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Author Topic: passing micro-amps through a diode with high efficiency?  (Read 892 times)

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Offline AdminTopic starter

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passing micro-amps through a diode with high efficiency?
« on: January 04, 2013, 01:50:42 PM »
I need to pass about ~0.01mA at ~4V through a diode at high efficiency. (that's 10uA, folks)

Anyone have any idea if that would even work? And what kind of efficiency I could expect?

All the datasheets on diodes I've seen don't look at anything lower than 1mA . . .

Offline billhowl

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Offline AdminTopic starter

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Re: passing micro-amps through a diode with high efficiency?
« Reply #2 on: January 04, 2013, 06:01:37 PM »
Have you try 1N60?
http://www.taitroncomponents.com/catalog/Datasheet/1N60.pdf

errrrr . . . what's special about this diode?

It says:
Minimum Forward Current - 4 mA @ VF=1V

Offline billhowl

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Re: passing micro-amps through a diode with high efficiency?
« Reply #3 on: January 04, 2013, 06:03:51 PM »
No, 1N60 had no minimum, it use for RF with low level signal.

or
You can Ops Amp
http://en.wikipedia.org/wiki/Precision_rectifier
« Last Edit: January 04, 2013, 06:06:12 PM by billhowl »

Offline waltr

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Re: passing micro-amps through a diode with high efficiency?
« Reply #4 on: January 04, 2013, 06:33:26 PM »
Figure 1 of the 1N60 DS supports what billhowl says.

I don't recall a diode having any minimum forward current, only a minimum forward voltage to over come the forward voltage drop. For the 1N60 this seems to be just over 0.2V at very low current.

Admin, have you tried measuring this with a few diodes?

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Re: passing micro-amps through a diode with high efficiency?
« Reply #5 on: January 04, 2013, 06:53:36 PM »
Another friend of mine said to look into diodes for RF, too. So I'll investigate that . . .

Admin, have you tried measuring this with a few diodes?
Not yet, as I just started looking into this today. I also don't have any equipment that can accurately measure ~1uA. But I know people that do.

Offline jwatte

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Re: passing micro-amps through a diode with high efficiency?
« Reply #6 on: January 04, 2013, 07:00:11 PM »
I need to pass about ~0.01mA at ~4V through a diode at high efficiency. (that's 10uA, folks)

What I would look at would be a diode with a low forward drop. Perhaps a Schottky type? I imagine this is for your micro-power harvesting project? I would be surprised if you ended up with very high efficiency there.
There's also the question of reverse leakage. If you have 10 uA forward, and the diode leaks 25 uA in reverse, then I don't think you're going to get much rectification out of it...

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Re: passing micro-amps through a diode with high efficiency?
« Reply #7 on: January 07, 2013, 10:06:41 AM »
Turns out there are energy harvesting IC's specifically for stuff like this lol . . .

Linear Technology and Maxim both have a few. I'll have to buy 'em and try 'em out . . .

Offline jwatte

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Re: passing micro-amps through a diode with high efficiency?
« Reply #8 on: January 07, 2013, 11:18:38 AM »
Quote
Turns out there are energy harvesting IC's specifically for stuff like this lol . . .

Yes, absolutely! There are even full boards you can plug into your source on one end, your battery on the other, and it's done.
Where on the spectrum of "eating ice cream" vs "milking a cow" do you want to fall?

Offline AdminTopic starter

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Re: passing micro-amps through a diode with high efficiency?
« Reply #9 on: January 07, 2013, 11:51:44 AM »
Where on the spectrum of "eating ice cream" vs "milking a cow" do you want to fall?
pardon? ???

Offline jwatte

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Re: passing micro-amps through a diode with high efficiency?
« Reply #10 on: January 07, 2013, 08:23:01 PM »
Where on the spectrum of "eating ice cream" vs "milking a cow" do you want to fall?

pardon? ???


How much of a ready product are you looking for? You can buy assembled battery-and-generator-and-harvester packs off the shelf. You can buy the parts and plug them together. You can buy the ICs and make your own PCB. Or you can design and build your own from discrete components.

Are you looking to get a working energy harvester to use in a project? Then buy a ready-made one! Are you looking to solve a design challenge? Then build your own starting with raw silicon crystals :-) Or do you have a particular reason to fall in the middle of that spectrum, where you won't just buy one off the shelf?

The simile I used was between starting from scratch (milking the cow; building diodes from silicon) versus just enjoying the finished product (eating ice cream; buying an off-the-shelf micro-energy harvesting solution.)
http://www.microstrain.com/energy-harvesting/harvesters
http://www.marlow.com/products/power-generators.html?utm_source=google&utm_medium=ppc&utm_campaign=marlowppc&_kk=0df1a415-b208-4ce8-9f68-40081f677e2c&_kt=28035761150
http://www.we-online.com/web/en/electronic_components/produkte_pb/demoboards/energy_harvesting/energy_harvesting.php

Also, out of curiousity: What's your energy source? Vibration? Heat differential? Stray magnetics from nearby power lines? :-)

 


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