The Battery Interface Working Group released the Battery Interface v1.0 specification in February, 2012. The specification is the first to address key consumer and manufacturers’ issues with safety, performance and technology. Additionally, the Battery Interface (BIF) Hardware Abstraction Layer v.1.0 was released in May 2013. This document defines a software interface that eases the adoption of BIF on common host platforms.
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Download the data sheet and whitepaper below for more information on the Battery Interface specification.
The Battery Interface (BIF) Specification has been defined to offer a cost-efficient and flexible communication interface solution between a mobile device Host and Battery Packs. The fundamental requirement for a battery interface is to provide a method to communicate battery characteristics information to ensure safe and efficient charging control under all operating conditions. The interface supports two battery types: an analog, low-cost battery interface that supports detection of battery chemistry and capacity for basic safety, and a digital smart battery interface with security features that can offer stronger protection against the use of counterfeit batteries and many functions for increased safety for mobile device end users. The BIF Hardware Abstraction Layer (HAL) Specification has been defined to compliment the BIF specification and describes the standard software interface on top of the BIF Master protocol and physical layer.
The smart battery interface supports multiple Slave devices within the Battery Packs or mobile device Host. The Specification defines the digital communication interface physical layer electrical requirements and characteristics, protocol and basic data architecture information for a mobile device Host and the Slaves in the Battery Pack with sufficient detail to allow development of the interface.
For Low Cost Battery Packs, in which only a pull-down resistor provides information about the Battery Pack, BIF specifies measurement range and accuracy. The specific measured resistor value assignment for capacity, chemistry etc. is left to the mobile device manufacturers. However, the range and accuracy are defined to comply with most of the low cost batteries already in the market.
A fast battery prescence and removal detection system is specified for both smart and low cost batteries. Any mechanical dimensions and properties like physical connector or battery form factors are outside the scope of this document.
Being the first complete battery communication interface standard for mobile devices, BIF simplifies both the Host and Battery Pack design while reducing development costs throughout the mobile battery ecosystem as a result of enabling use of a single interface over a wide range of mobile device products.
Battery chemistries are constantly evolving and present new challenges to charge control, battery life time prediction and other similar requirements. The BIF is designed to allow future expansibility and room for new innovative functions and services for product differentiation while coexisting smoothly with other standards in the mobile battery technology area.
Every effort has been made to enable a low cost solution in a Smart Battery Pack and mobile device Host design without compromising compatibility or design choices and service content in the Slave ICs.
Battery Interface Smart battery pack and low cost battery pack diagrams
Standard Functions and Data Objects, along with the BIF HAL have been defined to support a standard BIF client driver for BIF Slave control on the host platform as well as a BIF Master high level software to control BIF Master devices from different suppliers. A possible BIF software stack implementation is shown below.