Better buy a new multimeter then a new battery!

innews:SvX3l.3181$ snipped-for-privacy@en-nntp-08.dc.easynews.com:

LOL! Now that's wishful thinking!

Dave.

We are thinking about custom packing some dice for rapid prototypings.

It's not that simple to retrofit COB.

We need a injection molded plastic base with groves to separate the leads. We need to stamp the lead frame with outer ring connected and fingers pointing inward. After bonding the chip and leads, we top it up with plastic and secure the frame. Then we cut the outer ring to separate the leads.

Unfortunately, we can't find anyone to do less than 100K pcs.

This is terribly ironic, because just a few decades ago, a "Red" was a communie.

Electrons are male because they issue forth from the Great Yang:

"I am Light, the Great Spirit, the Great Yang. I am the essential and universal masculine force of Creation. My energy is like electricity, like lightning, the energy of inspiration, ideas and thoughts. And as I evolve, more and more of me finds my truest nature... Loving Spirit." ... "The other essential half of Deity is the Great Mother, the cosmic womb of creation. She is the one I love, and to whom I owe my existence in manifestation. It is she who opens and holds the space that contains my Light. She is the magnetic field of being within whom my colors and hues take form.

"She is the Mother of Creation, the great feminine power of the universe. She is known as the Holy Mother, the Mother of Everything, the Great Yin. She is the Will of Creation. Her essence is magnetic, like the energy of gravity... it is drawing, holding, supporting and nurturing. The Mother's energy is both subtle and powerful... emotional, feeling and grounding." ---

And protons are feminine, and made of condensed Will essence.

So, electons are male, and protons are female.

I'd have thought electronics guys would be amenable to the idea that, since everything is made of electromagnetic energy, (E - mc^2, and all that), the fundamental constituents of the Universe are Electricity (Yang) and Magnetism (Yin).

And Electricity is the source of Intellectual Consciousness, and Magnetism is the sourse of Sentient consciousness.

Hope This Helps! Rich

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What can you get blank lead frames? I contacted some manufacturers, but they don't seem interested to sell less than 100K. I figure that it would be easier to order plastic bases and stamped pins and bond them together.

In some applications where you have 5V available, I think that you can find a 5v to 9V isolated DC-DC converter on very old ethernet cards. I think that they figured out a way to avoid needing the DC-DC converter on newer network cards. Anyway if you find a computer in a skip (that isn't working and faster than your existing fastest computer), that is one thing to strip out and reuse.

Chris

m.

These pads are too small for that. We use at least 50 mils pads for test probes. We just have to make sure every COB pad is connected to another big pad somewhere.

ill

Actually, we have to throw away lots of COG OTP chip during developments. Sometimes, we dump 20 to 30 boards per day.

The ICs and wire-bonds are good, but the firmware is not perfect yet.

If you just want a few of them, get some (empty) moulded packages including the epoxy and leadframe and everything except the actual silicon die and bondwires, then get a milling machine and mill a pocket down to the paddle that the chip goes on. Extend the milled pocket to cover the tips of the pins that you have to bond onto. Then you can do the die attach and bonding by hand and "glob top" it with that epoxy stuff. That's how I've seen it done when you want less than a couple of dozen parts ready the same day or thereabouts. If you have a week and a few thousand dollars then you could get a few thousand proper machine-bonded moulded parts which would have a higher yield and be more reliable.

Chris

If you have a bad chip bonded to the PCB or a faulty bondwire, then you will have to throw away the entire PCB. Sometimes it is cheaper to test the IC and throw out the defective PCB before you have wasted the solder and components to fit all of the other parts on the board.

Chris

I don't know where we got them from. They weren't just blank lead frames but included the epoxy with the pins embedded, just like a normal plastic packaged chip, but without the chip itself. That's why we needed to mill to get to the leadframe in the middle. The epoxy was just to keep the thing from falling apart. I guess we ordered some like a normal packaging order. The packaging place seemed to be willing to do orders down to 10 parts or so, though I think that they had to mix up enough goop for a few thousand at least. Perhaps they were willing to do small orders because we also placed very large orders, I don't know the reason for sure.

You could try milling some packages that *do* have chips in them, I don't know what that would do to the milling cutter though, it might be ok with carbide cutters.

