hybridfree/eevblog-posts huggingface dataset:
DC Power output protection against shorts, faults, and maybe external voltage - Page 1
Forum section: electronics / projects

author: Thumper_LV
author_rank: Contributor
timestamp: February 12, 2023, 11:12:16 pm
content: I'm starting a design journey for a new project. The primary function will be a circuit that operates from 24-50VDC, and from 0-3A. Given a power supply of the requisite capacity - I now want to protect that output as best I can. I also need to know if there's a power supply failure of some kind. To provide both control and protection the circuit has a high-side NMOS switch to (dis)connect the circuit as required.The external circuit will run on 18AWG or larger wiring and be from 0-5000 feet. Could be in-building, could be underground, could be whatever a creative installer feels like using it for. Lightning protection will be reserved to external protective devices - but I need to be able to accommodate transients.In theory - I'm going to assume the power supply, via it's switching controller, has inherent over/under voltage protection and probably overcurrent as well. I will be using these powered outputs for different methods - one of which will require the use of a current sensor to determine the load at a given moment. The current sensor will be connected to a MCU which also controls the NMOS switch.My first question - what is the both the most reliable, and fastest, method to detect and protect against a wire-to-wire short on this output? Just consult the current sensor and turn off the switch or is there a better method?Next - what, if any, additional filtering/protection should I add to protect against transients or "fun stuff" coming from connecting/disconnecting external devices?And something that I need but really don't understand how to accomplish - how can I detect if either of the external conductors has a short to earth ground? I assume it means my controller will itself need some kind of protected connection to ground - it's that "protection" that I don't understand.Voltage, relays, and resistors make sense to me. Capacitors & transistors less so. Ferrites are a mystery. As for the other tools in the designer's toolbox...

author: jonpaul
author_rank: Super Contributor
timestamp: February 13, 2023, 10:20:36 am
content: In that common range, (see 24..48V 100..250W) lots of off the shelf PSU readily available with PFC, regulatory compliance, transients protection, current limit, etc.Why DIY? Quantity per year intended?Your goal, market, unique requirements?Environment eg cinema, industry, construction, mariné, security?jon

author: Thumper_LV
author_rank: Contributor
timestamp: February 13, 2023, 05:57:40 pm
content: Why? Well...there's always the excuse that I'd like to learn how, or just be able to say I've done it. But since that's not enough...First, I should say the power supply itself is considered a separate component. I need to be able to accept the power in, verify it, and then do things with it on the output. Which will include pulsing it on and off for communication with external devices.The goal is for possible future UL listing for fire alarm application.
DC Power Rating for Rotary Switches - Page 1
Forum section: electronics / projects

author: Farley
author_rank: Regular Contributor
timestamp: June 01, 2013, 09:10:07 pm
content: The rotary switches I'm finding are specified the current rating at a specific AC voltage. The application I have in mind would use one pole of a rotary switch to switch 12VDC with a maximum current of 2A. I'm not sure I understand how to determine the DC current handling capability of a specific switch when the spec sheet only specifies the maximum current at AC (usually 120VAC or 240VAC).Here's a representative specification from the Mouser catalog:http://www.mouser.com/ds/2/13/SR2511F-185523.pdfMy spidey sense tells me it is more complicated than simply computing total power handling and recalculating for 12VDC.

author: bilko
author_rank: Frequent Contributor
timestamp: June 02, 2013, 09:40:41 am
content: I wouldn't exceed the AC current rating for the switch. It doesn't say if it is rated for inductive or resistive loads. I would assume resistive and de-rate accordingly for inductive.
dc power supply  - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: September 18, 2015, 06:26:30 am
content: Hi guys,I replicate a HP power supply for 30v 5A . when I tested the power supply the output ripple was around 20mvP-P , but when I connect a dc motor to the power supply the ripple gone to around 500mvP-P but for the other load it works fine. can sombody tell me what is the reason. I also used diode for reverse polarity protection.regardsN.Baskaran

author: jeroen79
author_rank: Frequent Contributor
timestamp: September 18, 2015, 11:17:35 am
content: Which power supply? Did you replicate it exactly?Which motor?Likely this is spikes from the motor's coils when it switches polarity.Does the riple's frequency match the motor's RPM?Does a resistor drawing the same current have a lower ripple?

author: calexanian
author_rank: Super Contributor
timestamp: September 18, 2015, 07:55:35 pm
content: As you load an unregulated DC supply, and in some cases even a regulated supply, ripple will increase. Its a function of the size and ESR of the filter capacitors. Look up the calculation of ripple in dc power supplies and i am sure you will find information. Generally as the load current increases the ripple will increase and it may not be in a linear fashion due to the dynamic characteristics of traditional transformers/inductors and capacitors.
DC power supply design - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: October 14, 2014, 12:37:47 pm
content: Can someone tell me how to select the AC emergency capacitors after the bridge rectifier?

author: lincoln
author_rank: Regular Contributor
timestamp: October 14, 2014, 11:56:54 pm
content: sure, select a value equal to 5/8 numble nuts by weight.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 15, 2014, 03:13:15 am
content: The what?

author: BradC
author_rank: Super Contributor
timestamp: October 15, 2014, 04:24:02 am
content: Quote from: lincoln on October 14, 2014, 11:56:54 pmNo, no, no, no... not by weight.. by volume! Even a plumber should know that!

