hybridfree/eevblog-posts huggingface dataset:
SO8FL (power 8SOIC package) and heat management of the 3 source pins - Page 1
Forum section: electronics / projects

author: Psi
author_rank: Super Contributor
timestamp: July 02, 2023, 12:44:16 am
content: For a SO8FL package high-current mosfet. How much do you need to think about heat management for the 3 source pins compared to the main/large drain-pad under the chip?I'm just doing some PCB layout and I'm not sure just how much I should prioritize drain heat management over source heat management. Obviously most of the heat is going to come out of the large drain pad, but is it 99/1 or 90/10 etc.If I can ignore the 3 source pins from a heat perspective it will make the design easier.Anyone have any comments?

author: Someone
author_rank: Super Contributor
timestamp: July 02, 2023, 01:12:20 am
content: Depends on the specific device packaging, not the footprint or outline:https://www.onsemi.com/pub/Collateral/AND9137-D.PDFIf thats not specified in the datasheet then its open to change (the better manufacturers provide advance notification of such details).

author: Psi
author_rank: Super Contributor
timestamp: July 02, 2023, 01:58:53 am
content: This is the main ones I was looking athttps://nz.mouser.com/datasheet/2/408/TPH1R204PL1_datasheet_en_20200626-2449268.pdfhttps://www.mccsemi.com/pdf/Products/MCAC130N04(DFN5060).pdf

author: Konkedout
author_rank: Frequent Contributor
timestamp: July 02, 2023, 02:56:26 am
content: I have used many MOSFETs over many years. If we assume that it is a "conventional" enhancement mode silicon MOSFET, I do not ever remember encountering any need to heatsink the source pin(s). For example, think of a through hole package such as TO220, or an SMT package such as a D-pak. You heatsink the drain. But for the source, just make sure you provide ample copper for conducting the current. If any heatsinking of the source pins is required or recommended, that seems unusual so should be indicated in the datasheet.

author: ArdWar
author_rank: Frequent Contributor
timestamp: July 02, 2023, 04:12:17 am
content: No need to worry too much about source thermal dissipation unless stated otherwise (some power module and specialized FET have the die flipped, with tab on source). Most "good design practices" allowing for source current carrying capacity will most likely put much more copper on it than what manufacturers use to test thermal characteristics anyway.Not to mention the standard JEDEC thermal test coupon, which is ridiculously amusing.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 02, 2023, 05:05:23 am
content: Basically two things come to mind:1. If it's a clip-bond type, useful heat can be drawn out through the source pins.2. You may need a lot of thermal capacity or cross-section just to handle the current -- basic ampacity. Which will do the same thing anyway, but for a different reason.Tim

author: Psi
author_rank: Super Contributor
timestamp: July 02, 2023, 06:45:05 am
content: Thanks
Socket pins - Page 1
Forum section: electronics / projects

author: AccelMotion
author_rank: Newbie
timestamp: August 25, 2015, 05:45:09 pm
content: I'm looking for something, and can't find it.It's a machine-pin socket strip, female on top and round pins on the bottom. It accepts .025" square pins on the female socket header part, up to a .2" depth or so.Has anyone any idea what these pin strips are called and how to find more? My searches always yield the expected socket strips that accept IC pins, but not .025" square (wirewrap) pins.Any thoughts about where to look?David

author: edpalmer42
author_rank: Super Contributor
timestamp: August 25, 2015, 06:15:10 pm
content: Keystone makes things like that. Most of the big distributors carry the brand. You'll have to check to see if they have that item.http://www.keyelco.com/Ed

author: w2aew
author_rank: Super Contributor
timestamp: August 26, 2015, 03:05:13 am
content: Also check Mill-Max, they make all sorts of pin sockets.

author: AccelMotion
author_rank: Newbie
timestamp: September 01, 2015, 07:52:36 pm
content: Lots of folks make sockets. I'm looking for a female machine-pin socket strip that would accept a.025"square pin..

author: Monkeh
author_rank: Super Contributor
timestamp: September 01, 2015, 08:07:23 pm
content: Quote from: AccelMotion on September 01, 2015, 07:52:36 pmhttps://www.mill-max.com/products/socket/801-XX-XXX-10-003000Quote

author: AccelMotion
author_rank: Newbie
timestamp: September 02, 2015, 06:08:59 pm
content: Thanks to everyone for help. The Mill-Max is an appropriate choice, but very expensive.Whatever we used to buy was much less expensive, but I just can't identify it.

author: fivefish
author_rank: Frequent Contributor
timestamp: September 02, 2015, 06:11:20 pm
content: The new Rohs compliant Mill Max are more expensive than the old non-Rohs millmax.3x more expensive on one particular model I'm using.
Socket Wire connector suggestions - Page 1
Forum section: electronics / projects

author: Revky27
author_rank: Contributor
timestamp: December 18, 2024, 06:44:16 am
content: Hi All,I want to mount some small temperature sensors (transistor type in an enclosure). I want these sensors to be removable hence I plan to use a tiny connector. On the other side I would like to have a wired socket fixed in a plastic holder with wires already routed hence I can swap the sensor.Does anyone know of any family which offer wired sockets (with crimps for easy assembly and avoid soldering) to PCB plugs? Ideally, I need only 1x2 with small pitch 1mm or 1.27mmThanks

author: jbb
author_rank: Super Contributor
timestamp: December 18, 2024, 08:31:54 am
content: It’s bigger than you’d like, but how about Molex Micro-Fit?

