hybridfree/eevblog-posts huggingface dataset:
Need a very simple Boost LED driver IC...ON/OFF control - Page 1
Forum section: electronics / general

author: zenerbjt
author_rank: Regular Contributor
timestamp: August 15, 2020, 06:33:21 pm
content: Hi,We were wondering if the attached type of simple Boost LED driver IC exists anywhere? I cannot find it. This is amazing because it is so simple….just ON/OFF control.(LTspice sim and pdf schem attached)We need it for a 5V input, with 4 series white LED load, internal switching FET….and power is maximum of 4W so having an error amplifier would be overkill.(We can find the MIC2287 but that has an internal error amplifier which we don’t need)

author: Kean
author_rank: Unknown
timestamp: August 16, 2020, 03:04:18 am
content: Have you looked at the range of LED boost drivers from Diodes Inc? Maybe AP3031 or PAM2841.Getting to 12V out at 4W from 5V in may be pushing them a little hard. I've done near 3W on AP3031 with similar parameters, and a quick glance at the datasheet seems to imply the PAM2841 is able to do 12V at 330mA from 5V.Very simple to use. They can do PWM dimming, but also just simple on/off control as well.

author: butech
author_rank: Contributor
timestamp: August 17, 2020, 09:20:43 am
content: If you mean the LT1243 as control IC, than you should be able to replace it by an standard uc1842,uc2842 or uc 3842, as the website of ANALOG states: "Pin Compatible with UC1842 Series." Therefore the LT1243 should only a better replacement but it should also work with the other ICs mentioned.
Programmable power supply design 24V,  48W - Page 1
Forum section: electronics / general

author: Cobalt 60
author_rank: Newbie
timestamp: August 09, 2020, 09:49:12 am
content: I want to design a programmable Power supply. I started with a fixed 9 volt power supply, then the output is taken through a 100 k digital potentiometer, I can control the digipot by arduino hence the output from 0 to 9 volt . After few minutes my pot burn since it drawing more current then the rated one. So, I stopped at this point . Someone please help how to proceed further to design 24v power supply

author: tom66
author_rank: Super Contributor
timestamp: August 09, 2020, 03:13:52 pm
content: Start with learning how to build a buck or boost converter.
I need recommendations on manufacturers - Page 1
Forum section: electronics / general

author: johan 121
author_rank: Newbie
timestamp: August 07, 2020, 11:33:06 am
content: Hi!I am looking for manufacturers of braking resistors for variable speed drives, I am a newbie in this world of electrical resistors and I need and would appreciate all kinds of recommendations.In case it helps you to understand better what I am looking for, I leave you a website that has what I am looking for:https://nugar.es/resistencias-de-frenado/
Solar power installation, telemetry/control ? - Page 1
Forum section: electronics / general

author: aristarchus
author_rank: Regular Contributor
timestamp: July 26, 2020, 10:06:23 pm
content: Hi,I'm thinkning to have a small installation of solar power (about 1KW).First time in this area so I'm still searching what the market has as offerings.Is there any off the shelf controller that delivers remote control and telemetry to your device eg to a PC or phone?Or even this functionality from an addon box or something?Thanks for any info.

author: nfmax
author_rank: Super Contributor
timestamp: July 27, 2020, 07:25:40 am
content: I have a grid-tied PV system, with an energy meter measuring the output so the power company knows how much to pay me. The meter has a pulse output, (opto-isolated) which gives 1 pulse/W.hr. I use a data logger to record the pulses and provide a record of energy generated.

author: aristarchus
author_rank: Regular Contributor
timestamp: July 27, 2020, 04:57:48 pm
content: Hi,Thanks for reply.What I'm trying to put in place is just a simple system and not a "net metering" to sell back to power company.It does put though some ideas, eg if it would be better if I move this little project towards this direction.Anyway, I was trying to see if there are any easy and cost effective solutions if someone wants to have a small solar panel setup with around 1KW inverter and be able to have measurements eg battery charge, remaining available power, voltage/current flow from panels, voltage/current input to inverter, overall power consumption on 110/220V output etc.Is there any solar panel controller that provides such functionality and s/w application with an acceptable price since I'm talking for a relatively small configuration?

author: fourfathom
author_rank: Super Contributor
timestamp: July 30, 2020, 05:07:56 pm
content: You might want to look at gear from Victron -- they have pretty decent bluetooth monitoring:https://www.victronenergy.com/live/victronconnect:mppt-solarchargers

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 31, 2020, 01:51:34 am
content: ESP8266 plus some kind of current sensor.

author: No.15
author_rank: Contributor
timestamp: August 08, 2020, 06:19:33 pm
content: I know both Victron and Magnasine have ways to see lot's of info on battery soc, usage etc.Victron might be better because almost everthing they have is bluetooth enabled. My magnasine uses an external module that you have to scroll through the info and it can be tedious.Edit: rereading your post you definatly need to look at Victron stuff, it has what you are looking for and it's quality product. I have started moving to them for the reasons you stated.
Primary peak current in TNY284 based flyback? - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: August 06, 2020, 01:26:03 pm
content: Hi,We are designing a flyback with TNY284.VAC input is 180-285VACVout is 15V at 1Watt.We are using an E13/7/4 former.LP = 484uH, Ls = 110uHWhen VAC is 285VAC, then Vpk will be 402V.This will give a di/dt in the primary of 831mA/us. This is far higher than the 50mA/us rise time stated in the TNY284 datasheet on page 14.As such, too what will the peak primary current rise to?TNY284 datasheethttps://ac-dc.power.com/sites/default/files/product-docs/tinyswitch-4_family_datasheet.pdf

author: chris_leyson
author_rank: Super Contributor
timestamp: August 06, 2020, 02:39:37 pm
content: Peak primary current is 250mA for TNY284 (page 13) and Lp = 484uH is way too smallBack of an envelope calculation, Vin = 400, Ton(max) = 3.8us (50% duty cycle), Ipk = 0.25ALp = Vin*Ton/Ipk = 400*3.8E-6/0.25 = 6.08mH. dI/dt about 65mA/us.

