hybridfree/eevblog-posts huggingface dataset:
LG 27LC2R LC TV Power Supply blowing the board fuse - Page 1
Forum section: electronics / beginners

author: Gsimon850
author_rank: Newbie
timestamp: May 01, 2018, 09:05:35 pm
content: Hello chaps this is my first post so please be kind.My nippers TV is blowing the power supply board 5Amp fuse, I am not an electronics engineer but i do have a basic knowledge of components very basic to be said.I have found that the bridge rectifier is buggered this is a given, I have also tested the other diodes on the board and they all check out fine, and none of the caps are blown or swelling pointing to them. but on the hot side of the board there is one another diode that reads 0.124V in both directions.Is this buggered I have never had a reading like this before from a diode in circuit and I don't know if another component could cause this (WTF) reading without removing the diode which I don't really want to do at the moment because really what the hell is this.I only have a multimeter and I know you have to remove caps out of circuit to test them, hopefully that's correct.Can you give me a pointer nothing is burnt on the board i have tested all the underside SMD resistors and alike. Like I said I am a noob but not totally thick just stumped and confused.The bridge rectifier is on order X10 from Ebay and I have not got them yet but the other diode has thrown me a curve ball do I need to purchase this one as well. problem is I don't have the schematics for the borad and i am shooting in the dark and determined to sort it out, like dog with a bone, lol.Many thanks upfront really appreciate your advice and time.Take care chapsSimon

author: picandmix
author_rank: Frequent Contributor
timestamp: May 02, 2018, 08:03:24 pm
content: Hi,Its not unusual for the fault to be just the diode block, they can overheat easily if their spec is minimal, often turning the solder joints dry or even burning the pcb with the heat generated.Be wary of the electro caps as they can retain a powerful charge long after the power has been removed that can give you a nasty shock and burn !

author: lordvader88
author_rank: Frequent Contributor
timestamp: May 03, 2018, 02:04:14 am
content: Is this the PCB ? (I'm looking at google images)https://spares2repair.co.uk/images/lg/LG%2027LC2R-ZJ%20-%20PSU%20-%20LGP2637N%20-%206709900016A%20-%2068709D0006B%20-%20REV%201.1%20-%20051202.jpgThere's are high current diodes that have a forward voltage drop of few 10s-100s of mV at the current a DMM would test it with.Wish I had more stuff to try fixing, it's like a mystery video game only in real life.

author: Gsimon850
author_rank: Newbie
timestamp: May 09, 2018, 05:35:41 pm
content: HiYes this is the very same board dude.
LG 50PT250 5A Fuse Keeps Blowing - Page 1
Forum section: electronics / beginners

author: Pele23
author_rank: Newbie
timestamp: February 12, 2017, 07:47:06 am
content: Hi there can someone please help me to troubleshoot this problem please. I have a LG 50PT250 that keeps blowing the 5a fuse on the main power board.

author: SeanB
author_rank: Super Contributor
timestamp: February 12, 2017, 11:45:45 am
content: Little more info please. Does the cfuse pop on power plug in, does it go into standby and blow the fuse after a while, or what.Blowing on power plug in very likely the mains bridge rectifier is shorted, or the main power switching devices and the driver chips are now very dead.

author: Pele23
author_rank: Newbie
timestamp: February 13, 2017, 06:02:54 am
content: Ok so all I have done is check all fuses and found that one to be faulty so I replaced the fuse, plugged it in, and straight away it blew again immediately when plugging into power supply. Would it be better to just buy another power supply board?

author: GoneTomorrow
author_rank: Regular Contributor
timestamp: February 14, 2017, 11:13:12 am
content: 5A fuse blowing instantly means there's a lot of current flowing, i.e. dead short somewhere. Looks like the mains input is that blue connector bottom-middle? Main input fuse that ceramic guy next to it? So the fuse that's blowing is not the main input fuse. Basically you need to figure out what is electrically in series with that fuse and start looking for likely culprits.Youcouldjust buy a new PSU, and it will probably come to that if its busted enough. But diagnosing it even if you don't bother repairing it wouldn't be a waste of time.

author: wraper
author_rank: Unknown
timestamp: February 14, 2017, 11:29:27 am
content: Expect dead MOSFET(s) and likely dead PFC/PWM controller IC too. Some other stuff might be gone as well.

author: wraper
author_rank: Unknown
timestamp: February 14, 2017, 11:31:11 am
content: If you are very lucky, could get away with shorted rectifier on the input.

author: Pele23
author_rank: Newbie
timestamp: February 15, 2017, 10:06:43 am
content: Thanks for the help guys I have decided to just buy a complete new board saves mucking around with it. It was only $39.00 on Ali Express so thought it would make things easier.
LG OS-3040D Oscilloscope Calibration - Page 1
Forum section: electronics / beginners

author: Shark
author_rank: Contributor
timestamp: June 09, 2013, 07:53:49 am
content: Hi guys!This is my first post on this forum. I have an LG OS-3040D oscilloscope and would like to calibrate horizontal and vertical deflection.This oscilloscope is similar to models OS-3020D and OS-3060D. It is also rebranded as Conrad, EZ Digital and Goldstar.I was able to find user manual on Google, but no service manual, where I could find out which pots to adjust. I welcome any suggestionsThanks.

