hybridfree/eevblog-posts huggingface dataset:
NCP1378 datasheet doesnt make sense concerning OVP snd skip level? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 16, 2022, 06:52:08 pm
content: The NCP1378 Quasi resonant flyback controller datasheet, on page 10, is offering the user the option of making the input to the demag pin a divider….in order to allow output overvoltage threshold limit setting.I don’t understand this, the reference to the OVP comparator is 5.2V…..and if there was no divider, then that would mean any auxiliary winding voltage above 5.2V was considered an overvoltage……..that is nonsense, because 5.2V isn’t enough to provide auxiliary power to the NCP1378.Why is it offering the user to use a divider….when the user would without doubt need to use a divider?Do you know what the datasheet means here?NCP1378 datasheethttps://www.onsemi.com/pdf/datasheet/ncp1378-d.pdfSkip level:Also, on page 9, it says you should set Rskip to a minimum of 420R.....so as to ensure Vskip is always "greater than 250mV".....but the skip current is 200uA, and 200uA x 420R is just 84mV.So either this doesnt make sense, or i have read it wrong?

author: wraper
author_rank: Unknown
timestamp: April 16, 2022, 07:35:15 pm
content: Quote from: Faringdon on April 16, 2022, 06:52:08 pmNot necessarily if IC is powered from something else, not the same auxiliary winding.

author: Faringdon
author_rank: Super Contributor
timestamp: April 19, 2022, 04:02:15 pm
content: ...Also, we wish to use an RC current sense pin filter with NCP1378, however, putting a resistor there adjusts the skip level........the datasheet is confusing about what skip level would be set by a given value of resistor......Skip level:..on page 9, it says you should set Rskip to a minimum of 420R.....so as to ensure Vskip is always "greater than 250mV".....but the skip current is 200uA, and 200uA x 420R is just 84mV.So either this doesnt make sense, or i have read it wrong?NCP1378 datasheethttps://www.onsemi.com/pdf/datasheet/ncp1378-d.pdf
TNY268 power supply hiccup mode - Page 1
Forum section: electronics / general

author: bogdan2014
author_rank: Regular Contributor
timestamp: April 19, 2022, 09:24:24 am
content: I built a TNY268 based power supply and when I power it up it goes into hiccup mode (it pulses on and off). I initially suspected the transformer or feedback loop, but I replaced it with a bulb and removed the optocoupler and I get the same behavior.Schematic is attached below. The test conditions are:- T1 replaced with an incandescent bulb (at the primary)- U2 disconnected- C1 is not populated- D2/D3 disconnectedI'm trying to test the chip itself but I'm not sure exactly what to look for. There is some switching activity at the EN/UV pin but only briefly as it tries to start. Maybe I have a faulty chip?

author: Faringdon
author_rank: Super Contributor
timestamp: April 19, 2022, 09:34:57 am
content: Try adding seroes 10R with the UF diode in pri.What voltage are you referring back to pri. (what is NP/NS?)What voltage are you referring to sec...what is vout?There is a fault when you dont use a UVLO res connected to EN/UV pin....it can go into fault.......due to leakage current (their website gives details)...add a EN/UV res and seeCheck BP pin cap value.Try reducing C4....maybe theres an overload timer?Also, it saYs it wOrks without a bias coil...but maybe its not so good....maybe throw in a isolated supply to the BP pin.TNY268https://docs.rs-online.com/a1d9/0900766b815f08d9.pdf..If you try all the above then its going to be fascinating if it still doesnt work....as theres not much to go wrong...maybe change the chip if its still bad.BTW, power.com have their own forum too...Lastly....have you got a dry joint or misconnection somewhere?.....this is usually the problem for all of us.Is your transformer properly phased?.....do you know how to check?...with L meter....put coils in series one way, then swap one and measure again...ect etc.
looking for a charging IC - Page 1
Forum section: electronics / general

author: zanzeoo
author_rank: Contributor
timestamp: April 10, 2022, 01:59:30 pm
content: Hello ,I'm looking for an integrated circuit which can charge a single 18650 LI ION CELL from either a solar panel or from USB with ideal power path diode to directly use the power into a DC DC or LDO ( see the drawing included )Does such circuit exist ?Thanks ![ Specified attachment is not available ]

author: Faringdon
author_rank: Super Contributor
timestamp: April 10, 2022, 05:14:41 pm
content: yes. analog.com and maxim do them... otherwise, just use PFETs....or NFETs with a drive voltage referenced to the source....use back to back fets if you dont want to suffer the fets diode conducting.

