hybridfree/eevblog-posts huggingface dataset:
Bridging different speed buses - Page 1
Forum section: electronics / projects

author: sirhaggis
author_rank: Regular Contributor
timestamp: December 06, 2016, 09:41:47 am
content: I am working on a project in which I have multiple boards each running a simple 8-line bus (at about ~8MHz) that I want to interface to common bus running at a higher speed (32Mhz). I want to be able to inject and extract data from the faster bus to the slower bus and vice versa. It seems I need some sort of buffering solution so that the slower controller can write ahead into a buffer to be clocked through the latch onto the faster bus and vice versa for receiving. Is there a standard, cheap solution for such a task?One method I have successfully tried has been to divide the faster bus into 4 channels and each attached board is assigned a channel and can RX/TX at its own slower speed. Using this method the data on the faster bus will be in 4 byte sequences channel 1,2,3,4. This works, but once the controller on the faster bus receives a sequence it needs to perform expensive operations to reassemble the streams. Preferably I would like to receive at least word sized (4 byte) sequenced chunks from each board that are far less costly to deal with. This means I would need to buffer at least 4 bytes at a time before clocking them onto the fast bus...Or perhaps theres a better way I haven't thought of yet? Any ideas?Luke

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: December 08, 2016, 02:28:43 am
content: Dual port RAM?

author: Berni
author_rank: Super Contributor
timestamp: December 08, 2016, 06:04:33 am
content: Sounds like a job for a CPLD

author: sirhaggis
author_rank: Regular Contributor
timestamp: December 08, 2016, 06:51:29 am
content: I love the concept of CPLDs but I haven't yet taken the time to learn how to use them.Dual port RAM sounds like an interesting option, I have never used it before.Time to investigate!ThanksLuke
bringing solder paste back to life - Page 1
Forum section: electronics / projects

author: ETITsynthesizer
author_rank: Contributor
timestamp: March 17, 2020, 08:27:40 pm
content: I have some T4 size leaded solder that was pretty much almost completely dry when I removed the seal for the first time immediately after shipment. I need either a tacky flux that is designed for reflow manufacturing in an oven or I will maybe thin it out with isopropanol.I found this but it is a bit more expensive than what I want to pay. it says "tacky" so that makes me think it is good for solder paste. is that correct?https://www.amazon.com/Clean-Tacky-Soldering-Flux-Grams/dp/B07DCD9M3P/how does this compare?https://www.amazon.com/gp/product/B005DNR01Q/
broken Metcal MX-RM3E (inductor valu and capacitor) - Page 1
Forum section: electronics / projects

author: dtses14
author_rank: Newbie
timestamp: September 17, 2018, 08:50:09 am
content: hi,my Metcal MX-RM3E seems to be dead as all the time cuts off to yellow. Once I replace it with a new one, MX500 station is back to life.I would like to repair the handle and foundherethat is might be inductor and capacitor that needs replacing.it is 22uH inductor, anyone knows cap's value? Unfortunately I didnt find any related info in the manual.thanks in advance!

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: September 17, 2018, 12:56:30 pm
content: Here is a picture of the beast, but unfortunately I cannot read the value. I never thought to record the value last time I repaired an RM3E. I don't think you will persuade anyone to dismantle a wand to check for you ! Can you not test the cap in your wand or has it been destroyed?Regards, BT

author: dtses14
author_rank: Newbie
timestamp: September 18, 2018, 08:25:13 am
content: dont have the tool unfortunately and not sure that cap (or inductor or both) will show correct specs since the handle does not work properly, almost after second touch to joint yellow light comes up on the base.I made a pic of the cap, but it doe snot say much - C85 and 9915.maybe someone changed the parts and know precise values?

author: JFJ
author_rank: Regular Contributor
timestamp: November 21, 2018, 07:57:06 am
content: Quote from: dtses14 on September 17, 2018, 08:50:09 amAs resonance occurs when the capacitor's reactance equals that of the paralleled inductor (XC= XL), the value of the capacitor can be calculated.Using the formula XL= 2πfL, the reactance of the 22uH inductor is 1866.11 - at Metcal's 13.5MHz operating frequency.Rearranging the capacitor reactance formula in terms of C, and substituting the inductor's reactance for XC, gives:C = 1/(2πfXC)= 1/(2 x π x 13500000 x 1866.11)= 6.3E-12Farads or 6.3pF

author: vanquyenhn
author_rank: Newbie
timestamp: March 10, 2024, 02:48:06 am
content: The value of the capacitor is: 271 = 270pF.
Broker lixincchip - Page 1
Forum section: electronics / projects

author: tarun172
author_rank: Regular Contributor
timestamp: January 15, 2024, 02:51:34 pm
content: Hello,I am curious if anyone has done business with or has experience dealing with the broker name:www.lixincchip.com. They are located in Hong Kong and have a US presence in Seattle.Thanks,tarun172
Brushed DC motor overload protection - Page 1
Forum section: electronics / projects

author: gaminn
author_rank: Frequent Contributor
timestamp: February 09, 2024, 11:37:30 am
content: Hi,my small 9V DC brushed motor has max. continuous current rating of 1 A which I'm supposed not to exceed very often in order not to damage the motor. The motor is driven by a PCB with some MCU with programmable firmware and DRV8837 driver. The driver unfortunately has no overload protection suitable for my motor and also the MCU can't measure and read motor current on the PCB.What do you think, is there anything I can do about the motor protection and that 1 A current limit for my motor on the current PCB (I can e.g. update firmware of the MCU) or should I redesign the PCB and measure the current?