Chris

On a sunny day (Mon, 22 Dec 2008 15:34:10 -0800 (PST)) it happened "David L. Jones" wrote in :

Here is picture from the outside, it really works! ftp://panteltje.com/pub/cheap_meter.jpg

turns... etc.

ringcore.

So I tried the ring core solution, took some ring core with about 50 turns from a choke in some old cellphone charger (switch mode). Cut the wire in the middle of the ringcore, so that left me with 2 separate isolated turns. Connected it as in above referenced diagram, but used an NPN this time: ftp://panteltje.com/pub/DC_DC_converter.jpg The grey wire through the ring is the base feedback, if it does not oscillate connect it the other way around. And, yes it works: ftp://panteltje.com/pub/DC_DC_converter_waveform.jpg It runs at 200kHz with 47nF parallel, a much higher frequency then the potcore versions, different permeability I think ... The wavefornm is not such a nice sinewave either. But, 12mA zero load, so at 10V about 120mW losses, likely the core (transistor stays cold). Vin is a little below Vout, depends on where you cut the original wire (transformer ratio). So, this circuit does it again, it works from less then 3V input to way above

15V. Cost: zero. If you test it, test it with say 100 Ohm in series, in case you got the phase wrong of the feedback, and it does not oscillate, that will limit DC current.

What they did was stop using coaxial cable, It's only the cards with BNC connectors that have them.

unfortuunately those DC-DC convertes produce 56mA instead of 60mA (so they may or may not work)

a blocking oscillator driving a forwards converter. efficiency will be low because the magnetising energy is not utilised.

That image it heard to read particularly the component values.

from a choke

connect it

The circuit pictured differs from the one in your diagram by not having the flyback derived "-ve supply" part attached to the primary.

when the transistor tries to turn off Vce will increase until the transistor lets the current through

a choke core will have low density ferrite "distributed gap", and so will store more energy before saturating, it's saturation that commutates a blocking oscilator, in your circuit this stored energy is wasted.

For a forwards converter you want a "transformer core" with the marnetic particles packed tightly together. for efficiency

it should possibly have a "reset winding" too which returns energy to the input when the transistor turns off.

On a sunny day (24 Dec 2008 12:54:35 GMT) it happened Jasen Betts wrote in :

I am not sure this is a 'blocking' oscillator, as it is simply a sine oscillator. Sure the transistor blocks, but not for more then one period as in some 'blocking' oscillators.

That is not true, as you have the choice on the secondary to either rectify the sine formed part (see scope picture) or the flat part, or both. ftp://panteltje.com/pub/DC_DC_converter_waveform.jpg

Those values can vary over a very wide range, and it will still work. That is the beauty of this simple circuit.

from a choke

connect it

Sure, that one was for a different project, IIRC it was to feed an EPROM programmer with > 30V, that was then stabilised. This one will feed a LM317, that will create a stable 5V voltage for a PIC circuit.

The core does not saturate, the transistor operates in class C. Look at the scope picture. ftp://panteltje.com/pub/DC_DC_converter_waveform.jpg The flat side is the transistor switching the LC to ground. The top side is the LC free running.

Well, this is all my view anyways, actually efficiency is very very good if you apply some load. Efficiency is always zero without a load ;-)

Mini Reel used to sell dummy ICs for test & practice soldering. I don't know if they still do.

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I think I can just get a 40 pins version of this:

Just hot press it into plastic and mill out the connecting points.

I am still looking for an existing part. If not, toolings should cost one to two thousand dollars. Stamping should cost less than 1 penny each. Rather than junking the entire COB (chip on board) PCB, we can just replace the COF (chip on frame).

By the way, I am going to make it round. Who said IC has to be squared?

ftp://panteltje.com/pub/voltage_converter.jpg ftp://panteltje.com/pub/DC_DC_converter.jpg ftp://panteltje.com/pub/DC_DC_converter_waveform.jpg

Committed to board, and working. The chip sockets have 5.00V Fully isolated, for 9 to 20V input (sealed lead acid). ftp://panteltje.com/pub/isolated_supply1.jpg ftp://panteltje.com/pub/isolated_supply_detail.jpg

The diode bottom left is reverse polarity protection. The large area is for a LCD display.

Early ones were round, and easy to install incorrectly.

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