555 Timer Voltage Inverter

RE: 555 Timer Voltage Inverter

foohoa — Sat, 05 Jan 2019 16:15:52 GMT

U can add in the power transistor to boost up the load handle

My teacher have this concept really long time ago, that time doesn't even have inverter aircond, we test it using light bulb and it save around 30% of current with same bright

And because of the inverter technology didn't implement, so this project just KIV

RE: 555 Timer Voltage Inverter

jw0752 — Thu, 29 Nov 2018 03:03:06 GMT

Hi Frank,

Seems that there is a lot of interest in doing electronics on this forum [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-e9cd9869-97d1-4f54-9edf-6521531c60ef/contentimage_5F00_1.png:16:16]. Thanks for a great post and don't you love the wealth of info in the comments afterwards.

John

RE: 555 Timer Voltage Inverter

shabaz — Wed, 28 Nov 2018 13:02:04 GMT

That's awesome : )

I was just looking a couple of evenings ago for a voltage doubling or tripling circuit for some other project, and had come to the conclusion that I couldn't do it cheaper than a 555, dual-diode SOT-23, and some electrolytics : ) Great to see this blog post.

RE: 555 Timer Voltage Inverter

jc2048 — Wed, 28 Nov 2018 12:45:43 GMT

The datasheet for the original 555 characterises it for 5 to 15V supply and up to 100kHz. It obviously works for you like this - just saying for anyone else who tries it and maybe doesn't get such good results.

I had a go with it in the simulator. TI have a model for the TLC555, which is a CMOS version, but it's painfully slow so I moved to using a voltage generator set to 507kHz and giving a 3.3V square wave out like this

[View:/resized-image/__size/460x182/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-e9cd9869-97d1-4f54-9edf-6521531c60ef/8666.contentimage_5F00_189230.jpg:460:182]

This is the result

[View:/resized-image/__size/620x442/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-e9cd9869-97d1-4f54-9edf-6521531c60ef/3808.contentimage_5F00_189231.jpg:620:442]

That's with a very light load, it doesn't do quite so well if you take 10mA from it. The slightly lower voltage probably comes from me using different diodes (did you use some 1N4001s, or something like that?)

Potential problems with operating it that fast are the turn-off time of the diodes, if you use rectifier diodes, and also that cheap electrolytics might be struggling a bit above 500kHz, though your tants can manage.

If you want to go a bit further with the circuit you could try this following one.

[View:/resized-image/__size/500x278/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-e9cd9869-97d1-4f54-9edf-6521531c60ef/8688.contentimage_5F00_189232.jpg:500:278]

Basically, I've duplicated the arrangement and sat one on top of the other in a nice ladder arrangement (it's a known circuit, I haven't just invented it, though it would more normally be drawn with the left side of C1 connecting to the junction of C3/D1/D2 to make it symmetrical up both sides of the ladder). That results in this

[View:/resized-image/__size/620x442/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-e9cd9869-97d1-4f54-9edf-6521531c60ef/2821.contentimage_5F00_189233.jpg:620:442]

If you wanted to, you could continue in that vein adding additional sections. You can also reverse all the diodes and go off in the other direction (up in voltage rather than down) if you want to [though in practice you'd then take the first diode D2 to the positive rail so that the whole thing sat on top of the supply voltage rather than ground - otherwise all the first stage would be doing is giving you the supply voltage less the diode loss].

Apologies if you already know all this, which you probably do if you've been searching around for info, but it might be useful to someone reading this.

RE: 555 Timer Voltage Inverter

14rhb — Wed, 28 Nov 2018 10:12:29 GMT

Hi Frank,

Great to see the 555 is still getting used to real effect. You've got a good output there and I'd be interested to see how it performs with some loading.

If you design anything using the Texas Instruments devices they have a really useful online tool called Webench and more specifically the Power Designer part of it. You might find that interesting to play around with as well - give it your power supply requirements and it will suggest some circuit designs and BOM based on whether you want the cheapest, highest efficiency or smallest footprint. There have been a few reviews on the Element14 site about this Texas Instruments

Rod