author: zanzeoo
author_rank: Contributor
timestamp: April 12, 2022, 08:25:09 pm
content: Quote from: Faringdon on April 10, 2022, 05:14:41 pmYes indeed
Does "proper" Boost PFC always make the best sense? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 10, 2022, 11:37:29 pm
content: Hi,We all agree that if you have a constant load, then the best power factor is gained by using a bona fide Boost PFC controller, such as eg LT1248 etc, and using the textbook low voltage feedback loop bandwidth etc etc.But what if you have a highly transient load, on/off/on......full load to no load and vice versa , continuously............is the usual Boost PFC stage actually of much use in this circumstance?Woudlnt a faster voltage loop COT (constant off time) Boost converter, which rose its current reference up from zero every 10ms, but then (if fully loaded) quickly went to peak current without waiting for the mans peak....woudlnt that actually give a better overall power factor in the case of highly transient load?I mean, take a standard Boost PFC stage, (ie low voltage feedback loop bandwidth of some 10 Hz or so) and no load to full load (and vice versa) it irregularly, every few seconds or so.......your mains current is not going to be a constant amplitude sinusoidal wave as you know....wouldnt some other way be better for "overall" PFC, in this case?
Why solve a light load "problem" in a Boost PFC? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 09, 2022, 08:13:10 pm
content: Hi,Page 35 of the UCC28070 datasheet shows extra components added to add an offset and PWM ramp to the current sense inputs of the UCC28070. They are effectively adding slope compensation. The sole purpose of this is to make the Boost PFC less noisy in light load. However, this is surely unnecessary, and can be omitted?All current mode SMPS’s are noisy in light load, and nobody usually cares about it. Why does the UCC28070 datasheet care, and why add so many extra components to solve what is essentially a non problem?The problem of light load ringing is made wosre by the use of a CT, which is essential for UCC28070, but still, light load is light load...who cares?UCC28070 datasheethttps://www.ti.com/lit/ds/symlink/ucc28070.pdf?ts=1649515969395&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FUCC28070
Is this the board for everything energy related, like energy saving tips? - Page 1
Forum section: electronics / general

author: cdev
author_rank: Super Contributor
timestamp: April 18, 2022, 09:53:53 pm
content: I ask because in my previous post I discussed a way to save a significant amount of energy on heat. Its been found that placing a fan near the ceiling of any heated space blowing down serves to mix the layers of air and conserves around 10% on heat. Fairly painlessly. So it pays for itself fairly rapidly.
Easy way to terminate transformer windings of LLC converter? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 09, 2022, 12:30:22 pm
content: Hi,Doing a Full Bridge 4kW LLC converter at 100kHz off 400VDC. Going to use E70 ferrite. Its former is “open” which will make it easier for my clumbsy winding. Wires will terminate to holes in PCB….i will never be able to cut the wires off at the right length, so will have them too long, and then loop them back on themselves (for field cancellation), and then terminate them in the PCB holes. (as in attached)Do you think this will be OK? Turns are several strands of 7/0.3mm TEX-ELZ
Damaging latch up on high side gate driver chip? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 21, 2022, 11:01:16 pm
content: Hi,We are doing a 2kW LLC half bridge with vout = 180vdc, vin = 400vdc, f(sw)~100kHz.We need to translate a gate drive signal up to a high side FET gate driver.The 2ED2101S06F purports to be able to do this with no chance of damaging latch up if the switching node spikes well below the GND pin.….Can this be true?......if true, then this is a revolution in high side gate drive.2ED2101S06Fhttps://www.infineon.com/cms/en/product/power/gate-driver-ics/2ed2101s06f/Even better...on page 10 of this..https://www.infineon.com/dgdl/Infineon-Selection_Guide_Gate_Driver_ICs-SG-v01_00-EN.pdf?fileId=5546d46250cc1fdf015110069cb90f49..they show a core-less" gate drive transformer which doesnt seem to suffer from the negative voltage spiking on the bridge switching node(?)...also quite cheap.....i am amazed this hasnt already started a revolution in high power, high frequency (100khz) high voltage (~400v) gate drive....or is it still potentially a candidate for destruction by the negative voltage spiking that can occur on the bridge switching node?
Fuses in parallel in offline PSU? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 09, 2022, 12:02:01 pm
content: Hi,Once reverse engineered a 750W 100-265VAC PSU....its input had two 5x20mm 8A fuses in parallel.That seems good as the holders and fuses at this size are cheap.Is it ok though?Supposing i have a PSU which draws 19A max from 240VAC....can i use two paralelled , 5x20mm 12A fuses for it?

author: pardo-bsso
author_rank: Frequent Contributor
timestamp: April 09, 2022, 12:37:23 pm
content: If it is for personal use you can do anything you want.Otherwise see what compliance rules apply and follow them.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 09, 2022, 02:32:53 pm
content: The main problem is that the fuses might not share current evenly, especially if they're from different batches. So probably OK from a safety viewpoint, but not from a reliability viewpoint.
Torroid inductor Mean Length of Turn - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 08, 2022, 07:43:49 pm
content: Hi,When you have turns wound evenly in one layer round a torroid, is it the case that the MLT is approx 1.4 * "single turn length"I see in the following datasheet, the factor is indeed 1.4 (for 70% fill factor)77083A7 torroidhttps://www.mag-inc.com/Media/Magnetics/Datasheets/0077083A7.pdf
Question baterries litihum - Page 1
Forum section: electronics / general

author: tiago1986
author_rank: Regular Contributor
timestamp: April 08, 2022, 12:24:37 pm
content: Is it true that the best long term storage of removable lithium and lipo batteries is at voltages between 3.75v - 3.85v? i have xiaomi BM20 and Nokia BP-5L batterieswhen the load in storage drops what value of load drop do i need to recharge these batteries again for storage voltage?

