Ok - I'm asking about the Diode? The 10V 0.57A Diode? The ones I got from DigiKey are unmarked - cant' tell which end is the cathode. I'll try swapping it around I guess. Looks like I'm getting no power thru it to the MCU. Voltage read near nothing.
I don’t see why not. 4.2-4.35v is perfectly safe for the ATtiny13A, so you don’t need the 0.25v voltage drop from the diode. It seems that the only thing it’s protecting is the MCU. If you have physical reverse voltage protection then you don’t even have to think about it.
Check them with the diode test (beep) mode on your DMM. They only work one way, so it’s easy to figure out by comparing the two diodes. I’d also assume that the the text is rightside up on both diodes when they are facing the same direction, but I could be wrong about that! As I said, easy to find out using the DMM.
Edited, figured out how to do it without piggy backing, this is the bottom of a BLF15DD V3 I’ve modded to work in a piston drive Nitecore D10, the ground ring has the traces to it cut so it can be the contact for the piston, a wire runs threw the drill hole from that ring to MCU pin 3, the top ground ring is still ground as is the 3 sections with via’s on the bottom.
Ohh, missed the datasheet link on DigiKey. Been looking around at generic sources. No idea how to do a "diode test" on a DMM. Looks like my best guess on the cathode following the lettering was wrong - I have to flip it around. This is my last effort to get this board working - resistors I measured on the board were dead on - the diode was the only thing left I could try.
Anode left and cathode right of the lettering. I had to look it up myself just yesterday. But my memory, you know…the 1 went towards the ground ring, the 4 towards the battery positive. That’s what I remember. Anode, cathode, geode, whatever.
Cathode is the “line side” so print right side up, cathode(line) is on the right. The only + trace for the tiny 10 goes from the through via to D1 to Vcc. The via is a direct path from B+ To led+.
Those diodes are marked silly. The only way I can remember it is that the "1" in "41" is on the side where the line usually goes ;)
Ok - the replanted diode from a Nanjg was the culprit. Replaced it (properly) and low voltage monitoring is working. I must have had the "41" in backwards... Ooops! I think it is consistent with the text (cathode to the right).
Wondering - used a Samsung 15M cell to test low voltage. It first triggered at about 3.0v, but if you measure the cell when not under load, it's about 3.2v. So under load, the voltage is lower... Is it fair to use the under load voltage then, or should the voltage level with the LED off be used? Of course it's impossible to test with the LED off, but maybe a fudge factor should be subtracted to account for the loaded drop?
Always measure cell voltage under load. I would elaborate on this but I can't quite think of a good example.
Actually I think Tom E is on the right track, at least in terms of cell damage. My understanding is that resting voltage is where you determine whether the cell is at risk of damage or not. That said, at 3.2v you may as well call it 2.5v. The cell is empty. So in terms of monitoring, the point is somewhat academic.
OK…Mattaus was kind enough to give me his brd and sch of the 7135, I have tweaked them to now be compatible with the IRLML2052, pads and all (so no need to cut the 7135 traces
Here is the Tiny10DD
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https://www.dropbox.com/sh/3zvo72x35ee0f7m/AADnLg-l5TtBHOsIz1y8jnlga
OSHPark permalink
https://oshpark.com/shared_projects/0JRNMWAV
Tiny12DD
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https://www.dropbox.com/sh/wiv2o4g7x0lclsr/AABKsKd58k6Dszc6gZOP4obfa
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https://oshpark.com/shared_projects/SCu1AzNb
These are Alpha release, untested, I have had Mattaus go over it to make sure I didn’t mess somthing up…I have gone over it about 10 times making sure I got the G/S/D pins right
Only change from 10DD to 12DD was a larger ground ring, and I moved the resistors ever so slightly on 12 to loosen things up a bit (since there was more room to play with
No idea how often it’s necessary because when I tested the irlm 2502 on a DD board the gate resistor was needed for consistent operation yet when Dbcstm used it in his neck Ti Texas Poker it was not. Any chance you could move the FET up and over a bit to allow enough room to cut the gate trace from the via and jumper it with a 100-130 ohm R if needed?
Your talking about what is R3 on a 17DD here? What were the reasons you say you needed it when using this baby FET? I’m running a Tiny10 with one of those FET’s and it’s got some quirks, it works but I’m wondering of this could be the answer.
So do you guys recommend that this have a gate resistor?
I will go ahead and put one in when I get home…so consider the first release “beta”
I will also create a separate thread as to not clutter this one
Perhaps it’s working in my Texas Poker because it uses the 10440 cell and doesn’t provide over 3A? But work, it does! Loving it! Thanks again Scott, Matt, my family, the fans that supported me, Country music radio and my agent and the mailman and….oh, sorry.
Um, I see where the positive via could go straight through but isn’t the negative via going to cause direct drive only? Shouldn’t the negative on the FET side of the board be the ground ring and the negative on the MCU side be LED only?
And if the FET can be moved around easily, why not go ahead and put a center contact pad for a battery?
Nevermind, the FET has to feed the negative from the LED through the board. It needs to be known though that the “-” sign is not for battery use but LED use only, that could get confusing to someone that isn’t electronics saavy, like me.
But, isn’t the schematic on the FET backwards to what’s on the board? Isn’t “G” going to pin 6? And “S” going to ground? I’m confused.
Just an FYI the 70N02 FET’s are no longer listed on ebay, the link under the BLF17DD is dead. I cant find any on ebay anymore but I can find lots of 70N03’s and 80Nxx’s. would those be as good or should I go with the digikey option?
That seller seems to have disappeared entirely. Maybe later those will show back up along with their other items?
As to your question - It looks to me that the 70N03 is not as good as the 70N02. 0.0081 Ohms at VGS = 4.5v is not as good as 0.0053 Ohms at VGS = 4.5 V. The Digikey link seems to be better than the 70N02 though, it has 0.0032 Ohms at VGS = 4.5v. I think all of those values are acceptable though, really.
The method for rating continuous drain current for the datasheets I looked at (“NTB75N03R, NTP75N03R” vs “SUD70N02-03P”) seemed to be different. To me it seems that continuous drain current is close enough. Voltages look OK. As I said, RDS (on) seems higher but acceptable. I don’t see a problem with using the 70N03.
0.0081 Ohms at VGS = 4.5v is not as good as 0.0053 Ohms at VGS = 4.5 V…That’s almost inconsequential (I believe…heck that .003 ohm might cause it to heat up 2x as fast for all I know)…sure it’s more but it’s a “viable” replacement until the 70N02 come out…as long as everything else is the same