Driver Info: HX-1175b & HX-1175B1 (Pic Heavy)

I swapped in some R086 resistors I scavenged from other drivers. Over 14A and started smoking. All the resistors have holes burned through the center.

Maybe the buck converter is oriented the wrong direction. Unfortunately they grind the label off of them. So I don't know how you could tell.

Thanks for testing this. You definitely got .049 and not 0.49? 13A across a total of 0.034 ohms should give about that much drop (1/2 volt). Sounds a lot like you are getting DD or as close as this driver will come (with the FET and inductor in the mix).

Could be I suppose. With QX5241 that just gives you a dead driver, but the pinout for QX9920 is different enough that it might give you DD; I’m not sure.

I think that it could also simply be a defective controller chip.

My DMM said .049v. I just set it to voltage, it’s got auto ranging. That’s all I know.

Seems like something is going on with the buck converter. Your driver is acting like mine did when I tied the PWM from an Attiny13a to the output pin of the buck converter. Wight pointed out to me then that I had basically turned the driver into a DD.

Later, I accidentally tore a leg off of that buck converter. I purchased a replacement that wight suggested may work. I will hopefully swap it tomorrow night. I'll let you know how it goes. The buck converters are fairly cheap.

wight,

Good call on the QX9920 buck converter. It works. Current to the emitter was as follows:

2S cells 4.5 amps (dropped fast to 4.4)

3S cells 7.15 amps

Thank you

Ouchyfoot,

Sorry it took me so long to get around to trying out the new buck converter. Here is a data sheet that wight linked me to. Here is where I bought mine from (link from this wight post).

EDIT: My chips were labled LEDA 1402. There was no indicator mark I could find for Pin 1. One of the short sides had a slight nub. I oriented the chip with the nub facing away from the inductor coil.

I added a couple R20 resistors to the above driver (using QX9920 buck converter). Pulls 9.65 amps with both 3S and 4S King Kong cells driving an MT-G2. Piggy backed an Attiny13a with JonnyC's STAR momentary modified by Tom E to include strobe. Wow, what a fun driver. I know exactly what light it's going in. Actually, I know 4 other lights that will be getting the similar setups.

EDIT: I just realized. I heard no PWM whine last night. The only things I did different was the FW just mentioned above and I completely air wired the MCU. In the past, I soldered the PWM leg of the MCU directly to the buck converter. Here is a pic (sorry, it's a bit blurry.)

Very interesting indeed!

Was hoping to find a spot on this driver to use for voltage monitoring. I poked and prodded with a volt meter using 2S and 3S cells, but could not find much of a drop in voltage anywhere on the driver. With 3S, most points read 5.27V. With 2S cells (resting at 7.92V) the same places measured 5.15 With such a small difference, I don't think it would do any good to install a voltage divider. I'm sure one would probably for for 2S, but not for 3S and 4S.

EDIT: Driver was under no load in the above measuring (no MCU or emitters connected).

It’s been a while since I thought about this driver (and I still don’t have one myself). Glancing over your pics again, maybe it does not have a voltage divider. That shouldn’t be showstopper though, airwiring a voltage divider should be an easy thing. I think I’ve covered the component selection (two resistors) pretty well over here (#917). For such a large driver I’d probably just use standard 1/8w or 1/4w through-hole resistors, you probably have the room for them. Higher values are better, less power draw.

Excellent. Great post you linked to there. I will be giving that a shot. I have a 4S build in progress. I should be trying it soon. I'll report back.

Let us know how the 4S goes. The big unknown for me on some of these Chinese boards is what the individual components, especially the capacitors and MOSFETs is voltage rated at. When you take into account the ringing that occurs I would hope to see a 25V rated input capacitor for 16V input use, but who knows? At least ceramics don't explode like electrolytics but I would definitely remove that little yellow tantalum cap. since you're probably not using it anymore, those can burn.