author: 128er
author_rank: Regular Contributor
timestamp: January 19, 2014, 08:46:33 pm
content: Hi,i know this topic is fairly old. But hopefully Shark is reading this. Or someone who is interested in the schematics. A few days ago i have buyed a broken Voltcraft OS-3020D with all schematics, for round about 30 €. Today i fixed it with a bit of tin solder. The storage mode doesnt work. On a pin of a SOT-23 transistor in the D/A circuit, was no solder.(by the way: the PCB is labled very nice)However, here are the schematics ...http://www.directupload.net/file/d/3507/8hpldj99_pdf.htmhttp://www.directupload.net/file/d/3507/5mv87yyl_pdf.htm

author: Shark
author_rank: Contributor
timestamp: February 28, 2014, 09:57:20 am
content: Hi 128er, wasn't expecting anyone would have found it as it's been so long. Thanks a lot!

author: bfsy
author_rank: Newbie
timestamp: July 18, 2024, 03:24:50 am
content: Could you please send me the schematics , Thanks very much !My e-mail : bfsy@163.com
LGA solder pad size - Page 1
Forum section: electronics / beginners

author: danbr
author_rank: Contributor
timestamp: April 28, 2015, 02:01:12 pm
content: Hey,I'm trying to build up a part in eagle cad using the LPS25H pressure sensor.The problem I'm having is that the datasheet for the part has a HORRIBLE diagram for trying to figure out the LGA solder pad size and placement. Its a HCLGA-10L package.Page 43:http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/DM00066332.pdfIs there something I'm missing here? Or does the diagram really suck. This is pretty much the only thing keeping me from going to the pcb printer.

author: chibiace
author_rank: Regular Contributor
timestamp: April 28, 2015, 02:16:43 pm
content: its not too bad, annoying not to have the numbers right there on the measurements though.

author: danbr
author_rank: Contributor
timestamp: April 28, 2015, 02:23:37 pm
content: The dimensions for placing the pads isn't so bad.But I'm I missing something, no where do I see the length and width of the pad listed. I know my geometry, and assuming that image is to scale I could figure it out, but that seems like a pain for what should be a simple listed dimension.

author: chibiace
author_rank: Regular Contributor
timestamp: April 28, 2015, 02:47:09 pm
content: b: 0.25 0.35

author: danbr
author_rank: Contributor
timestamp: April 28, 2015, 02:59:15 pm
content: What the hell?!B = b?Why couldnt they just use matching notataion

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 28, 2015, 05:55:08 pm
content: Yep... have fun with that...You'd think it was drawn in China......maybe it was..Seems like they're missing a full page: detail "B" is missing; notes 3, 4 and 6 are indicated but missing (no idea about the remaining notes); section A-A is missing; and dimensions b and L are missing from the drawing (likely belonging to detail "B").b and L are IPC standard symbols for width and length of the pad, in any case, so that should be what you need. Mind that pads 1, 2, 6 and 7 are rotated.IPC rules are usually pad = pad (nominal zero side fillet), with NSMD (non soldermask defined) preferred.The product page,http://www.st.com/web/en/catalog/sense_power/FM89/SC1316/PF255230?s_searchtype=keyword#suggests this (Design Resources / TN1198), but sadly doesn't provide the missing drawing sheet!You can email them about it. You might get a response, which is nice; but in my limited experience with ST, you won't get action.Tim

author: danbr
author_rank: Contributor
timestamp: April 30, 2015, 01:43:17 pm
content: I contacted ST support and they did get back to me!They suggested that I use the LPS25HB, as both the documentation is better (for dimensional drawings) as well as its a waterproof sensor! The electronics are the same I was told, so I will just go with this new part.

author: michael.hill
author_rank: Unknown
timestamp: April 30, 2015, 05:37:58 pm
content: I'll never understand why component manufacturers don't utilize reference dimensions...The rest of the world has learned to use them.
Li-Ion 18650 Charging - Page 1
Forum section: electronics / beginners

author: metrologist
author_rank: Super Contributor
timestamp: June 08, 2017, 09:57:45 pm
content: I have some good quality LG 2800 mAh cells from a laptop battery. If the cell is discharged to it's minimum spec (3V) and then applied 4.2V, how much current would you expect?

author: sleemanj
author_rank: Super Contributor
timestamp: June 09, 2017, 12:07:22 am
content: Quote from: metrologist on June 08, 2017, 09:57:45 pmThat depends almost entirely on it's internal resistance, let's say 50mR:4.2 - 3 = 1.2 dropped over the internal resistance1.2 / 0.05 = 24Afollowed closely by smoke, explosion, flame, running and screaming.This is why you do not charge a lithium ion cell with a simple constant voltage, you need current limiting to do the bulk of the charge.

author: metrologist
author_rank: Super Contributor
timestamp: June 09, 2017, 02:38:17 am
content: I was asking because I got an Anself CMTD Li-Ion PWM solar charge controller and someone pointed that out. The device does seem to have proper voltage control for an 11.1V battery pack (3S, 9V low voltage cutoff, 11.1V resume charge up to 12.6V) and I guess you just need to have a battery that could take it's full output, limited only by the panel and its rating of 20A.I was aware of the proper charging scheme, just expected the controller to be a little smarter. 20 amps is a lot of batteries.

author: Audioguru
author_rank: Super Contributor
timestamp: June 09, 2017, 02:56:20 am
content: A charge controller is designed to charge ONE battery so it can sense its current and voltage. Then 20A is not the charging current for a lot of batteries, it is the charging current for ONE very large Li-Ion battery. Most Li-Ion charger ICs allow the charging current to be programmed.