author: Whales
author_rank: Super Contributor
timestamp: December 18, 2024, 10:02:41 am
content: > wired socket fixed in a plastic holderAre you specifically after "panel mount" options?I'm not sure how that mixes with no soldering, unless you're after screw terminals on inside to screw the legs of your temperature sensor to? Can you draw a picture of approximately what you're after?I was originally thinking of suggesting 3.81mm pluggable terminal blocks, but they require soldering or a PCB on the inside:https://www.lcsc.com/product-detail/Pluggable-System-Terminal-Block_DEGSON-15EDGRM-3-81-02P-14-00A-H_C507015.htmlhttps://www.lcsc.com/product-detail/Pluggable-System-Terminal-Block_Ningbo-Kangnex-Elec-WJ15EDGK-3-81-2P_C8466.htmlhttps://www.lcsc.com/product-detail/Pluggable-System-Terminal-Block_DORABO-DB2EVC-3-81-2P-GN_C395686.htmlhttps://www.lcsc.com/product-detail/Pluggable-System-Terminal-Block_Ningbo-Kangnex-Elec-WJ15EDGRC-3-81-2P_C8387.html

author: Revky27
author_rank: Contributor
timestamp: December 19, 2024, 07:32:45 am
content: The problem are those options are too big.If there was a molex-micro fit with 1.27mm pitch would be ideal
SODIMM angle socket pin delay - Page 1
Forum section: electronics / projects

author: Kapciokl
author_rank: Newbie
timestamp: March 27, 2023, 07:40:18 am
content: Hi, everyone.I had a question that I had never thought about before.Is there any difference in the pin delays for top and bottom rows of angle DDR sockets (https://www.te.com/usa-en/product-2309407-1.html)?At first glance, the internal length of the upper row of pins is much longer. But I don't find any mention of this on the connector manufacturers' websites.I would like to use this information to align the signal lengths in the DDR buses more precisely.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 27, 2023, 04:30:24 pm
content: You should have contacts lengths in the connectorSince you have cad files and others you should have some specsShitty website who ask to register an email ?

author: Someone
author_rank: Super Contributor
timestamp: March 27, 2023, 08:53:22 pm
content: Quote from: coromonadalix on March 27, 2023, 04:30:24 pmMake Your AccountEnter Email Now: [ ]or not
Soft Latch Circuit Project - Its kinda backwards!! - Page 1
Forum section: electronics / projects

author: nukejr
author_rank: Newbie
timestamp: December 20, 2012, 01:17:33 am
content: To keep along storyshort: I have assembled the circuit pictured below. It works beautifully, EXCEPT for that fact the circuit immediately latches upon introduction of the source power.It is my desire to have the circuit, upon initial introduction of voltage (power), be in theunlatchedstate until the switch contact is closed.Any suggestions or solutions.

author: hlavac
author_rank: Frequent Contributor
timestamp: December 20, 2012, 03:05:15 pm
content: Your power supply is connected backwards.

author: hlavac
author_rank: Frequent Contributor
timestamp: December 20, 2012, 08:58:38 pm
content: Also, you are missing a diode across the relay to stop the inductive kickback from frying the transistors.
Soft Latch Switch Circuit with Buck Converter Load Does Not Work - Page 1
Forum section: electronics / projects

author: Emremutlu01
author_rank: Newbie
timestamp: May 26, 2021, 10:49:24 am
content: I have been experimenting with soft latch switches. There is one that EEV Blog has developed that only uses 2 NPN transistors and a P-Channel Mosfet. Below is a link to his video. The circuit is seen on 14:44 in the video.Link :I have connected that to a Buck converter and I am observing some strange behaviour. You can find my full schematic below.The Connection is as follows:USB/12V --> Voltage Selector --> Soft Latch Switch --> Buck ConverterOn power up the circuit delivers a 5V to the Vin of the Buck Converter and it works on regulating it to 3.3V. However when I press the button the voltage at the output of the soft latch drops to ~4.375V and reverts back to 5V when I release the button.I am monitoring it on the oscilloscope and what I would expect in such a situation is an oscillation when the button is pressed. But what I am observing is a fix DC voltage.What may be the cause of this? I don't really understand what is going on. Any input would be appreciated.The schematic can be found in the attachments.

author: penfold
author_rank: Frequent Contributor
timestamp: May 26, 2021, 01:59:10 pm
content: Your MOSFET Q5 is back to front, also the diode in the symbol looks to be the wrong way about.
Soft Latch Switch with Hold x seconds to turn off - Page 1
Forum section: electronics / projects

author: piperpilot
author_rank: Newbie
timestamp: January 17, 2021, 03:52:47 pm
content: Hey Gurus,I'm working on a new project where I want a soft latch switch. I like the EDN article that has been posted here many times that uses the below schematic. I believe it can be implemented for a few cents using CJ2301 P-Channel Mosfet and S8050 NPN Transistors.Anyways, my question is...is there a way to modify this either by changing resistor values or adding capacitors to make the OFF state happen only after holding the button for a couple of seconds? I have seen all of the microcontroller based solutions and really want to use something standalone.Thanks!Curtis

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 17, 2021, 10:28:56 pm
content: I think you can try to connect the gate of the power MOSFET to the ground through a capacitor and return it to the circuit through a high-resistance resistor.

