High side switch question - Page 1
Forum section: electronics / beginners

author: neo
author_rank: Super Contributor
timestamp: April 08, 2017, 02:54:57 am
content: I have a 6 volt signal i need to make a 12 volt signal, my solution was to buy ir6226 high side switch.http://www.irf.com/product-info/datasheets/data/ir6226.pdfI have pin one grounded pin 2 connected to my signal and 12 volts going to the vcc pin. All is fine and well one paper but my output voltage is 3 volts. The signal is the carry out of a 4017 decade counter. Any advice to make this work or any other methods to step up the voltage would be greatly appreciated.

author: BrianHG
author_rank: Super Contributor
timestamp: April 08, 2017, 03:06:20 am
content: Are you saying you only have 6v and you need to generate 12v + convert the 6v IO into 12v as well?Or, do you have a 12v supply with 6v logic IO you wish to convert to a 12v IO?Or, is this just a power switch? Like a Relay...How much power do you need on the 12v output?Does the 12v output go from 0v to 12v, or, 6v to 12v?How fast does this conversion need to be?

author: neo
author_rank: Super Contributor
timestamp: April 08, 2017, 03:20:38 am
content: I have 12 volts in and need the logic level to be at that for the rest of the circuit. A relay would work fine except i would need to replace it every year or two since this would trigger a relay twice a minute, once when the carry goes low and again when it resets. 12>6v regulator>arduino>4026>4017>rest of circuit and any point after that has to be 12 volts. Its for a digital clock circuit which i have functioning, the second half needs to be at 12 volts for the display and the carry out is too low for it. I would also like to use what i have on hand if possible which eliminates optocouplers, comparators and mosfets unless i buy them.

author: BrianHG
author_rank: Super Contributor
timestamp: April 08, 2017, 03:32:06 am
content: Quote from: neo on April 08, 2017, 03:20:38 amWhat do you have on hand?Once again, how much current do you need at 12v? Something like a NPN 2N3904 and PNP 2N3906 and a 4k7 and a 10k resistor may work for you...

author: neo
author_rank: Super Contributor
timestamp: April 08, 2017, 04:07:43 am
content: A few MA of current, enough to clock the next chip its not doing anything other than that. Crude schematic but its what i could do. Also, i would like a semi conductor solution but if i decide to use a relay would this be a good one,http://www.ebay.com/itm/RadioShack-2750232-SPST-1AMP-5V-Reed-Relay-Switch-PL1-9501-275-0232-NIB-/351993880726?hash=item51f4786096:g:kUMAAOSwfVpYtdz3

author: neo
author_rank: Super Contributor
timestamp: April 08, 2017, 04:10:47 am
content: BrianHGBasic logic chips and whatever i can find on old circuit boards, i should be able to find working pnp and npn transistors for example. I also have a couple MTP3055E N-channel mosfets

author: neo
author_rank: Super Contributor
timestamp: April 08, 2017, 04:15:27 am
content: the 4017 carry is high for 40 seconds low for 20 then high again repeating that cycle over and over again.

author: neo
author_rank: Super Contributor
timestamp: April 08, 2017, 04:22:58 am
content: A thought occurs to me, i can get a solid state relay on ebay fairly cheap and as far as i know solid state relays should last indefinitely.

author: neo
author_rank: Super Contributor
timestamp: April 08, 2017, 04:35:43 am
content: evb149(g) i checked wiring to it already(f) have yet to try that but will(e) it is i checked both with my oscilloscope and a fluke DMM(d) when i checked it there was no load(c) i don't even know how to use dg pin(b) why both?(a) see (d)it should also be noted im learning and would rather have overkill that is simple than a sensible circuit that is not as simple.

author: digsys
author_rank: Unknown
timestamp: April 08, 2017, 04:37:49 am
content: Quote from: neoQuote from: evb1492 million .. PPFFTT :-) I've been using these for 20yrs -https://www.onlinecomponents.com/datasheet/mss21a12.aspx?p=405124092+ Billion operations at up to 300Hz. Mine run at 5Hz, 24/7, up to 500VAC peak (carrying 2mV data), 100mA. I replace them every 3-5 yrs.For your rate, that's about 200,000yrs :-)

author: neo
author_rank: Super Contributor
timestamp: April 08, 2017, 04:44:14 am
content: digsysThank you, although i cannot find any at a reasonable price, because i can't find any sold by the piece. If you could point me to where to find one it would be perfect

author: digsys
author_rank: Unknown
timestamp: April 08, 2017, 04:58:00 am
content: Quote from: neoI have a few 100 "used" ones, some with only 50M, and up to 250M cycles left :-) I'm happy to send you a few (or 100 :-) ) free-of-charge with 1 provision. As these contain mercury,they have to be disposed of as hazardous waste, when done. I've been waiting until I get an even 500 or so, before I do, as it costs a bit.Just PM me your mailing address, if interested.Edit:Quote from: evb149Yeah, as these are 12V, you'll need a simple NPN transistor to drive them.

