Toshiba boffins claim battery life boost with SRAM tweaks
Standby power consumption reduction of 85 PER CENT in tests
Japanese electronics giant Toshiba claims to have found a technology solution to the perennial problem of mobile device battery life, offering a reduction in standby power consumption of up to 85 per cent.
Announced at the 2013 International Solid-State Circuit Conference in San Francisco last week, the innovation in embedded static random access memory (SRAM) can reduce active and standby power consumption in conditions ranging from room temp to high temperature, the firm said.
Toshiba explained the following:
Longer battery life requires lower power consumption in both high performance and low performance modes (MP3 decoding, background processing, etc). As low performance applications require only tens of MHz operation, SRAM temperature remains around RT [room temperature], where active and leakage power consumptions are comparable. Given this, the key issue is to reduce active and standby power from HT [high temperature] to RT.
The key to reducing power consumption lies in Toshiba’s use of a bit line power calculator (BLPC) and a digitally controllable retention circuit (DCRC).
The BLPC helps to predict how much power the system will need by using replicated bit lines to monitor the frequency of the ring oscillator, and minimises the active power of SRAM “in certain conditions”, said the firm.
The DCRC, meanwhile, is able to take a big chunk out of standby power consumption by waking up from time to time to update the buffer size of the retention driver.
The techniques have enabled power consumption at 25C to be reduced by 27 per cent (active) and 85 per cent (standby) in prototype tests.
Toshiba said the low-power tech would be perfectly suited for smartphones and other mobile devices, but gave no indication when it would be available commercially. ®
Standby times are pretty good as is, power consumption is on the order of 5mA in standby, including 3g standby. This gives you a standby battery life of over a week.. Improving that to 2 weeks or 4 weeks with same battery sounds fantastic, but...
The issue is that the amount of time our devices spend in standby is very low. There's stuff constantly updating in the background for no good reason, and the controls available to the user is poor.. Every widget and app seems to think they're special, that they can ignore being a good citizen because the user installed it they must have the right and obligation to constantly update their UI, data and what not, even if user hasn't used or looked at it all day..
Even if standby power use could be reduced to 0, we'd still not get more than the day or two of battery life..
Re: yeah, yeah, yeah
"Meanwhile... nothing's changed"
Battery life HAS improved tremendously, BUT phone designers keep using up any gains made on bigger / brighter screens and thinner handsets, and application designers eat up the rest with always-on connections, unneeded use of GPS et etc
As a result we have batteries that could power my old Nokia 3310 for probably around 6 months, but can't power my new HTC for 24 hours
Meanwhile, back in the distant past
I was designing (as it happens, Toshiba) SRAM into battery-powered handheld mobile computers over 30 years ago, and was able to get the standby power consumption of the devices down to a few microamps by doing nothing more than reducing the RAM voltage and turning everything else off. But then, 2KB was a lot of memory back in those days...
how much power the system will need by using replicated bit lines to monitor the frequency of the ring oscillator, and minimises the active power of SRAM
<-- icon is for me.
Reducing the power needed is a better solution than providing more power but want to see this in action.