author: ebclr
author_rank: Super Contributor
timestamp: June 09, 2017, 03:06:32 am
content: Lipho Batterie charge have 2 phases1) Constant current2) constant voltageIt's not a good idea to connect 4,2V before passing the constant current phase or getting approx 4.1V ( this is approx I didn't remember the acurate number )

author: zoidiano0
author_rank: Newbie
timestamp: June 09, 2017, 12:16:47 pm
content: To be sure u should charge them at 500maIf u need faster charging go for 750-900maCheck in the data sheet what the charging voltage some are 4.1 and other 4.2If the battery bits completely dead charge them at lower current if there's around 3.5 or 3.7 u can go for 700-900 with no problemsIf u r in a rush go 1 ampAnd make sure your battery it's not getting hotHope this be usefulSent from my Moto G (4) using Tapatalk

author: amyk
author_rank: Super Contributor
timestamp: June 10, 2017, 02:29:58 am
content: Limit the current to 0.5C or less, and limit voltage to 4.20V (officially +/- 0.05V --- better to err on the lower side). The cell will try to take as much current as it can until the voltage reaches 4.2V, at that point the current will gradually decrease and you can consider it charged once the current drops to ~0.01C or less.Lion chemistry has no memory effect or other special needs, just keep the voltage and current within limits and it will work well.
Li-ion Batteries: Built In Charge Protection? - Page 1
Forum section: electronics / beginners

author: tommygdawg
author_rank: Contributor
timestamp: January 12, 2015, 03:43:41 am
content: Hey all,I've had a question for some time that I've had a hard time finding an answer to. If you have a Li-ion battery with built in charge protection circuitry, do you still need external charge protection? I have this battery:http://www.amazon.com/Fenix-ARB-L2S-Protected-Rechargeable-EdisonBright/dp/B00G9KHL4II was just curious as to the protocol with these kinds of batteries. Suppose you were to wire it to a small solar panel, would you still need external charge protection, since the battery has built-in protection? Any insight would be helpful!Thanks!

author: IanB
author_rank: Super Contributor
timestamp: January 12, 2015, 03:51:27 am
content: The protection circuit is a last resort safety device in case other things have gone wrong. It is not a substitute for a proper charging circuit.Lithium ion batteries like that one need to be charged with a lithium ion charger using a proper charging protocol.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 12, 2015, 03:58:19 am
content: I recommend charging to 4.1V at C/2 or less. Solar is an interesting problem to solve. Most standard charging chips are not usable, but there are a few that can be used, such as the LTC4070 for small panels.
Li-Ion Battery charger LED problem - Page 1
Forum section: electronics / beginners

author: Majek Ondrovic
author_rank: Contributor
timestamp: August 20, 2020, 03:49:57 am
content: I'm having an issue with a circuit I'm testing that uses a simple Li-ion charger IC. I'm using a Chinese brand TP4054 IC from LCSC that I assume is a clone of the LTC4054. I'm only using the knock-off because it's a Basic part for JLCPCB assembly service. See my crude schematic attachedThe issue is with my charge status LED circuit. With the battery attached, everything works fine, however when there's no battery and VCC is supplied, the LED toggles on and off rapidly at a dim level, and the Charge status pin reads about 2.6v. Unfortunately I do not have access to a scope. The datasheet says that the Charge status should be 10ma pull-down when charging, and a weak 20µA pull-down when complete, but in undervoltage lockout it goes high impedance. I'm not sure what the pin does when no battery is present.I notice the datasheet mentions to use an output capacitor to reduce ripple voltage when no battery is present. It also says to add a 1 ohm series resistor if low ESR caps are used.I put in a 10uF ceramic cap by the battery but forgot about adding any resistor. Should I add that resistor ?, and how does that effect the battery when it's plugged in?Thanks

author: Peabody
author_rank: Super Contributor
timestamp: August 20, 2020, 04:46:44 am
content: I'm not sure the TP and LTC parts are the same. They are not the same for the 4056. So I'd suggest you use the TP4054 datasheet in case there are any differences. But it's possible the blinking LED is the intended behavior if the charger is powered but no battery is present. The TP4056 has separate pins for the charging and charge termination LEDs, and it turns both on if there's no battery.

author: kjr18
author_rank: Regular Contributor
timestamp: August 20, 2020, 04:52:24 am
content: If there is no battery connected, Stand-by led should be lit, and charging led should flash at about 1 to 4 Hz. At least that what datasheet says.
Li-ion battery charging - Page 1
Forum section: electronics / beginners

author: jeet55
author_rank: Contributor
timestamp: August 29, 2017, 08:36:21 pm
content: How critical is the float charge voltage of a li - ion battery and can i make a single cell charger using lm317?

author: Rick Law
author_rank: Super Contributor
timestamp: August 29, 2017, 08:52:35 pm
content: Quote from: jeet55 on August 29, 2017, 08:36:21 pmEverything I have read say LiIon batteries should not be float charged.

author: edpalmer42
author_rank: Super Contributor
timestamp: August 29, 2017, 09:53:55 pm
content: Most lithium batteries* should be charged to 4.2 +- 0.05V with an appropriate current limit (varies for different batteries). Then hold the voltage constant and monitor the current. When the current has dropped to ~10% of the limit value, disconnect the charger. Lithium batteries shouldNOTbe float-charged unless you really, really,reallyknow what you're doing.*LiFePO4 should be charged to 3.65V. There are a few other specialized types that have different charge voltages.