author: neo
author_rank: Super Contributor
timestamp: April 08, 2017, 05:11:40 am
content: The thing with mercury and lead is that they may be potentially bad there just isn't a good substitute.

author: digsys
author_rank: Unknown
timestamp: April 08, 2017, 05:21:40 am
content: Quote from: neoYup, absolutely NO substitute at all !! Switching frequency, NO arcing or bounce, uV to 100s V signals, a dream switch. Note: They MUST be orientated correctly !

author: neo
author_rank: Super Contributor
timestamp: April 08, 2017, 05:44:38 am
content: Quote from: digsys on April 08, 2017, 05:21:40 amHow should they be oriented?

author: digsys
author_rank: Unknown
timestamp: April 08, 2017, 10:17:44 am
content: Quote from: neoVertical, Pin#1 to the top. Mercury must cover the contacts. Check the specs. It will still work horizontal but you won't get the full 2-5B operations.On 1 site, I calculate 25B clicks (at 10Hz), 24/7, 5-8yrs

author: neo
author_rank: Super Contributor
timestamp: April 08, 2017, 11:12:45 pm
content: Well that is certainly convenient, my entire clock is vertical due to the display.

author: digsys
author_rank: Unknown
timestamp: April 08, 2017, 11:33:46 pm
content: Sample pack of ~12 is ready to post :-) 2x new, 2 types, rest are swap-outs, and should still have ~50+M closures. Just test for dead ones.

author: Zero999
author_rank: Super Contributor
timestamp: April 09, 2017, 12:33:08 am
content: Quote from: evb149 on April 08, 2017, 03:35:47 amIt's better to move the NPN's base resistor to the emitter and add a pull-up on the PNP. It's much faster and has a higher input impedance.

author: SeanB
author_rank: Super Contributor
timestamp: April 09, 2017, 04:49:18 pm
content: Added bonus is that there is no digit ghosting from amplified base current leakage as well, so you can use the Vces voltage instead of the Vceo voltage.

author: neo
author_rank: Super Contributor
timestamp: April 12, 2017, 05:12:28 am
content: This idea is completely irrelevant it doesn't work. I tried it.

author: digsys
author_rank: Unknown
timestamp: April 12, 2017, 05:27:23 am
content: Naaaaa, there's nothing good about that circuit AT ALL ! With the NPN on, you have 4.4V/220R current draw, for no reason. Do either one of the NPN/PNP solutions, or the NPN/Relaysolution. Use ~2K2 to NPN base, and the relay to 12V. That way there is no OFF current. You can put a 100-220R in series with the relay coil to reduce draw even further.

author: neo
author_rank: Super Contributor
timestamp: April 12, 2017, 06:32:06 am
content: I must be terrible at this everything i can get my head around makes little to no sense in practice it seems. Will a tip 137 work for the pnp in the npn pnp solution? I know it is overkill but i got one. Also going into the specifics of the simulator, it says there little current draw current so either falstad is wrong or its missing a law of physics, im not trying to be annoying just trying to understand

author: digsys
author_rank: Unknown
timestamp: April 12, 2017, 06:46:10 am
content: Quote from: neoDon't panic, it gets easier with time and practice. Just about ANY PNP will do. The TIP137 is a darlington, so you'll lose ~1V, which should be perfectly OK.

author: neo
author_rank: Super Contributor
timestamp: April 12, 2017, 07:19:51 am
content: I didn't panic at all the first 3 months, now i panic alot because the more i learn the more confused i get.

author: neo
author_rank: Super Contributor
timestamp: April 22, 2017, 12:25:50 am
content: I tried the pnp high side and found this circuit to work well. Yes, that really is a germanium.

author: Zero999
author_rank: Super Contributor
timestamp: April 22, 2017, 12:29:56 am
content: Quote from: neo on April 22, 2017, 12:25:50 amYes, that should work fine in real life too.The only issue might be speed, with such high value resistors, otherwise it's a good idea.By the way, why did you decide on a germanium transistor? Is it just because it's cool to use old parts?

author: neo
author_rank: Super Contributor
timestamp: April 22, 2017, 02:06:49 am
content: Its germanium because it was handy. Its for a 1 hertz signal, i physically built it and it worked well.

author: brunoital
author_rank: Newbie
timestamp: April 22, 2017, 03:39:37 pm
content: Schematics?

author: Zero999
author_rank: Super Contributor
timestamp: April 22, 2017, 04:18:02 pm
content: Quote from: brunoital on April 22, 2017, 03:39:37 pmPlenty of schematics have been attached to the posts. You'll need to be logged in to the forum to see them. If you are having problems viewing them, check your firewall settings.

author: Zero999
author_rank: Super Contributor
timestamp: April 23, 2017, 06:44:45 pm
content: Here's another option which only uses one NPN transistor.

author: sanwal209
author_rank: Regular Contributor
timestamp: April 23, 2017, 09:17:21 pm
content: Make life simple, There are tons of IC load switch and cost you 44 cents. Try this one outhttps://www.digikey.com/product-detail/en/vishay-siliconix/SI1865DDL-T1-GE3/SI1865DDL-T1-GE3TR-ND/4494407