author: gnif
author_rank: Unknown
timestamp: April 08, 2022, 12:37:34 pm
content: You already asked this several times now... why are you asking it again?https://www.eevblog.com/forum/beginners/question-storage-batteries/https://www.eevblog.com/forum/renewable-energy/question-storage-battery/
Three phase Boost PFC for 4kW - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 08, 2022, 10:23:23 am
content: Hi,Could you please confirm that to do Boost PFC with three phases using UCC28070, we will need three UCC28070 chips, and should give each one a sync signal 120 degree apart?Then we just have to ignore the "other" paired driver stage in each UCC28070?To get them to act in parallel and share with each other, we simply tie together the VAO pins it seems.UCC28070https://www.ti.com/product/UCC28070
How to test a battery charger? - Page 1
Forum section: electronics / general

author: mojoe
author_rank: Frequent Contributor
timestamp: March 31, 2022, 01:18:43 am
content: I just got a Genasun MPPT boost charge controller. It will be used to charge a 48 V lithium ion battery. The Genasun takes the solar panel output (up to 19 V @ 6 A) and charges the battery with a maximum output of 54.2 V.My question is, using a Maynuo DC load, how can I simulate the battery as it charges from 0-100%? I'll use a bench supply to simulate the solar panel, as I don't have it yet.I know how to use the DC load to test a battery, but I'm not sure if it can simulate one.

author: mojoe
author_rank: Frequent Contributor
timestamp: April 02, 2022, 02:22:02 am
content: Never mind. I did things manually.

author: simon mugo
author_rank: Contributor
timestamp: April 03, 2022, 06:57:12 am
content: would you let me know how you did it manually?

author: IslandDog
author_rank: Newbie
timestamp: April 08, 2022, 07:17:14 am
content: no idea about Genasun MPPT. I use victron 75/15 MPPT to control the charging from solar panel to battery, and monitor the charging status on its APP
Why does a class D amplifier PSU need to sync with amplifier - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 05, 2022, 09:45:21 am
content: Hi,Why does a class D amplifier PSU need to sync with the amplifier.Eg, why should its switching pulses occur in synchrony with the amplifier?I mean, "beating" would be the normal answer(?), but if theres a significant capacitor bank between them, then why sync up?

author: Berni
author_rank: Super Contributor
timestamp: April 05, 2022, 09:51:43 am
content: Yep the two switching frequencies could intermodulate each other into the audio band.In theory yes there are lots of capacitors but those capacitors have an internal resistance and the copper connecting them has resistance so no matter how big of a capacitor you use the ripple will never be 0, it just gets closer to 0.Additionally the large currents involved could magnetically couple into things, especially at the high frequencies where even a little bit of mutual inductance can transfer a pretty large signal.

author: Faringdon
author_rank: Super Contributor
timestamp: April 05, 2022, 11:13:43 am
content: Thanks, as you know, even if sync'd, you cant garantee the stages switch off at the same instant....maybe you can make the "On's" line up, but not the "offs"?

author: dmills
author_rank: Super Contributor
timestamp: April 05, 2022, 11:32:21 am
content: Don't matter the pulse width just impacts the harmonic structure, but it is still harmonics of the switching rate so intermod will not be a big issue.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 05, 2022, 01:27:14 pm
content: A more common approach nowadays is to make sure the PWM frequencies are sufficiently far apart that any beat frequencies would be above the audible range.
Is TEX-ELZ wire easily solderable? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 04, 2022, 07:36:42 pm
content: Hi,We need to wind the secondary of an LLC transformer with (9 turns of) 3 strands of 7/0.3mm TEX-ELZ.So we have to strip them and solder the three ends together, then solder that to a pin on the former.Is this physically feasible?TEX-ELZ triple insulated windings.https://powermagneticsstore.co.uk/shop/furukawa-triple-insulated-wire/tex-elz-wire.html

author: TimNJ
author_rank: Super Contributor
timestamp: April 04, 2022, 07:41:57 pm
content: For litz wire in general, solder it all at once with a molten solder pot. The insulation will burn off and the wires will solder to the pin. For TIW litz, you can attempt to remove the yellow outer layers first with something like this:https://www.weller-tools.com/professional/USA/us/Weller+Erem/Tweezers/Cutting+tweezers/15AGWThe above tools works very well for stripping normal (not litz) TIW.Make sure you are using a thermoset bobbin, not thermoplastic, because the latter will deform (melt) when exposed to the high heat of the solder pot.
Power factor is 0.988 so why is this illegal? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: April 07, 2022, 10:22:25 pm
content: Hi,The attached LTspice COT Boost converter is showing PF of 0.988, so why is it illegal?Surely the idea was to get real power = apparent power...and it very nearly is here.

author: thm_w
author_rank: Super Contributor
timestamp: April 07, 2022, 10:34:03 pm
content: https://www.edaboard.com/threads/pfc-flyback-led-driver-lt3799-questions.332473/The datasheet is just an example, it is not a certified working product that has passed any testing.Who said it is illegal other than you?

author: f4eru
author_rank: Super Contributor
timestamp: April 08, 2022, 08:51:59 am
content: What is illegal ?