author: Cliff Matthews
author_rank: Unknown
timestamp: August 30, 2017, 12:41:59 am
content: Buying 3 of these at 87 cents eachis cheaper in the long run (and no heat sink required either).
Li-ion battery discharge question(s)  - Page 1
Forum section: electronics / beginners

author: Hagis2k
author_rank: Regular Contributor
timestamp: April 09, 2014, 07:05:32 pm
content: Was some time ago since i studied electronics lolBut i have one 18650 cell and lets say if i run a constant current discharge at 100mA/h between 4.2V down to 3.0V and if it lasts 5hrs and 7min wouldn't that cell have the capacity of roughly 511mAh?5 * 100 = 500 / 100mAh/60=1.66 7min * 1,66 11.6mAh if im not mistaking then it shall be around 511mAh ?I think im on the right track but i just ask again to confirm

author: cyr
author_rank: Frequent Contributor
timestamp: April 09, 2014, 07:24:25 pm
content: "mA/h" is a nonsense unit, and I don't quite follow your calculations.But yes 100mA for 5 hours is 500mAh, and that seems to be the approximate capacity of your battery.

author: Hagis2k
author_rank: Regular Contributor
timestamp: April 09, 2014, 07:33:34 pm
content: Yes then at least i remembered something i assume, my calculations are 5hrs x 100mA = 500mAh then i divided 100mAh in 60min and get 1.66mAh per minute then 7min x 1.66 which gives me 11.62mAh for the 7min then 500+11.62 so i assume my battery delivers around 511mAh and not the claimed capacity

author: Neverther
author_rank: Regular Contributor
timestamp: April 09, 2014, 07:34:07 pm
content: 100mA/h seems wierd unit (as stated above, Ive also seen W/h written, but that's the internet...) current change of 100mA in an hour.With 100mA constant current you are draining 100mAh in one hour.So just convert the dischargetime to hours decimal and multiply with the constant current used to drain.5 7/60 h * 100 mA = 511.6666... ~ 512mAh at 100mA load.That's rather poor for 18650 so I assume you got either old laptopcell or old laptopcell rebranded as new chinese cell.Not even two watthours at nominal 3.7V figure so even alkaline AA has more energy than that.

author: Hagis2k
author_rank: Regular Contributor
timestamp: April 09, 2014, 07:52:19 pm
content: Yes it is a chinese cell lol with fantasy ratings on it seems like the quality of the two shitty firepeak differs one is around 511-512mAh and the other is closer to 1000mAh so nothing near 3200mAh lol only ones i know is panasonic 3100mAh and 3400mA and yes i have ripped a few laptop batteries apart too

author: amyk
author_rank: Super Contributor
timestamp: April 09, 2014, 08:36:06 pm
content: That's horrible even by Chinese 18650 standards... I'm guessing it's either areallyworn-out recycled cell (most of the recycled ones are still 1500mAh+) ornot a real 18650.
Li-ion battery selection - Page 1
Forum section: electronics / beginners

author: ZeroResistance
author_rank: Frequent Contributor
timestamp: May 06, 2017, 07:45:26 pm
content: I am looking at Li-ion battery chemistries that would be suitable for inductive / motor loads. Basically my loads are bldc motors and the total wattage would be around 30 watts.Fromhttp://batteryuniversity.com/learn/article/types_of_lithium_ionI see that NMC battery seems to be well suited for this is has good energy density, specific power, safety cost performance and lifetime.The Lithium Iron Phosphate(LiFePO4) battery also looks interesting although its energy density is low compared to the other Li-ion chemistries but it is highly safe.A search on amazon revealed that Panasonic is a reputed and reliable source of these batteries and they generally go in the 18650 form factor however the battery chemistry is stated as NCR, any idea how NCR compares to the NMC battery?I'm open for Any other suggestions for battery chemistry to power the loads I stated earlier.

author: chota.sanjiv
author_rank: Contributor
timestamp: May 07, 2017, 09:58:37 am
content: https://batterybro.com/blogs/18650-wholesale-battery-reviews/18880255-battery-chemistry-finally-explained

author: ZeroResistance
author_rank: Frequent Contributor
timestamp: May 07, 2017, 12:10:17 pm
content: Quote from: chota.sanjiv on May 07, 2017, 09:58:37 amThat's some excellent info. Many thanks!!!I would like to keep the batteries as a backup source so during mains operating they would be either in charging or standby mode.My next question is my loads are rated for 12V, although I thing bldc motors can work over a wide range of voltage correct me if I'm wrong.So lets say if the nominal voltage of the battery is 3.7V and I charge it to a max of 4.2V and if I use 3 cells that makes it 4.2 x 3 = 12.6 volt max and lets say that I can use it upto a min of 3V per cell so that makes it a min of 9V. So the battery voltage would vary from 12.6 to 9V.for 4 cells the battery voltage would be from 16.8 to 12V.So should I use the 3S configuration or the 4S?
LI-ION Cell Charger HELP! - Page 1
Forum section: electronics / beginners

author: XMA
author_rank: Contributor
timestamp: April 14, 2018, 06:48:39 am
content: okay so I've got this Li-ion charger and the weird thing I don't understand is, that the charger shows that the battery voltage is at 4.19v, but when I go and measure the cell with my multimeter it shows 4.26v? what is happening here? my guess is that the charger is showing the voltage under a load or something. while the multimeter is showing it on idle without load resulting in a higher voltage. or my cheap Chinese multimeter is trash.also for some reason, it's taking forever to reach 4.20v.