author: ocset
author_rank: Super Contributor
timestamp: August 06, 2020, 02:46:58 pm
content: QuoteThanks, i must admit i used two layers of 35swg but accidentally used the M.O.D. for 33swg , so my new LP is now 467uH, but thats by-the-by now.The 467uH will be fine on the E13/7/4 core as the Isat is 0.423A. As you know, the power is only 1W so this doesnt need be anything special.(AL = 160 and NP now = 54)Considering the original LP of 484uH.......From page 14 of the datasheet, for TNY284, it says that max peak current with 50mA/us current rise rate, gives a peak current of 0.267A.Page 16 of the datasheet gives a “current limit delay” of 150ns.In 150ns, a current rising at 50mA/us rises by 7.5mA. As such, this (probably) means that the actual peak current limit is (0.267 – 0.0075) Amps, which equals 0.26A.Page 16 also states that Leading edge blanking time is 215ns. As such, the primary switch will always be on for at least 150ns + 215ns = 365nsWith LP=484uH, and at 402VDC input, the primary peak current is rising at 0.861A/us. So in 365ns, this means the primary current rises to 0.303A.I think this is the answer. However, the datasheet is not clear******************************************************************************************************In 150ns, a current rising at 0.861A/us rises by 129mA. As such, you would expect the current shut OFF threshold to be at (0.26+ 0.129) Amps, which is 0.389Amps. This is above 0.303 Amps…..so that means that the primary peak current is likely to be 0.303 Amps.What is strange is that the datasheet doesn’t simply tell us what is the reference voltage on the current limit comparator, and then with the “current limit delay” figure from page 16, we can then very simply work out the peak current. Why do they “go round the houses” and give figures for a 50mA/us rise time?…..it just confuses things and makes you wonder what their datasheet figures really mean.****************************Please note:Ive now found two TNY284 datasheets each giving different current thresholdshttps://ac-dc.power.com/sites/default/files/product-docs/tinyswitch-4_family_datasheet.pdf...and the one on the power.com website
DCM fixed frequency PFC controller IC  - Page 1
Forum section: electronics / general

author: butech
author_rank: Contributor
timestamp: July 30, 2020, 09:10:51 am
content: Hello everybody,actually I am searching an integrated controller IC for a DCM PFC at fixed frequency. My problem while searching the web is that most ICs which are marked as DCM are TM (transition mode) or BCM (boundary conduction mode) with a varying switching frequency. I recall that there was the NCP1601 which is obsolete now and the LT1249 which is available, but has a fixed frequency of 100kHz.Therefore my question is, if anyone kows a suitable IC which suitable for DCM PFC with a fixed, but externally settable frequency (ideally some 8 to 14 pin smd package like soic or ssop)? Or does anyone have an idea for a CCM controller IC which can be used without problems in a DCM operation?

author: TimNJ
author_rank: Super Contributor
timestamp: August 04, 2020, 03:47:24 am
content: I think most modern CCM controllers will run okay in discontinuous mode. Obviously just set your inductance value sufficiently low. I am using UCC28180 mostly in CCM, but partially in DCM at low load and don’t have any issues. Only anecdotal. TI says this controller can maintain good power factor even in DCM. I’m not sure if it’s actually doing anything special but might have something to do with the current averaging scheme.Maybe others have more experience they can share.

author: butech
author_rank: Contributor
timestamp: August 04, 2020, 08:13:38 am
content: Thank you Tim for your suggestion.Yes I also thought that most CCM controllers should be able to operate in DCM if the inductance is selected low in value (actually they will operate in DCM, but the question is if the PFC works "acceptable"), but I could not find a datasheet mention it until now. Therefore, I looked at the datasheet of the UCC28180, you mentioned, and at least it is said that you can choose the ripple current high to allow operation in DCM, although THD will increase. Therefore maybe I try and build a prototype using this IC.In the meantime I also found that the NCP1605 is available from distributors, which is supposed to operated in DCM but in its lifecycle is set NRND and the replacement part (NCP1608) is variable frequency critical conduction mode type.Maybe there is still someone out there who has used a CCM ic in DCM.
Best practices and solutions for regulated, isolated DC power supply in an EV - Page 1
Forum section: electronics / general

author: bobsaccamano
author_rank: Contributor
timestamp: August 28, 2020, 08:44:51 pm
content: Hi,I'm looking for a power management solution for two 12V DC Motors each with an ECU (max. current 6A) in an EV. The Main Battery of the EV has a nominal voltage of 44V and a max. discharge current of 140A. The secondary battery has 12V and 7 Ah which means it is insufficient to power both ECUs.I've looked into System Basis Chips (SBCs) that are used in Automotive, essentially combining power, comms, diagnostics and supervision into one single board but my feeling is that this would come with a lot of overheads..I'm really looking for the simplest solution that can still be demonstrably safe.
Electric car complete teardown until the last screw !! - Page 1
Forum section: electronics / general

author: f4eru
author_rank: Super Contributor
timestamp: July 17, 2020, 12:09:06 pm
content: Hello all,Munro offers a cool huge report on the BMW I3.https://insideevs.com/news/434166/sandy-munro-selling-bmw-i3-teardown-10/Yes, it's focused on the economics, but there is a lot of insight into electronics, and their cost, but there are still interesting board arch overviews for practically all PCBs.Very interesting, and from my experience of previously working on the design of one of those parts, even cooler to see someone tearing a complete car down to it's last screw !!! Absolutely amazing work, and so cool of Munro to offer it to enthusiast public and us geeks for such a low price !!!!!!!

