PWM Regulator for Lantern bodies, JM-PhD-X1

[JimmyM]

I've been doing some messing around with the board design. Right now it's 50mm wide by 73mm long. Not including the detachable output section. That adds 35mm to the length. Overall it's 50mm x 98mm. Do you guys have that much room?
If it's too big, let me know now before I build these things. If it absolutely HAS to be smaller, I can use a smaller micro-controller and reduce the auxiliary inputs/outputs to a bare minimum.

I also have, in the design, secondary drive sections that are an exact copy of the drive section shown above. I have added room for heatsinks that will be included (they're small but will help) and a provision for a drive section cooling fan which will be up to the buyer to procure/install. I've found very nice small fans at Digikey. They're 25mm x 25mm x 10mm thick and can move 3.5CFM at 12V. They draw ~86mA each.

 

[Starlight]

Jimmy,
I just pulled out my light and checked it for board size. If the board doesn't go over 4 inches, it will fit fine. However, if you could add the 35mm on the side rather than the end, it would be better (85mm x 73mm, rather than 50mm x 98mm).

 

[JimmyM]

Jimmy,
I just pulled out my light and checked it for board size. If the board doesn't go over 4 inches, it will fit fine. However, if you could add the 35mm on the side rather than the end, it would be better (85mm x 73mm, rather than 50mm x 98mm).

I'll see what I can come up with. But keep in mind, the drive section is removable for mounting more conveniently or nearer the high current path. You just score with a knife and snap it off. Or I could do it before shipping.
Heavy gauge wire attachment can be done via solder or #8 machine screws and ring terminals.

 

[JimmyM]

After some quick rearrangement (this may change a little)

Overall board:
86.8mm x 72.3mm

Control board:
51.9mm x 72.3mm

Drive Section:
34.6mm x 72.3mm

 

[JimmyM]

This is a serious matter whose answer is NOT "As high as possible".

The answer will seriously affect the final cost/size/complexity of the regulator.

A 60V unit is easier to design for rather than 80V+.

So 2 questions...
1) How much voltage to you guys see actually putting into this thing?

2) Will you operate additional items off of this? Status LEDs, etc.

I know we've discussed this along with lots of other bells and whistles, but seriously. How much are you willing to pay for stuff you'll never use?

$75 for a single channel regulator with no external outputs?
$175 for a dual channel bad boy with features galore?

 

[smopoim86]

For My use, 60v would be acceptable (16 A123 @ 56.7v). I'd love to have some of the bells and whistles. I've ordered a couple of the cheap volt meter displays and they require 5v supply, it would be nice to be able to power one or 2 of those. That would make the need of battery status leds void. I'd love to have a way to power a 12v fan, but it's really not a real necessity. Offering a dc>dc converter separate might make more sense.

As for price. I probably wouldn't be interested at 175. I'd be willing to play up to around $130 depending on features.

Daniel

 

[JimmyM]

I may have a partial solution...
The onboard regulators will be able to handle 70V Max but just be able to power the micro-controller and FET drive circuitry. Nothing else. But I can leave a provision on the board for a 3-pin switching regulator that you guys could add if your needs dictated it. I found a simple 3-pin switcher that can do Up to 60V and is adjustable. SO you could use it to supply 12V or 5V or whatever to drive accessories you want. The devices can sill be controlled by the micro-controller since it will have high voltage FETs as auxiliary outputs. They just switch the ground lead of your added device.
The switcher I found is here HV Adjustable Switcher
Sound like a possible solution?

 

[smopoim86]

Seems like a good way to add additional options without raising the price for everyone
.

 

[petrev]

Hi Jimmy

Sounds a good way to go.

Nice idea and I guess you could parallel 2 units to drive both 12V and 5V (for a fan and a small volt meter display say ?)

Nice find.

Cheers
Pete

 

[Starlight]

Jimmy,
60V is plenty for me. I probably won't go much over 40V, dropped down to about 30V. It's the high current capability that is needed. I need at least 25 amps, and 35 would be better. If someone just wants more battery capacity, they can always parallel battery packs.