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: April 08, 2022, 11:24:04 am
content: Hi,There is nothing illegal about the LT3799. It is an LED driver that regulates current. The FB is used to limit the output voltage if the LEDs are open circuit.The LT3799 model you provided does not have a voltage control loop. If you remove the resistive load the output voltage will increase until the output capacitor or the rectifier fails.The LT3798 is designed for voltage output. You can use a divider on the FB pin to set the output voltage.*** Itshould be illegalto design PFC without a voltage control loop ***Jay_Diddy_B

author: Faringdon
author_rank: Super Contributor
timestamp: April 08, 2022, 02:58:06 pm
content: Yes thanks, i know what you mean.....i would put in a feedback loop.....and have it pull down the CTRL pin to get in regulation.I am thinking the power factor will be worse as the power draw reduces.......more so than a standard PFC stage.....but i still think PF will be pretty good at low power draw.I am wondering about PF when the load is pulsey, on and off over the 100ms or 1s lengths of time.....and how Boost PFC stages give very poor power factor when the load is highly transient in nature like that...and in fact, a PFC stage based on the top post may in fact give a better power factor when the load is pulsey and irregular....better than a "standard" pfc stage.I mean, take a PFC output from full load to sudden no load...and that PFC cant respond well....it will rail high , and simply go into off mode till its output caps discharge back down eventually...........think of the load doing that all the time....and what is your PF going to be like?....i bet it would be poorer than a PFC stage like in the top post (please assume that the bandwidth of the top post one would be several 100 Hz for the top post one, not 10's of hz like a "standard" PFC.)Basically, i am postulating that "standard" boost pfc stages give worse power factor than "non standard" PFC stages when the load is pulsey.
Offline SMPS in bits...wired together. - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: March 31, 2022, 11:18:59 pm
content: Hi,We are doing a 2kW LLC converter prototype from 180-265VAC.It will have a 10ms interchanging 2.5kW Boost PFC upstream.We only want to check the power stages and the controllers work….so will just hash it together on 3 PCBs…..1 PCB for the mains filter/fuse/inrush limiter/txient protect1 PCB for the two PFC stages and PFC controller1 PCB for the 2kW LLC.We will just wire these together. Shan’t bother wiring earth to them, just Line and neutral.Will this cause any problems with noise? We will ensure each PCB has sufficient input/output caps, and will twist the interlinking wires.
What is centre hole for in PM62/49 ferrite core? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: March 31, 2022, 02:06:15 pm
content: PM62/49https://www.tdk-electronics.tdk.com/inf/80/db/fer/pm_62_49.pdfHi,What is the centre hole for?Is it so you can put a plastic post through and hold the core halves together?Do you have to get the plastic post made yourself?

author: chris_leyson
author_rank: Super Contributor
timestamp: March 31, 2022, 02:34:43 pm
content: For ferrite that is used in signal applications it's usually for access to an adjustment (tuning) slug. As it's ferrite for power applications, N27, N87 then there is no real need for adjustment slugs. Maybe it's easier and cheaper to use the same manufacturing moulds for both signal and power cores.

author: jwet
author_rank: Frequent Contributor
timestamp: March 31, 2022, 04:42:08 pm
content: In my experience, its also used for mounting and securing in prototypes during development vs. the spring clip and official holder, etc. You can use standard nylon hardware, it comes in all standard sizes. You can put a hole in your board and use it for mounting too in prototypes. I found it nice to be able to play with different Pri/Sec configurations during development with pot cores. The spring clips are little fiddly.
A revolution in offline SMPS? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: March 27, 2022, 01:51:32 pm
content: Hi,Is this a revolution in Offline SMPS?It shows here a 500W offline SMPS, in ON/OFF control…….no opto needed…digi isolator to port the comparator signal through to pri. No degradation of opto to worry about.No feedback compensation.No slope compensation needed even though duty is 0.7.Super fast transient response.As long as the application can tolerate the ~+/-1% vout ripple then its fine.It is of course “bursty”….but the bursts are pulled from PFC output capacitor bank…..not from the mains…so its OK?Here is the revolution? Why not?LTspice and PDF schem attached.

author: uer166
author_rank: Super Contributor
timestamp: March 28, 2022, 06:48:34 am
content: On/Off control has definitely been done before, e.g.https://www.digikey.com/htmldatasheets/production/104896/0/0/1/TNY274-280.pdf. They still use an opto but the feedback is digital regardless. Since your topology is buck-derived there really are not many compensation issues to be had (as opposed to boost/flyback with the RHPZ).At 500W I bet that it would be horribly loud (audibly) due to all the low frequency harmonics that constantly shift. I suppose it's fun in that a digital isolator can be used..
Grid metering ? - Page 1
Forum section: electronics / general

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: March 28, 2022, 12:50:22 am
content: Must be using the wrong terms in search .Looking for independent metering of grid consumption .At this time mostly with RV , but sometimes to get a handle on someone's home that we are considering alternative power etc.I have searched ebay , amazon but with more & more junk on the market - just looking for known recommendations ?

