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APPLICATION NOTE A V A I L A B L E
3 or 4 Cell Li-Ion BATTERY PACKS
Preliminary Information Preliminary
X3100/X3101
FEATURE • Software Selectable Protection Levels and Variable Protect Detection/Release Times • Integrated FET Drive Circuitry • Cell Voltage and Current Monitoring • 0.5% Accurate Voltage Regulator • Integrated 4kbit EEPROM • Flexible Power Management with 1µA Sleep Mode • Cell Balancing Control BENEFIT
4 cell / 3 cell
3 or 4 Cell Li-Ion Battery Protection and Monitor IC
• Optimize protection for chosen cells to allow maximum use of pack capacity. • Reduce component count and cost • Simplify implementation of gas gauge • Accurate voltage and current measurements • Record battery history to optimize gas gauge, track pack failures and monitor system use • Reduce power to extend battery life • Increase battery capacity and improve cycle life battery life Using an internal analog multiplexer, the X3100 or X3101 allow battery parameters such as cell voltage and current (using a sense resistor) to be monitored externally by a separate microcontroller with A/D converter. Software on this microcontroller implements gas gauge and cell balancing functionality in software. The X3100 and X3101 contain a current sense amplifier. Selectable gains of 10, 25, 80 and 160 allow an external 10 bit A/D converter to achieve better resolution than a more expensive 14 bit converter. An internal 4kbit EEPROM memory featuring IDLock™, allows the designer to partition and “lock in” written battery cell/pack data. The X3100 and X3101 are each housed in a 28 Pin TSSOP package.
DESCRIPTION The X3100 is a protection and monitor IC for use in battery packs consisting of 4 series Lithium-Ion battery cells. The X3101 is designed to work in 3 cell applications. Both devices provide internal overcharge, over-discharge, and over-current protection circuitry, internal EEPROM memory, an internal voltage regulator, and internal drive circuitry for external FET devices that control cell charge, discharge, and cell voltage balancing. Over-charge, over-discharge, and over-current thresholds reside in an internal EEPROM memory register and are selected independently via software using a 3MHz SPI serial interface. Detection and timeout delays can also be individually varied using external capacitors. FUNCTIONAL DIAGRAM
VCC
RGP RGC RGO
UVP/OCP
OVP/LMON AS0 AS1 AS2 AO
VCELL1 CB1 VCELL2 CB2 VCELL3 CB3 VCELL4/VSS CB4 Over-charge Over-discharge Protection Sense Circuits Protection Sample Rate Timer
5VDC Regulator Internal Voltage Regulator Power On reset & Status Register
FET Control Circuitry
Analog MUX
4 kbit EEPROM Over-current Protection & Current Sense Protection Circuit Timing Control & Configuration OVT UVT OCT Configuration Register Control Register
S0
SPI I/F
SCK CS SI
VSS
VCS1 VCS2
REV 1.1.8 12/10/02
www.xicor.com
Characteristics subject to change without notice.
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X3100/X3101 – Preliminary Information
PRINCIPLES OF OPERATION The X3100 and X310.