author: florian-x
author_rank: Contributor
timestamp: January 17, 2021, 11:30:44 pm
content: I've found such a circuit in the following page:http://www.mosaic-industries.com/embedded-systems/microcontroller-projects/electronic-circuits/push-button-switch-turn-on/latching-toggle-power-switch

author: davidb
author_rank: Contributor
timestamp: January 18, 2021, 03:04:56 am
content: Quote from: florian-x on January 17, 2021, 11:30:44 pmI used the circuit found there (fig 9), and it was twitchy as heck. Some boards worked great, others didn't at all.I ended up having to go with an LTC2955, which worked great.

author: piperpilot
author_rank: Newbie
timestamp: January 18, 2021, 09:39:50 pm
content: LTC2955 looks great, but is a FEW dollars each. This is for a volume project so I need to keep costs as low as possible. I've heard a lot of people say they had issues with the mosaic design, so kinda staying away from that. Dave's video on the subject is pretty good as well, was just hoping someone had a proven good design for 3-4V (Lithium Battery) input levels.

author: Terry Bites
author_rank: Super Contributor
timestamp: January 19, 2021, 10:39:35 am
content: If its for a volume circuit then its a commercial enterprise and you should be asking for free advice from your piers.Shabby.

author: Zero999
author_rank: Super Contributor
timestamp: January 19, 2021, 11:43:15 am
content: Quote from: Terry Bites on January 19, 2021, 10:39:35 amIf you read the forum rules, you'll find there's nothing against asking for advice for a commercial product. There are a lot of professionals on this forum, who advise others working on commercial products for free and receive advice from others, for their commercial products for free. If you don't want to help, then don't reply.Quote from: piperpilot on January 17, 2021, 03:52:47 pmIs there any particular reason why you want a standalone product? A small microcontroler would probably be cheaper and easier.
Soft latching on/off switch redux++ - Page 1
Forum section: electronics / projects

author: Howardlong
author_rank: Super Contributor
timestamp: September 18, 2020, 05:58:25 pm
content: I was revisiting this a few weeks ago with a view to minimising parts count.There's quite a reluctance to use MCUs, undoubtedly because there's a concern over sleep current draw.But what if I were to tell you there are a few MCUs out there with <100pA current draw in sleep with a voltage range of 2V to 5V? Yes, PICOamps. That's 268,000 years on a CR2032.At 2V, in sleep, the PIC10F20x devices sip only 27pA in SOT-236 and 35pA in DIP-8, and this seems to be reasonably consistent across a long date range of parts.BOM:1 PIC10F20x SOT23-61 PMN27UP P-Ch 5.7A 20v mosfet SOT23-61 10k resistor1 push button switch1 100nF capCode:// PIC10F206 Configuration Bit Settings// 'C' source line config statements// CONFIG#pragma config WDTE = OFF // Watchdog Timer (WDT disabled)#pragma config CP = OFF // Code Protect (Code protection off)//#pragma config MCLRE = ON // Master Clear Enable (GP3/MCLR pin function is MCLR)#pragma config MCLRE = OFF // Master Clear Enable (GP3/MCLR pin fuction is digital I/O, MCLR internally tied to VDD)// #pragma config statements should precede project file includes.// Use project enums instead of #define for ON and OFF.#include <xc.h>#include <stdint.h>#include <stdbool.h>#define _XTAL_FREQ 4000000__persistent bool _b;// 27pA @2V, 36pA @3.0V, 68pA @5V sleep// 26.7uA @2V, 77.8uA @ 3.0V, 231uA @5V Button down//int main(void){TRIS=0;// ADCON0bits.ANS=0b00; // Digital IO, not analogOSCCALbits.FOSC4=0;CMCON0bits.CMPON=0;OPTION=0b00011111; // Wake on change enabled (bit 7), Global pull ups enabled GP0, GP1 & GP3 (bit 6), Disable T0CS (on GP2)(bit 5))if ((STATUS & 0b11111000) == 0b10010000) // See DS40001239F p37, Table 9-2{uint8_t u8NewState=GPIO;uint8_t u8OldState;uint16_t u16Count=0;// Debouncedo{u8OldState=u8NewState;u8NewState=GPIO;if (((u8OldState ^ u8NewState) & 0b00001000)!=0){u16Count=0;}} while (u16Count++<1000); // 1000 is about 31.8ms @ Fosc 4MHzif ((u8NewState & 0b00001000)==0){if (_b){_b=0;GPIObits.GP2=1;}else{_b=1;GPIObits.GP2=0;}}}else{ // PIC's pOwer on resetGPIO=0b11111111;_b=0;GPIObits.GP2=1;}STATUSbits.GPWUF=0; // Clear wake up from pin change flagSLEEP();// Should never reach here, 10f2xx devices don't support PC+1 wake upwhile (1){NOP();}return 0;}
Soft latching power switch IC (Any?) - Page 1
Forum section: electronics / projects

author: YTusername
author_rank: Regular Contributor
timestamp: March 16, 2024, 07:33:20 am
content: Hi,I'm familiar with load switch ICs such as the TPS22919 and AP2401. While I may not be using the correct terminology when searching for the appropriate IC, it appears that there is no IC available that directly implements a soft-latching power switch similar to the one featured in David's design (EEVblog #262 - World's Simplest Soft Latching Power Switch Circuit). I understand that such an IC would likely require an external capacitor to operate, but I'm wondering if there is any IC available with a built-in button soft-latching power switch function.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: March 16, 2024, 01:28:10 pm
content: I've got an digital "dial" indicator from some unknown chinese brand. It's got a capacitive button switch in it (Zero, on / off and Metric / Bananas). You can look up the current consumption of those. I have not measured it. The thing runs on an CR2032 and I use it about once a year. The battery holder in this thing is a sort of little "drawer". When I put the thing in storage I usually take out the drawer, and insert it upside down, and that way the battery does not make contact at all.But what is your application? Often you want to be able to define when you turn the thing off, and that usually involves a microcontroller pin. I quite like the power circuit as used in the ubiquitous "transistor tester". It just uses a few transistors, and a dedicated IC is not likely to be much cheaper or smaller (You can get 2 BJT's in an SOT23-6) BJT's usually have a smaller off leakage then MOSfets, but low power design always needs special attention. For example a leaky electrolytic capacitor can easily dominate the current consumption.

