We have all seen optimistic claims for electronic products that fail to match the reality, and [Electronic Wizard] is following one up in a recent video. Can a relatively small IGBT really switch 200 A as claimed by a dubious seller? Off to the datasheet to find out!
The device in question is from Toshiba, and comes in a TO-220 package. This itself makes us pause for a minute, because we suspect the pins on a TO220 would act more like fuses at a steady 200 A.
But in the datasheet, there it is: 200 A. Which would be great, but of course it turns out that this is the instantaneous maximum current for a few microsecond pulse. Even then it’s not finished, because while the continuous current is supposed to he half that, in the datasheet it specifies a junction temperature of 25 °C. The cooling rig required to maintain that with this transistor passing 200 A would we think be a sight to behold, so for all intents and purposes this can’t even switch a continuous 100 A. And the real figure is much less as you’d imagine, but it raises an important point. We blindly read datasheets and trust them, but sometimes we should engage brain before releasing the magic smoke.
Typo. :)
Can that little guy switch as much current as your starter solenoid?… Maybe just once, very very briefly
More than once., and yes very briefly.
This particular IGBT is designed for plasma displays (that´s written in the datasheet)
The 200A value is for pulse switching (also written in the datasheet) and the typical application is “PDP sustain, energy recovery and separation circuits” (yo, the datasheet):
typically a few microseconds pulses at a frequency of dozens of kilohertz. Low, low duty cycle, high current, high voltage: that´s what makes the image quality of a plasma display. Vibrant colors.
Some are better at harvesting clicks than reading a datasheet. And a self-called “scribe” was ready to take the bait without proofing anything.
I’ve replaced a heavy starter solenoid with much lighter MOSFETs (4 in parallel) in a very weight sensitive aerospace application. With a low resistance, in a suitable package (TO-220 is ancient technology), 100+A at relatively low voltage is perfectly feasible.
He doesn’t know how to read a data sheet, or a typical use case for an IGBT.
That was my first thought too. Anyone using an IGBT has in mind a very specific application and will be well aware of the constraints of the device and why things like pulse current are critical figures of merit, not just marketing fluff.
For example, one common use for an IGBT is in a lighting dimmer. Have a look at the peak current requirements of UL 1472. For an 5A typical load current, the dimmer must be able to withstand 500A for 1.4ms. Why? Inrush. Put 30 or 40 LED bulbs in parallel and all that bulk capacitance adds up. The capacitors used for synthetic load testing are pretty darn impressive.
No-one is born knowing how to read a datasheet ya donut, people read this site to learn stuff.
If you already know everything go do something useful don’t hang round in the comments making snide remarks.
Totally true. I think people that belittle others were often a victim of that behaviour growing up.
When one self-name himself “Electronic Wizard”, others expect some serious knowledge, not just an inflated Yt ego talking head.
Let’s not kid ourselves into believing that this title is anything other than click-bait.
The implication that somehow the manufacturer doesn’t know the capabilities of their devices and that the datasheet is somehow “wrong” is a little disingenuous at best, and exceedingly poor writing.
Of course. But making a video screaming “scandal” “lies” when one does not grasp the topic one is talking about is… an excellent way to get some well-deserved negative comments.
Yes people read the site to learn stuff. So when both the video and the article are providing bad information it is great to have commenters give proper information. These comments are what helps keep hackaday great.
Those “snide remarks” are actual knowledge. If you don´t want to learn WHY the video fully misses its point, then don´t read here.
Although you don’t “know” how to read it, there is a difference between the people that think a single variable is enough knowledge to “know” how to use the particular device, and the people that think the other information in the datasheet might be important too.
There is never a single bit of superflous information in a datasheet. The exact opposite of most youtube videos.
In the context of some applications specs like these are relevant and useful. High speed pulsed LED light sources for high speed photography, for example, take 100 amps for a microsecond. The duty cycle is so low the IGBT switch doesn’t even need a heat sink. Heck, the gate driver gets warmer than the output device.
Even more impressive, the IGBTs used in xenon photoflash service. A tiny (3-5mm) DFN device, at Vge(on) = 6V, can handle 100A for some ms, and stand off 450V or so. Risetime a bit under a µs, pulse rep rate f-all. These things are inside every digital camera (or, they were last few I checked, which granted was a long time ago), setting exposure by turning off the xenon tube after it’s ignited. Design of these IGBTs must be just straddling the line between maximum bipolar gain (the conductivity modulation due to injected minority carriers) and latchup; they’re quite peculiar devices, but well suited to their task.
Neither Electronic Wizard nor Jenny List understand what they are talking about. Spec’ing a part like that is a standard way to give the user a baseline (in conjunction with the thermal impedance spec) from which to calculate the usage limits at other current levels and pulse widths. I worked in the semiconductor industry for over thirty years and engineers who know what they’re doing rely on that kind of spec.
