# Wiring help on DX SKU 4735



## rizky_p (Jun 1, 2008)

I am confuse on how to wires this board. Can anyone help?

Thanks
Rizki P


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## rizky_p (Jun 12, 2008)

i tried wiring as per DX thread instruction but the board get really hot even when 2xAA is connected and even hoter whileusing single 14500. 

Draws 1.7A from single 14500, current to led is 850ma which indicate something is wrong. Connected to Cree P4.

I post a picture on how i wired this up. Can anyone suggest other solutions?







Thanks.


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## rizky_p (Jun 12, 2008)

I hope that this picture helps a little.


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## VegasF6 (Jun 13, 2008)

Hmm, I am anxious too to find out how to wire this, as I have 3 of them sitting on my desk in front of me. I had planned on wiring it just like you as per the pics on DX. Did you only try one of them? 

What is the brown component at the top of the board? Some sort of filter cap? I see on the older model some people soldered there connections to each side of it?

I also wonder about the empty solder pad on the upper left where the diode is. 

I am afraid I really don't understand much about how this works, but I thought the sense resistor was just that, only to sense current (or voltage?) and control the inductor. When I traced the pad marked - to the left side of the resistor it shows that they are connected. Does that mean by wiring it this way it passes the full current through the sense resistor and overheats it? Or perhaps R2 is the sense resistor? Sorry I am rambling, but I am TRYING to help 

So I guess my best guess is my first one, one to each side of the filter cap I will give it a shot if I can ever get my test bench set up, and if I can find the darn 115V muffin fans I had set aside for this purpose.
Good luck.


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## rizky_p (Jun 13, 2008)

VegasF6 said:


> So I guess my best guess is my first one, one to each side of the filter cap I will give it a shot if I can ever get my test bench set up, and if I can find the darn 115V muffin fans I had set aside for this purpose.
> Good luck.



Thanks for the help, i tried 2 board and still get the same reading one identical to another, i have one more board untested but i can safely assume that it will have the same result.

Anyone please?


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## marschw (Jun 13, 2008)

This is a bit of a shot in the dark, but have you tried replacing the brown capacitor with a higher value? (And soldering the leads to either side of the capacitor as well, as VegasF6 suggested).


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## VegasF6 (Jun 13, 2008)

This is probably small consolation but I am having my father look at these for me Sunday. He is (to me at least) a bit of an electronics guru, so hopefully he can help me figure this out. I am not so sure if it is wired wrong, a poor design, or defective. He did agree with me over the phone that the full current shouldn't be running through R2 if it is a sense resistor, but I may have explained it wrong. Also, I just got another 3 pack of these in an order that I forgot even placing, so I hope I can find something to do with them 

P.S. I am very thankfull for the pics you took with the light shining through it. It is probably an old trick, but it seemed ingenious to me!


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## VegasF6 (Jun 16, 2008)

Well, just looking at it he said he wasn't able to tell much. Said he would take it home and play around with the o-scope. Did mention that the resistors aren't designed for that sort of load, but we know that already. The IC switching transistor mosfet thingy whatever it is should be handling the load. So that probably means wiring the emitter to it, probably the top left pin if holding it so the IC is on the bottom. Or, to both sides of the ceramic cap. 

Also, looks like I may not get the chance to do a test run of that before next weekend 

Sorry not to have more information. 

Also, I could swear I found an older thread about this board and they didn't have much more luck efficiency wise, though I can't seem to find it now. In this thread, I think they were using a lithium cell to begin with, and were actually happy with the output, but the draw looked way too high to me.


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## VegasF6 (Jun 16, 2008)

Well, I couldn't get this out of my head and have been looking it over some more. If I could find a data sheet for this IC it would be easy, but since I can't, here is another guess.

Lets assume the IC has 6 pins (well it does) and the one at the top left is 1, top right is 3, bottom left is 4, and bottom right is 6.

I think pin 6 is the ground circuit, and if you notice the small lead that is to the right of the IC that doesn't go anywhere really, I think that is your - emitter hookup. I tested resistance to the pin from that spot and it is pretty much a direct connection.

I think pin 3 is the mosfet switching side of the IC and it controls power to the inductor. After passing through the inductor, you can see it goes to the tiny filter cap that is to the right of the large diode, and then it comes out to the + point that you used.

I think pin 4 is the sensing pin. As far as I can tell, it comes out, goes to an empty pad for another diode that wasn't used, goes into R2, then R3 and finally to ground. Just to sample the current being drawn apparently. 

Power comes in where the through hole is in the center. It then passes through the brown ceramic cap for some reason I can't imagine, maybe it is designed that way if for some reason you have a dirty power source? It then goes to the right into the diode, comes out of the diode, into pin 2 to power the chip. It also passes into R3 at the same time. From R3 into seems to go into pin 1 for whatever reason. 

And finaly pin 5 appears to be unused, but it test with no resistance from pin 2, I think it goes straight through.

If you look at the picture Koala99 uploaded on the sales page for this item, on the old design, it appears that he is recomending hooking - to pin 4 and positive to pin 6. Well, pin 6 should be fine, but I believe by using pin 4 for his positive lead, he is hooking it up exactly the same way you did. I think the positive needs to be attached after the inductor, and after the filter cap, which on the old circuit would probably be the other side of the yellow cap at the bottom. I don't think that would really change the efficiency any, but it smooths out the output and should help with any flickering. 

If you get around to changing the 1 lead for the negative to either pin 6 or the solder point above and to the right I would love to hear your results!


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## koala (Jun 16, 2008)

I copied and posted the wiring from a Nuwai/Gentos? light that I have. I tried to look for the datasheet as well but no fruit.