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 28, 2022, 04:57:15 am
content: Just look up "power meter module", AcuRev is one brand although fairly expensive.Consider DIY if you want something cheap. It's quite safe if you use isolated sensors for the current readings.https://openenergymonitor.org/

author: pqass
author_rank: Super Contributor
timestamp: March 28, 2022, 04:58:56 am
content: Try searching Google for "home power monitoring" or "opensource energy monitoring".I managed to find:https://nerdtechy.com/best-smart-home-energy-monitorAnd this:https://www.homedepot.ca/en/home/categories/building-materials/electrical/power-distribution/home-energy-monitors.htmlAnd this:https://www.amazon.ca/Home-Energy-Monitor/s?k=Home+Energy+MonitorAnd this:https://learn.openenergymonitor.org/electricity-monitoring/ac-power-theory/introduction

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 28, 2022, 12:57:09 pm
content: Quote from: evb149 on March 28, 2022, 05:17:24 amIf you go that route, get ones that support Tasmota.
Kool mu torroid inductor design template - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: March 27, 2022, 07:28:54 pm
content: HiJust done a 500W Full Bridge SMPS at 70khz, Vout = 175Vdc and Vin = 380vdc.It uses a 1mH output inductor with ipk = 3.3A and Iped = 2.5A at max load.I used a 77620A7 Kool mu torroid for this, wound with 55 turns. (of 7/0.3mm TEX-ELZ)Calculating core loss as 0.7W, and winding loss as 1.5W(As in the green tab of the attached)77620A7https://www.mag-inc.com/Media/Magnetics/Datasheets/0077620A7.pdfAny double checks/ball park checks on the bold figures above?....i haven’t yet fully got my “kool mu torroid calculation” template up to scratch yet, a few more hours needed on it yet. Its only too clear that designing inductors with kool mu torroids needs first several hours of homework in compiling a calculation template…the attached is the as yet unfinished version of this.Its the green tab
Sydney EV Expo - 19 March 2022 - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: March 15, 2022, 11:03:42 pm
content: For those in Sydney interested in EV's, there is an EV expo this weekend.Tesla, Polestar, Porsche, Kia, Hyundai, Nissan, Zero, Renault, Mitsubishi, and DIY EV conversions will be on display.https://www.thehills.nsw.gov.au/Upcoming-Events-Activities/Hills-Community-Electric-Vehicle-Expo?fbclid=IwAR1JnWDJ5z1S7Mf540FsOCU4UzeaqH2uKs3oyIhvKaR-fetjyyaQjXf6c0U

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: March 15, 2022, 11:16:09 pm
content: Can we expect to see you there with the C5?

author: EEVblog
author_rank: Unknown
timestamp: March 15, 2022, 11:29:11 pm
content: Quote from: Ed.Kloonk on March 15, 2022, 11:16:09 pmI'd have to wheel it in on a trolley.
Motor with different ohm values - Page 1
Forum section: electronics / general

author: Hesseltjuuh
author_rank: Newbie
timestamp: March 13, 2022, 04:35:47 pm
content: Hello everyone,For a new project i want to make a micro windmill and for that i got a three phase motor out of an electric fan.Now when i measured the resistance of the three pins i got 2 different values show in the picture below.Also i have three pins but 4 coils and it seems that two are connected together. My question is what kind of motor is this and can i generate electricity with the 2 different ohmic values.Thanks!

author: f4eru
author_rank: Super Contributor
timestamp: March 13, 2022, 09:56:31 pm
content: 4 poles on thee stator :This is a 2 phase motor, not a 3 phase motor.90 deg or perhaps even 180deg phase shift between thetwo windingsNot a good thing for generating power.
Fusion Breakthrough Once Thought Impossible - Closer to Reality - Page 1
Forum section: electronics / general

author: DougSpindler
author_rank: Super Contributor
timestamp: February 19, 2022, 11:49:44 pm
content: We are one step closer to fussion reactors being a reality.https://scitechdaily.com/fusion-breakthrough-once-thought-impossible-brings-energy-device-closer-to-realization/

author: jonpaul
author_rank: Super Contributor
timestamp: February 21, 2022, 03:38:57 pm
content: Since its inception in 1950s fusion power always has progess and is always 30 years till practical.Jon

author: f4eru
author_rank: Super Contributor
timestamp: February 21, 2022, 07:44:18 pm
content: Fusion is clearly physically possible.From an energy stand point it may break even, 50% chance in the next 30 years.However, economically, it will not be competitive with any other electricity source for the coming 50 years, or perhaps more probably forever.Now, yes, those guys really feel the need to publish some regular "break through", which, in fact are more like baby steps.Without that, they would not get the credits for their "vital" "research", which looks more and more like a geek cottage industry for scientists who do not understand economics.

author: Cerebus
author_rank: Super Contributor
timestamp: February 23, 2022, 01:11:54 am
content: Having now read the article, let me un-clickbait that title for you:Fusion BreakthroughMinor Improvement in Design Tools for Fusion Containment FieldsOnce Thought ImpossibleBrings Energy Device [Ever So Slightly] Closer to Realization [If Designing for the Stellarator Containment Technique That Lost Out to Tokamaks]

author: Circlotron
author_rank: Super Contributor
timestamp: February 23, 2022, 01:27:08 am
content: I predict that Linux will be mainstream on the desktop before fusion is a commercially practical power source.

author: rfclown
author_rank: Frequent Contributor
timestamp: February 23, 2022, 03:14:38 am
content: Quote from: Circlotron on February 23, 2022, 01:27:08 amThis made me laugh. There is an engineering jokes thread.

author: Bassman59
author_rank: Super Contributor
timestamp: March 13, 2022, 09:05:42 pm
content: Quote from: Circlotron on February 23, 2022, 01:27:08 amI'm not so sure about that!!!
Type 2b Error amplifier in SMPS is pointless? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: March 08, 2022, 02:51:21 pm
content: Hi,Do you agree that the Type 2b Error Amplifier is a waste of time in SMPS feedback compensation and should be done away with?Its a fact that any feedback compensation that can be obtained with a Type 2b Error amplifier, can be improved on with a Type 2, Type 2a, or Type 3 Error amplifier.The Type 2b offers no phase boost whatsoever, and clamps the gain which often isnt necessary, and the same gain (at whatever frequency) can be achieved with Type 2,2a or 3 anyway.The only single use for a Type 2b, is where a low value resistor is used in parallel with the feedback cap, to prevent the error amplifier from saturating (to prevent integrator windup) ...however, this gives large DC offset error, and is simply not necessary in virtually all SMPS applications....if not all of them.