You give the extremes and interpolate the middle.
That said, a lot of the industry itself cannot read or understand datasheets – on purpose. See for example LED lamp specs. Lumen output and luminous efficacy are defined at Tj = 25 C, but you can print those numbers right on the box because hey, who’s checking? Here’s our brand new 400 lumen flashlight that magically runs 20 hours on a single AAA battery.
Only 400 lumens? Dude, Aliexpress is full of 20000 lumens flashlight running on a vape’s battery. I’ve seen many 4000 lumens 4K video projectors for $30 also.
That’s normal.
What you get is reputable brands like Varta selling a 4 Watt camping light that runs 24 hours on three C batteries. Nnnnope… that’s 8 amp-hours from 4.5 down to 3 Volts. You do the math.
What they have is a 4 Watt diode regulated down to 1 Watt because that’s what you do so you don’t overheat it, and the alkaline batteries can’t handle the current without fading early, but the datasheet says 4 Watts so that’s what they print on the box.
That’s not how marketing works.
The camping light is 4 Watt. It runs for 24 hours on 3 C batteries.
Those are 2 separate claims.
Nobody is claiming the light will run for 24 hours at 4 Watt with 3 C batteries.
Except it wasn’t. It was never run up that high. Found the brochure again; it was actually D cells (10 Ah) for 20 hours and up to 150 hours dimmed to lowest setting. The average output from the batteries would be about 1.8W at the highest setting, and the bulb power would be around 1-1.5 Watts given the appropriate forward voltage drop.
IF they were running the LED completely unregulated, it might peak at 4 Watts with full batteries, but it would also burn the diode pretty quickly since it’s cased in plastic and only has the PCB for cooling. It also wouldn’t run for 20 hours like that.
So any way you look at it, at least one of the claims has to be false.
man every day i say to myself what a crazy world it is!!
i feel like people who buy these ridiculous flashlights are happy with them but i found myself typing into the search bar “reasonable flashlight that’s not too bright”. and i was successful, and that light lasts for-ev-er on a battery that weighs less than two angel’s farts. the specs on things these days are just absurd
reminds me of my friend who bought a harbor freight battery drill…never charged it, just took it out of the box and used it. whenever he wanted to do anything, just used it. never thought about it until 5 years later he finds the charger when he’s cleaning a closet and decides to charge it for the heck of it. it’s just amazing that when you read the self-discharge specs in a lithium ion battery datasheet, that’s real! that means something!
I’m shocked he managed to get that far without charging it still 6 months maybe a year max I’d have bet. Clearly doesn’t need to make holes in things very often and never in hammer action to get through that solid brick wall. Though I do agree Lithium batteries as a rule have great self-discharge which is really nice (though the BMS in some of these power tool packs will drain usually for some reason only one cell and then lock up if you leave them alone too long).
For power tools, that’s a very typical use scenario. You buy a cheap drill for a job, make a couple holes, then forget it in the cleaning closet for 1-3 years. Usually the battery will die, and the cost of a spare plus shipping is equal to a new drill, so you buy a new one. This is why the lowest end power tools are so bad: they’re essentially made to be single use.
Dude – i agree that seems like a common use pattern but it seems to have ended. that’s my point. that experience of having every nicad battery turn to trash after 5 years is just a memory, a story for people over 30 to reminisce about. obviously for professionals who drag an impact driver into every attic and crawlspace, they’ll want something more. but for casual household use, the cheapest tool is still good years later!
You can trash a lithium battery just as quickly if you leave it sitting in a device with ill designed under-voltage protection. The protection circuit is designed to cut the battery out when it goes under 2.5 Volts, but if the self-discharge continues below 2 Volts it dissolves the electrodes and the battery is done.
Technically, the self-discharge will continue anyways regardless of the protection circuit. It’s just a matter of time. With a badly designed circuit, it’s going to add a few hundred nano-amps to the drain and make it faster.
yeah that’s another aspect that is fantastic – well-designed “battery management systems” are not any more expensive than badly-designed ones and almost everything made in the past decade actually does a pretty good job on leakage! i had a laptop battery go wrong and when i really started digging into it, it was amazing how many features were packed into the tiny pcb that sat between the battery’s 3 cells
I don’t think Jenny misunderstands at all. Based on having read many of her articles here, I’m pretty sure she knows how to read a datasheet properly and how to take into account things like peak current duration.
The key phrase is “blindly read datasheets and trust them”. I would have written “blindly read datasheets and trust our initial interpretation of them without digging deeper”, and I suspect that’s what she had in mind. I think she just expressed herself poorly in this article – maybe because she’s a busy gal with a zillion things on the go at once. For me she has more than enough cred to have earned the benefit of the doubt several times over.
Nah. She called the spec a lie, and that just shows ignorance.
