OPEN SOURCE: "CC-Boost" - 2.4 Amp boost driver - RC1

paul1598419 · Oct 6, 2014

I built a dummy load with ten 10 amp rectifiers and a 0.1 ohm 5 watt resistor. I think something like this would work for your test load. I used header pins and shunts to select the load. That might be a weak point at 10 amps, though.

rhd · Oct 6, 2014

paul1598419 said:
I built a dummy load with ten 10 amp rectifiers and a 0.1 ohm 5 watt resistor. I think something like this would work for your test load. I used header pins and shunts to select the load. That might be a weak point at 10 amps, though.

No worries. ARG, I won't send it unless I can also supply an appropriate test load.

This is a neat driver tough, so I hope I can. It's not cheap, I think the parts alone approach $25. But it's neat. Very high frequency, so I'm hoping the noise is minimal, even though the current is high and it's relatively small.

RGB · Oct 6, 2014

First off: I`m sorry, but I didn`t read all 16 pages, so maybe what I write now is unnecessary...
I could offer to produce a batch (amount is entirely open to you) as it would fit in my orders I`m doing anyways...
Sadly, I would not be able to distribute myself, just don't have enough time... I could however, send it to rhd or somebody else as one package. I can`t tell you any price yet, but if general interest is here I`l talk to the factory and also rhd (because I think at least some $ is a MUST

)
Let me know

EDIT: also, of course the 10A version. BTW @ rhd, thats the sad thing in open source

vortish · Oct 6, 2014

Here is a thought guys... I have most of the versions saved on a external drive. I do not have the ability to produce these drivers as I dont have a re flow station but if some one has a re flow and the time since it was a group effort between RHD ARG and a couple others why not find some one that is willing to do the re flow for these and sell them at 8-10 dollars each with I dont know 10 cents of each one being send back to the team in order to fund RHD and ARG and the guys that are building these to keep them open sourced! IF I could that is what I would be doing. This is a expensive hobby and the ones that are makes the effort to improve our drive options are the ones that should be applauded! If I had a reflow station That what I would be doing.. Any way that is my two cents whether or not it matters or not

The Lightning Stalker · Oct 6, 2014

I have been doing some testing on these
today, the two I have built. Before trying to
sell one or connect a diode, I wanted to
scope them and make absolutely sure they
are running properly, and it's a good thing I
did. They both seem to be doing the same
thing, so it isn't a component soldered in
wrong or anything. I double checked too
just in case.

(Current waveform, 1A/div)

This could also explain why the inductor
seems to be running pretty hot at 2.2A,
enough to burn my finger. Any idea what is
going on?

rhd · Oct 6, 2014

The Lightning Stalker said:
I have been doing some testing on these
today, the two I have built. Before trying to
sell one or connect a diode, I wanted to
scope them and make absolutely sure they
are running properly, and it's a good thing I
did. They both seem to be doing the same
thing, so it isn't a component soldered in
wrong or anything. I double checked too
just in case.

(Current waveform, 1A/div)

This could also explain why the inductor
seems to be running pretty hot at 2.2A,
enough to burn my finger. Any idea what is
going on?

How quickly does it get that hot? And did you depart from the parts list at ?

What's your power source, specifically.

djQUAN · Oct 6, 2014

It appears that the current feedback loop is unstable. You might need to adjust feedback compensation or there is a problem with the PCB layout.

rhd · Oct 6, 2014

djQUAN said:
It appears that the current feedback loop is unstable. You might need to adjust feedback compensation or there is a problem with the PCB layout.

My thinking is that you may be powering this from a cell that can't handle the load. Ie, you need a cell capable of 4A+. If your cell can't handle that, voltage input will drop dramatically very quickly under the attempted load, and the ripple will become larger.

djQUAN · Oct 6, 2014

following from what rhd just said, it can also be that the wires between your power source and the driver dropping too much voltage.

ARG · Oct 6, 2014

What voltage is being dropped by your test load Lightning Stalker?

Edit:

djQUAN said:
following from what rhd just said, it can also be that the wires between your power source and the driver dropping too much voltage.

That too. The 26ga wire everyone uses was okay back when the maximum current was 1.8A for A140's, but not so much anymore.

Tomorrows System · Oct 6, 2014

I have been doing some testing on these
today, the two I have built. Before trying to
sell one or connect a diode, I wanted to
scope them and make absolutely sure they
are running properly, and it's a good thing I
did. They both seem to be doing the same
thing, so it isn't a component soldered in
wrong or anything. I double checked too
just in case.

Could you just make a test using Lab bench? Actually This kind of scope is quite normal for me, especially if we:
don't use bigger capacitors like 200-400uF
don't use 10-20uH Inductor for high current rates

Do we have some really tiny boost drivers which have "flat" scope for 2-3A current?

It doesn't mean that current shown on the picture is dangerous for the diode, because mean Power will be normal,and this frequency is just normal for the diode. Only really high peas can damage the diodes, but 20% overdrives not especially if they are quite short.

rhd · Oct 6, 2014

For those who haven't followed the thread, this driver design has already been scoped cleanly, so the question we need to address is what was different about the drivers TLS reflowed and tested, to create that ripple.

To answer that, we need some further info about TLS's testing conditions, and if that doesn't reveal anything, then we should probably get some high quality photos of the boards he reflowed posted so that we can try to visually spot concerns. If that doesn't solve it, then it would be worth getting one of his drivers to someone who can compare it side by side with one that tests clean.

The Lightning Stalker · Oct 6, 2014

This is cool and thanks for all the great
responses. The power source is 3 paralleled
Panasonic CGR18650C. They can source one
hell of a lot of current. I accidentally
shorted them out momentarily through a
large alligator clip and it instantly welded
itself and got so hot it burned my finger.
The voltage at the terminals under load is
3.6-3.8V and an almost flat line on the
scope. I did meter the current and it was
something like 5A of input @ 2A out.

The test load is dropping 5.1V @ 2.2A, so
there isn't a whole lot of boost. The wires
are the ones from Flaminpyro since the holes
aren't large enough for the 24AWG, but they
are connected DIRECTLY to the battery
terminals and only about 2" long.

There were no substitutions. All parts are
the exact ones listed in the BOM. I tried
getting some closeups of one of the boards
with a scanner, but the depth of field is so
small that the height of the chip sitting on
the glass is enough to make the board blurry.

rhd · Oct 6, 2014

Just photos are fine.

I don't see any obvious problems with your testing conditions. Maybe photos will reveal something.

Can you post a link to the IC source you used?

The Lightning Stalker · Oct 7, 2014

Here is where I got the FP6298.
Original+NEW FP6298 Contact Supplier-in Integrated Circuits from Electronic Components & Supplies on Aliexpress.com | Alibaba Group

The ZXCT1009 were purchased on DigiKey.

These aren't hi-res, but this is the best
camera I have with good macro capability.
This board is complete except for the coil
and RSENSE2 and is otherwise identical to
the others, except no wires to get in the
way of the shot.

ARG · Oct 7, 2014

The Lightning Stalker said:

Where's the inductor?

OPEN SOURCE: "CC-Boost" - 2.4 Amp boost driver - RC1

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