author: EEVblog
author_rank: Unknown
timestamp: July 21, 2020, 01:04:24 am
content: Thanks, purchased!It's incredibly impressive!

author: max_torque
author_rank: Super Contributor
timestamp: July 21, 2020, 08:10:06 am
content: my i3 is staying in just the one piece!Don't take it apart, turn it on (and drive it)
Flyback CCM vs DCM?  Total losses? - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: July 26, 2020, 01:43:57 pm
content: Hi,The attached are Flybacks, both with Vin = 330VDC and Vout = 48V, 1A and same F(sw)(LTspice sim, plus pdf schem , and pri/sec waveforms shown)One Flyback is just in DCMThe other Flyback is just in CCMNaturally, you would think the CCM version would have higher FET and diode losses due to reverse recovery.However LTspice gives losses of 1.12W and 1.23W respectively for DCM and 1.2W and 1.5W for CCM….so it seems that LTspice doesn’t model Reverse recovery properly. (I don’t think any simulator does?)Anyway, what would you expect, roughly, to be the difference in FET and Diode losses in these cases, if they were real, on the bench?
Where are they?  Ambri and Liquid Metal Battery - It's been 3 years. - Page 1
Forum section: electronics / general

author: DougSpindler
author_rank: Super Contributor
timestamp: July 19, 2020, 05:27:29 pm
content: What's the status of Ambri? This is is the company MIT Professor Donald Sadoway created with funding from Bill Gates to create Liquid Metal Batteries. Three years ago Sadoway gave a TED talk saying they be commercially available in 2019/2020 time frame.Wondering what the current status of Liquid Metal Batteries.

author: cliffyk
author_rank: Frequent Contributor
timestamp: July 19, 2020, 10:17:50 pm
content: It would appear, from a quick bit of "surfing" and superficially perhaps, that the technology is not currently commercially feasible.
HiperTFS Two transistor forward SMPS controller - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: July 15, 2020, 11:01:49 am
content: Hi,These questions concern the HiperTFS Two Transistor Fwd controller by Power.comPlease advise. Just while I am reading and interpreting the HiperTFS datasheet, please advise on the following.?...1…Can I disable the Flyback part and just use the two transistor forward? I wish to use an external TNYswitch for the bias power in one particular design.2….I see the datasheet shows the R pin being supplied by both the Flyback leakage reset current, and also the Two tran fwd magnetising current reset. Is it necessary to do both?. For example, can I just use the flyback leakage reset current only? I would rather recycle 2TranFwd magnetising reset current to the input capacitors.3….If I am using both flyback and forward, is it possible to temporarily disable the two tran fwd part?4….isn’t a bootstrap diode also needed?, in order to more quickly charge up the VDDH pin capacitor in cases of no load to full load transient?5…Can I feed the R pin just with an isolated winding from the flyback?6…Could I feed the R pin from a combo of a bootstrap diode, and also the Flyback leakage reset current? (not the two tran fwd magnetising reset current)HiperTFS datasheet:https://ac-dc.power.com/sites/default/files/product-docs/hipertfs-2_family_datasheet.pdf
TNY287 Offline Flyback with no optocoupler - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: July 14, 2020, 12:59:37 pm
content: Hi,We are doing a 6W Flyback (240VAC in). We dont need the isolated secondary to be directly regulated......but do need the primary side auxiliary coil to be regulated.Can you think of a better way than the attached to do it? (we dont want to use an opto)TNY287 datasheethttps://ac-dc.power.com/sites/default/files/product-docs/tinyswitch-4_family_datasheet.pdf

author: fcb
author_rank: Super Contributor
timestamp: July 14, 2020, 06:55:46 pm
content: Are you back in-business treez?Is the coil winding you need to regulate isolated? Is you don't need the isolation can you not just turn the to-be-regulated rail into a current (current mirror between the Source and EN/UV)? Feed the input to the mirror with a resistor from the to-be-regulated rail.

author: ocset
author_rank: Super Contributor
timestamp: July 15, 2020, 01:59:52 pm
content: Thanks, to be honest i am just submitting something to someone in Berlin who's not yet paying.The 2-B-reg'd rail doesnt need isolation.The TNY287 skips cycles whenever current drawn from the EN pin exceeds 115uA.....but the EN pin is clamped to 1V only. Therefore, the arrangement of the top post is the only way i can think of for now.....(apart from too rough zener diode type regulation schemes)
Adjustment needed to Modulator & Error amplifier transfer function of TL431/Opto - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: July 09, 2020, 07:16:03 pm
content: HiWe are calculating the Bode Plots for the 65W Offline DCM Flyback SMPS in DER-243 by Power Integrations……Please help to adjust the Modulator & Error amplifier transfer function? It needs modifying due to inclusion of an NPN (Q2) , as on page 7 of DER-243….DER-243: 65W Flyback (Schematic on page 7)https://ac-dc.power.com/design-support/reference-designs/design-examples/der-243-65-w-adapter/The Modulator & Error Amplifier transfer function (without the NPN) is as on page 467 (equation 8.35) of the attached (Basso) book page. (some of this expression is also defined on page 455).(Attached Page 466 shows the same TL431 based schem as in DER-243, but unfortunately the component designators are different.)Anyway, would you agree that Equn 8.35 on page 467 should be modified by simply multiplying it by the gain of the NPN? (ie, a number between 70 and 100) (albeit perhaps a bit less than 70 due to the emitter degeneration resistor , R25, seen on page 7 of DER-243)
Rebadged Mean Well PSU? - Page 1
Forum section: electronics / general