author: globoy
author_rank: Frequent Contributor
timestamp: March 16, 2024, 03:27:32 pm
content: I've used the MAX16150 from Maxim and the less expensive XC6192 from Torex. Both include a built-in load switch and the ability for an attached micro to implement a soft power-off feature. Both also include a long-press hard power-off feature which is useful for cases where your micro has crashed or locked up. They are self-timed.

author: YTusername
author_rank: Regular Contributor
timestamp: March 17, 2024, 09:49:10 am
content: Thanks. Both MAX16150 and XC6192 are just what I'm looking for.
Soft latching push button ONLY on short press - MOM on long press? - Page 1
Forum section: electronics / projects

author: roomwillow
author_rank: Newbie
timestamp: June 16, 2021, 05:19:33 pm
content: Hello,I am working on a simple audio control circuit and need to integrate a PTT function using a button, I've been able to find a few soft latching schematics online, but they all seem to be soft latch 100% of the time... what I want is soft latching only on a very short (think half-second or less) press, if the button is held for more than a half-second, I want it to MOM and immediately disconnect the circuit when the button is released if the button has been held for more than a half-second. The catch here is i'd like to do this passively, and if not passively, in as simple, low draw circuit as possible, that will still MOM only if say... the active circuits battery were to die.Suggestions? I'm stumped on how to do this without involving a microcontroller
Soft soldering stainless steel - Page 1
Forum section: electronics / projects

author: ChristofferB
author_rank: Frequent Contributor
timestamp: February 08, 2019, 01:35:33 pm
content: So, i'm in need of soldering some very small stainless steel parts together, specificly, 3mm tubing, 1.5mm tubing and hypodermic needle-size tubing.The entire assembly needs to be insulated in a PTFE ferrule, as it's to be used as an electrode for a micro-flame ionization detector, so joining with fittings is out of the question. Epoxy and such is too.Is there any flux that would allow soft (Sn97Ag3) solder to do this job, or do I need to silver solder/braze. If the latter, do you think it can be done with a micro propane burner? They get fairly hot and the thermal mass is tiny.Any input appreciated! Thanks in advance--Chris

author: DTJ
author_rank: Super Contributor
timestamp: February 08, 2019, 01:56:43 pm
content: No practical experience but it seems it can be donehttps://sciencing.com/silver-solder-stainless-steel-6144307.htmlI've used a micro-burner for silver soldering small parts (non stainless) before.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: February 08, 2019, 03:56:54 pm
content: Maybe it can be done but I wouldn't trust it as far as I could throw it. Can you find somebody to laser or beam weld it?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 08, 2019, 04:57:40 pm
content: Yes, use acid paste flux.Tim

author: ChristofferB
author_rank: Frequent Contributor
timestamp: February 08, 2019, 05:35:08 pm
content: Acid paste flux, gotcha. I'll try that. If it doesn't work I might try my luck with those ebay silver solder+flux kits.I don't suppose dilute hydrochloric acid would work as flux? That'd be delightfully simple.Thanks all!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 08, 2019, 07:02:52 pm
content: Nah, too cooling, and it doesn't stick around. Once it's gone, oxides are back. You can make your own zinc chloride by dissolving the metal in it though.Tim

author: Domagoj T
author_rank: Frequent Contributor
timestamp: February 08, 2019, 08:19:57 pm
content: Quote from: ChristofferB on February 08, 2019, 05:35:08 pmDon't dilute it. Dissolve zinc in it, as much as will dissolve (make sure you add little by little zinc and do it outside).Careful with the final product as it will rust anything it touches and most things in proximity. Again, try soldering outside if possible. Neutralize with sodium carbonate (washing soda).

author: David Hess
author_rank: Super Contributor
timestamp: February 09, 2019, 02:03:38 am
content: Quote from: ChristofferB on February 08, 2019, 01:35:33 pmA propane or butane torch is absolutely hot enough for silver brazing using roughly 50% silver alloys.
Soft start circuit based on charge pump & Nch MOSFET provides nice linear ramp. - Page 1
Forum section: electronics / projects

author: Konkedout
author_rank: Frequent Contributor
timestamp: April 13, 2025, 08:48:52 pm
content: This is an LTSpice simulation. I have tested similar in hardware.Ideally this ought to be done with a "linear" MOSFET. Littlelfuse and Infineon make some of those.But I think that so long as the voltage and current stress is not so severe, a good Nch Power MOSFET will work well enough.

author: incf
author_rank: Frequent Contributor
timestamp: April 13, 2025, 10:47:28 pm
content: seems reasonable to me

author: Benta
author_rank: Super Contributor
timestamp: April 13, 2025, 10:59:30 pm
content: Where is a linear soft start needed? Please educate me.