author: Rerouter
author_rank: Super Contributor
timestamp: October 15, 2014, 09:20:07 am
content: To give an actual answer, i am going to assume that you mean smoothing capacitors (or bulk storage capacitance) a general rule of thumb is about 1000uF per Amp of demand, in reality it varies a bit on how much headroom your supply has, e.g. if your rectified AC peaks at 24V DC, and your regulating down to 5V then it doesnt worry you if the voltage on the smoothing caps droops a few volts mid cycle, but if on the same supply you were regulating down to 19V, and burns a volt over the regulator itself it may become more of a concern and may need more smoothing capacitance to prevent any droops on the output,

author: rob77
author_rank: Super Contributor
timestamp: October 15, 2014, 11:16:41 am
content: 1000uF per ampere is the very minimum for a generic power supply. if you're designing some more serious audio stuff, then 2000-5000uF per ampere is what are you looking forand please don't use terms which are making no sense - no one on Earth (except you of course) knows what is an "AC emergency capacitor".

author: mikerj
author_rank: Super Contributor
timestamp: October 15, 2014, 11:31:24 am
content: Quote from: rob77 on October 15, 2014, 11:16:41 amThe wording was intentional, readthis thread.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 15, 2014, 03:34:59 pm
content: 1000uF per amp is about typical at 25V supply. Scale inversely with operating voltage.Tim

author: David Hess
author_rank: Super Contributor
timestamp: October 19, 2014, 03:17:30 pm
content: For a 60 Hz AC input and full wave rectification, it is 8300 microfarad amps per volt of ripple.
DC simulation - Page 1
Forum section: electronics / projects

author: marios
author_rank: Contributor
timestamp: January 28, 2011, 05:38:07 pm
content: i am trying to design a DC step up converter and i am finding difficulties to simulate my circuit. I can find all the components(i.e MC34063) i need for the simulation. I am using Multisim 11 and Ultiboard 11 for the PCB design. Although i manage to skip the MC34063 by using a pulse to mimic the operation of the chip the problem is that i can to the same for the PCB design so i stucki attached the circuits on the message, any suggestions how i can make the PCB design?(in the doc file is just a representation of the circuit)Thanks

author: tyblu
author_rank: Frequent Contributor
timestamp: January 29, 2011, 03:32:22 am
content: Code:if(file.type == "docx")break;

author: Zero999
author_rank: Super Contributor
timestamp: January 29, 2011, 10:05:32 am
content: OxygenOffice Professional reads that docx file perfectly - it's basically OpenOffice with lots of stuff added in.It does annoy me though when people post pictures in Word format when a simple PNG would do. I've translated it from M$ to a universal format which everyone can read.I use KiCAD for PCB designs but many people here use Eagle.I can't help you with the simulation other than suggesting LTSpice which is designed for simulating SMPSes.

author: blackdog
author_rank: Frequent Contributor
timestamp: January 29, 2011, 10:43:29 am
content: Hi! Marios,Download this "Design Worksheet" from the site of OnSemi :http://www.onsemi.com/PowerSolutions/supportDoc.do?type=tools&rpn=MC33063AThis wil hel you with step up and down converters.Kind regarts,Bram
DC Supply for digital ICs  - Page 1
Forum section: electronics / projects

author: joniengr081
author_rank: Regular Contributor
timestamp: June 21, 2024, 06:19:23 am
content: The digital IC usually need 3.3 V or 1.8 V as supply voltage. If the main supply to the PC board is 5V then which power supply option is the better for digital ICs in terms of low ripples, the Linear Regulators or DCDC converters ? Quantitatively how much we can expect Vpp ripples in Linear Regulators and DCDC converters ?

author: moffy
author_rank: Super Contributor
timestamp: June 21, 2024, 06:37:42 am
content: Quote from: joniengr081 on June 21, 2024, 06:19:23 amDepends on power consumption, for modest power you use a linear regulator for high power a DC/DC step down converter, sometimes for high power loads like some CPUs, multiphase.

author: magic
author_rank: Super Contributor
timestamp: June 21, 2024, 07:57:50 am
content: A linear regulator adds no ripple of its own and filters out at least some of the ripple present on its upstream rail (to know how much, see Power Supply Rejection Ratio vs Frequency in the datasheet).A switcher inevitably creates ripple, the exact amount depends on switching frequency, circuit design and component selection. If noise is more important than efficiency, use linear.

author: Siwastaja
author_rank: Super Contributor
timestamp: June 21, 2024, 10:29:55 am
content: Define "low ripple", and why do you think it's important?Usually the choice is simply based on consumption and thus, the amount of heat you can dissipate (or battery life / other energy requirements). It's very common to use linear regulators for 5V -> 3.3V/1.8V simply because even if the current is some hundreds of mA, the amount of power loss is still modest, and linear regulators are the cheapest for this job (and do not require an inductor). And many/most of those "digital ICs", including small microcontroller, consume just a few mA.However, exceptions are larger CPUs/FPGAs etc. which consume more than a few hundred mA, possibly tens of A. Then a switch-mode converter becomes pretty much mandatory simply from thermal management viewpoint - it is easier not to generate heat to begin with, instead of spending on heatsinking.
DC TIG to AC TIG with a H-bridge - Page 1
Forum section: electronics / projects

author: popopboat
author_rank: Newbie
timestamp: November 09, 2021, 06:15:11 pm
content: Hi everyone,mechanical engineering student here, i know some "basic?" electronics, so dont be too harsh one meAs the AC TIG machines are extremely pricey, i got an idea to make a AC TIG from DC TIG welder.Ive seen 2-3 threads with the same idea, but they are few years old now.This is the schematic of the idea, H bridge, IGBT or 4 separate MOSFETs, and arduino for controlling frequency, duty cycle.The idea is ofcourse not to do some high quality welds, but rather fix some holes, spots and such.My question is, what are the main flaws of this design, could it work, do i need any more components?