author: soubitos
author_rank: Frequent Contributor
timestamp: April 14, 2018, 07:11:35 am
content: Quote from: XMA on April 14, 2018, 06:48:39 amWhich charger are we talking about?What multimeter are you using and is it at all reliable/tested against known voltage or reference multimeter?Taking forever to terminate charging sounds more like aged cells to me or low quality cells.Of course it all depends on the charger too, charge current and other factors

author: XMA
author_rank: Contributor
timestamp: April 14, 2018, 07:23:47 am
content: Charger is a VONTAR ZL220CMultimeter is a A830LThese cells are from laptop batteries, so its probably because of its age.

author: KL27x
author_rank: Super Contributor
timestamp: April 14, 2018, 08:22:19 am
content: QuoteThis is just calibration error unless proven otherwise. And why would you think otherwise?QuoteIt might be due to age that they will no longer hold a float voltage of 4.20. But how long is long? When the battery is at 4.19V, there's only a hundredth of a volt trickling an itsy charge current into the battery. The last 1% takes really long. Most chargers will just cut off when the charge current drops to an arbitrary trickle and turn on the green light, "bing." You don't need a green light to tell you when it's done charging. You have a voltage display. When it's high enough for you, it's done charging.
Li-ion charge discharge ic - Page 1
Forum section: electronics / beginners

author: Belrmar
author_rank: Regular Contributor
timestamp: November 01, 2017, 12:46:03 pm
content: Basically i am designing a product but i am starting to get some problems with the footprint of the "single cell bms" i designed because basically i have a 11mm radius to sqeeze into all my circuitry.I have been loking for a IC that cuould do the same as my circuitry when talking about introducing a undervoltage cutoff and linear charging but i cant find anything costeffective or suitableAny thoughs on IC's that could do that?Sorry for my bad english and feel free to point any faults on mu squematic

author: fourtytwo42
author_rank: Super Contributor
timestamp: November 01, 2017, 04:34:44 pm
content: You mention 11mm radius but you dont specify the length, so maybe you should be considering re-orientating your pcb

author: Belrmar
author_rank: Regular Contributor
timestamp: November 01, 2017, 05:45:38 pm
content: well basically i am getting forced to a small area by the objet that the pcb goes into, basically it sits on the bottom of a 11 mm inter radius tube

author: ebclr
author_rank: Super Contributor
timestamp: November 06, 2017, 02:26:31 pm
content: I'm not suresomething like this

author: Belrmar
author_rank: Regular Contributor
timestamp: November 06, 2017, 03:46:45 pm
content: this is actually perfect, ty very much
Li-ion protection circuit - Page 1
Forum section: electronics / beginners

author: nonsubscriber
author_rank: Newbie
timestamp: May 04, 2023, 09:29:29 pm
content: Hi folks. Thanks for any replies...I believe the answer is "of course," but just checking. I should be able to use a protection circuit for 18650 batteries with 14500 batteries right? Guessing with voltage being the case ie. 3 cells = ~12V what is being safetied is the charging current right?

author: thm_w
author_rank: Super Contributor
timestamp: May 04, 2023, 09:42:45 pm
content: Its not really charging current that you are protecting against, its overcurrent when discharging or when the pack is shorted.The overcurrent protection designed in for 18650's might be a bit high for 14500's.But the main function is the under and over voltage protection, which would be the same.

author: amyk
author_rank: Super Contributor
timestamp: May 04, 2023, 10:20:25 pm
content: The most common protection ICs e.g. DW01xx series use the resistance of the MOSFETs to set their current limits.
Li-Ion protection IC- current sensing? - Page 1
Forum section: electronics / beginners

author: rexxar
author_rank: Frequent Contributor
timestamp: May 26, 2014, 07:51:18 am
content: I'm looking at using theBQ29700Li-Ion protection IC, and I can't quite figure out how it does current sensing. There's no sense resistor, so I wonder if maybe they're using the RdsON of the FET to do the current sensing? That doesn't seem to make much sense though, as the RdsON is different between different kinds of FETs

author: amyk
author_rank: Super Contributor
timestamp: May 26, 2014, 12:22:02 pm
content: Indeed it does. Look at page 20.
Li-ion Solar Charging circuit - Page 1
Forum section: electronics / beginners

author: ripper121
author_rank: Contributor
timestamp: April 16, 2015, 12:00:59 pm
content: Hi,I need a charging circuit for a 7.4V Li-ion Cell and a 14V 300mA (measured in the sun so i think its a 12V Panel).I read many about the LM317 bad and good, but i dont know what IC and circuit I should use.I need a easy and cheap circuit for charging a 7.4V Li-ion Cell with a 12V Panel and optionally external Power.Thanks

author: Simon
author_rank: Unknown
timestamp: April 16, 2015, 12:03:13 pm
content: You will need a proper charging circuit for Li-ion as otherwise your battery can become a hand grenade. You'd best use something that is based on a switchmode design to maximise efficiency as the LM317 just turns power into heat and wastes it.

author: ripper121
author_rank: Contributor
timestamp: April 16, 2015, 12:06:13 pm
content: Yes i know read this many time before.But do you have a good IC and schematic for me?

author: Simon
author_rank: Unknown
timestamp: April 16, 2015, 12:52:31 pm
content: look for a li-ion charge controller IC, it may do the switchmode bit itself or you may need to put a SMPS in front of it.

author: ripper121
author_rank: Contributor
timestamp: April 16, 2015, 02:32:28 pm
content: What do i have to change in this Circuit to fit my App.In 12V out 7.4V.
Li Ion suppliers - Page 1
Forum section: electronics / beginners

author: John80
author_rank: Contributor
timestamp: July 05, 2011, 10:38:03 am
content: Do you know any web site for Li Ion batteries? Something like:http://www.powerstream.comEspecially in Europe for VAT purposes...