author: avandalen
author_rank: Contributor
timestamp: February 12, 2024, 12:12:05 pm
content: Use a Hall current sensor ACS712ELC-30A od so..
no text - Page 1
Forum section: electronics / projects

author: daywalkerdha
author_rank: Contributor
timestamp: March 27, 2013, 05:01:20 pm
content: no text

author: SeanB
author_rank: Super Contributor
timestamp: March 27, 2013, 06:37:18 pm
content: Just use 4 wire PC cooling fans, which are quite happy to run off 12V but have both a tacho output and a PWM input for speed control. Also available in a few sizes.

author: SeanB
author_rank: Super Contributor
timestamp: March 27, 2013, 07:16:51 pm
content: Depends on the fan, use around 100Hz and it will probably do for most of them, and most will go to either a very low speed or off if you have the PWM low.

author: baoshi
author_rank: Regular Contributor
timestamp: March 28, 2013, 01:28:12 am
content: Hi daywalkerdha,I made this a while ago. Since I do not have 12v rail I used a boost converter, controlled by a PWM. Output is 7-12V driving a Sunon 0.7W fan.Bob

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 28, 2013, 08:41:10 pm
content: Quote from: daywalkerdha on March 27, 2013, 11:44:39 pmSome fluid dynamic bearings dislike low speed operation and wear out very quickly. I presume MagLevs might have the same problem. (Ball bearings should be fine.)

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 28, 2013, 10:19:13 pm
content: Quote from: daywalkerdha on March 28, 2013, 08:51:40 pmQuoteI suggest a buck converter to derive a variable rail voltage. It can even be an open loop control.

author: smashedProton
author_rank: Frequent Contributor
timestamp: March 29, 2013, 07:28:27 pm
content: I think that it looks good! I didnt know that photodarlington transistors existed! Your circuit looks nice, but you may run into a problem where one fan reaches a higher rpm than the other due to different resistances. That problem will only get worse. You could, however, create a second channel running off the same opamp with a different FET. Maybe even use the sense pin on the brushless motor.
BS 7671, Isolation & Switching product (BSxxx) attributes on data sheets - Page 1
Forum section: electronics / projects

author: 741
author_rank: Frequent Contributor
timestamp: December 05, 2020, 12:45:07 pm
content: In BS7671, Table 537.4 "Guidance on the selection of protection, isolation and switching devices" there appear references such as "BS60947-4-1".Would I require the exact reference (BSxxx) to appear on accompanying documentation such as data-sheets when selecting a contactor for a given application?In particular, would the Durakool DG34 series be allowable for the "BS60947-4-1" requirement?The end product is going to have 2 series relays/contactors. One does the normal switching (comes on first, switches off last), the other is in case the main device has contact weld.

author: bjbb
author_rank: Contributor
timestamp: December 05, 2020, 09:07:22 pm
content: Insufficient information. If you are modifying an existing install, then the governing statement is “ Does not result in a lesser degree of safety”. Otherwise it is a systems-level assessment question that is not answerable in this venue.What are the certifications and conditions of acceptability and installation instructions for the contactor ?What type of isolation and protection from shock is required per BS7671 per the scope of the intended end-use installation?What are the over-load and interrupt requirements?Have you talked to the engineering people at your supplier? Have you talked to your local Notified Body or test house?

author: themadhippy
author_rank: Super Contributor
timestamp: December 05, 2020, 10:35:32 pm
content: Quotewhy not ask the manufacturer

author: 741
author_rank: Frequent Contributor
timestamp: December 07, 2020, 09:16:17 am
content: Sure: I understand "this venue" is informalI am not directly involved in specifying the relay. I'm simply trying to verify (informally, independently) that the decisions made are rational because I am uneasy. I have been assured by others that the relay in question is OK when I put this same question to them.I feel the application amperage etc is not relevant to this query, which is of a higher level - it is more generic question.I am simply after an informal second opinion whether:If the table says BSxxx thenthat is something that absolutely must be on the data sheet
BT Line tester - Page 1
Forum section: electronics / projects

author: veedub565
author_rank: Frequent Contributor
timestamp: September 11, 2015, 06:57:42 am
content: Hi,Long shot but just wondering if anybody happens to have a circuit diagram for the SA9083 telephone line tester ? I think originally they were made by Robin but latterly JSD Testphone ltd. There is a picture of what it looks like herehttp://www.telkominternational.com/tester-sa9083.htmlI already have a copy of the test procedure and user manual.
BT phone box idea looking for advise  - Page 1
Forum section: electronics / projects

author: andybarrett1
author_rank: Regular Contributor
timestamp: March 15, 2018, 09:54:01 am
content: Hi Thank you for readingAm still looking at a future idea... Involving an old BT Telephone Mech.I need the existing "Dial" to give me one digital pulse for each digit dialled..... :-As I understand it at the moment the number 6 for example is dialledAs the dial rotates back to its rest position I will get a pulse train of six pulses ......Hi Hi Hi Hi Hi Hi ..... for 4 I will get four pulses as it rotates back ...Hi Hi Hi Hi.....etcHow might I convert these pulses into single pulses ... one for each digit dialled.The BT Phone box (K6)in question is a UK listed landmark and needs to stay as authentic as possible.Otherwise would just use PB switchesHelp / Advice WelcomeBRAndy

author: fourtytwo42
author_rank: Super Contributor
timestamp: March 15, 2018, 10:06:25 am
content: In a strowger exchange that would be the slugged CD relay. Depending on whether you want your exchange equipment from the same era you either need a strowger selector from somewhere (expensive) or do it in software on an MPU or use a simple logic monostable.