author: CaptDon
author_rank: Super Contributor
timestamp: November 10, 2021, 12:32:55 am
content: Your circuit is no where near including all of the parts it will need. The IGBT devices capable of the currents for welding will have lots of gate capacitance so you will need driver circuits and also you will need very specialized high side driver circuits and tons of EMI suppression!!! I'd say your drawing is missing about $100.00 worth of parts.

author: Andy Watson
author_rank: Super Contributor
timestamp: November 10, 2021, 02:21:28 am
content: As CaptDon has suggested, there is a whole lot more detail needed to achieve the required H-bridge switching. Look-up IRF application note AN 1045, it gives a summary of the basic requirements.Quote from: popopboat on November 09, 2021, 06:15:11 pmWhy do you want AC? DC is good for tig/stick welding on most materials, except aluminium.

author: jmelson
author_rank: Super Contributor
timestamp: November 10, 2021, 02:44:04 am
content: Is the DC TIG machine "scratch start", or does it have HF? The HF system is essentially a Tesla coil that can add about 10,000 V to the torch electrode when the arc has not been established. That will fry your transistors. Even without HF, sputters in the arc will cause HUGE voltages to develop on the welding machine's output terminals. You need to put your polarity switcher before the output inductor or HF transformer of the welder. If you are not an experienced power electronics designer, do NOT try to do this. You will burn up a lot of expensive parts and not get it to work.Jon
DC to DC buck converter 4layer layout - Page 1
Forum section: electronics / projects

author: geot51
author_rank: Newbie
timestamp: March 04, 2018, 04:26:39 pm
content: Hello,I'm designing an IoT board which consists of a DC to DC step down converter.I'm a little confused about the right way to place the via in the output stage for power delivering.I'm using the TI's TPS54340 IC.To be more exact.Datasheet is quite clear about the proper layout.But I always wondered, how and where should I place the via in the output stage if I want to deliverthe power through an inner layer?I upload a photo about my two thoughts about this.The plan A shows the way I choose, but I'm not sure if this is the right way.Will the extra vias the Plan A has cause a problem?Should I take the power from the spot after output capacitor?EDIT: my second picture is my layout in which the inner layers (power plane and ground plane) are not shown.Also it is not the final design cause many grounds are missing, it's just a draft but I upload it to show how I placed the vias in the output stage.
DC to DC converter help needed - Page 1
Forum section: electronics / projects

author: David1988
author_rank: Newbie
timestamp: May 28, 2013, 06:48:43 pm
content: Hello folks, has anyone got any easy DC to DC converter projects I could build?I have built many"Jaycar" DC voltage regulator kitshowever it's output current of 1.5 amps is no longer adequate, I need more current for my future projects.The supply voltage will be from 12 volt lead acid batteries, typically 12.6~13.2 volts.The DC to DC converter I'm looking for if possible would have variable voltage (between 0 and 12) and able to deliver above 10 amps.Anyway Thank You for your time reading this, look forward to your suggestions.

author: Paul Price
author_rank: Super Contributor
timestamp: May 28, 2013, 11:20:07 pm
content: Just use a LM339 quad comparator for feedback for all four switchers (schematic below) in parallel. Can you figure out how to do this by placing one comparator in each feedback loop to the feedback pin?You will need at least two car batteries wired in series to get any voltage above 9V or so with just one battery with up to 12 amps output. Short circuit protection, current overload protected, small power supply size, and cool operation.You only need then just 1 pot to vary the output voltage all the way up to about 24V or so at 12 amps with fully charged batteries.You don't need the HV version of the switcher chip, just the -adj version.With a single 555 chip configured as a charge pump, you can create a well-regulated -2V supply that will allow you to adj. the output down to 0-Volts. Circuit available on request.

author: mariush
author_rank: Super Contributor
timestamp: May 28, 2013, 11:58:50 pm
content: If you don't care that much about efficiency (though even so it's not that bad), you could just put three-four LT1083/LT1084/LT1085 linear regulators in parallel.The datasheet :http://cds.linear.com/docs/en/datasheet/108345fg.pdfeven has example on how to do it.LT1083 can do up to 7.5A with a maximum of 60w power dissipationLT1084 can do up to 5A with 30w power dissipationLT1085 can do up to 3A with 30w --- ,, ---1V Dropout voltage, so you could get 0-12v reliably with a full battery. These regulators also don't really become unstable when they have less than 1v, they just output less than the value you want.The only part that sucks is that they're a bit expensive, but linear is pretty good at giving samples, if you don't get greedy they should give you two of each of the higher end regulators (you shouldn't request more than 4 in total)

author: Paul Price
author_rank: Super Contributor
timestamp: May 29, 2013, 12:18:53 am
content: Let say you go linear, so you set your output to 1V and your gold-recovery circuit is drawing 10-amps. That's about (13V * 10 Amps) 130 watts of power your power supply is wasting and just heating up your room to give you the 10W for your circuit with.Don't even think of the electric bill charging your batteries every few hours. That's just 10-watts out with 130 watts of waste adding their little part to global warming.You're going to need a big fat heatsink and one or two fans.
dc to dc converter ic external reference - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: June 02, 2016, 03:59:43 pm
content: Hi guys,why none of the dc to dc converter or flyback converter does not allow to run from external reference which made easy control of out put voltage.