author: aix
author_rank: Regular Contributor
timestamp: July 01, 2020, 11:11:42 am
content: I have these two 15V PSUs of unknown origin. One is branded Mean Well; the other, Sunpower.I've never heard of Sunpower, but the two look very similar. I am thinking that the Sunpower is probably a rebadged Mean Well.Is there anything in these pictures that would make you suspect that either might not be a genuine Mean Well article?

author: aix
author_rank: Regular Contributor
timestamp: July 01, 2020, 11:15:27 am
content: Oh I see, they're a UK distributor of Mean Well. Would still love to hear your thoughts on whether there's anything not looking quite right about either of the power supplies (other than the PSU on the right having physical damage to one of the transformers).

author: Doctorandus_P
author_rank: Super Contributor
timestamp: July 04, 2020, 01:54:21 pm
content: As you've already discovered,https://www.sunpower-uk.com/seems to be a distributer of MeanWell.Also note the MeanWell logo on the Sunpower PCB (Lower left corner, next to the black Elco's.One of the most common issues with cheap clones is that they do not use thermal paste between the transistors (diodes) and the aluminimum housing, but they smear some white garbage over the transistors after they are mounted (They really do this literally !!!).It's also common that the semiconductors are not even flat against the Aluminimum.I use the cheap clones for non critical applications, but when I want some reliability I use MeanWell.Meanwell is known as a brand that has reasonable quality power supllies for a moderate price point.
Simple ON/OFF charging of a cell at 1C can't be done? - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: July 02, 2020, 09:28:02 am
content: Hi,Is it true that you can’t charge any battery (any chemistry eg LiPo, Lead acid etc etc) by simple ON/OFF charging at 1C?(ie, for example, charging a LiPo cell at 1C, and then simply having a comparator with hysteresis to stop it charging when the cell voltage got to 4.2V…then start charging again (at 1C) when cell voltage falls below 4.15V, etc etc………………………)I think if this were done, then the cell voltage would have a square wave superimposed on top of it of magnitudes say 4.5V, 3.9V…is this correct?

author: Siwastaja
author_rank: Super Contributor
timestamp: July 02, 2020, 10:36:14 am
content: 1C is quite a lot for many "energy optimized" (as opposed to power-optimized) li-ion cells if you want full lifetime out of them, especially near 100% state-of-charge. Go for 0.5C max if unsure. Power tool cells are obviously OK at 1C.Most charging algorithms work like you describe, plus a CV step: they charge until the cell voltage is 4.2V, taper the current down by holding the cell in constant voltage of 4.20V to top it off, then stop, then restart if the cell gets below some threshold say 4.1V. Note that unless you have a load attached, it takes forever for the cell to self-discharge that much.You can omit CV step no problem. Just note, the larger your charging current is, the further you stay away from true 100% charge. This also means, when you suddenly stop, the voltage jumps back down almost instantly. So if you are charging at such high current as 0.5C let alone 1C, and are not doing a CV phase, better leave a wide hysteresis so that you are not oscillating.On the other hand, oscillation isn't catastrophic. From the cell viewpoint, it's notthat muchworse to alternatively charge at 0.5C and 0C at any frequency, than to just charge at, say, 0.2C.You lost me at the "superimposed square wave of magnitudes 4.5V, 3.9V". If you always stop charging at 4.2V, I fail to see how you could ever see voltages higher than 4.2V in the system.

author: ahbushnell
author_rank: Frequent Contributor
timestamp: July 02, 2020, 01:49:41 pm
content: You do not go higher then the max cell voltage. So if its 4.2 volts 4.5 will damage the cell. When the cell is at a high state of charge you need to start regulating at 4.2 V.

author: ocset
author_rank: Super Contributor
timestamp: July 02, 2020, 01:55:59 pm
content: QuoteThanks, Sorry perhaps i didnt explain well..i did a NICAD charger once, and it was just ON/OFF control with a comparator looking at the cell voltage (no tapering off of charge current)....but when we looked at the labview cell voltage plot over time....when the cell got up to fully charged voltage, the cell voltage was jolting up and down with a certain period. The peak of the jolts were higher than the comparator trip level.It was a bit weird, because i just expected the cell voltage to end up going flat at the fully charged voltage.
Interpretation of LT1248 PFC controller datasheet? (Multiplier output current) - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: June 29, 2020, 12:57:36 pm
content: Hi,We are trying to set up the LT1248 PFC controller, however, the datasheet appears incorrect…The equation for “IM” (multiplier output current) on page 7 of the LT1248 datasheet appears to be wrong.The equation given on page 7 is as follows….Quote(near bottom right of page 7)However, if you observe the graph in Fig 1 of page 7, and pick off values from that graph, then clearly, the given equation for “IM” is wrong.…For example, If I pick off the graph, VAOUT = 7V and IAC = 500uA and put these into the equation above, then I get IM = 500uA……however, the graph gives ~268uA.However, the equation is a lot more accurate if I pick a part of any graph that’s not levelled off……For example, at VAOUT=7V and IAC =250uA than IM = 250uA and the graph almost confirms that and is ~230uA, …quite accurate.So anyway, why does the IM value on the graph level off at 268uA?Nothing in the datasheet suggests that IM is clamped at 268uA.In fact, at the top of page 7, there is another equation for IM as follows….Quote(top left of page 7)….now, RSET can have a “Legal” value of 10k…(RSET is shown as being 10k in the graph at top right of page 5)…….that would; give IM(MAX) as 375uA ….so why does the graph on page 7 show IM being clamped to 268uA ?LT1248 datasheethttps://www.analog.com/media/en/technical-documentation/data-sheets/1248fd.pdf
DC DC Buck Converter Noise Problem - Page 1
Forum section: electronics / general