VegasF6 - lets hope your dad could give us some directions. Very interesting.


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## rizky_p (Jun 16, 2008)

Interesting indeed. I'll try the solution you mentioned.

thanks



VegasF6 said:


> Well, I couldn't get this out of my head and have been looking it over some more. If I could find a data sheet for this IC it would be easy, but since I can't, here is another guess.
> 
> Lets assume the IC has 6 pins (well it does) and the one at the top left is 1, top right is 3, bottom left is 4, and bottom right is 6.
> 
> ...


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## CampingLED (Jun 17, 2008)

VegasF6 said:


> Well, I couldn't get this out of my head and have been looking it over some more. If I could find a data sheet for this IC it would be easy, but since I can't, here is another guess.
> 
> Lets assume the IC has 6 pins (well it does) and the one at the top left is 1, top right is 3, bottom left is 4, and bottom right is 6.
> 
> ...


 
Just need to confirm that I am not reading your message incorrectly. At some stages you refer to pin 6 as the negative, but also mention that Koala99 hooked his positive to pin 6.

When I studied the pics on DX my understanding of the old circuit is as follows:
- Pin 4 is the negative of the LED
- Pin 5 and Pin 6 connected to each other and to positive of LED
- The old circuits have two versions of the 2106F, 0731/20 (same as new one) and 0623/20. Not sure what the difference is.

My best guess on the new circuit:
- Little connection on Pin 6 to positive of LED (not negative)
- Either Pin 4 or the connection between R1 & R2 to negative of LED. You are currently using the one between R1 & R2.

Start by moving your LED red wire to the little connection on Pin 6.

I must confess that I have not done your detailed analysis of the other components like you did.


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## koala (Jun 17, 2008)

Here's what I posted, if it's any help...


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## CampingLED (Jun 17, 2008)

I know this is alittle off topic, but do not want to start a new thread. Will these circuits drive a Rebel LED well or is the low Vf (3.15V) of the Rebel a problem. I have a flashlight that is not performing well and suspect the circuit. Will also be nice if it can also accept 14500's in future.


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## Tohuwabohu (Jun 17, 2008)

I ordered some of these drivers too. They were shipped a few days ago but did not yet arrive. So I only have your pictures as information and can not do my own research/testing.



VegasF6 said:


> Well, I couldn't get this out of my head and have been looking it over some more. If I could find a data sheet for this IC it would be easy, but since I can't, here is another guess.
> 
> Lets assume the IC has 6 pins (well it does) and the one at the top left is 1, top right is 3, bottom left is 4, and bottom right is 6.
> 
> ...


Current does not pass through a capacitor (at least DC doesn't). I think the small device on the right is a diode, the larger black one (labeled 100 6V) is a capacitor.



> I think pin 4 is the sensing pin. As far as I can tell, it comes out, goes to an empty pad for another diode that wasn't used, goes into R2, then R3 and finally to ground. Just to sample the current being drawn apparently.
> 
> Power comes in where the through hole is in the center. It then passes through the brown ceramic cap for some reason I can't imagine, maybe it is designed that way if for some reason you have a dirty power source? It then goes to the right into the diode, comes out of the diode, into pin 2 to power the chip. It also passes into R3 at the same time. From R3 into seems to go into pin 1 for whatever reason.


Again, current does not flow through a capacitor. I think the brown ceramic cap smoothes output current, the big black one input current (it is connected parallel to the battery).​ 


> And finaly pin 5 appears to be unused, but it test with no resistance from pin 2, I think it goes straight through.
> 
> If you look at the picture Koala99 uploaded on the sales page for this item, on the old design, it appears that he is recomending hooking - to pin 4 and positive to pin 6. Well, pin 6 should be fine, but I believe by using pin 4 for his positive lead, he is hooking it up exactly the same way you did. I think the positive needs to be attached after the inductor, and after the filter cap, which on the old circuit would probably be the other side of the yellow cap at the bottom. I don't think that would really change the efficiency any, but it smooths out the output and should help with any flickering.
> 
> If you get around to changing the 1 lead for the negative to either pin 6 or the solder point above and to the right I would love to hear your results!


I'm not sure if the old design can be used as a reference to the new one, it seems to be completely different.


If the technical data on the dx-website is correct (1.5V~4.2V Input, 3.7V Output) the driver should be a buck-boost converter http://en.wikipedia.org/wiki/Buck-boost_converter. This means that the polarity of the output voltage should be opposite to that of the input. So my first guess would be to connect the LED just the other way round as rizky_p did in post #2. But of course I am not sure if this is correct, I am just guessing. I think it would be safer to use a resistor than a LED to test this, 5ohm 2W should be a good choice.

Could one of you check the polarity of the small black diode?
Is the lower end of the inductor connected to ground? I can not see it in the images.


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## VegasF6 (Jun 17, 2008)

I do want to make it clear up front I am no expert on this and am just theorizing out loud.

CampingLED: you are right, I did say pin 6 was negative, and now I am thinking I was wrong on that one. 

Koala, can you tell us which pins you are referencing for your positive connection in your picture? Pin 5? Pin6? Or 5 and 6 bridged?

I have been trying to trace this out with my meter set for continiuty, but I am getting funny results and not really sure I am reading it right. 

Tohuwabohu, it will be good to have someone with more electronics knowledge than me to chirp in on this one. What I have been trying to do is find another boost buck board to reference to get some idea how they work, as I can't imagine they are all that different. I hope that by referencing the old board I can at least see what they have in common for pinouts on the IC, I think the main difference is just other added components, but the function should be pretty much the same?

You are right about the small device on the right being a diode I guess, since it is labeled D1, hah. Again, I am a rookie at this.