author: Jeroen3
author_rank: Super Contributor
timestamp: June 02, 2016, 04:12:34 pm
content: Some have tracking ability that can be used for this.You can always use a digital potentiometer.

author: tszaboo
author_rank: Super Contributor
timestamp: June 02, 2016, 04:34:22 pm
content: You can always use an external difference amplifier which goes to the feedback pin. But better use a fast amplifier, and a dc-dc which has external compensation, because you will run into stability problems. Not can, will.

author: ajb
author_rank: Super Contributor
timestamp: June 02, 2016, 06:43:39 pm
content: You can always apply a control voltage to the feeback node via a third resistor.

author: Jeroen3
author_rank: Super Contributor
timestamp: June 03, 2016, 05:32:38 am
content: Quote from: NANDBlog on June 02, 2016, 04:34:22 pmCan confirm.
DC Voltage Buck booster with LED flasher - Page 1
Forum section: electronics / projects

author: geobee
author_rank: Contributor
timestamp: August 30, 2018, 11:04:58 pm
content: Hi all, would anyone have knowledge of a small DC to DC buck booster module with an onboard LED flasher 500ma to 1 amp would be great. I have read they are available, but haven't been able to locate them. Cheers.

author: electrode
author_rank: Regular Contributor
timestamp: September 02, 2018, 10:06:06 am
content: I think you'd probably need to specify your required input voltage range and desired output voltage(s) as a starting point.

author: Zero999
author_rank: Super Contributor
timestamp: September 02, 2018, 06:42:20 pm
content: It can be built from modules. A standard LED buck converter, plus a lamp flasher module.https://www.ebay.com/itm/Parts-Flasher-Relay-Auto-Waterproof-Lamp-Plug-and-play-Vehicles-Cf14-0-02A-20A/263907015378?hash=item3d72157ad2:g:3XgAAOSwyUtbh8OZhttps://www.ebay.com/itm/5w-LED-Driver-board-buck-Constant-Current-1A-Step-down-DC-DC-power-supply/161107894230?hash=item2582c75fd6:g:ie8AAOxy2FZSNt3a

author: geobee
author_rank: Contributor
timestamp: September 02, 2018, 10:58:39 pm
content: Many thanks. I will be using two AA batteries to drive a 1 watt star module which likes around 3.6volts, hence the need for a DC to DC booster, of which there are plenty available. I also have my little flasher circuit which I have mentioned here earlier, but it would be good to have the DC booster and the flasher on the one little board is possible, as I will be putting these out in quantity, and the simpler the assembly, the better. Would be ok to have two small boards, one to boost, and the other to flash, but very nice to have them combined. I did read somewhere that they are available, but have been unable to find that information for the life of me.
DC/DC converter filter values - Page 1
Forum section: electronics / projects

author: 741
author_rank: Frequent Contributor
timestamp: November 22, 2019, 02:33:28 pm
content: Ages ago I asked Murata about the NME series and they came up with a specific set of L, C valuesper individual "VIN:VOUT" variant(not just per 'series' of DC:DC). Took ages to get this info, then only got the info for one specific model.I'd now like similar info for XP's IE0524S, and Murata's CRE1S0515SC. Does anyone out there have this information please?Also: Murata give minimum load, and tell us what happens if the load is too light. I cannot see this amount of detail from XP...QuoteQuoteHuh? Can they elaborate?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 22, 2019, 03:34:08 pm
content: They're saying the same thing in two different ways. Output voltage is one of the specs. They may not meet output voltage. Therefore...These tiny modules are all just open loop choppers, so the output is just whatever you get, and also proportional to input. Or if they're regulated, they may be primary-side regulated, so the secondary does whatever.Filter values will be similar for all models, and yes, suited to different voltages. Mind that both differential and common mode filtering are likely needed.Tim
DCDC Inductor value selection calc when min load can be down to zero - Page 1
Forum section: electronics / projects

author: Psi
author_rank: Super Contributor
timestamp: February 15, 2023, 07:44:18 am
content: I'm just trying to follow this PDF about inductor selection for a SEPIC top of page 2, and it assumes 20% minimum load and hence 40% peak to peak ripple current in the calculation.But if my SEPIC needs to operate down to a minimum load of zero (like charging a battery) what should I use here?Obviously I can't divide by zero in the following equation "L2 = 4.5 x (1.69 x 10-6/0.4)".I think the answer might be that it doesn't matter a huge amount for battery charging as some ripple doesn't really matter?https://www.eaton.com/content/dam/eaton/products/electronic-components/resources/technical/eaton-inductor-selection-sepic-designs.pdfQuote