author: yagizhanugur
author_rank: Newbie
timestamp: June 27, 2020, 12:31:55 pm
content: Hello,I am newbiee for power electronics. I am trying to build a 100A DC DC Interleaved Buck converter.My converter generates too much noise even i isolate DC Power and Converter power.I added RC snubber parallel to diode, it reduces noise but there is still too much noise.I ve used SiC Mosfets SCTW90N65G2V and SiC Diodes C5D50065D. Also i use FAN73711 for mosfet gate driver. I am producing PWM signal with STM32F407, isolated with logic optocoupler.I added my circuit.Note : When i get 20A, 2.5Vpp noise occurs on 12V Input Power(Power side and DC 12V isolated).I consent with output noise but problem occurs on DC side. I already use isolated power supply for PWM generation and mosfet driving. How it affect DC side ?Thank you.

author: yagizhanugur
author_rank: Newbie
timestamp: June 27, 2020, 02:13:05 pm
content: Quote from: blueskull on June 27, 2020, 12:55:37 pmYou are right about SS16. Boot resistors are burned and i changed it with 1N4007. It looks like working but noise issue revealed.MCU is isolated with an isolated DC DC converter.I will try US1MW for DBoot diode. May be my 1N4007 is the problem. Also i am planning to increase Gate resistance, according to this gate will on/off will be slower. I hope it will reduce voltage spikes. What you think about it ?Thank you for your answer.

author: David Hess
author_rank: Super Contributor
timestamp: June 28, 2020, 03:17:29 pm
content: Make sure your layout minimized ESR and ESL to the input capacitors and that the input capacitors have a low enough impedance at the operating frequency to suppress the input ripple. Make sure the layout uses single point grounding where appropriate to minimized ground loops. It may be necessary to use one or more LC filter sections on the input.
Solar pwm controller for alternator? - Page 1
Forum section: electronics / general

author: Ian 2
author_rank: Newbie
timestamp: June 24, 2020, 08:30:00 am
content: HiI'm looking for a way to safely charge my lithium 3s100p battery pack using my van's alternator. Dc to Dc charge units designed for this seem to be hard to find and expensive. I was wondering if i could use a pwm solar charge controller like this onehttps://de.renogy.com/renogy-wanderer-li-30a-pwm-charge.../between the alternator and lithium battery.If the battery and alternator can both handle more than 30A, will the charge controller be overloaded or will it just run at its maximum load without causing problems?Does anyone know if this would work or do i need to look for a better solution?

author: ocset
author_rank: Super Contributor
timestamp: June 26, 2020, 12:08:27 pm
content: Hi, Your link is broke.Does the battery pack have outputs so each individual cell voltage can be monitored?..Or does your battery pack contain cell balancing circuitry within it?What is the A.h of your battery?Does your battery pack comprise circuitry which automatically switches out the batteries when the battery pack is fully charged?When these details are known, we can get you a nice charger for it.**************____________________**********************________________________OK ive just seen your other post so i have the details now...https://www.eevblog.com/forum/renewable-energy/dc-current-limiter-li-ion-charging-from-alternator/
Novel and simple method for driving Two Transistor forward FETs not in use? - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: June 25, 2020, 04:09:09 pm
content: Hi,This concerns a Two transistor forward with "DC restore type" transformer gate drive to only the top fet.Do you know why nobody recommends delaying the turn ON of the bottom FET in the Two Transistor Forward...in such cases?(attached is LTspice sim and jpg schem)The good thing about the two transistor forward when driven with “DC restore type Gate drive transformer”, is that you can drive the bottom fet directly…and then drive the top fet from a DC restored gate drive transformer (GDT). This means that you get fast turn off of the top fet and bottom fet (because the top fet has a PNP turn off circuit)…but also, you get slow turn ON of the top fet due to the GDT leakage inductance………however, one gets round this be delaying the turn-ON of the bottom FET…then the top fet turns on first into NO current…so problem solved…this is why we like the “DC restore type” gate drive for Two Tran fwd.Though why is nobody doing this?......i mean this method relaxes the demand for super low leakage inductance in the gate drive transformer.(The attached word doc shows the  extents that one needs to go to to get low enough leakage inductance in GDTs)