Near as I can tell, the bottom of the inductor goes to positive. From other designs I have studied, they usually boost positive voltage, and perhaps go through a filter cap? Or so I thought, but you are mentioning a cap doesn't pass current, so that must be my mistake. 

IF I am using the meter correctly, the anode of the small black diode points down towards the inductor.

The cathode end of the diode has no drop between it and the positive pad. There is also no resistance from the anode of the diode to the base of the inductor, nor any resistance from either the base of the inductor or the anode to pin 3 of the IC. Also, there is .4 ohms resistance from the positive connection on the bottom of the board to pin 3 (but my meter shows .4 ohms even when I dead short the leads, so that is zero??) . So, what does that mean? 

Even if we can't get better results from this circuit, I really want to understand the path the current takes. So, if there is something I can do to help, IE if you need me to check something else on the board, feel free to ask.


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## koala (Jun 17, 2008)

VegasF6 said:


> Koala, can you tell us which pins you are referencing for your positive connection in your picture? Pin 5? Pin6? Or 5 and 6 bridged?



Positive output is the connection between the two caps. The strip marking side of the caps is positive.


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## koala (Jun 17, 2008)

Good News! it's a Boost chip.

I digged hard and found the datasheet in my harddrive . (I uploaded it to filedropper because China webby are behind the great firewall they are so slow.)

Brothers who can read Chinese, please download the datasheet above and help translate. Thank you.!

Product page http://www.ic108.com.cn/ic108_Product_2418195.html (I'm guessing) The HT2106 is a clone of the popular Belling BL8532.

Here's what Google translator says about the chip... 





Chip Internal stuff...













Reference Circuit taken directly from the datasheet... pg.4


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## koala (Jun 17, 2008)

I think we need to *revise our pins* for further discussion, because there's no Pin 6 in the datasheet.


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## VegasF6 (Jun 18, 2008)

koala said:


> I think we need to *revise our pins* for further discussion, because there's no Pin 6 in the datasheet.


 
Well that's for sure, there are only 5 pins, and they are not even close to the order I had guessed them at either. I wonder should I just edit out the guesses I made in my post back near the beginning or leave them? I suppose it won't hurt for people to see my mistakes, just hope they aren't used for EVIL, bwaaaa haaa haa haaa (that's my evil laugh.)

Great job finding that. Now if someone with more knowledge can look at this circuit, we can see where we are. But it is looking like this is for low current applications only, huh? And either they have designed it way out of spec, or somehow we are just really overdriving it.

Can't wait to see what this will bring anyhow.


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## rizky_p (Jun 18, 2008)

Wow i have been away for 2 days and this thread springs to life 

As we found out that we are actually shooting in the dark until the real spec on the IC is found well koala seems to have the real spec. 

@vegasF6, i tried as you mention and it didnt light up the LED nor destroy it fortunately  Any news from your dad? 


Thanks.


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## VegasF6 (Jun 18, 2008)

No, I haven't heard from my dad on this yet, he does work, so I don't imagine he will get to this right away, but I will ask him again. Now that it looks like we have a datasheet, it should be much easier for him to explain the design of the circuit for me. 

What I was calling pin 6, which in all reality is pin 3 was completely wrong. At the time I wrote those pinouts I was really excited, thought I was onto it, but I think I just fubared it all up. Sigh, I apologize for that.

At this point, with my limited knowledge I am thinking that it is just supposed to be hooked up with + where you have it, and - either where you have it, or to pin 5 (top left) or simply to your battery ground, which could just be tied into the bottom. 

What I originally called pin 2 isn't even a pin at all, so that shows how much I was mistaken. 

It looks like I am reading the max voltage for this thing is VF + .3 volts as well, so unless I am wrong, a lithium cell is too high a voltage. Should probably start experimenting with 2AA alkaline for now. And as suggested by Tohuwabohu a resistor instead of a LED just for safety sake. 

What I think we have, or will wind up with is a relative high efficiency board to run a 500mA load from 2AA so I guess if you want a not too bright light with decent run times, this might be it, but I don't see any pocket rockets coming from it. 
Sorry I steered you wrong, I have to learn not to put my foot forward so quick.


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## Tohuwabohu (Jun 18, 2008)

VegasF6 said:


> ...
> Sorry I steered you wrong, I have to learn not to put my foot forward so quick.


That is exacty what I am thinking about what I have written.

I think the english datasheet of the compatible BL8532 contains all necessary information. But I will not make any more guesses before I have these drivers in my hand.


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## rizky_p (Jun 18, 2008)

Dont get me wrong, you gave me the suggestions but it was always my call to try it. I know the risk(sort of) and i accept it. So there is no need to apologize 





VegasF6 said:


> No, I haven't heard from my dad on this yet, he does work, so I don't imagine he will get to this right away, but I will ask him again. Now that it looks like we have a datasheet, it should be much easier for him to explain the design of the circuit for me.
> 
> What I was calling pin 6, which in all reality is pin 3 was completely wrong. At the time I wrote those pinouts I was really excited, thought I was onto it, but I think I just fubared it all up. Sigh, I apologize for that.
> 
> ...


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## CampingLED (Jun 18, 2008)

Tks Koala for the circuit and datasheet. Looking at your post #18, in the single LED circuit I still want to stick to my suggestion under post #12 (just change the original nominated pins to the correct numbers). If the correct pin 2 & 3 are connected to each other under the IC it should be correct (not visable in the photo).

