Buck and Boost Drivers, Testing, Modding, and Discussion (Pic Heavy)

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snovotill
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And here’s another energy harvesting driver which will run an LED off of body heat via a Thermoelectric Peltier or TEG, only 25mV required! The resistor and capacitor in center can have two different value pairs, depending on the design revision. The caps with question marks need to be pulled off the board and measured out of circuit. They’re 0402 parts! You can buy the PCB for only $12 from the usual electronics component distributors.

sb56637
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Hi, please do not post embedded images, as they cause server load issues. All of the ones in this thread were just removed. Thanks.

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Barkuti
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sb56637 wrote:
Hi, please do not post embedded images, as they cause server load issues. …

What is considered an embedded image in this context? 

 

sb56637
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Barkuti wrote:

sb56637 wrote:
Hi, please do not post embedded images, as they cause server load issues. …

What is considered an embedded image in this context? 

 



<img src="data:image/png;base64,..." alt="Base64 encoded image"/>

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Barkuti
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Quick question fellows, does anyone knows which type of reverse polarity protection MOSFET the H1-A driver employs? It's the small 3 pin thing at the board backside, just g00gl€d the markings but no hits. The usage of such small MOSFET is also a tad strange to me, it totally looks inadequate given the amount of input current it should handle. 

 

kikkoman
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Barkuti wrote:

Quick question fellows, does anyone knows which type of reverse polarity protection MOSFET the H1-A driver employs? It’s the small 3 pin thing at the board backside, just g00gl€d the markings but no hits. The usage of such small MOSFET is also a tad strange to me, it totally looks inadequate given the amount of input current it should handle. 


 


Isn’t that the LDO?

Barkuti
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kikkoman wrote:
Barkuti wrote:

Isn't that the LDO?

Jensen567 commented something concerning reverse polarity protection in the past, now I can see it is present in the H2-C driver but not in the H1-A:

 

H2-C diagram

 

H1-A diagram

 

Came here with this tune in mind because a ForoLinternas fellow recently reported their H1-A driver blowing up because he tried to make it work with a cell in the wrong way. Aaaah! I understand now, master kikkoman

 

Cheers Party 

Hellie112
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Just tried to resister mod the h2-c driver from KD. It’s is now garbage, stuck on low power blinky mode. The driver also uses an different layout (compared to the pictures in the convoy L2/l6 mod thread ). The sense resistor on my version also had an r50 instead of the r100.

Barkuti
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The sense resistor was never an R100 in the H2-C Hellie112. Jensen567's early unit had two R100 resistors stacked, that equals 50mΩ (=R050).

Carefully check what you did to the sense resistor or other parts of the layout. “Low power blinky mode” looks to be low battery warning. If you have increased the power output and are using just 1 cell as input bear in mind other parts in the circuit causing voltage drops need to be optimized, this means good switch and well done spring bypasses or high current springs (you should optimize the current path anyway). Maybe you went overboard reducing the sense resistor.

 

Party 

Hellie112
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I didn’t had much time this afternoon. Guess never mod when you are in a hurry Silly But a trace on the backside (close to the spring) was completely burned. Did a bypass but now the driver pulls 10 amps (at the battery).. no change in output when changing modes. But I still got the flashing mode..

wildstar87
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I have a KX70 driver that has been modified exactly as Jensen567 had detailed, putting on a 2.8V LDO, moving the cap, with .01875 sense resistor. Everything seems to be working, except for one thing. The driver doesn’t fully turn off. The momentary goes through the modes using 1 press per switch, and it doesn’t seem to cycle off, so I hold to momentary down, and it seems to turn off, except the led (XHP70.2) is slightly lit, almost like a moonlight mode. Is there anything I’m missing?

Hellie112
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Just ordered a new h2c driver.
But I got a quick question. Is this the sense resister?

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Hellie112 wrote:
… got a quick question. Is this the sense resistor?

Yes. Smile 

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