When did this stuff get so compact!? - Page 1
Forum section: electronics / projects

author: RoG
author_rank: Newbie
timestamp: January 01, 2022, 05:20:54 pm
content: I have been away from electronics tinkering for awhile (about 7 years). We built our on RV, toured the USA, built a barn in the mountains, built a house.Recently, getting a little back into some projects I needed a portable 5V DC source with a hefty current. I decided to use a Milwaukee 18V battery (because we have a ton of them from the house build)Went back to trusty old Digikey and found a wide range input, 5V at 24A output DC-DC module that seemed to be of decent quality and had an exposed heatsink plate.OMG is this thing small. How? It works perfectly, high efficiency. I swear they were not this compact a decade ago when I was using Vicor bricks.This particular one is a IRE-5/24-Q12PF-C from Murata Power Solutions Inc.https://www.digikey.com/en/products/detail/IRE-5%2f24-Q12PF-C/811-IRE-5%2f24-Q12PF-C-ND/11503753?utm_medium=email&utm_source=oce&utm_campaign=4251_OCE21RT&utm_content=productdetail_US&utm_cid=2372367&so=73238608&mkt_tok=MDI4LVNYSy01MDcAAAGBP8ab8msd9H9iIaKC97yFV6D8nheGovZ8DxAWF4tYqiHS82yOTmdHh3yYlAimulnH7uhdkJtbhBWpWl1UECupRl1RbYztFfwIe-CBrdzxI feel like I have been in a time machine and skipped forward. Don't get me started on blue lasers....it looks like 1 watt lasers now come in cereal boxes as a prize.

author: Bud
author_rank: Super Contributor
timestamp: January 01, 2022, 06:22:45 pm
content: Conversion frequency got higher, the higher the frequency the smaller the magnetics (transformers) can be.

author: Simon
author_rank: Unknown
timestamp: January 01, 2022, 06:32:05 pm
content: Mosfet's have only gotten better and with booming power electronics industries driving things these days. The losses of Mosfet's in a SMPS are about how fast it can be turned on and off, now that these will witch faster the frequency can increase. There are plenty of single chip controllers with low and high side switch built in that will run at 1MHz with extremes of 2MHz in some good ones.

author: coppercone2
author_rank: Super Contributor
timestamp: January 01, 2022, 08:28:47 pm
content: You can look through the timeline on the product catalog of major transistor manufacturers. They have generation plots of the different transistors (and IGBT). Usually available in a few different substrates too.

author: Terry Bites
author_rank: Super Contributor
timestamp: January 02, 2022, 05:14:59 pm
content: Yes Herr van winkle!

author: Siwastaja
author_rank: Super Contributor
timestamp: January 02, 2022, 05:25:18 pm
content: Higher switching frequency -> smaller L, but also smaller C.Also controller chips that are stable to zero ESR -> MLCC-only solutions.Packaging: you are not forced anymore to buy massive amount of plastic, holding the tiny die inside. Minimized packages are nearly the size of the die.Small packaging allows small stray inductance, again enabling faster edges and finally, high switching frequency. So the miniaturization has a positive feedback; making things tiny allows making them even tinier.For extreme miniaturization, there are GaN MOSFETs allowing even higher f_sw, but the things you are looking at don't even need those, it's possible with traditional Si MOSFETs. This means, there is even more room for improvement ahead.This was all possible 7 years ago (i.e., there is no significant breakthrough during that time), but what was "bleeding edge" back then, is everyday stuff now.

author: amyk
author_rank: Super Contributor
timestamp: January 02, 2022, 10:26:33 pm
content: The components are also run closer to their limits, as a form of cost-optimisation.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 03, 2022, 02:11:49 am
content: I think it might help to understand what allows these higher switching frequencies and faster switching times:https://www.powerelectronicsnews.com/gan-transistor-for-several-power-applications/

author: coppercone2
author_rank: Super Contributor
timestamp: January 03, 2022, 04:43:16 am
content: Quote from: amyk on January 02, 2022, 10:26:33 pmthats true... don't think modernization is the same as rebounding systems to tweak reliability

author: cdev
author_rank: Super Contributor
timestamp: January 03, 2022, 09:44:47 pm
content: Quote from: amyk on January 02, 2022, 10:26:33 pmAm I correct in that the importance of adequate or even over-heat sinking has increased substantially? Your heatsinks can't be too big. But they can easily be too small.

author: Simon
author_rank: Unknown
timestamp: January 03, 2022, 09:52:51 pm
content: i think it may be more of a case that things that handle the power are smaller and if you go by older standards you are surprised at the size of the heatsink unless you appreciate the power dissipated.

author: coppercone2
author_rank: Super Contributor
timestamp: January 03, 2022, 11:30:55 pm
content: Quote from: cdev on January 03, 2022, 09:44:47 pmwell when you have more thermal mass the system is more tolerant to problems usually.

author: Siwastaja
author_rank: Super Contributor
timestamp: January 04, 2022, 10:12:59 am
content: Designers have had to increase efficiency as well. Not only due to energy saving goals, but because making the thing smaller means less surface area to dissipate the heat. You can't increase temperature much beyond what the old designs already had, so you need to increase efficiency.It happens, heatsinking is alsoexpensive. So wasting power makes no sense. Many older designs were inefficient for no good reason, just laziness. Now fairly trivial ideas like synchronous rectification are mainstream. Increase in integration level means that adding complexity does not add cost. It's all contained within a tiny IC which is sold in hundreds of millions.Capacitor loss has also gone down thanks to near-zero ESR types being used.

author: Simon
author_rank: Unknown
timestamp: January 04, 2022, 01:15:56 pm
content: heat dissipation is one of those snowballing things. Take a mosfet, usually you get a channel resistance stated for a die temperature of 25C, this is of course ballocks! so you go find the graph of channel resistance temperature dependence. At the maximum temperature the die can withstand, usually 150-175C you will note that the channel resistance is 150-200% what was stated for 25C. So if you try to put more power through you get more heating not only due to the power increase but also due to the new hotter temperature, so it's not a linear function of power handled to heat dissipated.Happily an exponential law while being terrible on the up is great on the down. If you give the mosfet just a bit more heatsinking then not only have you improved the overall thermal performance but now the heat generated will not be as much anyway as the channel resistance is lower at the same power level.