VegasF6, tks for the starting point to nominate / assume the pin numbers. We needed a number to pin link to talk the same language. After the datasheet info from Koala we all now know that the pins should be as follows:

Nominated pin 1 = Pin 5
Nominated pin 2 = not used
Nominated pin 3 = Pin 4
Nominated pin 4 = Pin 1
Nominated pin 5 = Pin 2
Nominated pin 6 = Pin 3

Therefore change the positive wire of the LED to Pin 2 & 3, which should be connected to each other. If it still does not work, connect the negative of the LED to Pin 1. First try where you have the negative at the moment as the extra resistor will add some protection and is also in line with the circuit in the datasheet. The extra components in the circuit are there for regulation and protection.

Wanted to order these circuits, but they are out of stock.


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## 12Johnny (Jun 19, 2008)

I am subscribing to this thread!


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## Tohuwabohu (Jun 20, 2008)

I think I know what's wrong: the resistance of the current sensor is too small.
According to the datasheet the HT2106 chip can deliver up to 500mA.
Output current is determined by the voltage at the feedback pin that is compared to the internal 200mV reference voltage.
With the 200 milliohm resistor this would mean an output current of 1A.
For 500mA output current the resistor should be 400 milliohm.

My boards arrived today. On my bords there is a + sign near the diode D1 and a - sign near resistor R1: 



I wired the board as rizky_p did and got similar current readings.
After a short while of testing at different voltages diode D1 was destroyed.
I didn't have a spare SMD diode so I replaced it with a through-hole Schottky diode.
I replaced the 0.2ohm resistor by a 0.53ohm (0.2ohm in series with 0,33ohm).
With this modification the board works as expected: 
I get an output current of aproximately 320mA over a wide input voltage range and the input current decreases with increasing input voltage.


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## jirik_cz (Jun 20, 2008)

I have here this electronic purchased 2 months ago



It looks like they use components with random values...:shakehead

I measured 800mA Iout with liion battery. Fortunately it still works


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## koala (Jun 20, 2008)

jirik_cz said:


> It looks like they use components with random values...:shakehead



:hairpull:


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## VegasF6 (Jun 20, 2008)

Tohuwabohu said:


> I think I know what's wrong: the resistance of the current sensor is too small.
> According to the datasheet the HT2106 chip can deliver up to 500mA.
> Output current is determined by the voltage at the feedback pin that is compared to the internal 200mV reference voltage.
> With the 200 milliohm resistor this would mean an output current of 1A.
> ...


 

What I am concerned with still is if the full current passes through the sense resistor. I think that is only a 1/4 watt or maybe a 1/2 watt resistor, and can't handle the current??


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## Tohuwabohu (Jun 21, 2008)

VegasF6 said:


> What I am concerned with still is if the full current passes through the sense resistor. I think that is only a 1/4 watt or maybe a 1/2 watt resistor, and can't handle the current??



That is no problem. Using a 0.4ohm resistor you would get a current of 0.5A with a voltage across the resistor of 0.2V. The power dissipated in the resistor is only 0.2V * 0.5A = 0.1W = 1/10 W. Even 1A with a 0.2ohm resistor would not be a problem: 0.2V * 1A = 0.2W = 1/5 W.

I did another test today with a 0.33ohm resistor as current senser.
It worked but not as good as with the 0.53ohm resistor I used yesterday: input current was about 1A independant of the input voltage, output current was around 0.7A. And again I killed something on that board.

I think it's better not to exceed 0.5A output current.
I found some 1ohm resistors an a defective hard drive. I will use two of them in parallel to get a regulated output current of 400mA untill I find a 0.4ohm resistor or get a replacent for my bords from DX.


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## VegasF6 (Jun 21, 2008)

Tohuwabohu, pardon my ignorance, that is where I am confused.

So, only the current for the value of the resistor is disapated through the sense resisor, and the majority of the current passes through the ground circuit elsewhere? Perhaps Pin 1? Or does this mean that R1 is in parralel with the ground circuit, not in series like I am presuming?

If you have the time, could you please explain to me the function of R2 and R3?

And, lastly, is this the sort of board that 2 of them can be paralelled to double the output current, like Rizky_P was able to do in this thread:https://www.candlepowerforums.com/threads/200752
I was surprised that he was able to do this, it has something to do with if you have a rectifier circuit vs a different type of high frequency circuit?

Thanks again for your knowledge.


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## Tohuwabohu (Jun 21, 2008)

VegasF6 said:


> So, only the current for the value of the resistor is disapated through the sense resisor, and the majority of the current passes through the ground circuit elsewhere? Perhaps Pin 1? Or does this mean that R1 is in parralel with the ground circuit, not in series like I am presuming?


 No, the whole current goes through R1and the other parts in series with R1: the inductor, D1 and the LED. But only a small part of the voltage is across R1 (~0.2V), the bigger part of the output voltage is across the other parts (~4V). With direct current you get the dissipated power by multiplying voltage and current. With a current of 0.5A only 0.2V * 0.5A = 0.1W is dissipated in R1 but appriximately 4V * 0,5A = 2W in the other parts.



> If you have the time, could you please explain to me the function of R2 and R3?


I'm not sure, but R2 could just be a protection for the the current feedback pin of the converter IC, it connects one side of R1 to the IFB pin. R3 is a pull up resistor for the chip enable input. CE could be pulled down by IC2, but that's not on the board.



> And, lastly, is this the sort of board that 2 of them can be paralelled to double the output current, like Rizky_P was able to do in this thread:https://www.candlepowerforums.com/threads/200752
> I was surprised that he was able to do this, it has something to do with if you have a rectifier circuit vs a different type of high frequency circuit?


I don't know. It looks different. I would not try to use two switching converters in parallel. I think it would be better to use one converter disigned for the higher current. I don't know if you can find something suitable at DX or KD, probably you would have to look for a higher quality driver at the Sandwich Shoppe. But flashlights and flashlight electronics is a fairly new field for me, so there may be other solutions.