I read it as LGBT data sheet and got confused for a second.
well, not far off: It is a … Gate Bipolar Transistor…
Oh no! Woke terrorists are indoctrinating your kids / invading your house via bipolar trans electronic devices – get rid of your dimmers, TVs and so forth immediately! (/S – just in case)
Demand all electronics do be banned in schools too!
lol – your two comments made my day ;-) (Home & Paul)
resistors with 100% tolerance
There are just two polarities: Plus and minus. When an electron “self-identifies'” as a proton, Maxwell’s equations kind of fall apart.
But when an electron self-identifies as positive and meets another electron, firworks happen.
But there’s an uncountable infinite number of voltage levels between any two potential differences… (wait, is that true or are they quantized & thus countable?)
And electrons are neuter aren’t they? They’re just “minus”/negative.
On the other hand there are so many https://en.wikipedia.org/wiki/Category:Leptons – even positrons…
i just feel like the sentence “We blindly read datasheets and trust them” is a complete non-sequitur
if you’re actually reading the datasheet then you’re not blind, imo. and if you actually trust it, you’re rarely led too far astray. pulse current is just that, pulse current. the heating of the thing is going to be determined by current * voltage drop and i’m pretty confident without even looking at it that the datasheet gives me plenty to come up with a good estimate for that. how much cooling it takes to run so many watts through a TO-220, i don’t know if the datasheet will tell me that but if you’ve ever intentionally run 200A through anything you made yourself, you’ve probably already got a good idea in your mind.
i got messed over by some like ultrabrightleds dot com sort of website that sold me a packet of great LEDs but printed on the bag by the reseller “1.7V 100mA”. i loved how they performed on the workbench but in the wild i didn’t have to wait long for them to fail. i knew there were other faults in my circuit (corrosion) so i didn’t think too much of it but when i was building the version 2.0 light, i decided to try driving them at less current just to see if i could improve the battery life. and i found 20mA was almost as bright as 100mA….and then for version 3.0 it finally occurred to me to hunt down the datasheet, and lo, they’re rated for 20mA! “100mA instantaneous 10% duty cycle.”
if i’d read and ‘blindly’ trusted the datasheet it would’ve saved me a couple iterations. so i’m just countering the article here to say, do read the datasheet! it may be a struggle to properly understand the implications of everything — to automatically apply V=IR and P=VI and say to yourself “oh wow that’s gonna be a lot of heat” — but you’ll be miles ahead of where you were before you looked at the datasheet!
I will be the first to admit I made a similar mistake myself. I was using a 2A rated (continuous) TO-220 package LDO, and figured I had plenty of margin when drawing only 200mA. Except… It was dropping 14V down to 5, so that’s almost 2W of dissipation. The thing got very hot!
Is this the fault of the datasheet? No, it is simply me failing to interpret it correctly. It could draw 2A, given a big enough heatsink… The thermal characteristics were listed right there in the datasheet for me to use. I won’t make that mistake again…
haha i think we all have this experience at some point where we realize why so many people use the phrase “linear regulator” like an epithet
I gave up after 8 minutes – they weren’t looking at the datasheet but the shorform catalogue. And surprise surprise the specs are for switching at high frequencies almost as if the devices were intended for switching supplies and inverters
There’s a term of art called ‘specsmanship’.
Datasheets have three jobs: they’re technical documents that save the manufacturer’s engineers from having to do phone support for people trying to use the part; they’re marketing documents because people choose to buy parts based on the specs; and they’re legal documents because a customer can sue the vendor over parts that don’t live up to the published spec. That means a datasheet is a negotiated agreement among a company’s engineering, marketing, and legal departments.
The result is an exercise in telling the truth the right way.
As an example: the datasheet for a human being would list the Olympic records for sprinting, high jumping, and weight lifting on the front page (the ‘banner specs’) and leave the reader to assume a single human could do all three of those things at the same time. The information published is clearly true, and the part that isn’t true is an assumption that isn’t supported by any claim in the actual text.
That’s why the Electrical Specifications section will always have a list of operating conditions up at the top, and the bottom of the page will be full of footnotes. If you don’t match those conditions, you can’t say the part isn’t doing what the manufacturer said.
A secondary skill when reading datasheets is to look for the things they don’t say. Try reading the datasheet for a DRV2605 motor driver to find how much current it can handle.. the closest you’ll get is a note about load impedance at a certain supply voltage.
Different companies reach different agreements about what will go in the datasheet. Analog, which now owns Linear and Maxim, is heavily engineer driven so their datasheets are heavy on useful information and light on sleight of hand. TI has mastered the art of having each section written by a different team so it’s easy to lose things in the shuffle. Nexperia, or whatever they’re called today, is pretty good. Bosch has a tendency to talk exclusively about their in-house code libraries so you don’t have to worry your pretty little head about things like register maps and settings.
Datasheets are always correct, especially if you replace ee with i.