Market share of linear vs. switching chargers in phones and tablets - Page 1
Forum section: electronics / general

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 25, 2013, 06:18:24 am
content: A few years ago, Kelly Wu designed a USB host enabled microcontroller board. (It was based on a PIC24FJ64GB002 plus some regulator circuits, so it's really more of a breakout board.) It never got popular enough to make it to mass production (originally intended for some USB datalogger application), but it did have a very interesting feature: the 5V USB supply could be margined from about 4.5V to 5.3V by turning a trimpot. The theory was that when using a USB Flash drive that ran all its internals from a LDO (nearly all of them nowadays), reducing the voltage would theoretically save a little power, or the voltage could be boosted to compensate for long cables.I have managed to build a DIY clone of the Kelly Wu and got it connected to various Android devices, which got me thinking: what's the rough percentage of devices that use switching chargers as opposed to linear chargers nowadays? In that case, a somewhat lower voltage would work great for keeping linear chargers cooler, but would slow down charging on a switching charger. Am I correct that almost every Android device made nowadays uses a switching charger?

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: February 25, 2013, 06:31:56 am
content: Quote from: NiHaoMike on February 25, 2013, 06:18:24 amThe last time I saw a device which still came with a linear wall wart was maybe 6 years ago. Everything else, no matter how cheap, is switch-mode these days.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 25, 2013, 02:53:16 pm
content: I'm talking about the actual charger chip inside the device, not the wall wart.

author: free_electron
author_rank: Super Contributor
timestamp: February 25, 2013, 03:22:48 pm
content: Inside the device? 100%. Nobody uses linear chargers.

author: SeanB
author_rank: Super Contributor
timestamp: February 25, 2013, 03:52:49 pm
content: I would guess anything other than the simplest non feature phone ( it makes calls and might do text but nothing more) would use a switching supply, simply to get the charge time down. Especially any phone that charges via USB will be using a switching supply, as they have limits on current draw and voltage on the port.

author: Sionyn
author_rank: Frequent Contributor
timestamp: February 25, 2013, 04:02:10 pm
content: only seen switching

author: Unknown
author_rank: Unknown
timestamp: February 26, 2013, 08:35:56 pm
content: SMPSU are nasty little Buggers... wide QRM spectrum noise, and short lived too; the worst idea ever created for AM radio or short-wave reception.

author: tom66
author_rank: Super Contributor
timestamp: February 27, 2013, 01:27:07 am
content: I'm guessing OP means the IC that actually charges the li-po/li-ion, the vast majority below 0.5A charge current are typically linear, above that are switching mostly. I would guess e.g. in a smartphone real estate would be limited so they would use a switcher (probably on the main power management IC too), but a tablet would not be as critical space wise so may use a linear IC.

author: BravoV
author_rank: Super Contributor
timestamp: February 27, 2013, 02:15:43 am
content: Quote from: NiHaoMike on February 25, 2013, 06:18:24 am99.999999 % switcherQuote from: NiHaoMike on February 25, 2013, 06:18:24 amYesQuote from: NiHaoMike on February 25, 2013, 06:18:24 amWow .. can you really do that nowdays at home ? Really-really curious what is your plan to do with her while she is connected, running some certain fun apps ?... j/k (sorry, just couldn't help it)

author: FenderBender
author_rank: Super Contributor
timestamp: February 27, 2013, 02:50:46 am
content: I just bought a pair of Altec Lansing speakers and it had a linear wall wart. Thank goodness! I don't need any cheap and crappy smps residue on the output!