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## Tohuwabohu (Jun 21, 2008)

I kiled one of the converter IC's.
I removed all components to take a photo of the naked board and the bottom side of the converter IC.




The components I removed:
C1 10uF
C2 100uF 6V
R1 0.2ohm (should be 0.4ohm)
R2, R3 1kohm
D1 Schottky diode, marking "S4"
IC2 2106F boost converter
L1 inductor, marking 3R3
IC1, D2 not on board


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## rizky_p (Jun 23, 2008)

Tohuwabohu said:


> I think I know what's wrong: the resistance of the current sensor is too small.
> According to the datasheet the HT2106 chip can deliver up to 500mA.
> Output current is determined by the voltage at the feedback pin that is compared to the internal 200mV reference voltage.
> With the 200 milliohm resistor this would mean an output current of 1A.
> ...




i removed the "270" resistor from the other board and soldered them in series that should give .540 ohm. It draws ~0.6A when the battery is fully charged and draw ~0.98A when the voltage drop below vF of the LED. At 3v Input it still draws ~0.9A. 

Thanks.


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## Nitroz (Jun 23, 2008)

rizky_p said:


> i removed the "270" resistor from the other board and soldered them in serial that should give .540 ohm. It draws ~0.6A when the battery is fully charged and draw ~0.98A when the lithiums drop below vF of the LED. At 3v Input it still draws ~0.9A.
> 
> Thanks.



Now that's funny! So it's get brighter as the battery power decreases.


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## Tohuwabohu (Jun 23, 2008)

Nitroz said:


> Now that's funny! So it's get brighter as the battery power decreases.


No, it doesn't. The input current goes up as battery voltage goes down, the output current is regulated and nearly constant over a wide range of battery voltage.
Brightness (photocurrent of a photodiode) against input voltage:



At ~4V the board goes into direct drive.


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## Nitroz (Jun 23, 2008)

Ooops, mis-read that one.


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## koala (Jun 24, 2008)

That's very clean job. :thumbsup:



Tohuwabohu said:


> I kiled one of the converter IC's.
> I removed all components to take a photo of the naked board and the bottom side of the converter IC.
> 
> 
> ...


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## rizky_p (Jun 24, 2008)

i also noticed that it maintain brightness down to somewhere 2.1v-2.3v. I can even fully use a LiFePo4 down to its empty voltage, at ~2.1v it start to dim, a good indication for LiFePo4.


Thanks


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## 12Johnny (Jun 27, 2008)

Thank you very much to all of you for your investigations, and then, for those (like myself) who are not very familiar with all these issues, I have one question:

According to what you have found out, would it be possible to use this driver "as is", without any modifications, just soldering the wires to some points, or would it be necessary to modify some components? 

Here you have some pics, in case that it would be possible to solder wires to other locations:












Thanks again! :thumbsup:


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## VegasF6 (Jun 27, 2008)

12Johnny, that is what we are trying to figure out 

So far I know you can connect your negative led lead at N as suggested, and your positive led lead can go to H or A (seems to be no difference that I can tell.)

From what I gather from Rizky it works ok, it is just horribly inefficient. I did play around with it some with 5mm leds and it worked fine for them, but the question is can we get a solid 1 amp from this circuit at something better than the 50% efficiency that he has. And, where is the extra current going? Why so hot?


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## jirik_cz (Jun 28, 2008)

12Johnny is this photo of your driver? R1 value on mine is also R270(resistor between O and P on your image) and it works fine! I get 800mA Iout with fresh liion. Runtime is almost 3 hours with one Trustfire 2500mAh, so it looks like it is very efficient. So far I used it more than 10 hours and it still works without problems.


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## CampingLED (Jun 28, 2008)

Finally had some time to study the thread in more detail and draw a schematic of the circuit. Tohuwabohu, I want to thank you for your great contribution. 
:bow::goodjob:

I just have the following questions based on the extra and missing components compared to the recommended circuit diagram (reference to R2, R3 extra, and 0.1microF missing):
- I think the 0.1 microF Cap will improve efficiency & ripple on the output?
- Has enybody tried to short R2 & R3 and measure the results without increasing the value of R1?


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## Tohuwabohu (Jun 28, 2008)

VegasF6 said:


> So far I know you can connect your negative led lead at N as suggested, and your positive led lead can go to H or A (seems to be no difference that I can tell.)


Correct.



> From what I gather from Rizky it works ok, it is just horribly inefficient.


It is inefficient but not horribly inefficient.


> I did play around with it some with 5mm leds and it worked fine for them,


Really? According to the data sheet of the Shanghai Belling BL5232 open load output voltage of the driver is 7.2V at 2.5V input. With the resistor on board the output current should be 500mA or higher with an apropriate load. With a 5mm LED you are somewhere in between, the LED should be destroyed very fast. Did you have an additional resistor in series with/parallel to the LED? 



> but the question is can we get a solid 1 amp from this circuit at something better than the 50% efficiency that he has.


No. The IC is designed for a maximum output current of 500mA.
According to the graphs in the datashet the efficiency is higher at 100mA output than at 300mA output. At 2.5V input and 300mA output the efficiency is approximately 80%.



> And, where is the extra current going? Why so hot?


It is converted into heat, that's why it is so hot.





jirik_cz said:


> 12Johnny is this photo of your driver? R1 value on mine is also R270(resistor between O and P on your image) and it works fine! I get 800mA Iout with fresh liion. Runtime is almost 3 hours with one Trustfire 2500mAh, so it looks like it is very efficient. So far I used it more than 10 hours and it still works without problems.