author: Faringdon
author_rank: Super Contributor
timestamp: March 09, 2022, 09:23:58 pm
content: The attached is i believe , proof that the Type 2b Error amp is a waste of time. (except for the rare case of avoiding "integrator wind up")It shows the Bode plots of Type 1, 2, 2b and 3. (and of an inv amp for good measure)The phase plot of the type 2b shows it all......The phase begins at -180degrees, then uselessly sinks down to -270degrees...and gives a lousy DC offset in the process....unlike the Type 2 and Type 3 that give the nice phase boost at the higher chosen frequency if wanted....the greater flexibility.You can keep the phase higher till higher frequencies by reducing the DC gain of the type 2b, but in return you are punished with higher DC offset.Not only that, but if the capacitor in the type 2b is >22nF say, then youre going to need a <1nF capacitor in paralell with it anyway, for noise abatement....and then you are using a type 2b with 4 external components...........But a type 2 has 4 external components.......and using a type 2b instead of a type 2 would be madness.....(unless of course you have the "integrator wind up" case to avoid, and can tolerate DC offset, and can tolerate relatively low feedback loop bandwidth)
What type of SYNC pulse does L5991 need? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: March 07, 2022, 03:52:48 pm
content: Hi,What type of SYNC pulse does L5991 need when its in "slave" mode?Page 8 says its "edge triggered" so presumably it doesnt matter how long the SYNC pulse is?(and presumbly its rising edge triggered?)The datasheet is not clear about thisL5991 datasheethttps://www.st.com/en/power-management/l5991.html
UC3902 Load share controller - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: March 06, 2022, 07:57:27 pm
content: HiAnyone got any schems of a UC3902 controlling the paralleling of some PWM controller based SMPS's...eg a couple of UC3842 based Converters, or whatever.Its just so we can see how the UC3902 interfaces to, and controls, the output current of the individual SMPS....from the datasheet, it looks like only the ADJ or ADJR pins can actually interface to the PWM controller...and adjust its output current?UC3902https://www.ti.com/product/UC3902

author: rob77
author_rank: Super Contributor
timestamp: March 06, 2022, 08:20:02 pm
content: have you tried to read this one ?https://www.ti.com/lit/an/slua128a/slua128a.pdf?ts=1646543611556figure 3.

author: Faringdon
author_rank: Super Contributor
timestamp: March 06, 2022, 08:39:31 pm
content: Thanks, in that fig 3, is R10, R20, R30 the upper divider resistor of the SMPS concerned?

author: rob77
author_rank: Super Contributor
timestamp: March 06, 2022, 08:54:15 pm
content: Quote from: Faringdon on March 06, 2022, 08:39:31 pmno , you need a remote-sense input on the SMPS.. need to have both positive and negavive remote sense inputs on the SMPS... note there is a current sense resistor between negative output of smps and negative remote sense.

author: Faringdon
author_rank: Super Contributor
timestamp: March 07, 2022, 12:35:58 am
content: Thanks,Also, UC3902 needs one SMPS to be the master, having the highest output voltage, and the others to be slaves.....if you randomly group the like for like SMPS's in parallel with UC3902's....how does the one know its the master?........surely the batch of power-supplies-to-be-paralleled is delivered randomly, and so how does the UC3902 know which is the master one? Or, how does the master know its the master?

author: rob77
author_rank: Super Contributor
timestamp: March 07, 2022, 09:40:47 am
content: Mr. Kirchhoff and his law will tell them
Linear reg...gone unstable - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: February 21, 2022, 05:25:54 am
content: We have a linear reg, 30vin to 24vout and 5A out.It goes unstable when we overload it...and vout becomes vin...the reg opamp bats from rail to raili am wondering if the reg has gone unstable (well i know it has)...and when the error amp slams to the positive rail, it saturates the three paralleled 2N3055 output transistors, and they stay on so long such that vin = vout?Could that be it?....ie saturation, meaning the 2N3055's take a few us to get out of sat, and in that time...current surges through them...making vout = vin?2N3055https://www.mouser.co.uk/datasheet/2/308/2N3055_D-2309270.pdf

author: pardo-bsso
author_rank: Frequent Contributor
timestamp: February 21, 2022, 11:19:17 am
content: (I left the crystal ball in my other set of pants... )Can you post the circuit? Without it all I can do is guess, and I'm not very good at that.
Recycled lithium batteries performing better than new ones - Page 1
Forum section: electronics / general

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 21, 2022, 09:34:29 pm
content: https://www.scientificamerican.com/article/recycled-lithium-ion-batteries-can-perform-better-than-new-ones/In summary, the "defects" in the recycled materials turn out to be a good thing.