author: Konkedout
author_rank: Frequent Contributor
timestamp: April 14, 2025, 03:36:59 am
content: It is a matter of degree.....This controls inrush current. If you want to limit your "hot plug" inrush current without taking too much time, then a linear ramp is likely to be what you want. "Hot Swap" circuits do similar but sometimes I prefer to not buy some other dedicated IC for a given function. If it were not a popular function, you would not see so many ICs here:https://www.digikey.com/en/products/filter/hot-swap-controllers/718?s=N4IgTCBcDaIBYHsAuACAzgdwIYAcQF0BfIAI remember trying to implement similar using Pch MOSFET and I found it to be surprisingly difficult. The ramp could be slow at some points but much faster at other points so that the total time was long and the inrush was high. The worst of both worlds.

author: mtwieg
author_rank: Frequent Contributor
timestamp: April 14, 2025, 11:50:13 am
content: Yeah this is basically a DIY hot swap controller. The switching frequency and the values of C3 and C1 determine an output dV/dt, which limits the inrush current due to C4, all seems pretty straightforward.Currently discussing SOA considerations for such an applicationin this thread.
Soft Start Circuit for POE - Page 1
Forum section: electronics / projects

author: goofson
author_rank: Newbie
timestamp: September 12, 2022, 10:41:51 pm
content: Hello,I want to put a soft start circuit for powering amplifiers. The 24V input is from POE and the POE dc-dc converter needs to see 24V before a certain timer or else it will shut off. Problem is the amplifier has large electrolytic caps which pull the voltage down due to inrush current. That's why I wanted to put this soft-start circuit in, but I am not sure how it works. Please help me understand what the soft-start circuit does to limit inrush current.Another problem being that the inductor L1 when put in the circuit between the voltage source and POE causes the softstart to not work under cold temperatures (-3 deg C : 37.4 F). I would like to know why and would welcome any guesses.In the image I used R2 as a theoretical load to act on behalf of the electrolytic caps mentioned previously.

author: moffy
author_rank: Super Contributor
timestamp: September 12, 2022, 10:56:21 pm
content: When the voltage V1 is applied and the PMOSFET starts to turn on (> Vd2) the output voltage across R2 starts to rise. As this voltage starts to rise C1 provides negative feedback trying to turn the gate off. It is the negative feedback provided by C2 across R3 that limits the rise time of the output voltage and acts as a soft start. Not sure about the temp sensitivity of L1 but it might be introducing some sort of oscillation?
Soft Start Circuit Help? - Page 1
Forum section: electronics / projects

author: M@
author_rank: Newbie
timestamp: October 10, 2013, 12:06:47 am
content: I've got a 400VA PT with roughly 510VDC full wave rectified on the secondary of the transformer feeding a load that draws anywhere from 300-400mA current draw. It feeds a 10H inductor and a capacitor bank.I am trying to design a soft start circuit and would like to know some books or sources that would be of some help or guidance on theoretically proven design ideas to think of?I'd also like to know the thoughts on soft-shutdown to prevent collapsing magnetic fields from causing inductive kickback at these voltages. Is a diode across the inductor at this level still alright or is there a better way?Want to stay away from PTC's. I had thought about a relay that bypasses a current shunt resistor.Any guidance would be greatly appreciatedThanks,-Matt

author: niflheimer
author_rank: Contributor
timestamp: October 10, 2013, 05:09:37 pm
content: http://sound.westhost.com/project39.htmIt's a good start point for a proven circuit and it doesn't uses PTCs ( though I kinda like them in some applications as long as you dont mind them staying hot )

author: SeanB
author_rank: Super Contributor
timestamp: October 10, 2013, 06:42:07 pm
content: Often with PTC units there is either a TRIAC or a relay that shorts them out after a second or so so that you do not have the heat dissipation and allow them to cool so they are going to operate with no cool down delay if the power is interrupted. I have seen many high inrush power supplies ( IBM server supplies do have this) with this.
Soft start circuit with Mosfet? - Page 1
Forum section: electronics / projects

author: guscrown
author_rank: Regular Contributor
timestamp: October 20, 2012, 05:24:17 am
content: I want to use a soft-start circuit for my design, as I am currently experiencing some inrush/sparking issue whenever I hotplug the external power-supply brick into my board. I reduced it by using some NTC Thermistors but the 2 minute reset time of the Thermistor is not going to be something we can work with.I know how the concept of the soft-start works, but I don't know how to put it down on the schematic. Can you help me out with some sample schematics?Here are my specs:Vin: 24V Imax: 8A P-Mosfet P/N: NTD20P06LT4GDelay time: 500msAny ideas?

author: AndyC_772
author_rank: Super Contributor
timestamp: October 20, 2012, 07:49:02 am
content: We'll need to start with your schematic to see how it might be adapted. Soft-start is rarely something that's bolted on as a separate feature.

