Electronics > Beginners

Having problems with a step up converter

<< < (3/4) > >>

MarkR42:
If it is the SX1308 (it looks like it), then they are very good. I've tested them.

The small pot has about 20 turns on it, and it doesn't have an easily detectable end-stop.

1. Connect the board to a power supply of NO MORE than 5v. If input voltage is >7v and the output is set too low, then something bad happens and the diode often catches fire.
2. Connect meter to output
3. Turn the pot anti-clockwise - it takes something like 10 turns before the voltage starts to rise significantly, then it starts going up quickly.

They are always shipped with the voltage set at minimum, it takes many turns anti-clockwise before the voltage rises. This is normal.

Once it is set at the desired voltage, I *think* you can use a higher supply, but always lower than the set voltage.

I also tried replacing the pot with a pair of SMD resistors and that worked ok too.

Changing the inductor looks possible, the one they ship is quite high (profile).

Moriambar:
Hi. I tried what you suggest, adjusting from the bottom through the top of the range. nothing change, I just have that schottky voltage drop and that's it.

spec:
Hi Moriambar,

Seems like you are having a bad time with the cheap ebay boost switching PSU. Not sure why, because thousands have been sold so they should work OK.

Your symptoms sound like the chip is locking out because it is not happy with the input supply characteristics.

Can you describe, specifically, what you are supplying the boost converter with, and can you post a picture of your test set up?

Moriambar:

--- Quote from: spec on December 02, 2018, 12:44:51 pm ---Hi Moriambar,

Sounds like you are having a bad time with the cheap ebay boost switching PSU. Not sure why, because thousands have been sold so they should work OK.

Your symptoms sound like the chip is locking out because it is not happy with the input supply characteristics.

Can you describe, specifically, what you are supplying the boost converter with. And can you post a picture of your test set up.

--- End quote ---

Hey, a problem from my part is why I posted here: I don't believe to be that unlucky, it's easier I'm clumsy.

Anyhow, I directly power it from my PSU, (VN+ or Vin on the… positive terminal, VN- or GND on the negative one) and attach the output terminals to my BM235. I'm not home thus I cannot provide pictures now, but my psu is an old TTi PL601, which I use normally without any problems and whose displayed voltages and current agree with the brymen.

Since the connection is direct, do you still need the pictures?

Thanks

spec:

--- Quote from: Moriambar on December 02, 2018, 12:50:55 pm ---Hey, a problem from my part is why I posted here: I don't believe to be that unlucky, it's easier I'm clumsy.
--- End quote ---
;D


--- Quote from: Moriambar on December 02, 2018, 12:50:55 pm ---Anyhow, I directly power it from my PSU, (VN+ or Vin on the… positive terminal, VN- or GND on the negative one) and attach the output terminals to my BM235. I'm not home thus I cannot provide pictures now, but my psu is an old TTi PL601, which I use normally without any problems and whose displayed voltages and current agree with the brymen.
--- End quote ---
All good!


--- Quote from: Moriambar on December 02, 2018, 12:50:55 pm ---Since the connection is direct, do you still need the pictures?
--- End quote ---
No, not needed thanks. You obviously know what is what.

Don't be offended by the following basic questions/procedures- I am not trying to tell grandma how to suck eggs, but it is always worth checking/testing.

BENCH PSU
[1] Are you sure that the current limit on the power supply is set to max?
[2] We once has a bench PSU that used to momentarily output 35V at turn on. It blew quite a few units randomly before we found out what was going on.
[3] I have experienced strange results with sophisticated PSUs and some equipment.  Have you got another simpler PSU or a decent battery: two LiIon batteries in series would be good.
[4] There may be something about the lab PSU turn-on voltage profile that the boost converter does not like.
[5] Remove the boost module positive lead from the lab PSU. Turn the lab PSU on and set the output voltage to 6V and the current limit to max. If there is a current fold-back selector on the lab PSU turn it to off.
[6] While the lab PSU is still on, touch the positive lead of the boost converter positive to the positive terminal of the PSU.

NEW BOOST CONVERTER, NEW POWER SOURCE
[1] Get a new boost converter, or at least one that definitely has never been connected to the bench PSU
[2] Connect a 220 Ohm, or there about, resistor across the output of the boost module.
[3] Connect a 2uF or greater low-loss capacitor directly across the input of the boost converter.
[4] Connect a 2uF or greater low-loss capacitor directly across the output of the boost converter.
[4] Connect the boost converter to a 5V to 9V DC source (not the bench PSU). Two 18650 LiIon batteries in series would be ideal.

Let us know how you get on. :)

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod