Micro Project : voltage stabilizer (step-up converter) for Mouse (micro size) - Page 1
Forum section: electronics / projects

author: max-bit
author_rank: Frequent Contributor
timestamp: October 25, 2015, 08:42:06 pm
content: Boost converter (step up) voltage stabilizer for MouseIssue:Power mouse with two rechargeable NiMH batteriesThe mouse stops working at a voltage 1,1-1,2V (2,2-2,4V))Purpose:Minimum voltage - 0,75 per cell (input voltage 1,5V to 3,3V)Output voltage - 3VSupply current up to 30mA5.5-?A Quiescent CurrentLow Cost ~5$Small size PCB 10mm x 15mmLow profile - height max 5mmUsed IC TLV61220Schematic:BoardAnd ...:

author: mariush
author_rank: Super Contributor
timestamp: October 25, 2015, 11:06:38 pm
content: May I suggest a Skyworks AAT1217 with adjustable output voltage that can be as low as 2.5v? Link :http://www.digikey.com/product-detail/en/AAT1217ICA-1.2-T1/863-1495-1-ND/4246169Or if you want to skip two resistors but lose some efficiency, maybe go with the fixed output of 3.3v :http://www.digikey.com/product-detail/en/AAT1217ICA-3.3-T1/863-1496-1-ND/4246188(your mouse will take it considering two AA alkaline batteries will be about 1.6x2 = 3.2v when new)It needs a higher voltage to start (0.85v) but it will continue to work with as low as 0.5v and unless I read the efficiency curves in the datasheets incorrectly, it should be more efficient. It's also cheaper at about $0.5 compared to $1.15 for the TLV61220 .. Oh, and it's also very thin (small height).. which should work well for your design.Pay attention to inductor and capacitor choice, that's a big deal for efficiency.

author: ralphd
author_rank: Frequent Contributor
timestamp: October 25, 2015, 11:42:51 pm
content: Or just use the 50c USB boost converter modules and change the resistors to get the converter to output 3V3 instead of 5V.

author: ovnr
author_rank: Frequent Contributor
timestamp: October 26, 2015, 02:02:34 am
content: An important thing to note for this kind of thing is the quiescent active current of the converter, as it has to stay on all day long. The TLV61220 is spec'd at 500µA typical, same as the AAT1217 that mariush mentioned.That results in the batteries being drained in around half a year even if it just sits in a box; this is generally acceptable. But a cheapo eBay converter willnotbe so kind.As it happens I did the same thing, but flipped it around and used a buck converter and Li-Ion batteries (higher energy density). I also threw in a supervisor IC that drops the output voltage when the batteries are close to empty, so the low battery indicator turns on in time to swap them out, as opposed to just suddenly dying.

author: Fungus
author_rank: Super Contributor
timestamp: October 26, 2015, 03:39:11 am
content: Quote from: ovnr on October 26, 2015, 02:02:34 amThe cheapo eBay converters I've measured had a standby current of about 60uA - far better than the ones you've mentioned.(They go into "standby" when there's less than 1mA of load on the output)

author: mariush
author_rank: Super Contributor
timestamp: October 26, 2015, 03:51:12 am
content: Those ebay converters often don't work with less than 3-4 volts, which would make them unsuitable for what he wants to do: boosting 2 rechargeable batteries ( 2 x 1.0-1.35v) to >2.4v60uA is a lot for "idle quiescent current", because I think that's what you refer to. The ICs mentioned above are typically in he 5-20uA range... 60uA is a lot for idle.

author: max-bit
author_rank: Frequent Contributor
timestamp: October 26, 2015, 08:30:31 am
content: The type IC, limit my purchase to Farnell (In the EU, does not pay to buy the digikey)For now, run the prototype in this IC (TLV), and to see how will be working .... efficiency, currents, etc ..

author: max-bit
author_rank: Frequent Contributor
timestamp: October 31, 2015, 05:21:31 pm
content: and finish :- batteries (rechargeable) were connected in parallel

author: Kalvin
author_rank: Super Contributor
timestamp: October 31, 2015, 06:20:20 pm
content: Silicon labs TS3310 has only 150nA no-load supply current, pin-selectable output voltage from 1.8V to 5V, input voltage range from 0.9V to 3.6V, and it is good up to 30mA load current.http://www.digikey.fi/product-detail/en/TS3310ITD1022T/336-3025-1-ND/4844019It may be a bit of pain to solder, as it is available only in 10-Pin, Low-Profile, 2mm x 2mm TDFN Package.

author: max-bit
author_rank: Frequent Contributor
timestamp: November 01, 2015, 07:08:25 am
content: 35mA very low current and with such low current, the mouse may not start

author: Kalvin
author_rank: Super Contributor
timestamp: November 01, 2015, 11:58:29 am
content: Quote from: max-bit on November 01, 2015, 07:08:25 amIf I understood the datasheet correctly, the output capacitor can be chosen such that it will be able to provide the needed energy during peak current.