author: andybarrett1
author_rank: Regular Contributor
timestamp: March 15, 2018, 10:22:52 am
content: I like the idea of a logic monostable.... Maybe get the 74 series books out lolThank you

author: Ian.M
author_rank: Super Contributor
timestamp: March 15, 2018, 10:45:09 am
content: IIRC on a classicGPOrotary phone dial mechanism, there is an auxiliary contact that indicates whether or not the dial is in its home position. I think it was used to mute the earpiece while dialling.OTOH if you are limited to hooking up to the two wire line interface of the phone, you'll have to detect the dial's pulsed interruption of the line circuit.
BT Split Keyboard Design -- Review Request - Page 1
Forum section: electronics / projects

author: k4black
author_rank: Newbie
timestamp: September 20, 2023, 01:02:14 pm
content: Hello everyone,I'm working on an OSHW Split Keyboard design and would appreciate feedback on the scheme!I am not a professional in PCB dev and sure missed a lot of small things.Here are the main details:* Split keyboard* Bluetooth for PC connection and sides connection (master-slave)Tech details:* MS88SF2 board with nrf52840 chip in both sides* Cherry MX Ultra Low Profile switches (hand soldering using through-holes)* 300mAh battery with integrated protection* USB-C for charging, and programming* Double-sided PCB (to make left or right side)Not yet made PCB layout, waiting to finalize scheme.Given the above, I would really appreciate any comments, advice, or suggestions you might have regarding the design. Your expertise and guidance would be invaluable to me at this stage.(pdf or png with scheme is attached)Best!
bt tester301c - Page 1
Forum section: electronics / projects

author: p.larner
author_rank: Frequent Contributor
timestamp: October 17, 2023, 07:42:41 pm
content: have this bt tester,will it be any good for measuring the length of magnet wire left on spools,also has anyone experiance using these,a service manual would be cool too or a schematic.

author: TimFox
author_rank: Super Contributor
timestamp: October 18, 2023, 12:05:06 am
content: Time-domain reflectometers are used to measure distances to discontinuities and other features of transmission lines (such as coaxial cables).I don't think it would work to measure wire length wound on a spool.Can you set up a resistance measurement (assuming the wire is insulated)?

author: p.larner
author_rank: Frequent Contributor
timestamp: October 18, 2023, 12:10:45 am
content: no as one end(far) is not get atable so imposible to resistance test without unrolling the lot.
BTS5016 High Side Dual Switch - Page 1
Forum section: electronics / projects

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: June 17, 2021, 03:21:45 pm
content: I am lost as to the lack of a proper "truth table" for the device.My question is, should the DEN pin be high or low for output?In Table 8 on page 28, it shows me that it should be high for the load to be provided supply voltage - current.Is this correct? I know it's and old Infineon part that they touted and dropped for the latest thing, but it's a question of having it in quantity already.Has anyone used this family of MOSFET switches before?https://www.infineon.com/dgdl/Infineon-BTS5016-2EKA-DS-v01_00-EN.pdf

author: mikerj
author_rank: Super Contributor
timestamp: June 17, 2021, 07:43:45 pm
content: Neither! The DEN and DSEL pins are for diagnostic purposes, not for controlling the output. The truth table for the diagnostic pins is in section 7 of the datasheet.The IN0 and IN1 pins control the output, and are active high as per the diagrams in section 5.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: June 26, 2021, 11:41:34 pm
content: I've been awfully busy to respond. I also haven't tested the IC yet, but I appreciate your feedback. Perhaps next weekend will be better to give it a go.
Buck-Boost controller fails but power switch survives - Page 1
Forum section: electronics / projects

author: luigi
author_rank: Newbie
timestamp: January 31, 2019, 04:31:08 am
content: Hi everyone,I am using the buck-boost controller LM25118, to generate 12V DC (7.5A max.) out from a 10-30Vin battery.This power supply feeds a H-Bridge that drives then a DC motor which will demand 7.5A in stall at 12V.The problem is that I am having many failures where the power supply chip fails without apparent reason.The failure consists of the LM25118 stop working and no voltage is measured in the output. There is no PWM in the gate of the MOSFETs.Replacing the chip (and only the chip) makes the circuit come back to normal and operate normally.Initially I considered that the failure could be caused by defective IC. But after having multiple boards from different PCB suppliers failing, I ruled that out.Sometimes at motor start-up the Voltage between the H-Bridge and the power supply drops down to Zero as there is little capacitance at the power supply output. But the power supply output seems to ramp-up back to the nominal voltage normally and will not enter any short circuit protection mode.After discarding IC malfunction, I thought that the overload condition could be the reason behind the failures, but in such case the failure point would be the power diodes or MOSFETs, not the controller.The only possibility left in my mind is a transient in the VIN that supplies the chip.The schematic for the LM25118 circuit is below:The design was generated by TI's Webench online tool, but I have made some changes.I've reduced the main inductor to one with Isat of 11A.In what circumstances, could a buck-boost controller with the topology as in the schematic above, fail while the power switches remain intact?

