Guide To Designing Low Power Handhelds

randomErr writes "iAppliance had a nifty article about designing handhelds. As the state-of-the-art in low-power CPUs races forward, the CPU becomes one of the most critical components in the design of a handheld. New CPUs such as Intel's XScale, Alchemy Semiconductor's Au1000, and Transmeta's Crusoe provide the ability to scale clock frequency and voltage dynamically. As power consumption varies linearly with clock speed and as the square of core voltage, you'll want to have hardware hooks to be able to adjust both clock speed and voltage as necessary, based on device performance."

Comments

Alchemy Semiconductor

[Neon Spiral Injector]

Just to point out to anyone who doesn't know, AMD aquired Alchemy Semiconductor.

Re:Rechargable packs

[Dr. Ion]

There are some good reasons why devices still use alkaline batteries instead of rechargable:

- It's cheaper. Making the user buy AAA cells is cheaper than an expensive built-in rechargable. Be angry if you want, but the same shoppers that gripe are the ones that will pick the AAA model because it's $10 cheaper. :)

- Charger required. more $$$, bigger packaging, more travelling weight, country-specific voltage, UL Listing, the works.

- Alkalines last longer (per charge) than rechargables. On a device may go weeks without seeing a charger, this counts.

- Rechargable cells die. What do you do with a PalmV that no longer charges well? LiIon cells only last a year or two before they start to degrade quickly.

I'm not saying that these are valid reasons to require disposable batteries, but these are factors that manufacturers look at in deciding which way to go.