PS3154 Power Smart, PS3154 Datasheet - Page 3

• Manufacturer Part Number: PS3154
• Description: (PS3153 / PS3154) 3 Cell Smart Battery Module
• Manufacturer: Power Smart

PowerSmart PS3150 Module Data Sheet
General Description
The PS3150 module is a SBS V1.1 compliant smart battery controller. The module is designed to operate
in a battery pack consisting of three or four series connected Lithium Ion cells. The module consists of
three major circuit sections - the PowerSmart PS331 SMBus fuel gauge, Mitsumi MM1253/4 based
primary safety circuit and a secondary safety circuit controlled by the PS331 to provide backup to the
MM1253/4.
Functional Description
P3 Fuel Gauge - The module fuel gauge provides State-of-Charge (SOC) and battery status data in
accordance with the SBData and SMBus standards version 1.1. The PS331 monitors the cell voltages,
battery temperature, and current to determine SOC and battery status. The PS331 also provides
remaining_time, terminate_charge, and terminate_discharge alarms when the battery is fully discharged,
fully charged or is under conditions of over-temperature, over-voltage or overdischarge. The State-of-
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Charge calculations are compensated for cell self discharge. The remaining time calculation is
compensated for temperature and discharge rate. An additional correction is made in the SOC for the
estimated integration errors, reported as Max_Error. The parameters for determining battery status flags
and alarm thresholds are all programmable as is the battery design capacity and the battery performance
model data. Please refer to the ‘P3 Users Guide” and the ‘PS331 Technical Data Sheet’ for details on
programming the P3 serial EEPROM data (programmable EEPROM data is capitalized in this text for
clarity).
Primary Safety -The primary safety circuit provides cell protection from conditions of overcharge,
overdischarge and overcurrent. The analog IC MM1253/4 from Mitsumi measures individual cell voltages
and voltage across the discharge FET. These measures are compared against internal reference values
and the gates of two P-channel power MOSFETs are controlled based on the comparison results.
Secondary Safety – The second level of safety protection is activated by Safeout (pin 21) of the PS331. This
pin is activated whenever any individual cell voltage is measured above a programmable limit. An N-
channel MOSFET is turned on and allows current to pass through the resistive heater section of a fuse.
This heating opens the fuse, permanently disabling the pack from further charge or discharge.
Updated 13 September 2001
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Copyright PowerSmart, Inc., 2001