I tested mine with a 0.33ohm resistor. I got an output current of 700mA but regulation was not working properly: the output current went down with decreasing input voltage and the board was quite hot.




CampingLED said:


> I just have the following questions based on the extra and missing components compared to the recommended circuit diagram (reference to R2, R3 extra, and 0.1microF missing):
> - I think the 0.1 microF Cap will improve efficiency & ripple on the output?


It will improve ripple but I don't think it will improve efficiency noticeably. To increase efficiency you can add the compensation capacitor (22 microF capacitor across the LED) mentioned in the data sheet of the Shanghai Belling BL5232. I did this on my board and I did notice a higher output current at the same input current. 


> - Has enybody tried to short R2 & R3 and measure the results without increasing the value of R1?


Chip enable is a digital input, shorting R3 should have no effect.
Shorting R2 could have little or no effect depending on the impedance of the current feedback input. I don't think it's worth testing it.


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## 12Johnny (Jun 28, 2008)

VegasF6 said:


> 12Johnny, that is what we are trying to figure out
> 
> So far I know you can connect your negative led lead at N as suggested, and your positive led lead can go to H or A (seems to be no difference that I can tell.)
> 
> From what I gather from Rizky it works ok, it is just horribly inefficient. I did play around with it some with 5mm leds and it worked fine for them, but the question is can we get a solid 1 amp from this circuit at something better than the 50% efficiency that he has. And, where is the extra current going? Why so hot?


 

Thanks for your response!  Given that my English is not very good, when I read so many technical things, I have lots of doubts...  Then, I will solder the wires to the indicated points, and see if it works! 



jirik_cz said:


> 12Johnny is this photo of your driver? R1 value on mine is also R270(resistor between O and P on your image) and it works fine! I get 800mA Iout with fresh liion. Runtime is almost 3 hours with one Trustfire 2500mAh, so it looks like it is very efficient. So far I used it more than 10 hours and it still works without problems.


 

Yes, this is an actual picture of my driver (I have 3 of them that I purchased in a pack), and I am happy that it seems to work in your case so I am confident that it will also work in mine (let's knock on wood  :laughing: ). As soon as I have some free time I will try it, and post my results! 

Thanks again! :wave:


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## 12Johnny (Jun 28, 2008)

Tohuwabohu said:


> the whole post


 
Wow!!!! Thanks for the information! :thumbsup:


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## VegasF6 (Jun 28, 2008)

Tohuwabohu (god that is a moutfull  )
I was using 4 of these paralleled. Trying different voltages in, I didn't document my results, but it seemed to drive them nicely with a pretty constant brightness even at 1 volt. 

http://www.dealextreme.com/details.dx/sku.1105


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## jirik_cz (Jun 28, 2008)

Tohuwabohu said:


> I tested mine with a 0.33ohm resistor. I got an output current of 700mA but regulation was not working properly: the output current went down with decreasing input voltage and the board was quite hot.



Yes output current goes down with input voltage, but only slowly. And with one liion it is almost unnoticeable.


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## Tohuwabohu (Jun 29, 2008)

jirik_cz said:


> Yes output current goes down with input voltage, but only slowly. And with one liion it is almost unnoticeable.



Your results look good, definitely better than mine with a 0.33Ohm resistor.

I have read the whole thread again to see if I had missed anything.
I found what you had written in post #28:


jirik_cz said:


> It looks like they use components with random values...:shakehead


 and than had a closer look at the other components.
On your board, 12Johny's board and koala's old board there is a 22 microHenry inductor. The inductors on rizky_p's board and on mine are marked '3R3'. I don't have an instument to measure inductance otherwise I would have measured it earlier when I desoldered all components from my board. But after some thinking I found a way to measure the inductance with my USB-scope and I am now quite sure that it is 3.3microhHenry, far less than the 10uH recommended as minimum in the datasheet of the converter IC.
It really looks like they use components with random values...:thumbsdow

The boards with the 22uH inductor seem to work with a 0.27Ohm current sensor, my board with the 3.3uH inductor needs at least 0.4Ohm to work in some degree.
I already contacted DX and get another article of about the same price as replacement for my boards.


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## VegasF6 (Jun 29, 2008)

In addition, R2 and R3 are different values than mine.


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## CampingLED (Jul 25, 2008)

Tohuwabohu said:


> ....On your board, 12Johny's board and koala's old board there is a 22 microHenry inductor. The inductors on rizky_p's board and on mine are marked '3R3'. I don't have an instument to measure inductance otherwise I would have measured it earlier when I desoldered all components from my board. But after some thinking I found a way to measure the inductance with my USB-scope and I am now quite sure that it is 3.3microhHenry, far less than the 10uH recommended as minimum in the datasheet of the converter IC.
> It really looks like they use components with random values...:thumbsdow
> 
> The boards with the 22uH inductor seem to work with a 0.27Ohm current sensor, my board with the 3.3uH inductor needs at least 0.4Ohm to work in some degree.
> I already contacted DX and get another article of about the same price as replacement for my boards.


 
Received mine yesterday and I was hoping that they would have fixed the problem. Was out of stock for quite a while when this tread was very active and I was hoping that they were busy fixing their bugs after Tohuwabohu's feedback. Wishfull thinking on my side. My R1 is R250, L1 is 3.3uH and the other two resistors have a number of 3001 (3k ohm ?).

My understanding is that I either need to change L1 to 10uH or R1 to R500 to make it work as desired.

Question: Should I just return the boards with a long explanation, should I mod and keep quite, or should I use them as-is?


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## Tohuwabohu (Jul 25, 2008)

CampingLED said:


> Question: Should I just return the boards with a long explanation, should I mod and keep quite, or should I use them as-is?