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 15, 2023, 07:57:37 am
content: Just from the quoted text, it doesn't sound like you may be using the correct calculator in the first place.This is because some converters (namely peak current mode with no slope compensation) cannot work in CCM at all: you are limited by controller behavior first.The 40% ripple assumption might be typical for a PCM with as much (i.e. 1/40% or ~2.5x) slope compensation, at full load. If that's the case, it's simply normal that it will drop into DCM at lighter load. Whether that breakpoint should occur at a nominal-minimum load condition or not, isn't very important. (The compensation and EMI of such a converter will change between CCM and DCM, but these will have to be evaluated anyway.)Average current mode controls may require CCM down to some minimum load; but they are usually compensated to maintain operation into DCM, and I would consider it a design problem if not.tl;dr just do what your controller/regulator datasheet says.Tim

author: Psi
author_rank: Super Contributor
timestamp: February 15, 2023, 08:17:15 am
content: Quote from: T3sl4co1l on February 15, 2023, 07:57:37 amThe one i'm using here has CCM and slope comp, it's the LM5158-Q1https://www.ti.com/lit/ds/symlink/lm5158-q1.pdf?ts=1676426576021&ref_url=https%253A%252F%252Fti.com%252Fproduct%252FLM5158-Q1There are no inductor value calculations in the DS, just this noteQuote

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 15, 2023, 06:46:52 pm
content: Yes, those will be at maximum load, and just check compensation at a few conditions.Ripple fraction just means, that much Ipp from the applied V. The inductor equation is V = L dI/dt, so, during on-time, Vin = L Ipp / (D T), and during off-time, (Vin - Vout) = L Ipp / ((1 - D) T). Which can further be reduced by noting Vin D = (Vout - Vin) (1 - D) (flux balance condition, forced in CCM). T = 1 / Fsw of course.Tim
DC/DC Module 100% ON - Page 1
Forum section: electronics / projects

author: luky315
author_rank: Regular Contributor
timestamp: April 25, 2014, 08:49:02 am
content: I am searching for a DC/DC converter module (=ready to use and EMI tested...) with 5V output (0.8A) and an input voltage range of 5 to 28V. This means that it is necessary to allow 100% ON-Mode to deliver (nearly) 5V from a 5V input. Are there any modules out there that I overlooked? A Buck/Boost Module with an input Range down to 3V would be even better, but is not absolutely necessary.By the way: Are the MagI³C Modules from Würth and the LMZ Series from National/TI the same thing? Each of them claim that they are own developments but the specs are exactly the same, down to details like ON/OF timings.

author: nickm
author_rank: Regular Contributor
timestamp: April 25, 2014, 01:49:14 pm
content: You will have a very hard time finding a integrated buck converter that can do 100% on time. The reason is bucks require high side drive on the fet and the high voltage rail is a bootstrapped power supply. To charge up this power supply the top switch needs to turn on and the bottom fet or diode needs to conduct for a brief period of time to charge the bootstrap supply up again. This is why on time is limited to about 97% on most bucks. Now if you were just making your own you would add a second rail that wasn't bootstrapped and it would do 100% no problem.A better choice would be a flyback but that will be physically larger to handle the same power. An even better choice would be to ask yourself if you really need to support down to 5V. A lot of times people get carried away overspeccing things and doing a lot of extra work when they really don't have to.

author: qno
author_rank: Frequent Contributor
timestamp: April 26, 2014, 07:37:42 am
content: Look for a SEPIC converter.

author: Psi
author_rank: Super Contributor
timestamp: April 26, 2014, 08:29:02 am
content: If you want 5v in 5v out it has to be sepic or an isolated transformer based converter

author: DaveW
author_rank: Frequent Contributor
timestamp: April 26, 2014, 11:03:31 am
content: The LTC3630 will go to 100% duty cycle, so the only losses will be the resistance of the internal FET and the resistance of the inductor. not a module I know, but at least shows they are out there...

author: luky315
author_rank: Regular Contributor
timestamp: April 28, 2014, 08:15:29 am
content: There are a few Buck Converter capable of 100% ON.Are there any Buck-Boost Modules out there?

author: Marco
author_rank: Super Contributor
timestamp: April 28, 2014, 02:48:35 pm
content: Quote from: luky315 on April 28, 2014, 08:15:29 amHaving a special mode for when the voltage is EXACTLY correct doesn't make much sense.There might be (non-inverting) buck boost controllers which go into a linear mode when Vin is slightly higher than the desired output voltage though.
DCDC output noise limits - Page 1
Forum section: electronics / projects

author: Psi
author_rank: Super Contributor
timestamp: November 05, 2023, 02:33:24 am
content: I've made up a buck-boost 3A circuit with the specs~10-30V inputH-bridge/ Synchronous rectification15V output at ~3A1.2MHz switching freq.It all seems to function well, thermals are good and it handles 3A no probs. but the output noise seems pretty horrible.The noise looks to be around 24mhz with repeating bursts of cycles around 1.2mhzMeasured with 1x probe and ground spring across ceramic output cap.20mhz bandwidth limitUnloaded 175mV peak to peak,3A loaded 500mV peak to peakNo bandwidth limitUnloaded 480mV peak to peak,3A loaded 1140mV peak to peakJust wondering if anyone has any comments on this, if it's as bad as it looks for this sort of dcdc, and any recommendations to fix it.I can probably tighten up the pcb design a bit, I left room for a bigger inductor that I ended up needing, getting everything more compact should help a 1.2Mhz converter.I could also drop the frequency I guess. Maybe 500mhz would be ok as long as inductor doesn't get too big and caps can stay ceramic or small electros (there's vibration limitations so i don't want any huge 1000uF caps)I tried a LC filter on the output and it did get better, about 50% lower. Perhaps I should try two filters?This is for a battery charger so the load doesn't really care that much about output noise but I don't want to be injecting HF noise onto the battery power rail just in case it might mess up other things connected to the battery.Any recommendations or comments welcome.Ignore the output current limit part of the sch below, I don't have that connected atm. Just working on the raw DCDC atmThe waveforms are with no BW limit, see above for 20mhz BW limited peak to peak values.

