LED boost driver in DIP package - Page 1
Forum section: electronics / projects

author: PeterFW
author_rank: Frequent Contributor
timestamp: June 22, 2016, 12:42:09 am
content: Hello!My google search was not that successful, so i ask here in hopes such device may be still exist.I had a silly idea for a small project that would require a LED boost driver that is available in a DIP package to run 4-8 white LEDs (~3V@100mA per LED) of a lithium cell.Why DIP? I want to spare me some work milling out a regular package and epoxy an smd device in there, to have an authentic working circuit like this:Picture:http://3.bp.blogspot.com/-1kZFCTevyxA/UQJuhvCqlaI/AAAAAAAACLQ/kfOgjQfbsk8/s1600/IMG_3393+(Large).JPGWebsite:http://runawaybrainz.blogspot.com/2012/04/audio-crystal-cmoy-freeform-headphone.htmlWhy? I got to use the left over resin i have for something, this came to mind.Greetings,Peter

author: mariush
author_rank: Super Contributor
timestamp: June 22, 2016, 02:18:10 am
content: 100mA per LED is a lot of current, are you sure the LED will stay cool inside all that resin?4-8 LEDs at 100mA each is 400-800mA .. again, that's a lot of power.See TLC5917 , seems like a good chip :http://uk.farnell.com/texas-instruments/tlc5917in/ic-led-driver-linear-16-dip/dp/1755252You'll have to program it somehow, so maybe also add a 6-8 pin micro just to initialize the chip through SPI and turn on the channels?

author: PeterFW
author_rank: Frequent Contributor
timestamp: June 22, 2016, 02:35:50 am
content: Quote from: mariush on June 22, 2016, 02:18:10 amI have played with LEDs a bit, i think it should work out:https://www.eevblog.com/forum/projects/solution-for-single-color-tubular-led-display/msg859222/The 100mA is just for short periods, most likely it will run on much, much less.The whole thing will have a micro in there as well, the micro got a ADC and i planed to use that to measure the resin temp near the LEDs as a fail safe.QuoteThanks, i was thinking more of a switched single channel driver with an efficiency around 85% and put all of them in series.So about 12V to 24V at 100mA for a series sting.Found many suitable drivers, but all SMD, i will just use one of them if there is no DIP but i wanted to at least try to use real DIP packagesGreetings,Peter

author: georges80
author_rank: Frequent Contributor
timestamp: June 22, 2016, 05:13:07 am
content: Simple answer is that no modern IC's are going to be available in DIP - no demand since pretty well everything has moved to surface mount.So, other than antiquated chips you're essentially out of luck.Even 4 series LEDs are going to be around 4 x 3V = 12V and at 100mA you have 1.2W at the output. I presume you mean lithium ion cell and not a coin lithium cell...cheers,george.

author: chris_leyson
author_rank: Super Contributor
timestamp: June 22, 2016, 06:55:22 am
content: I think you're going to out of luck finding LED drivers in DIP packages. Maybe a SOIC to DIP adaptor would work but finding one with an addition thermal pad and with a small DIP sized footprint isn't easy.

author: PeterFW
author_rank: Frequent Contributor
timestamp: June 22, 2016, 07:35:15 am
content: Quote from: georges80 on June 22, 2016, 05:13:07 amIndeed, i allways get the right term mixed up since english does not translate well in my head sometimesQuote from: chris_leyson on June 22, 2016, 06:55:22 amI will just bodge some small package in there, can not be much more difficult then a SSOP dead bug.

author: dannyf
author_rank: Super Contributor
timestamp: June 22, 2016, 10:55:46 am
content: There are some thin film sip orr dip dcdc converters - some Japanese companies make them.Putting that so close to audio circuits isn't a great idea in my view.

author: ebclr
author_rank: Super Contributor
timestamp: June 22, 2016, 12:24:20 pm
content: Do the DIP yourselfhttp://pt.aliexpress.com/item/SMD-switch-DIP-switch-DIP-SO8-SOP8-adapter-plate-SOP-turn-DIP8-adapter-plate-with-pin/1965589032.html?spm=2114.02010208.8.76.6tbmQg

author: Fungus
author_rank: Super Contributor
timestamp: June 22, 2016, 01:15:27 pm
content: Quote from: PeterFW on June 22, 2016, 02:35:50 amI just had a thought: You could maybe useAN6884. Each chip will sink about 85mA by tying all the pins together and they're easy to switch/PWM from a micro.The disadvantage is that you need one chip per LED, but... hey: They're SIP packages so you can pack them tightly, arrange them artfully... whatever.

author: Galenbo
author_rank: Super Contributor
timestamp: June 22, 2016, 01:46:39 pm
content: I use ULN2803A to drive 8 relays, up to 500mA, DIPhttp://www.ti.com/lit/ds/symlink/uln2803a.pdf

author: ebclr
author_rank: Super Contributor
timestamp: June 22, 2016, 01:58:45 pm
content: What about the old guy 555http://pt.aliexpress.com/item/Free-Shipping-20pcs-10-each-NE555-IC-555-8-Pin-DIP-Sockets/655593597.html?spm=2114.02010208.3.2.gKmEl4&ws_ab_test=searchweb201556_8,searchweb201602_4_10037_10017_10033_10032_10040,searchweb201603_10&btsid=55cdd2bd-8e44-416a-a7e5-a6c913dec9c0

author: PeterFW
author_rank: Frequent Contributor
timestamp: June 22, 2016, 02:40:30 pm
content: Quote from: ebclr on June 22, 2016, 12:24:20 pmBut that does not look like a DIP package, im searching for dip because of the look, not because i can not solder it.Wiring a MSOP with enameled wire or etching a PCB is totally within my comfort zone and capabilitiesQuote from: ebclr on June 22, 2016, 01:58:45 pmQuote from: AcHmed99 on June 22, 2016, 12:19:41 pmOh... i had not thought of this. Thank you very much, that is spot on!Saves me additional components and looks cool, exactly what i was aiming for.Will have to do some further reading on that!