Sold/Expired High efficient 5A/9A Buck Converter for SST-50, SST-90

[Der Wichtel]

Got it working with a MCU finally. It was pretty difficult as there are so much interference that the MCU shuts off or doesn't respond anymore. Tried different capacitors from 0.1µF to 15µF without luck then found out that one trace is too close to a power trace.... removing that trace and bypassing it with a wire solved it :twothumbs

http://www.youtube.com/watch?v=H-OD2xaAILs&feature=channel

 

[jspeybro]

Any idea on what modes you're going to offer?

 

[Th232]

Sweet! Also interested in the modes and what you ended up with for switching (was that just a pushbutton?).

 

[Kaulquappe]

Hi, looks great. Which MCU is installed?
When can i order one?

Regards from Switzerland
Luca

 

[Der Wichtel]

Any idea on what modes you're going to offer?

I will use the same modes as in the as in the 2.8A driver again with version A and B. But I'm open to any other ideas.

Sweet! Also interested in the modes and what you ended up with for switching (was that just a pushbutton?).

Modes are changed with a momentary switch. I was too lazy to solder a switch onto the board so I used the multimeter leads.
There is still a little problem which can't be solved that easily. The quiescent current is around 6mA which will suck the batteries emtpy in a week. I tried to use a mosfet to disconnect the driver from power but that does not work properly. The few mOhms across the mosfet will cause voltage ripples so that the MCU doesn't work anymore. The only solution I can think of is using an additional switch in combination of the momentary switch or simply unscrewing the tailcap a litttle bit if the light is not in use.

Of course I could also program the driver to change modes by turning the driver on and off within ~1-2s but I'm afraid that the switch will wear off very fast by the big sparks.

Hi, looks great. Which MCU is installed?
When can i order one?

Regards from Switzerland
Luca

It's the attiny25v-10su.
As soon as I get the parts I need. The attiny25v-10su has a lead time of 18weeks for example. So have to find another source.

 

[jspeybro]

I will use the same modes as in the as in the 2.8A driver again with version A and B. But I'm open to any other ideas.

In dive lights all these modes are not really useful (at least not for me, but I don't think I'm alone with this), just a high and a lower (not LOW) mode would be fine, like 100% & 40%.
As for switching, haven't thought about that much. I was planning to use a read swich with a mosfet as a switch, I guess you already implemented that but left the read switch out. Anyway, for dive lights it's wise to physically disconnect the batteries somehow to prevent accidental turn-on in your car so a low rest current wouldn't be a big issue.

I think packhorse has been experimenting with some mosfets for his SST-90 lights. Maybe he has something for you that works. It should be on the forum somewhere if it worked.

 

[Der Wichtel]

The problem I have is the mosfet can't be controlled by the MCU to turn the light off completely. Because the mosfet will add addtioninal resistance and cause interference so that the MCU stops working. I tried using several mosfets with Rdson of 1-2mohm without luck.

If you use an external mosfet controlled "by hand" then there shouldn't be any problems.

If you just want 2 modes you can just use a 10k pot or a switch to switch between 2 resistors. A simple voltage divider.
Just like this
http://www.youtube.com/watch?v=etxDyqYyO9E

 

[irv_usc]

I will use the same modes as in the as in the 2.8A driver again with version A and B. But I'm open to any other ideas.

I would love just a 3 mode low medium high, but version A would be fine.

 

[Kaulquappe]

I would like to change the brightness as shown in the last video, with a variabel resistor.

Regards
Luca

 

[Th232]

If you just want 2 modes you can just use a 10k pot or a switch to switch between 2 resistors. A simple voltage divider.
Just like this
http://www.youtube.com/watch?v=etxDyqYyO9E

Interested in this version, I note that in the OP and datasheet it says that the output is still fixed at 5A or 9A. Is this pot controlled version for sale yet?

 

[jspeybro]

Interested in this version, I note that in the OP and datasheet it says that the output is still fixed at 5A or 9A. Is this pot controlled version for sale yet?

if this works with the fixed 5/9A drivers, maybe this is something to add to the datasheet.
I'm interested in a driver that can work with a voltage divider to choose between power levels, but I think I'll need some assistance with the circuit...

 

[Der Wichtel]

I can't add things which are not available... :thinking:
maybe you should start reading from post 77

 

[jspeybro]

oh, yeah those stupid lead times... we have the same problem at work.

guess I was a bit too enthusiastic when seeing the video's oo:

 

[Th232]

oh, yeah those stupid lead times... we have the same problem at work.

guess I was a bit too enthusiastic when seeing the video's oo:

+1, my bad. Definitely looking forward to that version though.

 

[ahorton]

I'm trying to put together something that will reduce the chance of these drivers being damaged when I power them from a running car.

Without much understanding I've put together a few zener diodes, transorbs and capacitors of various sizes across the input power. There is also a 20A fuse in the + input line.

Will the caps be harmful to the operation of the circuit?

Is there a better way to add some protection for the circuit?

Cheers

 

[Der Wichtel]

Your idea is correct. The fuse can be placed right after Vcc. The diode prevent voltage spikes that could damage the driver. You should use a high current version so that the excess voltage can be burned away through the long wires or the fuse which should have enough resistance. So place the diode as near as possible to the caps and the caps as near as possible to the driver.

As for the caps use low esr versions and use 4 or 5 caps in parallel. The ZL or ZLH series from Rubycon are very good. Panasonic has also some nice stuff but I'm not very familiar with their product lines.
I'm not sure how big the voltage ripples can be in a car but you should use overall at least 1mF.

 

[ahorton]

Thanks

1 mF is bigger than I was planning to use but I'll go and get some of these now.

 

[Der Wichtel]

if you use 3x 330µF then you'll have 1mF. That's not much

 

[copperfox]

Just to be clear, one of these drivers shipped to US is 41 euro, or about $52.xx?

 

[Der Wichtel]

that is correct