The 86.8mm x 72.3mm board will be very good.

 

[smopoim86]

I've been looking for a less expensive option for acc power and found these http://focus.ti.com/docs/prod/folders/print/tl2575hv-05.html#samples

Looks like you could build a Vout fixed at 12 or 5v for just a few dollars extra. I'm definitely no expert at electronics, but it seems like it could be a viable option.

Maybe have the board made for the components and have it as an option?

 

[JimmyM]

I've got a new board design.
69.9 mm x 62 mm including the drive section. It includes mounting pads for the Switching regulator above.
I used a surface mount micro-controller and removed the I2C and SPI headers. I'm testing out a new sampling divider disconnect to hopefully reduce parasitic current drain. We'll see. The math works.
Also included with the rearrangement is room for 2 heatsinks for the high current FETs. I managed to keep all of the auxiliary I/O pins. Still working on it.

 

[JimmyM]

Can I get a show of hands to see how many I should build?
I won't be making a hundred of these like the D1s.
So whoever wants one, please make your needs known or this run may never happen. I can't afford to loose $1000 if I only sell 2 of these things.

 

[JimmyM]

I've got a new board design.
69.9 mm x 62 mm including the drive section. It includes mounting pads for the Switching regulator above.
I used a surface mount micro-controller and removed the I2C and SPI headers. I'm testing out a new sampling divider disconnect to hopefully reduce parasitic current drain. We'll see. The math works.
Also included with the rearrangement is room for 2 heatsinks for the high current FETs. I managed to keep all of the auxiliary I/O pins. Still working on it.

The sampling disconnect works great. As does the high voltage primary regulator. It was able to run a 20 mA LED at 50V input and just barely get warm. It was also able to run 2 LEDs at 40V input. That's the same power dissipation as 20mA at 80V input. SO I think we're looking good there. FETs will be 75V units. The over all unit will be officially rated at 70V input.

 

[smopoim86]

I'm in for 1, possibly 2. Really depends on how the current project turns out

 

[JimmyM]

I'm in for 1, possibly 2. Really depends on how the current project turns out

What current project? This X1 project? How do you like how it IS going? Any feedback?

 

[smopoim86]

Sorry, I wasnt clear at all. I meant a current project of mine.

This project seems to be going well. I like your quick response to the feedback.

Daniel

 

[JimmyM]

Here's yet another revision of the PCB design.


Things have changed so much over the course of this thread. LCD screens, blah blah blah.
Here's what we have. In no particular order.
Atmel ATMega88 microcontroller
Regulator architecture capable of driving 2 regulated outputs.
Dual 75V FETs on detachable drive section. (Single output)
Additional drive section can be purchased if desired.
Heatsinks on output FETs
70V input rating.
Current rating to be determined.
2 on/off FET switched ground auxiliary outputs (1A each)
2 PWM FET switched outputs (480Hz)(1A each)
3 defined button inputs (only need one with current software)
2 auxiliary A/D inputs
Sample divider disconnect
4 unused I/O pins brought out to pads
Mounting position for customer installed switching regulator with power output pads.
Diagnostic I/O pin. Can be re-tasked if needed.
6pin Standard AVR programming port.

An LCD screen/button can be installed by the user using the AVR programming port's SPI pin connections.

If there's something else you can think of, let me know now.
Thanks.

 

[Starlight]

Jimmy,
I want 2 for sure and I may buy a third. What does an additional drive section do for me?

 

[petrev]

Hi Jimmy

That is a lovely looking board you got there - Super Nice.

I will have 1 for definite - people this side of the pond don't seem to want to spend any money on my big lights - so I will just make a super 1000W light for me and see if there is any respose when it's done . . .

You should run through the major options available with your super expandable and customisable outputs and inputs. It would be good to know what you have managed to incorporate from the long list that has appeared all over this thread ! I'm just not technical enough to be able to work out all that can be programmed in and added on ?

Cheers
Pete