author: ocset
author_rank: Super Contributor
timestamp: June 25, 2020, 09:00:50 pm
content: Thanks, i believe it could be a thing, for some semico to make a 2TFC controller with just a resistor connection say. to determine the short delay time for the low fet.
PFC controllers don't allow independent Output overvoltage level setting - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: June 23, 2020, 05:48:42 pm
content: Hello,Do you know why virtually all PFC controllers give you no choice over the output overvoltage threshold level?I mean, take the PFS7623H PFC controller …https://led-driver.power.com/design-support/product-documents/data-sheets/hiperpfs-4-data-sheet/….This (its error amplifier) has a feedback reference of 3.85V…..and the feedback signal is also internally connected to an Overvoltage comparator with a reference voltage of 4-4.1V. Being internally connected means you cannot adjust it.This means that with a 200W PFC stage, one must have a PFC output capacitance of at least 150uF so that you don’t keep tripping the OVP with normal 100/120Hz output ripple voltage.This is extremely inconvenient for people who want to use all Film capacitors at the PFC output.I can only find one PFC controller on the market that allows one to independently set the output overvoltage level (the LT1248).Needless to say, digikey etc unfortunately don’t allow one to sort PFC controllers on “independent OVP setting”.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 23, 2020, 06:13:38 pm
content: Commercial products designed for commercial applications? Say it ain't so!Can always multiply the capacitor with a synchronous boost; this was done, with GaN FETs and Cera-Link(R) capacitors, in the winning Google Little Box competition from some years ago.Tim
Asking for Ups module / battery protection circuit - Page 1
Forum section: electronics / general

author: hiocks
author_rank: Newbie
timestamp: June 05, 2020, 12:55:14 pm
content: Hi. First, my english is not good. Not english country.I have small desk light. And it powered by 1.5v AAA x 3So i will replace that. To Li ion battery.I make like this.5V In ( by adaptor ) ㅡ ( ups 5V/3V In ㅡ 3.7 Li ion ㅡ ups out 3V/5V) ㅡ stepup trans(3.7>4.5) ㅡ lightBut i have qestion before making.1. I have 3.7v 18650 li ion battery. That have protection circuit in battery already.And I have ups module. That is not awesome like as expensive true UPS device.just can be charging battery and supply out at the same time.Problem is this : battery have protect circuit. But UPS provide battery protection too. It's double.dIf i connect it each, isnt there problem???2. I need 4.5v. But module provide 3V or 5VIt maybe trans in that.(because battery is 3.7V but in/out is 3V or 5V ㅡ i can choose )So i buy other trans board.I can adjust voltage as i screw something.So it is problem.May i be increasing voltage?Module always provide 5V. But i down it 4.5VIn that precessing, other problem ( overpower.. overheating..) is not occur?I dont understand how make circuit with transformer.Not principle of that. Just during make circuit.And i want to understand...Sorry and Excuse for my pool english...My country forum give not useful advice. So i come here.help me, genius!

author: bin_liu
author_rank: Contributor
timestamp: June 15, 2020, 05:26:51 am
content: See, I have done similar projects, you can refer to it.Of course, you need to dissect the LED driver circuit of your small table lamp.

author: Peabody
author_rank: Super Contributor
timestamp: June 15, 2020, 02:06:13 pm
content: Can you post a link to the UPS module you have, or a picture of it?I don't think there is any problem with double battery protection. I have used protected batteries in modules that also have protection, and have not experienced any problems.Also, I think it's unlikely that providing 5V to the lamp would cause any problems. Do you know how much current the lamp draws?

author: ocset
author_rank: Super Contributor
timestamp: June 20, 2020, 11:47:06 am
content: is this your setup? (attached)...which bit do you have problem with?

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 20, 2020, 01:48:03 pm
content: Almost all of those simple LED lights just use resistive current limiting. Replace that with a current regulator and it will work perfectly with 1S lithium ion. For a charger, all you need is some form of regulator that limits the voltage to 4.1V and the current to less than the 1C rate of the battery, preferably 0.5C.
location of inverter DC input in relation to snubber capacitors - Page 1
Forum section: electronics / general

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 10, 2020, 01:39:45 am
content: He claims that the location of the input to the DC bus can greatly affect the load on the snubber capacitors. That doesn't make sense to me since the DC input has a much higher impedance than the snubber capacitors at high frequencies. Is there some effect I'm not considering?

author: fourtytwo42
author_rank: Super Contributor
timestamp: June 10, 2020, 07:58:14 am
content: Never did find anybody who knew what they were talking about on any of these youtube video's, long ago stopped wasting my time watching

author: max_torque
author_rank: Super Contributor
timestamp: June 13, 2020, 06:47:24 pm
content: total BS.He's running the DC link above the std voltage, so i suspect it's a simple case of when the load ramped up, the snubbing voltages ramped up, and exceeded the rating of the small snubber cap, and once it was gone,the main cap then got all the ripple and that overheated a bit later.....

author: max_torque
author_rank: Super Contributor
timestamp: June 17, 2020, 07:13:42 pm
content: turns out it was uncontrolled shoot through leading to parastic driven voltage overshoot.......

author: Dave
author_rank: Super Contributor
timestamp: June 19, 2020, 01:21:47 pm
content: The problematic part of connecting the supply lines behind the DC-link capacitors is passing EMC. But killing the capacitors on the DC-link... yeah, no.
Setting the voltage on the VAOUT pin of the LT1248 Boost  PFC controller IC? - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: June 14, 2020, 10:20:39 am
content: HiWe wish to affect voltages on the VAOUT pin of LT1248 PFC controller. Will the circuit number 5 of the attachment be ok to do this?(Will any of the shown circuits 1 to 5, be ok to do this?)(The Boost PFC will be operated open loop here, with a long led string on the output)LT1248 datasheethttps://www.analog.com/media/en/technical-documentation/data-sheets/1248fd.pdf
VRLA charging voltage - Page 1
Forum section: electronics / general

author: theleakydiode
author_rank: Regular Contributor
timestamp: June 15, 2020, 02:22:42 am
content: Hi, I've just noticed my ctek (XS0.8 ) charger only puts out 14.4v max and many 12v VRLA datasheets state 14.5v for these AGM types.AGM is mentioned on the charger product page, but some of their higher end models have dedicated AGM modes which charge at slightly higher voltages.What implications will this have for the batteries long term? They're the typical sealed 12v 7ah UPS style batteries, but I have a couple for project use.Thanks.