author: Psi
author_rank: Super Contributor
timestamp: November 05, 2023, 02:40:37 am
content: Here's an image of the actual PCB, with ruler so you can see the size.I'm guessing this really is a bit large for 1.2ghz.If so, what freq do you think something this size should run at?
DCDC Push Pull Feedback Compensation calculation - Page 1
Forum section: electronics / projects

author: Echo88
author_rank: Frequent Contributor
timestamp: July 07, 2020, 01:55:25 pm
content: Is there a simulation tool/calculator/easy way to calculate the needed capacitor/resistor-values which are needed to get a correct feedback compensation in Push-Pull DCDC-topologies?I found the following document which details the usage of the often used TL431 in the feedback path, but failed to find the described design tool:https://www.onsemi.com/pub/Collateral/TND381-D.PDFhttps://www.poweresim.comseems to be a very good tool and also calculates the (quite convoluted) TL431-feedback RC-network, but i cant reproduce the poweresim-results in LTSpice with, for example, an LT1683. Also it seems to only have one optocoupler available and diodes like "PED2A100" which im unable to find datasheets for.Anyway: Is it absolutely necessary for me to learn poles/zero-calculation before being able to simulate push pull DCDC with well working feedback?

author: David Hess
author_rank: Super Contributor
timestamp: July 07, 2020, 08:18:35 pm
content: You can find the values empirically. Or you can use a Bode plot to find the values. Sometimes where I have unknowns, I have found the values empirically and then used them to work back to a Bode plot of the open loop response which allowed me to calculate the unknown values.
DC/DC step-up constant current source / LED boost driver w/ analog dimming - Page 1
Forum section: electronics / projects

author: Dakano
author_rank: Newbie
timestamp: August 14, 2021, 10:59:51 am
content: Hello,I am using 3 halogen lights with 5V/0.5A each controlled by a constant current source (or basically "LED driver") because of light accuracy. Right now I am using the PT4115 (step down led driver) for each light bulb, but this one is also getting really hot. Input voltage is 12V. For another revision, I was planing to run all light bulbs (those 7.5W total) with only one IC because of limited PCB space. I was looking around the whole last day but couldn't really find what I was looking for. There are many step up led drivers, but those are really made to drive led's at true colour with PWM dimming instead of analog diming.Functional schematic:For example, the Analog Devices led driver can be run on PWM (or frequency set) mode with additional analog diming, but not on analog diming alone, example:https://www.analog.com/media/en/technical-documentation/data-sheets/80421fb.pdfThe RT-pin doesnt go down to 0 Hz, but can be only minimised to 250 kHz, which is not suitable, since I need constant lighting without PWM flimmering.Is there something commonly used that I could go for and you could recommend for this application? (Since efficiency and power dissipation is quite important) Any help is welcome.
DC/DC Synchronous Boost Buck Converter component identification - Page 1
Forum section: electronics / projects

author: amrus2011
author_rank: Newbie
timestamp: February 24, 2017, 02:40:59 pm
content: Greetings one and all,I have a problem that I need some expert help with since I don't know what else to do. I purchased two buck converters and I didn't realize that they were missing some components. I needed one that had both Voltage and Current, but these only had a pot for voltage. Adding a pot is not a problem or even the SMD 0603 resisters. I have searched the Internet looking for close-up photos so I could buy the parts to finish them, but so far have had no luck at all. I was hoping that one of you experts could help me to identify the part I so desperately need so I can populate the boards and finish my project. I have found out what the resister values are and the S4 Schottky diode, but there is a part with 5 legs and the number 321 stamped on top that I have no idea what it is. I have attached a photo of the board that I found that has both pots attached hoping to see what the component is. I would appreciate any and all help with this. I'm really not sure if this forum is for this type of thing, but I thought I would give it a try. Thanks in advance for your help.

author: soul40k
author_rank: Newbie
timestamp: February 24, 2017, 02:58:21 pm
content: I only looked up the part number, here is what I found:R3112N211C -http://www.mouser.com/ds/2/792/r3112x-e-844262.pdfhttp://ca.mouser.com/ProductDetail/Ricoh-Electronic-Devices-Company/R3112N211C-TR-FE/?qs=sGAEpiMZZMuI1aKsGLfKZKIdPgnDpLuw04Kd5CD%252bz5A%3DXC6104A332MR -http://pdf1.alldatasheet.com/datasheet-pdf/view/181945/TOREX/XC6104A332.htmlHopefully this helps.

author: amrus2011
author_rank: Newbie
timestamp: February 24, 2017, 06:22:03 pm
content: Thanks so much for the effort. I do appreciate your information. I have since done some more digging and I found a part that has 321 on the top, but it's an OpAmp. Any thoughts on this? I need to be sure I buy the right thing. The numbers on the info you gave started with 3112....If you could continue to help me pick the correct part I will be very grateful. I have attached a photo of the part I found.

