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Newly published on March 20, 2001!  Check out our new Smart Battery Data Accuracy Testing Guidelines

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Errata to Smart Battery Data Set Specification

An errata to the Smart Battery Data Specification is being issued to correct recently discovered inconsistencies between the 1.0 and 1.1 specification SpecificationInfo() Revision and Version nibble definitions. As presently defined, systems implementing the 1.1 specification may not be able to correctly identify batteries built to the 1.0 specification. Download the full errata here, Smart Battery Data Set Specification Errata, Version 1.1a.

Summary of the errata:
1. SpecificationInfo() has had the Revision and Version nibbles combined into a SpecID byte. The values for 1.0, 1.1 without PEC support and 1.1with PEC support are clearly listed:
* V1.0 SBData SpecInfo() = 0x0010
* V1.1 SBData, no PEC SpecInfo()=0x0021
* V1.1 SBData, with PEC SpecInfo()=0x0031

2. A minor change has been made to substitute the word "re-learn" for "condition". There has been some confusion about the meaning of "condition."

5.1.4, 5.1.13, 5.1.21, 5.1.25, 5.4.1

Smart Battery Charger

 

The Smart Battery Charger Specification, Revision 1.10, incorporates input from SBS developers to clarify the original specification and adapt it to the current industry practices in SBS system design.

 

Global changes to the document were made to update the thermistor pin to its new name of safety signal, and to rename the Battery Controlled and Host Controlled charger types to Level 2 and Level 3, respectively. All figures were updated as necessary. Definitions for Programmatic Maximum and PEC were added tot he Definitions section. The References section was updated to refer to the latest SBS and other industry specifications.

All

The definitions for Level 2 and Level 3 charger types were re-written and a table was added to illustrate their differences. A Level 2 charger is a slave device which is controlled by the Safety Signal, ChargingCurrent(), ChargingVoltage() and AlarmWarning() data from the battery. All other chargers are Level 3. A Level 3 charger must poll for ChargingCurrent(), ChargingVoltage() and AlarmWarning() data from the battery at least every minute. It is suggested that this polling not occur more frequently than every 5s. Level 2 chargers operate in a default mode that assumes the Smart Battery?fs current and voltage scale factors are unity. Only Level 3 chargers may use non-default scaling factor values.

4.2, 4.3, 5.2

The accuracy definitions for ChargingCurrent() and ChargingVoltage() have been changed to meet the safety requirements of all battery chemistries. They also promote charging to a higher capacity for chemistries which use constant voltage charging. ChargingCurrent() must be " of the programmatic maximum current or better." ChargingVoltage() must be "+1%/-9% of the programmatic maximum voltage or better."

5.1.1, 5.1.2,  5.2.1,   5.2.2

No changes were made to the ChargerMode() bits, however this function is defined to be expressly write-only and can not be relied on to return meaningful data if read.

5.1.4

In ChargerStatus(), MASTER_MODE bit was renamed POLLING_ENABLED to communicate its function more clearly, and the VOLTAGE_NOTREG and CURRENT_NOTREG bits are specifically designated as optional as originally intended in the V0.95 specification. Bits indicating the thermistor range were renamed (THERM_OR to RES_OR, THERM_COLD to RES_COLD, THERM_HOT to RES_HOT, THERM_UR to RES_UR). The descriptions of nearly all bits were improved, without changing the original definitions.

5.1.5

ChargerSpecInfo() includes two new values for the CHARGER_SPEC nibble. 0010 signifies support for SBC 1.1 without PEC and 0011 signifies support for SBC 1.1 with PEC. A master device that wants to use the PEC protocols will check CHARGER_SPEC to determine if the PEC protocols can be used with the charger. All unused bits in ChargerSpecInfo() must return a zero value when read.

5.1.6

The Safety Signal ranges have been defined to include guard-banding to allow for less than perfect detection of the ranges. The new ranges for the safety signal in ohms are as follows: under-range (less than 575), Hot (425 to 3150), Normal (2850 to 31.5k), Cold (28.5k to 105k), over-range (95k or greater). The specification also explicitly allows the use of discrete resistance values to control charging and therefore, the 103AT thermistor curve in Appendix F was deleted.

6.1.1, Appx. F

Some miscellaneous changes are: the wake-up charge description now allows an option for host to set lower time-out than nominal period as added safety, a recommended max leakage current of 100uA is specified to prevent a charger from overcharging a pack when ChargingCurrent() = 0, and the condition of RES_OR = 1 was added to state 15 of the transition table in Sec 6.1.8. A note that SMB Alert and AlertResponse protocol defined in the System Management Bus Specification are available as interrupt mechanism was added to Sec 6.1.10.

