Portable Computer Power Management Design

What type of battery is used for portable power design?

The popular single-cell Lithium-Ion (Li-Ion) battery carries a nominal 3.6V, with an actual range of 2.7V to a fully-charged 4.2V. Other battery types that are used for portable power design include Lithium Polymer (Li-Pol), Lithium-Manganese Dioxide (Li-MnO2) coin-cell batteries, and Nickel-Metal Hydride (Ni-MH) batteries.

Why is advanced power consumption management important?

With the demand for converged voice, data, web-browsing and audio/video playback functions, the challenge in advanced power consumption management has become critical. Figure 1 shows an evolutionary path of the increasing number of functions and the battery life expectancies.

How do embedded processors save power?

Thus the power savings are solely performed by the embedded processor’s firmware code. While applications processors have been the panacea for SoC solutions, the low-power design consideration rating is now measured in milliwatts per Megahertz (mW/MHz) performance.

How can A PMIC support dynamic voltage scaling?

To support dynamic voltage scaling, the PMIC will need an additional programmable output power supply that ranges from 0.85V to 1.55V for powering the core voltage. The programmable range will have a resolution step-size value of 50 mV to 100 mV (see Figure 2).

What is a power saving mode?

Power-saving modes were usually pre-programmed within the processor and included doze mode, burst mode, and sleep mode. For a PDA profile, the system can process user-requested tasks (such as touch-screen input) and then implement a standby mode for the next touch-screen input.

What is the power dissipation of a processor?

Usually a processor has a power dissipation that is propor-tional to the square of the core voltage input voltage as defined by the following equation: f = frequency.