author: georges80
author_rank: Frequent Contributor
timestamp: January 31, 2019, 05:57:24 am
content: Long wires from the power supply to your switcher can cause inductive transients, especially since it appears you only have ceramics as input caps to your switcher.Add some higher ESR electrolytic caps (say in the 100uF range) in parallel with your C20 cap. If it's input voltage transients killing the switcher, the the electro cap can 'dampen' them.You could probe with a scope (use a spring 'ground' clip on the probe end) and likely see some nasty high voltage transients when you connect/disconnect your power supply.Anyhow, this also assumes you have a decent layout and good ground planes, i.e. the design is otherwise good and within safe operating limits.cheers,george.

author: jbb
author_rank: Super Contributor
timestamp: January 31, 2019, 06:52:30 am
content: It’s quite hard to say. Have you checked all of the pin ratings? They’re probably OK, but...Also, the compensation network connections look a bit odd. Some chips are very sensitive on the feedback and compensation pins.

author: uer166
author_rank: Super Contributor
timestamp: January 31, 2019, 07:00:51 am
content: Also check for negative transients on switch node (HS pin of IC), it's rated to -4V, but inductance in switching loop can make that lower.
Buck-boost Converter - Page 1
Forum section: electronics / projects

author: curiousmech
author_rank: Newbie
timestamp: September 04, 2014, 06:21:25 am
content: Greetings,Could anyone look at the following and tell why i cannot achieve 13.5Volts at the output while i change the duty cycle also

author: Niklas
author_rank: Frequent Contributor
timestamp: September 04, 2014, 06:57:57 am
content: You need to separate the two drive signals to the MOSFETs. When the lower one is on, from where can it sink current through the inductor? Should be through the top FET. Also check the top drive circuit. What will the gate-source voltage be shortly after after that FET in turned on? The gate is at a fixed potential, but how about the source?
Buck-boost for 1-4.2V input & 3.3V output. Max. power 1W - Page 1
Forum section: electronics / projects

author: plazma
author_rank: Frequent Contributor
timestamp: March 15, 2017, 01:58:53 pm
content: I'm designing a small metering device for an university embedded course.I would like to use any AA sized battery. Primary or rechargeable.Input voltage may be as low as 1V with LSD NiMH and as high as 4.2 with a LiIon 14500 cell.I need 3.3V for the MCU and sensors.I found a one chip solution LTC3106.http://www.linear.com/product/LTC3106However this chip got a poor performance at lower voltages.Any suggestions for a buck boost solution with good performance? Two different chips?

author: tszaboo
author_rank: Super Contributor
timestamp: March 15, 2017, 03:30:53 pm
content: You are making your life very difficult with those requirements. I would suggest a stepup with 2 AA/AAA battery or a stepdown with the 14500 cell. It is easier with the 14500 if you dont want to charge it, with the two AA/AAA it is more user friendly.The issue with complicated power systems is simple. You use two dozen components and complicated design, hard to source inductors. IMHO, inductors in the Bill of material are pain in the ass. And you spend all that time on the power system, instead of spending it on the application. Nobody will raise an eyebrow, if you need two batteries for it. You can even run the entire system on it, without any power management, if parts are selected for that.Or use a coin cell, or oversized coin cell.

author: plazma
author_rank: Frequent Contributor
timestamp: March 15, 2017, 06:12:21 pm
content: At the moment I'm going with the LTC3106. It's a decent buck-boost for LiIon. Using NiMH or alkaline remains an inefficient but usable option.There is only space for one AA. Two AAA sizes is not an option. The battery is inserted into the device from the side through a round hole.However I'm still interested in making the NiMH and alkaline option more efficient.

author: DBecker
author_rank: Frequent Contributor
timestamp: March 16, 2017, 01:55:30 am
content: Remember that it's easy to get lithium rechargeable cells in AA size. You'll still need a buck-boost to get 3.3V and use most of the capacity, but if you don't need the full capacity, a micropower linear LDO may work for your application. And it will be far quieter than a switching regulator, which can be a real advantage when you don't want to waste the power to filter samples.

author: plazma
author_rank: Frequent Contributor
timestamp: March 16, 2017, 09:34:00 am
content: A linear regulator + a boost is what I'm researching? atm. The buck and linear regulator are quite close for 3.3V when using LiIon cells.
Buck-boost INPUT voltage regulation stability (MPPT) - Page 1
Forum section: electronics / projects

author: Ern
author_rank: Newbie
timestamp: November 25, 2016, 08:40:18 am
content: *

author: jbb
author_rank: Super Contributor
timestamp: November 25, 2016, 08:35:49 pm
content: I haven't done it with a buck-boost converter, but I have done a simple boost MPPT stage. After a certain amount of screwing around, we found that the easiest move was to just drive the stage with fixed PWM duty cycle (D = Vin_ref / Vout) and let the dynamics take care of themselves. Remember that the PV panel is current limited. For extra credit, you can do some more complicated maths to encompass Discontinuous Conduction Mode (DCM) operation.Your PV panel appears to have an open circuit voltage of 18V. I would suggest that you use a simple buck converter. LT makes some which have (approximate) MPPT built in (http://cds.linear.com/docs/en/lt-journal/LTJournal-V20N4-02-df-LT3652-Jay_Celani.pdf), which would be easier to manipulate than a generic converter. Alternatively, you can place a discrete MOSFET, diode and gate driver, directly controlled by a micro controller PWM pin.Also don't forget about transients! I suggest your buck stage input have a 30V TVS diode and use 45V devices. (Note TVS diodes clamp voltages to around 1.3x - 1.5x their rated voltage.)FYI, your PV panel model is pretty crude, and may give misleading results.
Buck Boost recommendation for 1Amp 5V from batteries - Page 1
Forum section: electronics / projects

