Author Topic: AC to DC using AD736JNZ  (Read 1423 times)

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Offline Nu7sTopic starter

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AC to DC using AD736JNZ
« on: September 07, 2015, 07:57:21 pm »
Hello EEVblog forum,

I'm a big fan of the EEVblog Youtube channel and I'm having some electronic problems, so what better place to ask?

I would like to measure my home's electric power consumption and bought some SCT013 split core current clamps. They give out 0-1VAC for a specific range.

DATASHEET
LINK TO PRODUCT

My home automation (Loxone) has only 0-10VDC inputs and because the SCT's only provide AC I cannot connect them directly. I've been looking for a way to convert the 0-1VAC to 0-10VDC and came across some different methods:
- Diode bridge rectifier : Cannot be used because the diode's require a minimum voltage wich is not provided.
- Mosfet bridge rectifier : I don't have the required electronic experience, nor equipment
- Phoenix Contact / Knick signal conditioner:  While possible, very pricy and a bit overkill. Also, they require room in the electrical cabinet.
- RS AC-P2-05 converter module: Also expensive and not common plus I cannot find a DIN-rail holder.
- Using an arduino with a power offset to condition the signal.: This adds 2 additional logic computers in the circuit. I would rather connect to my home automation directly.

However, I recently came across the AD736JNZ IC, wich according to the datasheet is able to convert true RMS AC to a DC signal.

DATASHEET
LINK TO PRODUCT

It has arrived today and I have undergone an attempt to connect it, but have failed doing so. I connected it like this:



I chose a 33µF cap as the "Cf cap" and none for "Cav" as described in the datasheet:



I am providing the IC with 3.3V. When I measure between pin 8 (COM) and 6 (OUTPUT) I measure 2.2V, no matter what input I supply.



Am I looking at this at a far too basic approach and I am missing vital components, am I connecting it wrong, is the IC faulty or is it unusable for my application?

Any help is welcome. If I need to provide more information, please let me know.

Friendly greetings from Belgium!
 

Online Zero999

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Re: AC to DC using AD736JNZ
« Reply #1 on: September 07, 2015, 10:17:41 pm »
The AD736 needs a negative supply to work properly.
 


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