6.1.8, 6.1.10

A section describing non-DC charger output was added to Appendix D to caution the system designer to consider the impact of charger output ripple on the battery. The specification specifically allows pulse charging if all system components are compatible with the particular pulse method, and it is safe.

Appx. D

This Appendix has been augmented to explain two methods of accurate charging, one by using the battery's measurements and the other by using a charger with a more precise output than intended in original SBS specifications. Examples of required charger accuracy for lithium-ion pack configurations are given.

Appx. E

Smart Battery Data

 

Many items throughout the specification were given more description and examples. Some areas include error checking, data retries, and data update rates. Where appropriate, tables were added to help in the clarification.

All

BatteryMode():
A new control bit was added to the BatteryMode() register. This allows the disabling of the AlarmWarning() broadcasts for up to 60 seconds at a time. The bit must be re-written to continue to suppress the alarm broadcasts.

5.1.4

CycleCount():
Instead of a defined value of 15% as in the V1.0 spec, the new CycleCount() value is incremented when the accumulated discharge capacity equals the value in DesignCapacity(). This then creates an "odometer" value when CycleCount() is multiplied by DesignCapacity(). The resulting value gives a estimate of the total capacity a battery pack has delivered, regardless of the depth of discharge or charge.

5.1.22

SMBus Protocols:
The SMBus revision 1.1 contains numerous updates. For one, an error checking byte was added as an optional feature in the data stream of some protocols. Since these protocols are detailed in the SMBus Specification, the diagrams were removed from the SBData Specification.

6.1, 6.2, 6.3

Smart Battery Selector

 

The Smart Battery Selector Specification, Revision 1.10, incorporates the changes of the wording that was accepted in the rest of the SBS specification. There was no impact to the implementation from this change.

The attempt to incorporate the simultaneous charging and discharging are now incorporated into the new Smart Battery Manager Specification 1.00, so this selector specification does not handle simultaneous charging and discharging functions.

All

Global change to the document was made to update the thermistor pin to its new name of safety signal. All figures were updated as necessary.

All

 

SelectorInfo() includes two new values for the SELECTOR_REVISION nibble. 0010b  signifies support for Smart Battery Selector 1.1 without packet error checking (PEC)  and 0011b signifies support for Smart Battery Selector 1.1 with PEC. A master device that wants to use the PEC protocols will check SELECTOR_REVISION to determine if the PEC protocols can be used with the selector.

5.3

Link to the System Management Bus

 

The System Management Bus (SMBus) Specifications, Bus and BIOS, have been moved to the SMBus Specs Page at:   http://www.smbus.org/specs/

 

 

Current, Released Specifications

Posted

Smart Battery Charger Specification, version 1.1
Click here to email your questions.

15-Dec-98

Smart Battery Data Specification, version 1.1
Click here to email your questions.

15-Dec-98

Smart Battery Selector Specification, version 1.1
Click here to email your questions.

15-Dec-98

Smart Battery System Manager Specification, version 1.0 (Release B): This specification describes an interface to a multiple battery system that is capable of charging or discharging multiple batteries simultaneously or in sequence. Release B changed the revision shown on the title page to version 1.0. Click here to email questions.

If you wish to access the originally posted specification, click on this link: Smart Battery System Manager Specification, version 1.0 (Release A).

9-Aug-99
15-Dec-98

The System Management Bus (SMBus) Specifications, bus and BIOS, have been moved to the SMBus Specs Page at:   http://www.smbus.org/specs/

 

 

SBS-IF Released Guildlines

Posted

The following document is a newly released set of guidelines for thoroughly testing smart batteries. Smart Battery Data Accuracy Testing Guideline, version 2.0

20-Mar-01

Smart Battery Data Accuracy Testing Guideline, version 1.0

15-Dec-98

 

Past, Released Specification Revision 1.0

Posted

Smart Battery Data Specification (SBD) Rev. 1.0 Release A: Defines the data set that is communicated by a smart battery. This specification is generic with regard to the type of battery chemistry, the battery pack voltage, the battery pack capacity as well as the battery pack's physical packaging.

15-Feb-95

Smart Battery Charger Specification (SBC) Rev. 1.0: defines the data that flows across the System Management Bus between the Smart Battery and Smart Battery Charger. It also categorizes the various types of charger implementations in relation to SBS batteries

27-Jun-96

Smart Battery Selector Specification Rev 1.0: is an adjunct to the Smart Battery Data Specification, providing a solution for the implementation of multiple-battery systems. This document specifies the data set used by a Smart Battery Selector and the minimal functionality that such a device must provide. The actual electrical and mechanical specifications will be covered by a battery selector component's manufacturer. This specification is generic with regard to the actual implementation.

5-Sep-96

 

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