DC to DC converter for project - Page 1
Forum section: electronics / general

author: mrcrud5
author_rank: Contributor
timestamp: September 15, 2017, 03:24:44 pm
content: Hi,I have a project I am working on which is powered by a 12 volt battery and I want need some suggestions for a cheap, small, high efficiency regulator to step down the voltage to about 3.3 or 5 volts. I don't want to waste a lot of power from the battery simply stepping down the voltage so I don't want a linear regulator. I will only be powering a micro and couple op amps using this regulator so it doesn't need to be able to source a lot of current. Any suggestions?

author: GreggD
author_rank: Regular Contributor
timestamp: September 15, 2017, 03:45:24 pm
content: https://www.digikey.com/products/en?keywords=LM2594

author: suicidaleggroll
author_rank: Super Contributor
timestamp: September 15, 2017, 04:30:57 pm
content: Do you want to design a board and build your own, or are you looking for an eBay/Amazon purchase of a $2 chinese board to do it off-the-shelf (and may or may not spontaneously explode).

author: Red Squirrel
author_rank: Super Contributor
timestamp: September 15, 2017, 07:11:01 pm
content: I would test with a linear regulator just to see how much current it really uses, for just a micro it might actually be so negligent that it's worth using for simplicity. A SMPS is still going to have a small standby power use so at those currents it might actually end up being the same.

author: thm_w
author_rank: Super Contributor
timestamp: September 15, 2017, 07:45:49 pm
content: Quote from: suicidaleggroll on September 15, 2017, 04:30:57 pmIf you are making a one-off, definitely do this. There are some very good dc-dc boards available for less than you'd be able to purchase the chip.eg:https://www.aliexpress.com/item/5-pcs-Mini-DC-DC-12-24V-to-5V3A-Step-Down-Module-Power-Supply-Module-Converter/32749335208.html~200uA quiescent (MP2315), multiple voltages.For the chip alone is ~$4 on digikey.If its for a large number of units and cost is a factor, look at AOZ1280 or AOZ1284, etc. One downside is 1mA quiescent, so not good for small batteries.

author: nctnico
author_rank: Super Contributor
timestamp: September 15, 2017, 07:57:50 pm
content: Quote from: GreggD on September 15, 2017, 03:45:24 pmThese are very inefficient! It consumes up to 15mA by itself. A low power microcontroller and a linear regulator may be a much better choice. There are linear regulators which use very little current themselves.

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 16, 2017, 02:17:57 am
content: Buck converters with super low quiescent current exist (I'm using some from LT in a project I'm working on), but if it's just a few mA, it would almost certainly make more sense to just use a linear regulator. Another alternative is a charge pump voltage divider.

author: Raj
author_rank: Frequent Contributor
timestamp: September 25, 2017, 06:40:20 pm
content: get a small solar cell to ake up for the losses,poof goes the ineffitiency (unless you don't get enough sunlight or the project doesn't support it.just design your circuit around 12v, or get a buck converter.what's your application?