author: NewBeginner
author_rank: Regular Contributor
timestamp: October 20, 2012, 09:54:09 am
content: A possible inrush current limiting circuit could be the one in the attached image.But please note that I am a beginner in electronics so this circuit may not be fully correct or it may not be 100% safe. So use it at your own risk.Maybe other, more experienced and more knowledgeable, members of the forum can shed a light on this.R2 along with C2 sets the turn-on time. The D1 zener ensures that Vgs will not be lower than -12V (PMOS) so the MOSFET will not get damaged.I believe that the zener should be selected based on your MOSFET specs. If a Vgs of -12V is too big for your selected MOSFET then a smaller value zener should be used to ensure that Vgs is kept within the specified limits of the MOSFET, but in the same time ensuring that Vgs will have a proper value to fully turn on the MOSFET.I think that the turn-on time can also be affected by the MOSFET used, increasing or decreasing based on the amount of gate charge of the selected MOSFET.Also the selected MOSFET should be able to handle the power dissipation, especially during the transition period (from off to on).Note that in this setup if the supply voltage (Vs) is decreased the turn-on time will increase.But again, I am a beginner so this my not be 100% correct. Please correct me if I am wrong.Thank you

author: guscrown
author_rank: Regular Contributor
timestamp: October 22, 2012, 02:05:57 am
content: I've prepared the following circuit. Feedback is very much welcomed.

author: guscrown
author_rank: Regular Contributor
timestamp: October 22, 2012, 02:08:15 am
content: My only problem with the above circuit is no matter how slow I ramp that Vgs voltage on M1, I am not getting a ramp-type voltage on Vds. It just goes from 0V to 24V instantly.Any ideas why?

author: hlavac
author_rank: Frequent Contributor
timestamp: October 22, 2012, 11:04:38 am
content: I would simply have a big resistor (10 ohm ish) in series with the power rail that is shorted by a MOSFET once the voltage rises enough.
Soft Start for 24V Hot-Plugged Devices - Page 1
Forum section: electronics / projects

author: OwenH
author_rank: Contributor
timestamp: September 20, 2023, 02:07:36 pm
content: I'm designing a 24V regulated battery operated power bus with multiple connectors for various devices that are hot-plugged into the 24V bus. I'm looking to incorporate MOSFET switches at each socket to monitor current, control power delivery and enable soft start when a device is plugged in.My challenge is to detect when a connector is plugged into the socket. Since the plug and socket of the external devices adhere to standardized configurations, I can't add an extra pin for plug-in detection.Is there a method or IC that can keep the MOSFET in the ohmic region until a load is detected, at which point it would initiate a soft start?I’m open to all ideas here and any suggestions are greatly appreciated!Owen

author: markietas
author_rank: Newbie
timestamp: September 20, 2023, 04:48:25 pm
content: There are ICs for this very purpose.These will do everything you want and more:https://www.ti.com/power-management/power-switches/efuse-hotswap-controllers/overview.html

author: OwenH
author_rank: Contributor
timestamp: September 21, 2023, 09:30:04 am
content: I'm trying to control the inrush from the Bus side. My understanding is that all the Hotswap controllers are designed to work on the device that is being plugged into the bus and on on the bus its self.
soft start for 6 volt motor - Page 1
Forum section: electronics / projects

author: WB8PFZ
author_rank: Regular Contributor
timestamp: December 31, 2020, 10:21:24 pm
content: I am looking for ideas to build a slow start circuit for a battery operated pedal car. There are two foot switches that control the motor. I would like to use the switches (no potentiometers) to ramp the 6 volts up gradually. Mike

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: December 31, 2020, 10:44:16 pm
content: How many amps? You could buy a brushed ESC with a programming card.

author: Gyro
author_rank: Super Contributor
timestamp: December 31, 2020, 10:55:23 pm
content: This question has come up once before (ok, it was 12V), but it might give you some clues to get started with...https://www.eevblog.com/forum/projects/electric-rideable-kids-car-soft-start/
Soft start motor control - Page 1
Forum section: electronics / projects

author: okw
author_rank: Frequent Contributor
timestamp: November 30, 2021, 01:13:51 pm
content: Hi! My nephew (3y) is soon getting old enough to ride an electric 90s train we have. It has a simple momentary button on the handle, which engages the motor. This makes it jump forward, rather abrasively. I've been searching for a soft-start motor controller, but to no avail. All I can find is pot meter controllers for variable speed. I need on/off, but with soft start.Anyone knows some Ali off-the-shelf products (DIY or prebuilt).If not, I'm open to designing something (with the right input and help).I do not know the motor rating as the motor is inside an plastic enclosure. But it doesn't look powerful (probably geared very low), and it's driven by a 6V 6Ah battery. It seems to have two motors, one for each rear wheel. I've attached some pictures, if that helps.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 30, 2021, 01:34:08 pm
content: Use a relay to start with the motors in series and then switch to parallel after a short delay.

author: SeanB
author_rank: Super Contributor
timestamp: November 30, 2021, 02:03:51 pm
content: Simplest is a resistor in series with each motor, roughly rated to reduce the current to half the run current as measured with a meter. Then after a half second or so a relay closes, using a large value capacitor, that is part of a RC delay, to short out the resistor to run at full speed. Simple, works well enough, and reasonably easy to build. Otherwise a simple speed controller with DC input, and with a RC delay to allow speed to rap up as the time goes by with the switch closed.
Soft start switch high current  - Page 1
Forum section: electronics / projects

author: davelectronic
author_rank: Frequent Contributor
timestamp: December 08, 2023, 11:39:48 pm
content: Looking for a power switch circuit, to turn the output of a 20 Amp power supply on and off, using a momentary push to make non latching. So if that makes sense. Kind of like a solid state switch circuit that can handle 20 Amps. Any recommendations on a circuit appreciated.
Soft starting a 100W led can it be done with a 555 and pwm? - Page 1
Forum section: electronics / projects

author: Hagis2k
author_rank: Regular Contributor
timestamp: September 28, 2014, 09:31:27 pm
content: Hi fellas been sitting here thinking a bit on how to get an 100W led to soft start the most easy wayi been trying to figure out if a simple 555 timer and a mosfet can do it as there is many circuits onlineon 555 pwm is there any way to make the duty cycle to increase on power on from like 0-100% in 3-4sec?Will probably take the breadboard and start playing around a bit i knowi can do it with aurdino but i rather stay with non microprocessor things for this

author: Marco
author_rank: Super Contributor
timestamp: September 28, 2014, 09:52:01 pm
content: The easiest is to buy a 100 Watt LED driver with dimmer and mod the dimming input.