author: nzo
author_rank: Regular Contributor
timestamp: August 16, 2011, 05:06:14 am
content: Maybe you already have your batteries. If not, tryhere
Library and Component Management, how do you do that? - Page 1
Forum section: electronics / beginners

author: 4a4ik
author_rank: Contributor
timestamp: January 29, 2016, 10:32:37 am
content: Hello, When you are working on a new project, and you need to create new components for your project (both schematic and footprint). What is the best way to organize that ?Is it better to make specific libraries for manufacturers and edit them afterwards ?Create component specific libraries like "resistors", "mosfets" ?Create new library for every new project ?And if you are working with someone how do you organize that ?For example 2 people are making PCB / circuit / or both, how do they share their libraries? they make them project specific ?Or they share all of the libraries they have ?

author: andre_teprom
author_rank: Regular Contributor
timestamp: January 29, 2016, 09:28:32 pm
content: Some PCB CADs are made so that already supports distributed design.Anyway, the criteria may vary depending on the company strategy.I personally don't have any specific policy, I just add new components to the main library.In the case of sharing the library, I just removed the unused parts, but not so often.
Library of open source designs? - Page 1
Forum section: electronics / beginners

author: mabartibin
author_rank: Newbie
timestamp: January 10, 2025, 11:12:54 am
content: In the context of a research project about electronic waste recycling, I’m looking for data about the composition of electronic devices. Essentially BOMs. It’s hardly possible of course to get our hands on the BOMs of a good selection of commercial products. But as a starting point I wonder whether there is some collection of open source designs?That would at least allow to produce statistics about the values (sizes) of used capacitors, correlations between certain ICs and associated passives (decoupling caps at least) etc.We could try to scrape github for shared design files, but that might end up being being quite a project in itself.I seem to remember (hallucinate?) reading about shared designs in connection with some PCB manufacturer…?Any hints appreciated!Martin

author: Nominal Animal
author_rank: Super Contributor
timestamp: January 10, 2025, 12:41:31 pm
content: I useoshwlab.com(seemy projects), and many but not all do include BOMs. When included, you can even download the BOM in Excel 2007+ format; I suggest you use Python and one of the Excel format libraries likepylightxlto read and convert the files. (Many of the OSHWLab projects are created using theEasyEDAonline PCB editor suite, which includes integration with JLCPCB manufacturing and LCSC parts catalog. Very gentle learning curve for hobbyists.)The downside is that these are typically hobbyist projects –– including mine! –– so quality varies a lot, and is predominantly on the lower end of the scale. There are also a lot of variants of the same project (due to Open Source HardWare making it easy to do so, especially for us hobbyists), so you'll get very skewed results unless you human-filter the projects. Auto-scraping the entire site would also be quiteunfriendly; at minimum, contact them and describe your project and intent for the data, first.

author: tooki
author_rank: Super Contributor
timestamp: January 10, 2025, 01:00:04 pm
content: Many IC manufacturers have huge libraries of reference designs and evaluation board designs one can download. I’ve used ones from TI and Analog Devices many times. Some of them are barebones, others are practically complete enough to package and sell.
LiFePo4 cell protection IC? - Page 1
Forum section: electronics / beginners

author: cdevidal
author_rank: Regular Contributor
timestamp: March 02, 2025, 09:37:46 pm
content: What do you use for cell protection on LiFePo4? Looking for more choices of protection ICs for LiFePo4 similar to the DW01, which is only for Li-Ion. These chips should shut off discharge at 2.5V. I only need to do one cell at a time.I found one. TheHY2112-HBwould work butJLC has none in stock, and their price to buy more is very high. JLC allows you to send them parts for consignment, so I could buy atanother vendorand have them mail the parts to JLC. But I also want other alternatives in case that becomes a dead end for some reason.I searched JLC's parts listing but I found no other cell protection IC for LiFePo4--that doesn't necessarily mean they have none; It might simply mean they didn't list it properly. Their site isn't the bestDigiKey showsnothing for single cells.Same with Mouser.

author: JustMeHere
author_rank: Frequent Contributor
timestamp: March 02, 2025, 09:47:53 pm
content: If it's just one part, solder it on yourself.

author: cdevidal
author_rank: Regular Contributor
timestamp: March 02, 2025, 09:50:28 pm
content: Quote from: JustMeHere on March 02, 2025, 09:47:53 pmThat's a maybe, but I'm trying to set up a small assembly line and would do that only as a last resort.Actually what I may do is use aDW01Seven though it's designed for Li-Ion, because the low cutoff voltage and overcurrent are my only real concerns. The charger IC handles the high voltage cutoff and is the only way path by which power can enter the cell, so it's not an issue that the DW01 would not stop overcharge. I can't find an English datasheet, but Google Translate did the job well enough.