author: trobbins
author_rank: Frequent Contributor
timestamp: June 15, 2020, 03:38:59 am
content: Do you have the specific datasheet for your battery - as that is what counts?Typical 12V 7Ah monoblocs for UPS don't have a "long term" per se, as they are not a premium battery.Have you checked your ambient temperature - you may well be charging at the appropriate level!There is typically a tolerance margin for float voltage at a given temp (or range of temp).Is your voltmeter accurate to +/- 0.05V, and in calibration?I can suggest making sure that any monobloc is put back on charge directly after any discharge - don't wait for hours/days.

author: theleakydiode
author_rank: Regular Contributor
timestamp: June 15, 2020, 03:43:51 am
content: http://www.farnell.com/datasheets/1524485.pdfThat's the datasheet for the battery and here's the datasheet for the charger;https://www.ctek.com/storage/3B5F787FDBF9FA75B284D84087DC7C91986D4BF8A0D41EAF7C9E3425565A3345/a5e69b216ecd4349a65af44ac5981423/pdf/media/e05ab7472c4246288bc1efdf8ce62f0b/XS_0.8-manual-low-UK-EN.pdfAmbient temperature here is usually between 15-25c depending on time of year (18-21c is more typical for most of the year), batteries are stored away from sunlight.

author: trobbins
author_rank: Frequent Contributor
timestamp: June 15, 2020, 10:14:05 am
content: What is your application? Charging at 14.06 to 14.9V may only be required if you really need to recharge at fastest allowable rate after a substantial discharge.

author: digsys
author_rank: Unknown
timestamp: June 15, 2020, 10:45:34 am
content: Just about every Lead-Acid battery "type" can take a range of "boost-charge" and "trickle-charge" voltages - loosely dependent on usage ie rate / #cyclesTrickle usually starts from 13.6V ish - usually 13.8V and boost from 14.2V ish to 14.5V ... you "usually" don't leave them on 14.0V and above ALL the time, unless you are drawing directly from the battery all the time. And "usually", a slightly lower charge is "better" anyway.
Auxiliary Flyback SMPS to damp mains LC  input filter ringing at zero crossings? - Page 1
Forum section: electronics / general

author: ocset
author_rank: Super Contributor
timestamp: June 13, 2020, 07:24:14 pm
content: HiWe are designing a 500W Boost PFC LED driver to operate in average current mode.Our contractor wants to add a small 15W Constant off time flyback to always pull current from the post bridge DC bus and also dump its energy into the leds. He says that this is necessary because otherwise there will be severe ringing in the mains input LC filter at the zero crossings which will adversely affect the THD of the mains input current. He says that this Flyback will act so as to damp out this ringing.Please can you confirm that his desire for this additional 15W flyback SMPS is bogus?I mean, yes, in very light load, (say <10W) there would be some ringing in the mains input current due to the mains LC input filter, and this will happen at the mains input voltage zero crossings, but this is nothing to worry about and there’s no need to damp it with an additional Flyback SMPS as described. Would you agree?
Buck test circuit - can I use signal generator for test pwm signal? - Page 1
Forum section: electronics / general

author: mikeinfodoc
author_rank: Regular Contributor
timestamp: May 17, 2020, 12:21:31 pm
content: I wish to test some buck designs.I have a dc bench-top power supplyI also have a signal generator (which can do sin or square and covers the needed range of frequencies I am interested in)Would it be reasonable (for testing/development only) to use the bench-top dc supply as my Vin supply,and use square wave output from my signal generator (into mosfet gate) as my pwm signal?(note: I would ground both to the same circuit ground)

author: David Hess
author_rank: Super Contributor
timestamp: May 18, 2020, 02:21:36 pm
content: If the switching regulator operates in continuous conduction mode, then that can work for simple testing because the input to output voltage ratio is fixed by the duty cycle.

author: ocset
author_rank: Super Contributor
timestamp: June 07, 2020, 01:16:47 pm
content: Yes thats right, but beware you dont keep pwm'ing it then accidentally turn the load off.....as the output volts will ramp up and up.....but at least with buck it cant go higher than vin.But remember you really need a proper gate driver to drive a switching fet......and you dont want wiring (which mightnt be very small in its loop area) driving a fet gate really....you can get gate drive oscillations etc.I think you need the gate drive cct to be layed out tightly with the rest of the smps to be honest...not coming in on wires

author: ocset
author_rank: Super Contributor
timestamp: June 07, 2020, 01:19:30 pm
content: please find pcb layout attachment here

author: David Hess
author_rank: Super Contributor
timestamp: June 08, 2020, 05:03:14 am
content: A good function generator has enough compliance to drive a pretty big MOSFET with its 50 ohm output. (1) I have done exactly what he is suggesting in the past for testing purposes.(1) All of my old style function generators can drive a minimum of +/- 7.5 volts into a 50 ohm load which means the MOSFET gate sees a 25 ohm driving impedance which is plenty low.

author: ocset
author_rank: Super Contributor
timestamp: June 08, 2020, 12:58:58 pm
content: I see, yes and connecting it via coax would be best.As you know, it will be open loop so somewhat limited in value.