author: wraper
author_rank: Unknown
timestamp: February 21, 2022, 09:56:16 pm
content: What a BS clickbait title. It should Say "Batteries made of recycled cathode material can perform better than those made of virgin material"
Who can help with increasing the power of the Amazon 36V 5A charger? - Page 1
Forum section: electronics / general

author: avandalen
author_rank: Contributor
timestamp: February 17, 2022, 09:00:28 am
content: It is currently not possible to charge an ebike in 20 minuteson the go. You need a high-power battery charger for that, but these weigh too much. This article describes how to build such a high-power, low-weight battery charger.The easiest way to make that is to modify an existing charger, such as the Amazon 36V 5A battery chargerSee my full article here:https://www.avdweb.nl/solar-bike/electronics/lightweight-high-power-flyback-converter-battery-charger-with-the-cr6842sWho can help with this interesting challenge?I don't have time because I'm developing a new mid-drive motor and a few other things.

author: richard.cs
author_rank: Super Contributor
timestamp: February 17, 2022, 11:20:38 am
content: Your link gives me error 404.It's not clear to me, are you proposing to increase the power output of an existing charger, or to take an existing high-power charger and modify it to suit a specific ebike?

author: jonpaul
author_rank: Super Contributor
timestamp: February 21, 2022, 08:36:29 pm
content: Lithium batteries can catch fire, or explode if improperly charged.Many such incidents involved injury or death. Facilitated by fast charges, failure or omissions of battery thermal cutout, or low quality chargers.in case of an incident you will be held responsible if you modified the charger.even unmodified chargers have caused incidents.A word to the Wise....never trust a cheap power supply...especially Chinese!Jon
mosfet in battery pack - Page 1
Forum section: electronics / general

author: classified
author_rank: Contributor
timestamp: February 21, 2022, 04:43:58 pm
content: hi there i am desinging my own EV and i originaly was going to use contacters for the battery packs but disided that mosfets would work better now the question i have is can i use a n chanle mosfet and a p chanle mosfet togeather to provide charge and dis charge of the packas the body diod in the mosfet will onaly let it be one way or the other and thoght the useing a n chanle and a p chanle togeather can over come this

author: f4eru
author_rank: Super Contributor
timestamp: February 21, 2022, 07:56:44 pm
content: you probably should review your decision.There are no EVs today with solid state contactor replacement, and there is very probably a solid reason for that, like, I don't know, for example failure shorted of the mosfet in battery short circuit condition, just when it is supposed to cut off the overcurrent.More clearly : when shit hits the fan, house burns down because your mosfet failed short at the worst possible moment.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 21, 2022, 09:25:42 pm
content: MOSFETs (or any other solid state switch currently in production) with sufficient current and voltage rating would be a lot more expensive than a contactor. But it would be reasonable to use them for precharge, where the current is much lower. Use a pair of N channel MOSFETs with a transformer isolating the gate drive. (They'll be pulsing, which is not a problem for precharge.)If you want to minimize idle current, you can use one contactor along with a "shunt trip" DC circuit breaker as redundancy.
Is Power supply "UL approved"? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: February 17, 2022, 11:04:11 am
content: Hi,If a power supply quotes "UL62368-1" in its datasheet, can we say that it is "UL approved"?I thought to be "UL approved" the PSU had to pass a number of UL regulations...not just UL62368-1?Eg, the following PSU quotes UL62368-1 in its datasheet...https://www.meanwellusa.com/upload/pdf/IRM-60/IRM-60-spec.pdfSo is it "UL approved"?

author: f4eru
author_rank: Super Contributor
timestamp: February 17, 2022, 01:04:40 pm
content: Not the same thing.1) UL approved = tested by the "UL" companyaccording to standards that apply for the application2) Tested by a NRTL lab : tested to be approved to use in the USA, from a USA approved lab (UL is one of those)3) UL standards: norms that have the UL name

author: dmills
author_rank: Super Contributor
timestamp: February 20, 2022, 07:48:10 pm
content: Look on Meanwells site for their certificate sectionhttps://www.meanwell.com/webapp/product/search.aspx?prod=IRM-60&pdf=SVJNLTYwLTE1LXJwdC5wZGY=&a=2and download whichever safety agency paperwork is appropriate to your application.These are UL recognised parts which makes certifying your product **very** much easier when doing it thru UL (But note that WHICH standard they are approved to matters somewhat as standards are in the process of being updated and the new ones are NOT universally accepted which is a bit of a pain). The CB report is actually IMHO more relevant then the UL one unless you are using UL to get all your approvals.Just took a product thru UL with a IRM30 in it, had some minor EMC shit (One of our clocks blew right thru the power supply and failed us by 0.1dB on conducted, grumble) but the power module passed safety rather easily.
You cannot get better SMPS stability margins with inv-amp type Error amp? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: February 13, 2022, 06:10:45 pm
content: Hi,The customer sent in a 1kW Buck PSU. They want it converted to a battery charger.So we added the circuit ringed in the attached. The only way we have to regulate current is to pull down the TRIM pin as shown. The customer wants us to have fold-out current clamping….eg, they want the battery charge current to increase when the battery voltage is lower.….Though please do you agree that this isn’t possible with the attached ringed circuit? (since it has a single fixed reference voltage). Also, the customer feels that the chances of instability can be reduced by adding DC feedback to the U8 based error amplifier…by way of adding R9….though please can you confirm that this is not a correct postulate?..An error Amp with such DC feedback will always be inferior to another error amp that has no such DC feedback? (ie, an integrating type error amp).LTspice sim and PDF schem as atatched.
Solar roadways done right?  - Page 1
Forum section: electronics / general

author: asnth
author_rank: Newbie
timestamp: February 03, 2022, 08:23:28 am
content: Out of Germany from the Federal Ministry for Digital Affairs and Transport:Ortstermin an der A 81: "Solardach über der Autobahn"(On-site meeting on the A 81: "Solar roof over the motorway" -- use your favourite translator if you can't read German).Interestingly, it's not full of hype, and is rather cautious compared to the press releases we usually encounter:Quote(Translation courtesy of DeepL).

