts 120 vac to 6 vdc and rated 5/6 watt. I looked at digikey and other suppliers online- all I found was 120 VAC to 5/9/12 VDC but none with 6 Vdc output. I have two latching relays for my project ,the coil runs at 6 V 200 mA . I thought to use one power source for both relays. Could anyone please suggest me if there is any board mount ac-dc converter chip with these configuration. I am trying to avoid regulating the output myself using linear regulator.I will really appreciate your help.
Thanks in advance.

 

[ronv]

Is your 120 volts ac isolated from the power line by a transformer? Most designs require isolation from mains voltage for safety reasons.

 

[robyn95]

I thought to use the power line directly to my chip. I didn't know that I should use isolation transformer. Do you suggest I could use 120 Vac to 6 V adapter instead if I don't use any transformer.As I am doing an entry level project is their any alternative of isolation transformer.Thanks for helping me!

 

[ronv]

I would look for something like this:

https://www.allelectronics.com/make-a-store/item/PS-616/6-VDC-1.6A-SWITCHING-POWER-SUPPLY/1.html

 

[Joe G]

what about a cell phone charger? their always laying around somewhere. some of them put out close to 6v. I used one and changed the resistor on the chip to put out 7volts. I think that one had a 7660 sm convertor in it. I just got the data sheet and traced it out. Can't hurt to try....I'd just use a regulator and as stated already, a transformer of some type, better safe then,....

 

[robyn95]

Hi Ronv thanks so much.That looks great. I am fairly new to electronic design world. Do you think I could simply adapter and cut out the output end to connect to my board.Thanks again.

 

[robyn95]

Hi Joe G, thanks so much. I was wondering if I use cell phone charger do I still need an isolation transformer.

 

[ronv]

Do you think I could simply adapter and cut out the output end to connect to my board.

Yes, that would work or so might the cell phone charger but most of them are 5 volts I think.

 

[alec_t]

Can you check to see if your relay will operate from 5V? Most relays have a quoted tolerance for pull-in and drop-out voltage/current.

 

[MikeMl]

... I was wondering if I use cell phone charger do I still need an isolation transformer.

No. All of the Consumer Electronics wall-warts (be they older transformer-based, or newer Switch-mode converters) contain an isolation transformer as part of making them safe and for UL and other certification.

I never pass-up a $0.50 wall-wart at a garage or yard sale. Whenever I need one, I already have what I need in my junk box. I use the 12Vdc at 3A ones as vehicle stand-by battery float chargers...

 

[robyn95]

Thanks a lot. My datasheet for relay shows that it will work from 4.7V t 7.2 volt, but nominal is 6V. If it does not hurt the relay I will try to use a 5v charger or may be the kind of adapter ronv sent the link for. Thanks to you all.Great help!