author: David Hess
author_rank: Super Contributor
timestamp: June 08, 2020, 06:36:57 pm
content: Quote from: treez on June 08, 2020, 12:58:58 pmThat is right, and the 50 ohm termination may or may not be required.In a high side designs or where the function generator is not floating with respect to the circuit, AC coupling can be used with a couple of switching diodes to keep the duty cycle from modulating the average DC voltage at the gate.
Buck - small inductor  - Page 1
Forum section: electronics / general

author: mikeinfodoc
author_rank: Regular Contributor
timestamp: May 17, 2020, 12:33:49 pm
content: Would a small 200uF inductor like this be acceptable for a small low current test buck circuit?https://www.digikey.com/product-detail/en/bourns-inc/78F221J-RC/M10139-ND/1305997I suspect the main draw back from other inductor shapes/sizes/specs, would be the small current limit...are there any other drawbacks to this size/shape of inductor?is it reasonably safe to assume the inductive reactance would/should besimilarto larger sized inductors with the same henry rating?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: May 17, 2020, 10:12:17 pm
content: I mean, it is what it is? But more importantly, WHAT "low current test buck circuit"? That is what matters.And I guess you're trying to infer something about its performance or behavior with respect to something at scale? What thing?Tim

author: nctnico
author_rank: Super Contributor
timestamp: May 18, 2020, 12:00:55 am
content: Perhaps Mike can combine his postings in one big question which includes the specifications for what he is trying to achieve.When it comes to inductors the core material is very important. Wurth has an online tool in which you can input the voltage, current and switching frequency. From there is will show you suitable inductors including the expected temperature rise in the inductor. Coilcraft has a similar tool. Sometimes I end up with a Wurth inductor and sometimes with one from Coilcraft.

author: David Hess
author_rank: Super Contributor
timestamp: May 18, 2020, 02:34:23 pm
content: Quote from: mikeinfodoc on May 17, 2020, 12:33:49 pmThe usual problem is saturation at low currents but the series resistance is also pretty high.QuoteThe other problem is lack of shielding. Inductors in switching regulators operate at high levels of flux so should be shielded or provide self shielding (toroids, pot cores, and e cores for instance provide a continuous path for the flux inside the core) to prevent generating interference in adjacent circuits.

author: ocset
author_rank: Super Contributor
timestamp: June 04, 2020, 11:22:16 am
content: In those sort of small inductors, i reckon the inductance would drop away more sharply as current rises up in the inductor...compared to one of the more high quality wurth ones etc.
How does battery runtime calculated? - Page 1
Forum section: electronics / general

author: eeguy
author_rank: Regular Contributor
timestamp: May 31, 2020, 06:10:52 am
content: Hi, according to this site, runtime is calculated as 60/C. So if C is 70, it means the battery runs out in 60min/70 = 0.84 min? Am I missing something?https://www.gettitanpower.com/blogs/news/short-and-long-answers-what-is-the-c-rating

author: Rerouter
author_rank: Super Contributor
timestamp: May 31, 2020, 06:35:05 am
content: C = the battery capacity, the C rating is how many times above that capacity in amps you can draw from it without causing permanent damage,so say you have a 3000mAh battery, if you discharge it at "1C" / 3A, it would last roughly 1 Hour (assuming your circuit can work that low, and your not expecting things to last too many charge cycles)So if you took that same battery and discharged it at 70C, that is 210A, 3Ah / 210 = 0.0143 hours, = 0.857 minutes = 51.43 seconds,However the ESR tends to crash when batteries are not at 100% charged, so I would not really trust a 70C battery to actually allow a 210A discharge at the lower part of its capacity,

author: Siwastaja
author_rank: Super Contributor
timestamp: May 31, 2020, 02:48:28 pm
content: Yes, discharging at 70 times C indeed, by definition, means the battery is drained from 100% to 0% in less than a minute.70*C means that a 10Ah battery is discharged at 700A, for example.Batteries that can actually be discharged at 70*C, i.e., fully in less than a minute, are rare. Consider ultracapacitors for such high rates; or, just increase the capacity beyond what you'd need capacity-wise.Note that HobbyKing and similar batteries said to be able to provide continuous 50C or 70C discharging current actually can not support it. Derate to half the marketing value to be sure.Do you have a specific application in mind?

author: eeguy
author_rank: Regular Contributor
timestamp: June 01, 2020, 12:46:01 am
content: Quote from: Siwastaja on May 31, 2020, 02:48:28 pmThanks. So if the mAh of two batteries are the same and one has 50C and the other has 70C, they are almost the same?I plan to use it to power some motors or a PC for about 20 minutes.

author: ejeffrey
author_rank: Super Contributor
timestamp: June 03, 2020, 03:03:11 am
content: Yes if you will only be discharging at 3C the current rating isn't particularly important.
Power Supply Design Information - Page 1
Forum section: electronics / general

author: Saitama
author_rank: Contributor
timestamp: May 25, 2020, 09:30:40 am
content: Hello! I've taken an interest in designing power supplies, but they are simple, non reliable and overall bad, so I want to do a bit of research on this topic to improve my designing skills. What books, papers, videos and other kinds of information do you suggest?Thank you for reading my thread and I will appreciate all replies

author: ocset
author_rank: Super Contributor
timestamp: June 02, 2020, 01:50:59 pm
content: Please find my free power supply design course in this doc....(it is linked in here somewhere, you will find if you read through)it depicts power supplies by way of annotated ltspice sims...ltspice is freehttps://drive.google.com/open?id=1cmk81KxXA7-EliHHWr8ZimpEp7HCMIcY