author: tszaboo
author_rank: Super Contributor
timestamp: February 03, 2022, 09:55:21 am
content: That's better. Much better. Although:QuoteI wonder if they could use those panels which are on glass carriers, which don't provide complete shading.Also, slightly related, this probably makes even more sense:https://www.theguardian.com/environment/2011/jun/06/tunnel-solar-belgium-rail
Current limit set point in a linear regulator? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: January 31, 2022, 08:32:23 pm
content: In the attached linear regulator schem, why are they setting the current limit of Q7 by varying POT1? Isn't that a dodgy way to do it?BTW, xtor P/Ns are incorrect...all i know is that Q7 is an MJ15022G...MJ15022G datasheethttps://www.mouser.co.uk/datasheet/2/308/1/MJ15022_D-2316114.pdf(The schem is a copy of the schem that i had (and its a real product, in use in industry)...but the schem had crossing traces, and it was impossible to know which traces joined at the crossings, and which didnt....so my version of it, attached, my not be a perfect copy)...BTW, actual product features nine Q7's in parallel.

author: David Hess
author_rank: Super Contributor
timestamp: February 01, 2022, 01:31:35 am
content: I think what is going on is that the current limit actually implements fold-back current limiting with R26 drawing more current through the emitter of Q5 when the output voltage drops.

author: Faringdon
author_rank: Super Contributor
timestamp: February 02, 2022, 08:02:21 pm
content: Thanks, do you agree that however POT1 is adjusted to give the current limit level....when Q7 gets hotter, that current limit level will rise?

author: Kleinstein
author_rank: Super Contributor
timestamp: February 02, 2022, 09:18:47 pm
content: Yes when Q7 runs hotter the current limit will go up.The current limit in this circuit is not an accurate regulation like in a lab supply, but more like a protection for regulator and to a limited degree also for the circuit to run from it.

author: David Hess
author_rank: Super Contributor
timestamp: February 03, 2022, 03:25:07 am
content: Just to expound on what Kleinstein said, it is called "Vbe current limiting" because the sense voltage is tied to the Vbe voltage of the transistor which is about 0.6 volts with a temperature coefficient of -2 millivolts per degree C. Vbe current limiting is simple but not particularly accurate making it suitable for protecting the regulator and load. The famous 723 regulator uses Vbe current limiting.The alternative uses a differential pair or operational amplifier to make a much more accurate current limit.
Finding the XL6009 IC instead of a module - Page 1
Forum section: electronics / general

author: csreades
author_rank: Newbie
timestamp: January 31, 2022, 08:36:10 pm
content: I have been looking for a boost converter than can take 12/24V input and output 36 V at 3A as well having an enable pin. The XL6009 modules you can get on eBay for ~£3 seem to have the perfect IC but I cannot find a source for the component. Is this unique - how realistic is buying modules to take the IC?Example module:https://www.digikey.co.uk/en/products/detail/dfrobot/DFR0123/6588566?s=N4IgTCBcDaIB4BsBsAGFBOEBdAvkAIC Datasheet:https://datasheetspdf.com/pdf-file/1462392/XLSEMI/XL6009E1/1

author: Algoma
author_rank: Frequent Contributor
timestamp: January 31, 2022, 08:53:12 pm
content: XLsemi is a manufacturer from China, Most of the low cost eBay DC-DC converters are based on their products.Here is XLSemi's DC-DC converter list from lcsc.com there may be an alternate as the XL6009 has been around quite a while.https://www.lcsc.com/products/DC-DC-Converters_484.html?brand=445if you translatehttp://www.xlsemi.com/there is quite a few variations on each product line.

author: trobbins
author_rank: Frequent Contributor
timestamp: February 01, 2022, 12:59:19 pm
content: Can you modify the ebay pcb to suit your aim? Are some of the parts on the pcb module not appropriate?

author: csreades
author_rank: Newbie
timestamp: February 01, 2022, 09:48:42 pm
content: That is a good question. I am trying to develop my own board and it just seemed to be the perfect IC. The module itself would actually work as it is (and be a lot cheaper).

author: edavid
author_rank: Super Contributor
timestamp: February 01, 2022, 10:11:43 pm
content: What is your actual power requirement? You are not going to get 36V @ 3A out of an XL6009.
Old power supply replacement...PFC? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: February 02, 2022, 08:49:09 pm
content: Hi,A customer has a failed (+13.5v)-0v-(-13.5v) offline 240VAC power supply which has failed (the pos rail draws 6A, the neg, 1.5A.)Can we put a 100W PSU (for the pos rail) , AND A 25W psu(for the neg rail) into a box and give it to them as a replacement?Its just one unit. It wont pass PFC overall, but each of the PSU's will pass all regs individually.