author: Stonent
author_rank: Super Contributor
timestamp: January 16, 2015, 04:40:20 pm
content: I'm thinking of building a portable device with an embedded Raspberry Pi and LCD. I'm not sure what kind of battery I want to use yet, but I'm estimating I'll need a continuous 5W of power to keep things running.I'd like to be able to work with a variety of over and under input voltages (We'll just say 1.5V to 12V). So that would give me options of NiMH batteries run completely flat, parallel or serial connected 18650 batteries, or a LiPo pack. (If I go lithium based I'll put in a pre-made battery protection circuit.)I don't plan on integrating charging into the device itself and plan on getting a Nitecore charger for that.http://www.nitecore.com/productDetail.aspx?id=115I'm looking for some recommendations for a through hole part that could handle the task.A parametric search on Mouser for that range in through hole gave me these 4MC34063MC33063MC33613LM78S40Would you recommend one of these over the other, or are there other through hole devices I didn't get on my list that you'd recommend more?
Buck converter (TPS5430) won't start (solved) - Page 1
Forum section: electronics / projects

author: judokan9
author_rank: Newbie
timestamp: October 29, 2022, 04:41:22 pm
content: Hello to all!I designed my first pcb with an buck converter circuit on it.Sadly the TPS5430 don't seem to start up correctly.For the part selection i used the TI WEBENCH:As my pcb assembler does not had all parts avalible i switched them out for similar parts:L1 ->https://jlcpcb.com/partdetail/ChilisinElec-SCDS104R_330MN/C280630D1 ->https://jlcpcb.com/partdetail/mdd_microdiode_electronics-SS210/C14996Cin ->https://jlcpcb.com/partdetail/14236-CL31A106KBHNNNE/C13585Rfbb -> 2.7khttps://jlcpcb.com/partdetail/13814-0603WAF2701T5E/C13167+ 510https://jlcpcb.com/partdetail/23920-0603WAF5100T5E/C23193Rfbt ->https://jlcpcb.com/partdetail/26547-0603WAF1002T5E/C25804Cboot ->https://jlcpcb.com/partdetail/58143-0603B103K500NT/C57112When i provide +12V to the input of my circuit i only measure 0.28V on the output Voltage.Vref reads 0.068v after the Rfbt resistor.This is my schematic:And my board design:I am not shure if my Board Design ist faulty or my part selection.Maybe one of you can point me in the right direction.

author: jkostb
author_rank: Regular Contributor
timestamp: October 29, 2022, 05:07:32 pm
content: If i look at your schematics I see that you don't have a compensation network. The tantalum polymer output capacitors have low esr, so you need to add them. I would use ceramic capacitors for the output.

author: langwadt
author_rank: Super Contributor
timestamp: October 29, 2022, 05:14:00 pm
content: Quote from: jkostb on October 29, 2022, 05:07:32 pmyou have it backwards, look at the datasheet ..

author: judokan9
author_rank: Newbie
timestamp: October 29, 2022, 05:55:51 pm
content: Thank you all for the quick answers!I just checked the parts placement for the tenth time (had debugged this circuit 2h long before posting here...) and realized, that the schottky diode where placed in the wrong way around...After rotating it 180 degrees the circuit is working.
Buck converter 50-400V to 24V what is best solutuon? - Page 1
Forum section: electronics / projects

author: Miyuki
author_rank: Frequent Contributor
timestamp: October 17, 2018, 06:58:45 pm
content: Hi folksI need small universal input step down from like 50V to 400V (rectified line) to 15-24V non isolated output with up to 200mAI found some chips like LinkSwitch what look like what I needJust want to know if someone have experience or know about ready made module for reasonable price
Buck converter acting up? - Page 1
Forum section: electronics / projects

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: December 11, 2019, 02:15:39 pm
content: I have attached a graph of the voltage and how it keep dropping from around 5.3 to 5V DC when not under load.At 1A load, the behaviour continues but the voltage drop is much less and at higher loads (4A) this is no longer an issue.Is this normal or is my unit shot? What could be the culprit and how can I fix it?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 11, 2019, 02:28:44 pm
content: No idea. I mean, doesn't sound right. But whatisit?Tim

author: drummerdimitri
author_rank: Frequent Contributor
timestamp: December 11, 2019, 02:37:31 pm
content: Quote from: T3sl4co1l on December 11, 2019, 02:28:44 pmI've attached the datasheet of the unit in question.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 11, 2019, 10:56:18 pm
content: I don't see any documentation or schematic or support contact or anything, so you'll have to figure out what kind of support the manufacturer provides, if any.Tim
Buck converter - at what current should inductor be calculated? - Page 1
Forum section: electronics / projects

author: shadewind
author_rank: Frequent Contributor
timestamp: August 28, 2011, 05:35:25 pm
content: Hello,I'm designing a buck converter using the NSC LM2738X regulator. I'm trying to calculate the inductor value to use and the formulas are very clear to me, that's not the problem. From what I can gather, you want approximately 33% of the output current as ripple current. But at what output current should I calculate this? I'm guessing I'll average about 50 mA of output current but I want to have some headroom up to about 0.5A. So how should I set the ripple current for this?I'm assuming that you never want the converter to go into discontinuous conduction mode at the average load current?

author: Afrotechmods
author_rank: Unknown
timestamp: August 30, 2011, 02:01:02 am
content: You calculate it as a percentage of the maximum output current. So 0.33 * 0.5A = a max of 165mA ripple current.

author: shadewind
author_rank: Frequent Contributor
timestamp: August 30, 2011, 02:04:43 am
content: But then it wil go into DCM at my median load of 50 mA.