author: amrus2011
author_rank: Newbie
timestamp: March 04, 2017, 08:01:41 pm
content: After some serious digging I found a close-up shot of the part I need to identify. If you could please tell me what it is I would be forever in you debt.I hope this photo helps.
DCS READ FROM MIPI DISPLAY USING TC358870XBG  - Page 1
Forum section: electronics / projects

author: pascaldao
author_rank: Newbie
timestamp: November 22, 2020, 10:05:52 pm
content: Hello,I am attempting to perform a short DCS read in order to get the display's power mode. I am using an STM32 and I am communicating with the bridge over I2C. Here is what I am doing currently:Write DCS read or generic read command to DCSCMD_Q (0x0504):_txBuffer = 0x05;_txBuffer = 0x04;_txBuffer = 0x14; //Generic READ, 1 param. PS: I also tried with 0x06(DCS read)_txBuffer = 0xA0; //get_power_mode (DCS read cmmd)HAL_I2C_Master_Transmit(&hi2c1, TOS_SLAVE_ADDR, _txBuffer, 4, 10000);Give control of the bus to the display://BTA (not sure if necessary)_txBuffer = 0x02;_txBuffer = 0x2C;_txBuffer = 0x01; //0001 -> BTA turn request ?HAL_I2C_Master_Transmit(&hi2c1, TOS_SLAVE_ADDR, _txBuffer, 3, 10000);Read DSI RX Header because this should be a short read://Read DSI RX Header_txBuffer = 0x01;_txBuffer = 0xBC;HAL_I2C_Master_Transmit(&hi2c1, TOS_SLAVE_ADDR, _txBuffer, 2, 10000);HAL_I2C_Master_Receive(&hi2c1, TOS_SLAVE_ADDR, _rxBuffer, 3, 10000);When I do this the 3 bytes I read from 0x01BC are all 0's, yet my display is on and displaying images. What am I doing wrong? How can I read from my MIPI display and send the data to the STM32 ?I have attached the datasheet of the TC358870XBG.Regards,Mawaba.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 22, 2020, 10:50:07 pm
content: Have you looked at the actual data lines with a scope to see what's actually happening on the bus ?Bear in mind that displays may not implement all of the features in the spec - for example why would a host actually need to read the power mode of the display, as it would be the host that put it in that mode in the first place!I wouldn't be at all surprised if some displays have on read functionality at all, as the consumer products they're designed for aren't likely to need it.

author: pascaldao
author_rank: Newbie
timestamp: November 23, 2020, 03:37:05 pm
content: Hello @mikeselectricstuff,Thanks for the reply. You bring up a a good point. I will search to see if the display I have has that capability. However, assuming that it did, do you think my code should work?
DDR external memory HELP!! - Page 1
Forum section: electronics / projects

author: xtr0d3m0n
author_rank: Newbie
timestamp: August 27, 2016, 06:52:55 am
content: Hi So In the ADR/CMD group in the memory side Theres a pin called A10/AP what is this pin? and it seems like it connect to a different pin in MPU called SDA10? why does it have a different name than normal address line(like A1,A2 etc).Also in JESD79-3E I don't see any lengh matching over view like match this group to this tolerance.may be that not that easy ?? How ever I manage to read a lot of documents and made my self a chart of length matching....Also can somebody please point out main differences between DDR,DDR2,DDR3,DDR4 in a layout perspective. I kinda have an Idea about how to layout things but I cannot distinguish what are the exact difference.I am trying to decipher the "black magic" and I am not that smart so any help would be very appreciated.The schematics I am referencing is thishttp://hforsten.com/making-embedded-linux-computer.html

author: bitslice
author_rank: Frequent Contributor
timestamp: August 27, 2016, 11:20:35 am
content: Quote from: xtr0d3m0n on August 27, 2016, 06:52:55 amthat's the auto precharge pin, part of the refresh systemhttps://www.micron.com/products/datasheets/%7BF93E3738-B1AB-44AE-B4D7-0CB043145517%7D?page=8it's connected to sda10 on the microcontroller, which is its inbuilt DDR2 control logic

author: nctnico
author_rank: Super Contributor
timestamp: August 27, 2016, 11:24:34 am
content: With SDRAM and DDRx memory the RD, WR and select signals form a 3 bit command instead of being used individually. The 11th address line serves a dual purpose. This should be explained in the memory's datasheet! If not clear you can download a datasheet from a different manufacturer to see if the explaination is more clear. The basics of SDRAM and DDRx memory are the same.
DDR Memory Connector as Board edge Connector? - Page 1
Forum section: electronics / projects

author: Bluestreak66
author_rank: Regular Contributor
timestamp: July 10, 2013, 03:31:05 am
content: What are your thoughts on using a DDR Memory connector as a board edge connector? They seem to be cheap they lock and could accept a 1.2mm pcb with little design effort. They have a large amount of pins and are design to handle high frequency and multiple pins could be used for high current applications. I would like to hear thoughts on this as I have not seen any used in this way and am trying to find a cheap locking solution for a back plane connector.

