Specifications

Smart Battery Charger Specification
SBS Implementers Forum -Page 1- Revision 1.1
1. Introduction
The Smart Battery Charger Specification presents one element of a complete system solution for
rechargeable batteries used in portable electronic equipment such as laptop computer systems, cellular
telephones and video cameras. Designed for use with batteries compliant with the Smart Battery Data
Specification (refer to the References section), the electrical characteristics of the Smart Battery Charger
feature charging characteristics that are controlled by the battery itself, in contrast to a charger with fixed
charging characteristics that will work with only one cell type. The Smart Battery/Smart Battery Charger
combination provides distinct advantages in system safety, performance and cost. First, charging
characteristics and safety limits are integral to the battery itself, allowing for chemistry independence and
ideal charging algorithms that match the specific cell types. Each Smart Battery defines the safe charging
scheme that is best suited to its chemistry and capacity, maximizing the usable energy at each charge,
reducing the charge time and maximizing the number of charge cycles. Second, the cost and complexity of
the system is reduced as the charger need only provide the charging voltage and current specified by the
Smart Battery, without duplicating the measurement and control electronics already present in the Smart
Battery.
This specification, as depicted below, defines the data that flows across the SMBus between the Smart
Battery and Smart Battery Charger. A more detailed description of the electrical interface, data protocols
and other devices can be found in the supplementary documentation (refer to the References section).
Smart
SMBus Interface
System Host
Smart
Other SMB
Devices
Battery
Charger
Battery
The Major Components of the SMBus Interface:
Electrical: Refer to the System Management Bus Specification for more information
Protocol: Refer to the System Management Bus Specification for more information
Data: Described in this specification and the Smart Battery Data Specification.
This specification defines the data set that is used to communicate with the Smart Battery Charger. It is not
designed to limit innovation amongst battery or charger manufacturers, but rather provide a consistent set
of information to communicate with any particular Smart Battery Charger.
1.1. Scope
This document specifies the data set that is communicated to or from a Smart Battery Charger. The
electrical specifications are covered by other specifications (refer to the References section). This
specification is generic with regard to the type of battery chemistry, the battery pack voltage, the battery
pack capacity and the battery pack's physical packaging.
1.2. Audience
The audience for this document includes:
• Smart Battery Charger manufacturers
• Smart Battery manufacturers
• Readers of the System Management Bus Specification
• Designers of device drivers for Smart Batteries
• Designers of power management systems for portable electronic equipment powered by Smart
Batteries