Test one of the boards. If it gets to hot contact DX customer support  and report a defective/broken item.
Write a short desciption of what is wrong and upload a photo of your driver.
I did this and one or two days later I received an email form DX:
"_Apologies for the inconveniences. As to the defective SKU4735,would you want a refund or other item around the same price as replacement?_"
I did not have to send back the driver boards.
I don't think you will have to send back yours.
You can keep them and torture them to death or you can mod them just as you like.
Regarding the mod: it would be better to replace L1 but it is easier to replace R1.
The value of the two other resistors is unimportant.


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## TorchBoy (Jul 25, 2008)

Some nice detective work in this thread. :thumbsup:


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## CampingLED (Jul 25, 2008)

Thanks :twothumbs


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## CM (Jul 25, 2008)

I see two pictures in this thread that shows different values of sense resistors. One shows 0.27, and the other shows 0.2. The part in the first picture is set to 1A which exceed the specs on the converter chip. The second one is 740mA, lower but still exceed 500mA. With efficiencies of ~80% and current to LED of 1A, the part will dissipate about 3/4 of a watt (ouch!) Won't take long before the thing goes belly up from all that heat.


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## jirik_cz (Aug 16, 2008)

In this post you can see how the driver works with R1 = R270 and inductor = 220. 

As you can see the regulation is really good with li-ion battery. It is really a shame that new circuits are bad :-/


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## TorchBoy (Aug 17, 2008)

jirik_cz said:


> As you can see the regulation is really good with li-ion battery. It is really a shame that new circuits are bad :-/


The output voltage of a li-ion battery is pretty consistent, so it stands to reason that the regulator output would be pretty consistent too, unless it's really badly affected by heat. :shrug:

I'm still trying to get my head around the two different versions. Edit: AND all the different values of resistors for R2.


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## Scattergun (Sep 29, 2008)

Would these be possible to run parallell against one single LED for a higher current?


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## Scattergun (Oct 9, 2008)

Got mine today, and they are back to the old version! Is this good or bad?? :duh2:

EDIT
Actually, I looked into it, and they seem to be an even newer version!!


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## jirik_cz (Oct 9, 2008)

Got any detailed photo?


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## Scattergun (Oct 18, 2008)

Sorry, all three are already in lights... one went into a Mag 3D with a SSC P4 U-bin... worked fine on 4,5 Volts. 
The other two, I connected in parallell and put inside a Mag 2D with a SSC P4U2... when testing the circuits on three wolts connected to a Cree P4 with a comparatively high Vf, the parallell-connected two gave 0.8 A, I guess close to 1A on a SSC P4U2SWOH.

The difference compared to the first design is mostly layout...


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## seaside (May 1, 2009)

I just received 4735 driver from DX.

Not what Tohuwabohu and others got.
Must be the new board what Scattergun was talking about.

Here's the pic.







As you see the board, the soldering is not completed.
The SS14 falls off right after I took this pic above.






I am going to ask DX replacement.

BTW, I have no idea what the inductor value, since marking is wiped out.
Hope everything works fine.


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## old4570 (May 1, 2009)

www.dealextreme.com/customerphotos/4735-0a3228cf-a82c-4edc-af2d-a7844326673f.jpg


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## CampingLED (May 2, 2009)

seaside said:


> BTW, I have no idea what the inductor value, since marking is wiped out.
> Hope everything works fine.


 
Interesting. It was the wrong inductor value that caused the board not to perform well in the 1st place and now the value is removed. Usually a IC value is removed to "protect" the design.

Tks for the feedback.


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## MegaTesla (May 7, 2009)

Hi. Can anyone tell me if a higher value inductor will improve the efficiency?

thanks


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## CampingLED (May 7, 2009)

If I remember the previous discussions correct it is exactly what is needed to improve the efficiency. Around 20 uH is a good value.


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## CircuitsToPlowshares (May 14, 2009)

I ordered some that arrived back in March, and again that arrived last week. The ones from March had the 22uH inductor, the ones this month look identical but someone was overzealous with the flux-off and no marking just like yours, but the inductor itself looks identical. I modified mine with a .51 ohm resistor and it pulls about 500 miliamps off the battery and drives at about 400 miliamps on the led (cree q5). I also added 22uF cap across the LED, which does seem to improve efficiency.

If you don't want to wait on a replacement from DX you could probably reflow them yourself on a spare skillet. Just crank up the temp all the way and either place the chips directly on or use a small flat peice of thick metal as a heat spreader. Watch the circuit and you will see when it reflows because the solder will go nice and shiny. Then just carefully remove with either a flat metal spatula or some tweezers. You have just baked yourself a nice batch of chips. Or you can individually reflow each of the joints with an iron.


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## seaside (May 14, 2009)

CircuitsToPlowshares said:


> I ordered some that arrived back in March, and again that arrived last week. The ones from March had the 22uH inductor, the ones this month look identical but someone was overzealous with the flux-off and no marking just like yours, but the inductor itself looks identical. I modified mine with a .51 ohm resistor and it pulls about 500 miliamps off the battery and drives at about 400 miliamps on the led (cree q5). I also added 22uF cap across the LED, which does seem to improve efficiency.
> 
> If you don't want to wait on a replacement from DX you could probably reflow them yourself on a spare skillet. Just crank up the temp all the way and either place the chips directly on or use a small flat peice of thick metal as a heat spreader. Watch the circuit and you will see when it reflows because the solder will go nice and shiny. Then just carefully remove with either a flat metal spatula or some tweezers. You have just baked yourself a nice batch of chips. Or you can individually reflow each of the joints with an iron.