author: Afrotechmods
author_rank: Unknown
timestamp: August 30, 2011, 02:44:20 am
content: Discontinuous mode may or may not be a big deal depending on how your controller handles light loads. If there is a minimum on time and no ability to pulse skip, then you may have to put a minimum load on your converter at all times and/or increase the output capacitance to dampen the unwanted extra pulses and/or look for a controller better suited for lighter loads. (50mA average for a buck converter is unusually low.) If your controller has pulse skipping or similar features that kick in at low loads then discontinuous mode shouldn't be a problem.
Buck Converter EN pin input voltage rating??? - Page 1
Forum section: electronics / projects

author: JoeyG
author_rank: Regular Contributor
timestamp: July 21, 2023, 06:11:09 am
content: Please refer to this ebay buck converter moduleMini DC-DC 12-24V To 5V 3A Step Down Power Supply Module Voltage Buck Converterhttps://www.ebay.com.au/itm/304174625197?var=603281751863I cant find the EN pin input voltage specifications.At this stage I'm assuming 5V (not Vin)

author: mariush
author_rank: Super Contributor
timestamp: July 21, 2023, 06:56:06 am
content: The chip is made by monolithic power systems , they have that scheme with a vertical bar followed by 3-4 letters as the marking.You could just look in their inventory for something that's capable of 3A and more than 12v input voltage and 500kHz or higher and then look in datasheets to see which has the marking like on the chip.MPQ2315 could be it or a slight variation, marking is AGCY :https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/MPQ2315/AGC: product code of MPQ2315GJ;Y: year code;Quote

author: Faranight
author_rank: Unknown
timestamp: July 21, 2023, 07:06:16 am
content: I have some of these buck boards as well, though, red in color. They have very poor transient performance. I couldn't power a micro board from them without the board resetting every once in a while due to UVLO.

author: JoeyG
author_rank: Regular Contributor
timestamp: July 21, 2023, 10:42:50 am
content: Amazing help full - Data sheet says page 13 Enable : general 100K pull up (as there is a 1Meg pull down and 6.2V zener clamp internally)
buck converter for current, rather than voltage - Page 1
Forum section: electronics / projects

author: jmole
author_rank: Regular Contributor
timestamp: June 22, 2015, 10:59:34 pm
content: I was talking with a friend of mine today who makes low-voltage (3.3-5V) LED chandeliers, and he's been having issues with installing them in houses with dimmer switches. Typically, he runs mains AC to an off-the-shelf isolated 3.3V or 5V PSU, and runs the sculpture from that. If his clients want a dimmable fixture, he'll supply them with a remote control they can use.But, he'd like to be able to dim them straight from the mains (i.e. a typical TRIAC dimmer) if the client wants to.Most of the IC's out there today are designed to dim a 20-40V string of LEDs at currents from 0.25A to 1.5A. He's looking at 1A - 5A @ 2V to 5V.So, I got to thinking, there must be some way to take a constant current output from a typical offline TRIAC dimmable LED controller circuit, and amplify the current/reduce the voltage, so it can drive a lower voltage at a higher current.Is my head in the sky here? Or is there actually a way about this? I still haven't figured it out.

author: moffy
author_rank: Super Contributor
timestamp: June 22, 2015, 11:49:52 pm
content: It is possible. You would need a step down/isolation transformer after the triac. The transformer would be full wave rectified but you would need a large enough inductor that at the minimum current, 1A, you maintain continuous current conduction. That way the current will vary with triac phase angle otherwise the power supply just becomes a peak detector.

author: Marco
author_rank: Super Contributor
timestamp: June 23, 2015, 01:05:35 am
content: Would be easier to just detect the phase angle of the triac dimmer and use that to generate input to whatever dimmer circuit he is already using.

author: jwm_
author_rank: Frequent Contributor
timestamp: June 23, 2015, 01:09:06 am
content: Since triac dimmers generally chop the waveform short, could you let the power supply run like normal, but measure the pulse width of the triac chopped AC voltage and feed that to your current regulator. Since even a very dimmed (from an incandescent point of view) line voltage is enough to drive a LED at full brightness.
Buck converter IC packages - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 02, 2015, 03:20:43 am
content: Looks like the majority of SO-8 packages with exposed paddle have the paddle go to ground. Makes sense, that's where the copper will be. Why would a manufacturer put the Vin on the exposed paddle?http://www.digikey.ca/product-detail/en/AOZ1284PI/785-1689-1-ND/4900905The Vin copper area would be tiny. Granted, the chip has a pretty low RDSon and no synchronous rectifier, so I doubt it would get too hot. But what's the technological reason for it? The converter happens to have a higher max Vin than the parts with grounded exposed paddle.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 02, 2015, 03:30:09 am
content: Lower supply inductance (but, higher ground inductance -- yuck!!)More convenient, better heatsinking (substrate is drain, on modern VDMOS and etc.)More clearance (though I've seen 100V capable controllers in TSSOP, so that doesn't matter)Why would the area be tiny? If you need cooling, you make that pour as big as it needs to be...Tim

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 02, 2015, 04:05:51 am
content: Quote from: T3sl4co1l on November 02, 2015, 03:30:09 amIt's for my TO-3 fetish. With the input LC filter, and the rest of the space taken up by the diode and coil, that doesn't leave much room. I guess there's a thermal path through the input coil, fuse and eventually the input pin and the system PCB.I just wondered why it's hard to find these little guys with input voltage up to 36V and a grounded pad.