author: temperance
author_rank: Super Contributor
timestamp: March 02, 2025, 10:58:20 pm
content: You will probably also need an over voltage shut down. For a single cell you can also use two voltage detectors. Something like this:https://www.onsemi.com/download/data-sheet/pdf/max809s-d.pdfJLPCB has this one which at first glance seems to be the same:https://wmsc.lcsc.com/wmsc/upload/file/pdf/v2/lcsc/1810171817_VP-VP809TEUR-T_C7895.pdf
LiFePO4 charger (ADP5063) used with a Li-Pol battery - Page 1
Forum section: electronics / beginners

author: DanioIO
author_rank: Contributor
timestamp: August 31, 2014, 05:23:17 pm
content: Hi,I have a couple of ADP5063 ic and i want to make a charger for my Li-Pol batteries can i use this ic safely? I will need to change the charging termination voltage to 4.2V but this ic allows it so are there any other stuff to consider?ADP5063 datasheet (http://www.analog.com/static/imported-files/data_sheets/ADP5063.pdf)

author: eas
author_rank: Frequent Contributor
timestamp: September 01, 2014, 05:56:07 am
content: Interesting chip.I'm just learning about this stuff myself. The thing that caught my eye is that you'll probably want to adjust the current thresholds for Iend. I think the typical guidance is to terminate charging when current drops to 1/10th of the constant-current phase charging rate. It looks like this chip configures those parameters independently from each other, and the default termination current is less than 10% of the default CC rate.

author: DanioIO
author_rank: Contributor
timestamp: September 01, 2014, 07:12:30 pm
content: Hmm, now im thinking about blowing a Li-Pol battery with this ic i wonder if its possible...
LiFePO4 charger design - Page 1
Forum section: electronics / beginners

author: tpimh
author_rank: Newbie
timestamp: March 16, 2018, 08:56:48 am
content: I'm designing a battery management system for 4-cell LiFePO4battery which will have protection, balancing and charging functions.For overcharge, overdischarge, charge overcurrent and discharge overcurrent protection and cell balancing I would use aR5436T508BA(datasheet). But I have no idea about the charging circuitry. As I understand, LiFePO4 uses constant voltage and constant current for charging, should be pretty easy to implement, right?I have three different chargers in mind: step-up (for example, 5V to 14.6V booster), step-down (for example, 24V to 14.6V) and buck–boost converter (wide range). This kind of charger may get pretty complex (example 4S LiFePO46-36Vincharger design) and I want to keep it simple, yet I don't want my battery to die soon. Could you please recommend some charger IC for charging that will behave well withR5436by it's side? If you think I don't understand something, please tell and optionally add a link to an article with explanation.

author: soubitos
author_rank: Frequent Contributor
timestamp: March 16, 2018, 10:50:03 pm
content: charging and protection/balancing are generally speaking separate things.. if you have the second covered, the first one should be a little bit "easier" as there are more options out there but still tricky as you need to find the right one...You can check ICs like LT3652, LTC4121, LTC4015 (these just from Linear and from a short search, i bet there are plenty more to suit your needs.... but keep in mind LiFePO4 is not that extensively available as "standard" LiIon or LiPo

author: jram
author_rank: Contributor
timestamp: March 18, 2018, 08:59:23 pm
content: I run a 600Ah Lifepo4 bank. In designing the protection system, I opted to protect the batteries from over and undercharging with custom parameters that would increase the life of my bank. Charging to 3.6V and discharging to, say 10V, will likely result in a shorter bank life so I chose voltages of 13.8 - 12V for everyday, low C useage. Our maximum current draw is about 180A (12.8V) when we have the kettle and the hot water heater on. Without knowing your use case, its hard to say what's right, however, I found no ICs that would allow me to set the parameters I wanted so I just use a microcontroller to provide warning and protection.
Lifted a SMD RGB LED pad off a mechanical keyboard, fixable? - Page 1
Forum section: electronics / beginners

author: taco1994
author_rank: Newbie
timestamp: November 19, 2017, 05:28:55 pm
content: Hello everyone! I'm Darren from Johor Bahru, it is nice to know you guys.I am a beginner in electronics but would love to dive into this field, it has been pretty interesting to work on a lot of different things thus far! This time is probably the first time i've ever accidentally damaged something, and am unsure on what could be done to rectify itIt's a mechanical keyboard with a few faulty SMD LEDs, so I had sourced for the replacements and have managed to fix most of the LEDs successfully, however on this last one, I had accidentally lifted off the solder pad for the one marked B (BLUE)This is how normal, undamaged LED SMD solder pads look likeSo yeah, for the B I had accidentally lifted the pad totally, i reckon it is poorly glued onto the PCB and was sensitive to heat..I had tried soldering on an LED onto it, evidently the blue hue is not functioning, but as the -ve, R and G are soldered fine, green and red lights or its combinations work perfectly well, just no light when it is changed to blue.I am hoping that there would be a way to fix this? Perhaps connecting a single core copper wire of some sort? I would appreciate any guidance given and thank you deeply for your time reading this..PS this is how the back of the board looks like (the solder holes are there because I removed the mechanical switch for that particular key)

author: Arjen_Arg
author_rank: Contributor
timestamp: November 19, 2017, 07:23:31 pm
content: Hi there. Just peel off all the solder mask from the remaining track all the way to the via hole that is right there. Exposing the cooper. Then just make a bridge from the via to the terminal on the LED, either with a thin wire or with just tin if you can.
Lifted pad for battery circuit. Help with repair? - Page 1
Forum section: electronics / beginners

author: Mp3
author_rank: Frequent Contributor
timestamp: July 24, 2018, 08:11:44 pm
content: Hi guys! i'm asking for a little bit of advice since there is a battery involved here and i don't want to do something stupid. I got an older machine which uses SRAM and has a soldered in 3.6v battery, the problem is after about 10 minutes of being powered off the machine would lose its memory despite having a new battery.I opened it and found the pad to the battery was lifted. It must have had just enough contact to let the battery keep it charged within a minute or two of being powered off.Looking at the circuit, the side with the lifted pad (negative) connects on the PCB to a nearby transistor(?) while the positive side connects to a nearby resistor.Is it safe to directly wire the leg of the battery to these two components the PCB connects them to? I don't like to do something so hacky, but i am afraid i don't have much other option.I've attached a photo of the pcb from the top side as well as clips from the service manual of the relevant parts of the schematicsThanks in advance!!!