 

Thanks for the info. 

Replacement is on the way, and DX lets me keep those in the picture. So I did play arround with the driver. 

Since I can't find out the value of the mystery inductor, I have no idea what the value might be. But I guess its not 22uH since it looks identical to one of 1.5uH inductor I got with different driver (which also does overheat) 

The driver rather acts like those 3.3uH inductor version some members described at page 1 and 2 of this thread. It draws over 1A and quickly overheats when used with li-ion battery. But kind of strange, it somehow as it is quite nice with AA battery without heat issue. 

I took 0.25 ohm resistor off from another board, added it on series, made it 0.5 ohm and tried it. That solved overheating problem as you and other folk have observed. I was not able to measure current at LED, but it pulls about 0.41A at 14650 battery side when used with Q5. It is like 1A with AA battery.

SMD soldering is not a problem for me, problem is my lazy *** gets moving. So, I haven't fixed the driver with fallen parts yet. But I am sure I will do that when I need that driver.

Thanks again for the head up.


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## CircuitsToPlowshares (May 15, 2009)

seaside said:


> Thanks for the info.
> 
> Replacement is on the way, and DX lets me keep those in the picture. So I did play arround with the driver.
> 
> ...



I have a comparison here between the two I received. The one on the left is the previous one, and the one on the right is the latest one. As far as the inductor goes I will say the gauge looks similar and possibly wrap count.


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## seaside (May 18, 2009)

CircuitsToPlowshares said:


> I have a comparison here between the two I received. The one on the left is the previous one, and the one on the right is the latest one. As far as the inductor goes I will say the gauge looks similar and possibly wrap count.


 

Thank you very much for the pictures.

I received the replacement, and they are exactly the same as what I've received before. Mystery inductor, R250 and the same board. I am bit disappointed though... well... I got another 3 boards to play with. So, that's ok by me.

You can notice your two boards above are slightly different. Take a close look at those through holes. Right board has exposed ring pattern arrounds them while left board doesn't. This could mean, two different companies, or variations from batch to batch. 

Mine is the same PCB with your left board, and the same parts with your right board. And this made me guess that they have at least two parts supply sources, and slap anything from any supplier into the board. That, and the fact mine has heat issue, and that I don't have 22uH to compare to, i still can not be sure the value of mystery inductor.

So, how's your right board? Does it have any heat issue when used with 14500... like mine does?

Man, we just don't know what we're gonna get till we actually have it on hands.


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## seaside (May 18, 2009)

Another update.

The replacement seems to be working. 
It looks the same with the driver I got before, but it pulls out less current (0.85A) than previous one (over 1A) with fresh charged 14500 at 4.18V. 

I put the replament driver in ultrafire C3, and boy, who'd thought C3 can be this bright? It is like... bit brighter than my R2 drop-in at 350mA. :twothumbs

It does make small ultrafire C3 body hot but not too hot to touch. That's nice, especially when I think the fact the previous driver made my other AA sized flashlight so hot almost unable to grab in 10 minutes. 

I guess two mystery inductors are different. I feel good about it.
And thanks to my laziness. I still haven't solder fallen parts to the previous driver. I will not be able to tell which is which if I already did it.


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## CircuitsToPlowshares (May 21, 2009)

seaside said:


> Another update.
> 
> The replacement seems to be working.
> It looks the same with the driver I got before, but it pulls out less current (0.85A) than previous one (over 1A) with fresh charged 14500 at 4.18V.
> ...




Well just for you (not because of a bad hot glue job and ripping an inductor off of a new one) I rigged up one of the new batches. With a .51 ohm resistor on a fresh charged li-ion battery I am pulling .39 amps which is roughly the same as before. So at least for my batch I will assume the new ones are 22uH.


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## uk_caver (Jul 1, 2009)

Just got some of the newer versions to use as boost drivers.
With the original components, the efficiency is terrible.
Input voltages seem to be near enough to 1v25/2v5 at most loads.
To calculate rough effieciencies, Ill take LED output voltage as ~3v2 (which seems the case at ~200mA), and ignore losses in wiring/ammeters, tough those losses would tend to make efficiencies look worse at higher currents. Efficiencies in brackets after input/output currents.

1xEneloop AA:
Iin/Iout: 570/105mA (47%)

2xEneloop AA:
Iin/Iout: 1420/257mA (23%)

Tried with another driver, got basically the same results.

Tried adding 33u tantalum capacitors (the only values I had to hand) across both the input and the LED, vaguely in line with the datasheet.

1xEneloop AA:
Iin/Iout: 760/144mA

2xEneloop AA:
Iin/Iout: 1600/453mA

Rough efficiencies there of 48%, 36%

So that significantly improves efficiency on 2xNiMH, not much change on 1xNiMH.
However, since I'm using various flying leads to connect everything together on the workbench, that may mean that I have more need in my test setup for an input capacitor than would be the case in a more direct connection to battery power - my initial 23% on 2xAA could be partly a result of that.

Changing the R250 for a 1R0, and losing the output capacitor, I got:

1xEneloop AA:
Iin/Iout: 840/150mA (46%)

2xEneloop AA:
Iin/Iout: 320/185mA (74%)

A fairly drastic improvement on 2xNiMH, no real change on 1xNiMH

Adding a 33u capacitor on the output:

1xEneloop AA:
Iin/Iout: 580/137mA (60%)

2xEneloop AA:
Iin/Iout: 290/180mA (79%)

Slight improvement for 2xNiMH, significant improvement on 1xAA
It does seem that on 2xNiMH, with a 1R0 current sense resistor, the current is at least within 10% of what it should be (200mA).

Will try later with a 0R500 current sense, and see what happens.


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