author: Phoenix
author_rank: Frequent Contributor
timestamp: November 02, 2015, 05:23:36 am
content: Quote from: Alex Eisenhut on November 02, 2015, 03:20:43 amMaybe because the Vin is a high power input, the gound is a signal level input. Ground inductance would be less important as the high frequency return current would flow external to the IC.
Buck Converter minimum input voltage - Page 1
Forum section: electronics / projects

author: maurosmartins
author_rank: Regular Contributor
timestamp: August 01, 2013, 02:25:11 pm
content: Hello all,I have a big question and I'm not being able to find an answer.If I have a DCDC buck converter and I need a output voltage of 5V how can I check the minimum input voltage that I must supply to the DCDC converter? On a linear regulator this would be a parameter called Voltage drop, but on a DCDC converter I don't have such parameter.I need to supply power to a raspberry pi from a 7.2V NiMh battery that can go as low as 6V. Besides the raspberry I have some more electronics and I estimate the total current draw to be between 2 and 3Amps peak.Best regards, Mauro.

author: mariush
author_rank: Super Contributor
timestamp: August 01, 2013, 04:45:06 pm
content: I would assume they would output 5v from as low as 5-5.1v but it depends on what inductor you use, the frequency the converter runs at, the duty cycle.. and other things.If you can't determine from datasheets you could build a simple constant current load and test the dc-dc converter... here's an example of such simple load :http://www.sleepyrobot.com/wp-content/uploads/2012/01/currentload-rev2.pdfAlternatively, pick a dc-dc converter chip that can also be simulated or has design software made for it...texas instruments has software "Switchers Made Simple" for LM2xxx dc-dc converter chips and others and they have some other online tools here:http://www.ti.com/lsds/ti/analog/webench/overview.pagelinear technology has ltspice and lots of their chips available to be simulated if you want to ..

author: Kremmen
author_rank: Super Contributor
timestamp: August 01, 2013, 05:46:37 pm
content: Does it have to be a buck converter? With minimal extra complexity you could use the SEPIC topology by adding just 1 cap and 1 inductor. Several switcher chips can run the SEPIC configuration as well as buck. Then your input voltage can be below, above or same as output voltage.

author: justinjja
author_rank: Regular Contributor
timestamp: August 01, 2013, 05:58:51 pm
content: They are all different, What DCDC Conterter are you using?Maximum duty cycle, Diode voltage drop, transistor voltage drop, inductor voltage drop, output current...all can play a role in dropout voltage.

author: CarlG
author_rank: Regular Contributor
timestamp: August 01, 2013, 06:17:16 pm
content: The long answer:Minimum duty cycly is one parameter you can check. May not be in all datasheets though. Theoretical minimum is 5/6 = 83,3%, but you'll probably need around 90% duty cycle depending on efficiency.Some buck converters can run at 100% duty cycle, then you'll be safe. Otherwise you'll probably need a synchronous buck to get high enough efficiency.The short answer:Use e.g. LT, AD, TI power design tools to see what fits your design.
buck converter question: need more current output! - Page 1
Forum section: electronics / projects

author: hazuki
author_rank: Contributor
timestamp: November 17, 2014, 12:41:53 am
content: Hi all! I am trying to build a switching converter that will take 16.5 - 48V and convert it to 15.5V with a maximum current of 16A. Yep, about 250W! I am still a beginner at this, so I am using TI's Webench design tool to help me. The tool doesn't find any solutions for me when I give it my requirements. However it gives me a single solution when I decrease the required output current to 10A. The solution is a synchronous buck using an LM5116 controller.From some researching (and other forum posts), I have determined that to increase the current output, I need toA) Use FETs with a higher switch current rating (Is this equivalent to looking for a lower RDSon?)B) Use a higher switching frequency (downside: decreases efficiency)C) Use a bigger inductor (Usually marginal gains in current)I am thinking about taking the design that was generated for me by the tool and simply doubling up the FETs. Is this a good idea? Are there drawbacks besides increased cost?Furthermore, does the controller care how much current is actually being delivered? Not that I would, but is there anything stopping me from using more and better FETs until I can get like hundreds of amps out of it? I'm assuming the only thing stopping me is gate capacitance?Thank you!

author: Niklas
author_rank: Frequent Contributor
timestamp: November 17, 2014, 01:27:46 am
content: Adding more MOSFETs might help a little bit, but not much. The inductor is probably a tougher problem. If you want 15 A output current, then the inductor must handle the peak ripple current of at least 20-25 A without saturating. Also the input voltage can affect the performance as higher voltage typically needs more inductance and lower switching frequency.Have you thought about a multiphase converter? Split up the current path into several parts, convert and then add together again.

author: Richard Head
author_rank: Frequent Contributor
timestamp: November 17, 2014, 06:54:48 am
content: I don't mean to discourage you but you really need to understand the intracacies of switchmode power supply design.The inductor will need to get bigger as well as the power switches and output diode. Also, if you opt for a non-isolated current mode buck converter then you will need slope compensation when the duty cycle gets above 50%, as it will when your input voltage drops below 31V.