author: SArepairman
author_rank: Frequent Contributor
timestamp: September 29, 2014, 02:38:23 am
content: you need two triangle wave generators and a comparator.One triangle wave goes to one input of your comparator (at the frequency of you PWM), the other triangle wave is the duty cycle (I imagine this could also be done with just a RC circuit, it does not need to be perfectly linear right?), the comparator will produce a square wave with a duty cycle that steadily goes up.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 29, 2014, 03:30:16 am
content: Easiest way is to use a current mode PWM controller and a RC time delay to ramp up the current setpoint.
Soft Switch Design Question - Page 1
Forum section: electronics / projects

author: kenny15963
author_rank: Newbie
timestamp: March 10, 2016, 06:02:38 pm
content: Put together a soft switch for a small project. Circuit is similar to many I've seen all over the internet. Having a small issue with my implementation though. When I'm applying the 9v, the circuit should be "off" but about 90% of the time it starts in the "on" mode. Not a huge issue for this particular application but would like to know how to ensure it starts in the "off" mode.More info on what I'm doing with this. Using the output to power 3.3v for an Attiny as well as a 9v rail to drive some LEDs. The "off" signal comes from an output pin on the Attiny going high (current limiting resistor not shown.)

author: kurt
author_rank: Contributor
timestamp: March 10, 2016, 10:26:20 pm
content: The instant you connect power to the circuit you will have a capacitive voltage divider made by the gate capacitance of the BS250P and the drain-source capacitance of the 2N7000. If the drain-source capacitance are to large compared to the gate capacitance you will pull the gate of the BS250P down enough to turn it on.I guess this could be fixed by adding more gate capacitance. I.e. putting a small capacitor in parallell with the leftmost 100K resistor (component designators would make it easier to talk about the circuit BTW).

author: kenny15963
author_rank: Newbie
timestamp: March 12, 2016, 07:52:07 pm
content: Thanks for the response. I tried your suggestion with no success. It did get me thinking about the capacitance of the gates though and I think I figured out what was happening from that. The P-MOSFET will initially be in a conductive state. Due to the capacitance of the gate, there will be a short time for the gate to charge up through the 100k resistor where the P-MOSFET will remain on. The gate capacitance of the N-MOSFET used is smaller than the gate capacitance on the P-MOSFET. So the N-MMOSFET is winning the "gate charging race" most the time and keeping the P-MOSFET gate low on initial power-up. I added a small cap between the N-MOSFET gate and ground which seems to have fixed the issue.Sorry for the lack of designators. Feeling the awkwardness of that mistake as I type this response. I'll be sure to include them in the future (I am trainable...)

author: kurt
author_rank: Contributor
timestamp: March 15, 2016, 02:51:52 pm
content: Right. I guess I missed something. And I think you have the right solution, but that you conclusion for why it worked is a bit offThe P-MOSFET will not initially be in conductive state, since it needs a gate charge for that to happen.But you have another capacitive / resitive voltage divider consisting of the P-MOSFET Csd, the rightmost 100k resistor and the N-MOSFET Cgs. If Cgs charge to the threshold voltage before Csd has eaten enough of the voltage you will have the N-MOSFET turn on.So your solution of adding more gate capacitance to the N-MOSFET should solve this issue.
Software Aspects - Page 1
Forum section: electronics / projects

author: sadasivamASK
author_rank: Contributor
timestamp: May 09, 2022, 04:19:51 am
content: Hi,For Embedded feasibility study on specific application, what are the software aspects we need to check in available datasheet? In other terms, how to choose IC using SW aspects on specific application..For eg,. My Application => Video Streaming from Camera sensor using MIPI to USB converter. I2C interface for controlling camera sensor registers...
software for designing hand wired prototype boards - Page 1
Forum section: electronics / projects

author: snarkysparky
author_rank: Frequent Contributor
timestamp: December 29, 2022, 02:56:33 pm
content: Messing around with a solar panel charge controller. Going to build it on square grid prototype board.I find it helpful to first draw the placement and wiring out on a drawing like attached. Makes it easier to keeps straight as i build and wire it.What would be REALLY helpful is if some smart people had made a software program to do this. It should present the user with a grid of 0.1 size holes and menus to drop appropriately sized parts onto the grid.Then drag around wires to connect it up.Print it out and tape to the wall and start building.Anyone ever seen such software ??

author: Ian.M
author_rank: Super Contributor
timestamp: December 29, 2022, 03:10:10 pm
content: VeeCADwith its preferred schematic entry packageTinyCAD? Although VeeCAD is known for stripboard layouts (and even has limited stripboard autorouting capability), it also supports one pad per hole protoboard.