I've already used the driver in free air with 4S driving an MT-G2 at about 10 amps (9.65 per the DMM). Same reading I get with 3S cells. Set up on the driver was

  • Two R20 resistors added
  • QX9920 buck converter swapped in because I broke a leg on the stock buck converter.
  • MCU swappped - Attiny13a with JonnyC's STAR momentary modified by Tom E to include strobe.

Used the stock FET. I did not run it for very long (just a few minutes because it was late), but it showed no signs of distress and worked great. Didn't even get any whine from the MCU.

wight wrote:

It’s been a while since I thought about this driver (and I still don’t have one myself). Glancing over your pics again, maybe it does not have a voltage divider. That shouldn’t be showstopper though, airwiring a voltage divider should be an easy thing. I think I’ve covered the component selection (two resistors) pretty well over here (#917). For such a large driver I’d probably just use standard 1/8w or 1/4w through-hole resistors, you probably have the room for them. Higher values are better, less power draw.

Tried out your above idea using 4S 18650's driving MT-G2 with HX-1175b here with STAR Momentary (Ramp Down at 130 and Sleep at 115) and it works. I need to fine tune it though as it may be stepping down a bit early at this moment. I didn't take notes during the process. So here is what I can remember.

  • First tried 110000 Ohms for R1 and 5100 for R2. Ramped down way to early. Like 13.x volts.
  • Second tried 110000 Ohms for R1 and 6200 for R2. Started ramping down modes around 11.3 and Sleeping at 9.x Too low.
  • Third tried 91000 Ohms for R1 and 4700 for R2. Started ramping down too high again, like around 13.x.
  • Fourth, tried 82000 Ohms for R1 and 4700 for R2 and adjusted Sleep in FW up to 120. Haven't tested this set up yet.

I think the Atiny13a used for the above has a high reference voltage. 10% either way from 1.1 volts per the data sheet. The resisters used were 1% accuracy metal films. I just used matched (resistance and capacity) healthy laptop pull cells.

Sorry for the slim data. I need to get a power supply. My take away is that wight's idea works and that these high voltage applications will require fine tuning on an individual basis.

EDIT: fine tuned wording (in bold).

Sounds like a good start. Nailing down the ramp-down voltage first and then tuning the value for sleep makes sense.

I slightly edited my above post.

I'm excited about this as Low Voltage Protection it is much more critical for these high voltage lights. In a single cell light, it gets dimmer up in the 3.9's. Of course, you still have the risk of the light being on while your not aware. So LVP helps with that. But in a 4S light with a single emitter, you can go low while using the light. I'm really glad you shared the knowledge to help protect against that. I really need to find a decent budget power supply.

For the MCU, I guess you all don’t have pinouts, but do you at least know where some of the pins on what you think is the MCU chip are going to? Just curious if that would help identify the MCU?

I’m not aware of an MCU in that package. At all. I think it’s… what, a 10-pin TSSOP? I looked through the product lines for Atmel, Microchip, and I think also Zilog. I couldn’t find anything in that form factor to compare the pinout to! I’ll admit that I had trouble looking through Zilog’s portfolio.

Anyway the point is that step one is to at last identify an MCU that can physically match that landing pattern.

Maybe it’s not an MCU? Maybe something like this:

Does the one you all are thinking is an MCU look like the 10-pin in the pic in this post (on the 266050 driver):

I’m a newb here, just dropping in, but I was thinking that if you could get some traces from the 10-pin chip to wherever they go, that might give you some idea what the functionality of that chip might be?

Just thinking (sorry :)!!)…

Hi Ohaya. The 10 pin chip is definitely the MCU. No clue which one though. The pin functions that I know are as follows (looking at the top of the chip):

PWM Not Used

Not Used Not Used

Ground Not Used

Positive Power Supply Don't Know, but traces appear not connected to anything

Not Used Don't Know, Looks like it could be used for Voltage Monitoring but traces appear not connected to anything

Here is the orientation of the chip for the above pin out: