About PowerWise® Interface (PWI)

Today’s portable electronic devices such as mobile phones, handheld gaming consoles and portable media players offer a host of new benefits for consumers.  However these benefits place a significant strain on the power budget.  Designers now face the dilemma of having to reduce the power consumption of digital processors while simultaneously maximizing battery life.

This dilemma demands a radical rethinking of power management, and a comprehensive approach to developing new systems.  IC and system designers are now turning to advanced power management techniques to minimize power consumption of digital processors in portable electronic devices.  These techniques are being used to dynamically reduce power consumption based on the application software workload and environmental conditions. Dynamic capability, however, requires highly adaptive and capable control elements and interconnects. PWI enables the rapid deployment of advanced power management solutions by providing an open, industry-wide standard for the interconnect between digital processors and power management ICs. Adoption of the standard across multiple regulator vendors and semiconductor manufacturers will ensure wide interoperability-a move that will generate the most energy-efficient solutions for handheld electronic devices to date.

PWI facilitates adoption of advanced power management techniques that can be used to monitor performance and control various processor voltages such as supply voltages, threshold voltages, etc.  The PWI Specification defines a communication interface between a processor and one or more external power management integrated circuits(PMIC).  PWI does not include OS interfaces for performance monitoring and control. 

The Specification

The PowerWise Interface specification defines a 2-wire serial interface connecting the integrated power controller of an SoC (System on Chip) processor system with a PMIC (Power Management Integrated Circuit) voltage regulation system that allows system designers to dynamically adjust the supply and threshold voltages on digital processors. The PWI specification defines the required functionality in the PWI-slave; the operating states, the physical interface, the register set, the command-set, and the data communication protocol for messaging between the PWI-master and the PWI-slave.  The PWI command set includes PMIC operating state control, register read, register write, and voltage adjust commands. The specification additionally provides provision for user defined registers in the PWI-slave.

An Open Standard

PWI has received significant contributions from key mobile phone, semiconductor processor and power management IC vendors and is the first open standard interface for system power management. This open standard will accelerate the adoption and deployment of advanced power management solutions. It will play a significant role in simplifying the design process for power management IC vendors because with standardization less time and effort will be wasted pursuing incompatible or conflicting paths. PWI will allow OEMs to re-use power management ICs in multiple designs, further accelerating the design cycle and overall time to market. More importantly, the adoption of PWI will allow consumers to take full advantage of all the applications and features on next-generation mobile devices. These devices will have an extended battery life while simultaneously maximizing user experience.

The PWI specification is available immediately for adoption on a royalty-free and license-free basis. Companies interested in adopting the specification can do so by submitting an adopter's agreement.