author: Relayer
author_rank: Contributor
timestamp: July 25, 2018, 12:32:23 am
content: Hello Mp3,QuoteYes, but you have to be very wary of how much heat you apply to the battery.Is it possible you could take a photo of the damaged pad and the surroundingarea? It would make it so much easier to see whether the pad and track it usedto connect to can be repaired, rather than soldering it all directly to the battery.Regards,Relayer
Lifted pad for battery circuit - Page 1
Forum section: electronics / beginners

author: Mp3
author_rank: Frequent Contributor
timestamp: September 02, 2018, 04:09:36 am
content: Hey everyone,I got an older device here I am repairing. The previous owner tried to replace the solder type battery and seem to have lifted the pad to the negative side of the battery terminal. It uses a 3.7v lithium battery for the SRAM. The SRAM contents aren't saved when power cycling, so i went to check the battery voltage and it was reading 3.5, so that is no problem. I then inspected on the other side of the PCB and found the lifted pad.The track from the negative side of the battery seems to lead to one side of a 2N4401 transistor "Q7"Do you guys think I could tie a wire between the battery leg and transistor leg? I know to be very careful with heat on the battery leg.Normally i would try without asking but since a battery is involved, i don't want to cause a problem.Thanks everyone

author: 6PTsocket
author_rank: Regular Contributor
timestamp: September 02, 2018, 02:16:35 pm
content: Yes. I have bypassed lifted pads and lands with a short piece of wire or glued the land back down with epoxy or a good cyanoacrylate (industrial crazy glue). Just use flux and work quick.Sent from my SM-G900V using Tapatalk

author: Terry01
author_rank: Frequent Contributor
timestamp: September 02, 2018, 02:24:19 pm
content: Quote from: 6PTsocket on September 02, 2018, 02:16:35 pmLOL I like that!

author: Mp3
author_rank: Frequent Contributor
timestamp: September 03, 2018, 10:33:33 pm
content: Cool, thanks guys, i was mostly worried a wire between the battery and transistor might cause something unwanted to happen. I'll go ahead and make that connection

author: Terry01
author_rank: Frequent Contributor
timestamp: September 04, 2018, 07:26:42 am
content: A nice pic of the finished results would be cool??
Lifted pad on PCB  - Page 1
Forum section: electronics / beginners

author: Rob Lo
author_rank: Contributor
timestamp: August 28, 2016, 02:37:39 pm
content: I was desoldering a pad this morning and, unfortunately, lifted it. It was for a 15k resistor.(R60)So I was looking to repair and I've done this once before by soldering the lead to the trace the pad was connected to.This pad, however, has no trace. The left lead of the resistor has a trace that connects to the resistor above it (r59).I am hoping maybe it's as simple as bridging the lead of the stripped pad to one of the joints on r59?

author: Macbeth
author_rank: Super Contributor
timestamp: August 28, 2016, 02:53:49 pm
content: I can only guess you are having trouble because this is a multilayer board and not just double sided? Have you also stripped the via as well as the pad? Chances are its a ground plane or power its connected to. You should be able to buzz it out with a continuity tester and find an alternative to bridge to.But the provided information on R59 and R60 is useless without any context like pics of the other side, or what this board is.

author: Rob Lo
author_rank: Contributor
timestamp: August 28, 2016, 03:44:57 pm
content: Ahh very sorry...It is a synth module. There is a pad on the top side also so it was a via? Not sure if I can just solder it to the top pad? I cannot see any trace from the top side of the board.I looked at the schems and it appears that r60 is connected to an opamp (in parallel?)I've attached a pic of the top side of the board and also the schematics.

author: PA0PBZ
author_rank: Super Contributor
timestamp: August 28, 2016, 03:49:12 pm
content: Quote from: Rob Lo on August 28, 2016, 03:44:57 pmI can clearly see a trace from both leads at the top side, so just solder the resistor in and make sure you also solder them on the top side - done!

author: Rob Lo
author_rank: Contributor
timestamp: August 28, 2016, 03:53:58 pm
content: I see the trace on the top side now as well! I dodged a bullet it seems. Thanks for the help!

author: Assafl
author_rank: Frequent Contributor
timestamp: September 02, 2016, 05:32:49 am
content: For the future: If you do a lot of repairs for multilayer boards - especially with ground planes and ROHS solder - you will probably want a high power (regulated temp) soldering iron.Low power (30W or less) soldering irons take too much time to heat up the connection which ends up with lifted pads or worse.

author: Jeff_Birt
author_rank: Regular Contributor
timestamp: September 02, 2016, 12:54:36 pm
content: When I used to do component level repair on two sided, through hole PCB we had a repair kit to fix a lifted pad. As I recall the brand name was something like 'Circ-Kit' but I could not find it with a quick search. I did find:http://www.intertronics.co.uk/products/eyelets.htmwhich is similar. You insert the eyelet through the hole, and use the forming tool to form a dome/hat on the other side of the eyelet (sort of like how you form a rivet. If provides a good mechanical repair and when you solder the component back in you have a good electrical repair.