* Posts by adamj

3 posts • joined 17 Jul 2008

Toshiba readies zero Watt standby mode telly

adamj
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It's always helpful to use some real numbers to see what difference it makes. For a typical scenario where the TV is on for 2 hours per day, and on standby for 22 hours per day, an 'on' consumption of 150W and a standby consumption of 1W, the TV energy will be 300Wh (on) plus 22Wh (standby). This means that the standby energy is 22/322 = 6.8% of the total. That is statistically significant and makes the effort to improve the design worthwhile.

It should also be noted that the standby circuits of set-top boxes, VCR (if you still have one) and hard drive recorder/DVD are often worse than 1W and their standby energy will be a bigger proportion of their overall energy consumption.

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adamj
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You're all missing the point...

...which is that it is actually very hard to design practical low power (microwatt) 50/60 Hz mains ac power converters. There are inherent losses in the rectification, smoothing, and switch mode (voltage change) circuits. At microwatt levels, the losses can very easily exceed the power actually needed by the downstream electronics by 10, 100 or 1000 times. Practical power converters in consumer electronics rarely consume less than 0.3W, the best ones about 0.1W.

The Toshiba innovation is very important. I suspect it will win awards. Parasitic mains power load is all over the place. It is bad in domestic environments but even worse in commercial environments. It is in desk phones, mobile phone charges, network switches, emergency lighting chargers, environmental controls and commercial light fittings (ie with addressable DALI or DSI controls). Everywhere you look there is parasitic load burning 24 hours/day, even when the equipment is not being used or the premises are unoccupied. Most of them are not using the most efficient power converters and will burn ~1W per device. It doesn't sound very much per device, but it adds up. For example, a commercial office building with 2000 lights switched off will be using more power (on that one system) than a house with its lights, PC, refrigerator and TV switched on.

The reason why this is not an issue in automotive electronics is that the system is driven by a low voltage DC source. There is no power converter leaking energy, just the functional electronics of the device itself.

The saving, which in % terms is significant, is that Toshiba have put in a capacitor which captures energy when the appliance is running, and can provide the micropower very efficiently for the relatively large number of hours when it is in standby. So the standby losses go away (not the IR sensor circuit load, which is not the issue). If this is replicated in other consumer electronics and commercial equipment there will be substantial environmental and resource saving benefits.

In conclusion, it's an essential next step.

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Acer Aspire One: the new sub-laptop to beat?

adamj
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available today

Like many people I've been hanging back waiting for an eee901 but I noticed the Aspire One has appeared on display in my local branch of PC World (Tunbridge Wells). The guy on the counter confirmed that they had 8 of them in stock (blue linux 8Gb).

The sample on display looked really quite good. The only snag is they've priced it at £249, which seems to be an uplift on the RRP for the base model.

They also had a plainer-looking own brand Advent machine with 80Gb hard drive for £279 (winXP).

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