author: Buriedcode
author_rank: Super Contributor
timestamp: December 29, 2022, 05:45:18 pm
content: http://bancika.github.io/diy-layout-creator/I've used this a few times to design things for people wanting to learn prototyping on stripboard.Before that I would use graph/grid paper and a pencilI now use plain old Eagle, with a 0.1" grid, and make the bottom layer the strips, and top layer the wire links - but all that required a custom library of "stripboard only" part footprints, like diagonal resistors/caps etc..I'm faily sure the above supports one-pad-per-hole layouts as I've seen them on guiatr effects forums:http://effectslayouts.blogspot.com/2016/08/korg-ms-20-filter.html
Anyone have a working (Tandy) TRS-80 Model 100 floppy disk drive (TPPD/2)? - Page 1
Forum section: electronics / projects

author: marmad
author_rank: Super Contributor
timestamp: April 19, 2013, 10:46:06 pm
content: I'm trying to get the data off of two 3.5" single sided DD 80-track floppies written by a TRS-80 Model 100 using either the Tandy Portable Disk Drive (TPDD - 100kB using 40 tracks) or the TPDD2 (200kB - 80 tracks) . Unfortunately, I have neither a Model 100 or the drives, so I'm just hoping to get a disk image (the file formats are fairly simple) using a standard PC 1.4MB drive.Obviously, the disks are about 27 years old - so they might be toast - but they were only written one time as an archive copy and then put into well-protected storage. So far, I've been playing with some freeware software called OmniFlop - but no luck. Any ideas for something else I might try?

author: marmad
author_rank: Super Contributor
timestamp: April 19, 2013, 11:12:49 pm
content: Well - just found this info online - which sounds fairly conclusiveDrive RSNum Media Dirs Files/Dir TotalBytes StockDOSTPDD 26-3808 dssd or dsdd 1 40 Aprox100K floppy.coTPDD2 26-3814 dssd or dsdd 2 40 Aprox200K floppy1) The tpdd2 will read tpdd2 and tpdd disks but write only tpdd2 disks. Thetpdd will only read/write it's own disks.2) Tandy used to repair these drives but no longer... so don't ask! Acquiremultiple units as backups.3) Neither drives disks may be read by any MS-DOS or Apple computers. Manyexcellent engineers have tried and failed. There is software available toallow a Cambridge Z88 to access a tpdd2.

author: BravoV
author_rank: Super Contributor
timestamp: April 19, 2013, 11:39:05 pm
content: Maybe this kind of tool would help ?http://www.kryoflux.com/

author: marmad
author_rank: Super Contributor
timestamp: April 20, 2013, 12:49:06 am
content: Quote from: BravoV on April 19, 2013, 11:39:05 pmThanks for the input - although I think it's rather overkill for just 2 disks - plus no guarantee to work since it seems people have been trying unsuccessfully for +20 years to read these disks with other drives.

author: darkstar614
author_rank: Newbie
timestamp: June 27, 2014, 11:50:26 pm
content: Quote from: marmad on April 20, 2013, 12:49:06 amI have one, would be happy to try to read them and convert them to an image for you!

author: marmad
author_rank: Super Contributor
timestamp: June 28, 2014, 12:03:23 am
content: Quote from: darkstar614 on June 27, 2014, 11:50:26 pmThanks very much for the offer - but I had it done by the company RetroFloppy - run by an extremely pleasant and helpful guy. Inexpensive, too!
Software for TTI1604 RS232? - Page 1
Forum section: electronics / projects

author: uslrs
author_rank: Contributor
timestamp: March 30, 2019, 12:25:21 pm
content: Does anyone know a source of the PC1604 software TTI produced for interpreting the RS232 output from the 1604 multimeter? I've got the info for the 10 character string and have captured the data using Realterm comms prog but extracting/translating the measured values seems a bit of nightmareAny thoughts would be appreciated.

author: JagV12
author_rank: Contributor
timestamp: March 30, 2019, 02:08:37 pm
content: Funny !!!This DMM doesn't actually send measured values but digit segments ! Writing a scripts for your terminal is probably not the best way here. But any programming language capable of bits manipulation will do. Which one is your favorite ? C ? Python ? Basic ?I've been playing with PureBasic these days and find it nice and easy...

author: uslrs
author_rank: Contributor
timestamp: March 30, 2019, 02:45:13 pm
content: Quote from: JagV12 on March 30, 2019, 02:08:37 pmThanks JagV12. I guess the approach would have to be to capture the RS232 output in a text file and put a prog together to convert to numeric values, but not sure it's worth the bother to achieve a basic data logger. I guess it may be possible to use an Arduino to do it in real time (like WaveyDipole's AR488 project for GPIB) - maybe one for a dark winter night (or two).

author: JagV12
author_rank: Contributor
timestamp: March 30, 2019, 02:59:53 pm
content: I don't know about Python but C and Basic can open the serial port, get the data stream and display it real time and log it as well. A microcontroller interface is possible but not necessary at all... It mainly depends on what you're comfortable with.

author: JagV12
author_rank: Contributor
timestamp: March 30, 2019, 04:21:12 pm
content: In case you want to try it with PureBasic, here is a link to learn more :http://forums.purebasic.com/english/viewtopic.php?f=13&t=51383The third (and last) version of infratec's program reads the serial port using "ReadSerialPortData(Com, @Buffer$, 14)" and logs the result in a file. It's the right place to insert your own code and manipulate the received bits to display meaningful data

author: 1NFR4R3D
author_rank: Newbie
timestamp: November 24, 2023, 03:23:28 pm
content: Hi uslrs!Did you get any code written for the meter? I need to use it soon, and would like to not start from scratch!