author: marshallh
author_rank: Unknown
timestamp: July 10, 2013, 03:36:05 am
content: They'd be fine but you're limited to the size of the DIMM/SO-DIMM board. I have seen them used for SOC modules and the like.A beter solution is to use pcb straddle mount PCI express connectors. Diigkey has them for ~3-4 iirc. Cheapest option out there

author: Bluestreak66
author_rank: Regular Contributor
timestamp: July 10, 2013, 04:04:20 am
content: With pcie connector they are meant to be supported at one end and only have one locking point also the connecting part of the board would require it to be milled at an angle vs a straight cut which would increase the tooling cost of the pcb. The ddr2 conecters are one $1~2 on digikey even in small quantities the only problem I have with them is they are 130mm long and 100mm pcbs would be prefered.

author: oPossum
author_rank: Super Contributor
timestamp: July 10, 2013, 07:59:20 am
content: 30 pin SIMM sockets where used this way almost 20 years ago...http://www.dontronics.com/dt.html

author: peter.mitchell
author_rank: Super Contributor
timestamp: July 10, 2013, 01:20:37 pm
content: or even SO-DIMM

author: lgbeno
author_rank: Frequent Contributor
timestamp: July 10, 2013, 01:39:04 pm
content: Checkout TI's control cards mostly used on their c2000 dev boards, that's one example.Q7 single board computers are another example.I think it's a fine idea, just pick an emerging standard because after the Standard goes obsolete, so does the connectors (or price goes up)
DDR SDRAM Signal Integrity - Page 1
Forum section: electronics / projects

author: Gizmo
author_rank: Regular Contributor
timestamp: December 19, 2016, 10:23:02 pm
content: I'm looking at using a DDR SDRAM as additional RAM for an old computer. I'm using a MACH XO2 as my SDRAM controller, and have written the controller code to do burst reads of 2 words (so 32 bit reads) which fits my requirements. I'm using the hardened DDR interface on the XO2 and it all simulates to a maximum frequency of just over 100MHZ, which is all good. With this frequency I can have an extremely simple SDRAM controller and still meet timing requirements for the existing bus. And DDR SDRAM is cheap, so I can have a good load of memory for next to nothing.The only thing which is new to me here is going to be the signal integrity side of things. Although any board layouts I've been able to find which use SDRAM for similar purposes (like the MIST FPGA board for example) don't seem to pay any attention to SI at all, and it works for them. But I dont really want to go for the approach of just hoping something works. I always find if you don't do the groundwork right in any job, then you just cause trouble for yourself later down the line.Length matching is no problem, but what I'm not very clear on is exactly where you would place a series termination resistor, and what sort of values would be appropriate. I know I should simulate this to figure out a suitable value, but don't have access to anything to simulate it... And the scope I have (100mhz Rigol) wont be of any use in seeing SI issues. So I'm working rather blind...I get the impression parallel termination at the SDRAM would be unnecessary given I am just using one SDRAM chip with short traces and only running at 100mhz.So any thoughts on this would be appreciated!
DDR3 Fly-By Routing length matching at terminator  - Page 1
Forum section: electronics / projects

author: RoadRunner
author_rank: Frequent Contributor
timestamp: September 29, 2023, 06:10:59 pm
content: I am trying to do Fly-By Routing with few DDR3 Chips and a SOC.I have length/Delay matched everything. Now I am wondering how closely do I need to length match trace from last Memory chip the termination resistors? Do they even need to matched?I have attached an image to help you understand what I am talking about. Trace Marked Red in the attached image are trace that goes to termination resistor from last Chip.Regards

author: Terry Bites
author_rank: Super Contributor
timestamp: October 02, 2023, 09:19:14 pm
content: I imagine that at those speeds termination is mandatory.Why not do it?

author: Someone
author_rank: Super Contributor
timestamp: October 02, 2023, 09:38:47 pm
content: Why is length matching used?Theoretically that stub to the terminator will have no reflection and the terminators don't care if they are time aligned. What happens when some reflections from non ideal termination occur?
DDR3 Memory Packaging - Page 1
Forum section: electronics / projects

author: bhj99
author_rank: Contributor
timestamp: July 08, 2024, 11:48:18 pm
content: Hello all, I am currently looking packaging alternatives for 1 GB DDR3 memory devices in order to reduce component size, weight, and power, etc for a side proejct that is board space constrained. Most commercial BGA packaging is large (almost that of FPGA in some instances) and consumes power >1W, and I was wondering if anyone here has seen or used other advanced/smaller package size while minimizing power.From some preliminary searched, I found that basically a company called Etron that offers a standard DDR memory product available in Wafer Level Chip Scale Package (WLCSP) and some other non-standard DDR products like Reduce Pin Count (RPC) and HyperRAM. But, other than that, I am struggling to find other companies. Any thoughts or opinions are greatly appreciated!

author: SiliconWizard
author_rank: Super Contributor
timestamp: July 09, 2024, 12:50:45 am
content: You should consider DDR3L or LPDDR3 chips. You'll probably have some trouble sourcing them, and would have more luck with LPDDR4, but if you're asking for DDR3 specifically, then I'm assuming that your design doesn't support DDR4.

author: asmi
author_rank: Super Contributor
timestamp: July 11, 2024, 08:54:01 pm
content: Quote from: SiliconWizard on July 09, 2024, 12:50:45 amThese two are not compatible with each other.---On topic - DDR3/DDR3L are only available in standard 0.8 mm pitch packages as far as I know. To save power, use DDR3L signalling (1.35 V Vccio), to reduce space on PCB, use clamshell placement if it's supported by your memory controller. But if you really want to save on power, you have to look at LPDDRx standard.