author: johansen
author_rank: Super Contributor
timestamp: November 17, 2014, 07:03:45 am
content: the LM5119 is a two phase chip that will do what you want.it will be a real learning curve to get it working, but the datasheet is well documented.
Buck converter series with robust supply chain - Page 1
Forum section: electronics / projects

author: madwolfe
author_rank: Contributor
timestamp: September 21, 2022, 08:24:08 am
content: Hi,I tried to search for a similar topic cos I feel like it should have been beaten to death already but came up blankI am looking to design something with a 24V->5V buck converter, >2A and no special requirements for the quality of the input/output besides EMC (it's all microcontroller stuff).I have not really kept up with the state of the market recently so this might seem like a very stupid question but I am wanting to manufacture in not a massive quantity, maybe 500 a year but I want the design to be able to last me, purchasing on an as-need basis without worrying about a re-design.I am using the LM5145 by TI in another project and that has been a nightmare dealing with procurement so ideally how can I avoid that in a years time.Is there any particular manufacturer or series of buck regulator that has been robust? Or is it all a bit random?
Buck Converter Simulation in Python - Page 1
Forum section: electronics / projects

author: VektorElektor
author_rank: Newbie
timestamp: June 24, 2023, 10:46:37 am
content: Hey everybody, first time here!As a personal project I am implementing a Buck Converter simulation in Python. My basic idea is to give a constant Vs supply and simulate the switch on/switch off steps in each switching period, calculate the increase/decrease in inductor current and calculate an output voltage Vo. The duty cycle is an input and the output voltage Vo should be a result.I started with a Vo = 0 and Vs = 230V. I expected the current in the inductor to gradually grow until it would reach steady-state operation. However, I am incorrectly updating the Vo, so it remains constant all the way and the current keep growing and growing forever. I based switch on and switch off steps on my notes from the picture.So in my simulation I'm following this process for each step (switch on for instance):- Calculate the voltage drop in the inductor VL = Vs - Vo- Calculate the current increase as /\iL = ( VL/ L ) * t_on- Update the inductor current as iL = iL_past + /\iLHowever, since the idea of a Buck Converter is to downstep the voltage, I'm also updating Vo like so:- VL = L * ( /\iL / t_on )- Vo = Vs - VLThis is where the Vo does not get updated and remains constant. I understand that I'm using the same formula to calculate iL from Vo and to calculate Vo from iL, so it's obviously redundant and wrong. Can someone help me rethink this? I'm also worried that a capacitor would be necessary in the output side, parallel to Vo.BTW, please tell me if this is the wrong subforum. New here
Buck converter using MC34063AD - Page 1
Forum section: electronics / projects

author: D4no0
author_rank: Contributor
timestamp: February 18, 2021, 12:45:00 pm
content: After watching Dave's video on designing a boost converter using MC34063AD chip, I decided to use the same chip in my design, I have ordered this chip from lcsc:https://lcsc.com/product-detail/DC-DC-Converters_HTC-Korea-TAEJIN-Tech-MC34063AD_C118241.htmlI require a buck converter, input voltage 9-24v capable of delivering up to 500mA of current.From the calculations in datasheets I obtained the following:V(in)24V(in)min9V(sat)1.1V(f)0.4T(ON) / T(OFF)0.804347826086956T(ON) + T(OFF)10 uST(OFF)5.5421686746988T(ON)4.4578313253012C(T)178.313253012048I(PK)1 AR(SC)0.3L(min)20.5060240963855C(O)12.5 uFNow when connected to 24V, it works as expected, output voltage is about 3.3V, however when I drop the voltage to 12V, the output drops to 2.2V. (tested at about 250 mA load)I am using the wrong chip for this? Taking in consideration that the T(ON)/T(OFF) is not dynamic I think that this converter cannot work in such ranges.What alternative would you recommend for such ranges or if my design is wrong what is the correct way to approach this?

author: Miti
author_rank: Super Contributor
timestamp: February 19, 2021, 11:10:20 am
content: Schematic? Something?

author: Zero999
author_rank: Super Contributor
timestamp: February 19, 2021, 11:18:40 am
content: What's the series resisistance of the inductor?

author: Alone GREYWOLF
author_rank: Newbie
timestamp: February 19, 2021, 11:26:25 am
content: http://drr.ikcest.org/app/s0025https://320volt.com/en/mc34063a-mc33063a-hesaplama-programi/http://www.nomad.ee/micros/mc34063a/

author: Alone GREYWOLF
author_rank: Newbie
timestamp: February 19, 2021, 11:31:27 am
content: https://drive.google.com/file/d/1uAN2gdaAdobFb0nRZE13divL-XX4u1Gv/view?usp=sharingmc34063 calculator

author: D4no0
author_rank: Contributor
timestamp: February 19, 2021, 11:48:35 am
content: Here is the schematic, exactly as in datasheet.

author: D4no0
author_rank: Contributor
timestamp: February 19, 2021, 11:54:04 am
content: series resistance at 100 kHZ is about 0.522 ohms

author: D4no0
author_rank: Contributor
timestamp: February 19, 2021, 12:16:51 pm
content: I used the calculator app and the Max esr is -0.085 ohm (yes negative), am I missing something, or the range of the input voltage cannot be so big?

author: Miti
author_rank: Super Contributor
timestamp: February 20, 2021, 12:19:20 am
content: In the datasheet in your link, L1 is 220uH and C3 is 470pF. Try those values and see how it goes.

author: magic
author_rank: Super Contributor
timestamp: February 20, 2021, 07:56:30 am
content: You seem to be using unusually small timing capacitance and hence unusually high frequency. Try the typical 1nF and 33kHz?This may require a higher value inductor.

author: D4no0
author_rank: Contributor
timestamp: February 25, 2021, 01:17:55 pm
content: Okay it seems the problem was the b220 schotky diode that is rated for 20V, it seemed to work a little until it got fried and then the chip got fried by reverse voltage spikes.