Rainbow Electronics DS2781 - Manual (Page 5)

DS2781: Two-Cell Standalone Fuel Gauge IC
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Figure 1. Block Diagram
V POR
DQ
1-Wire
Interface
BIAS/VREF Timebase
Temp
&
Voltage
ADC
Current ADC
15 bit + sign
Rate,
Temperature
Compensation
EEPROM
Status
&
Control
Accumulated
Current
EN
SNS VSS
VPLS
OVD
PIO
VIN
Voltage
Regulator
VB
DETAILED DESCRIPTION
The DS2781 operates directly from 2.5V to 10V and supports single or dual cell Lithium-ion battery packs.
Nonvolatile storage is provided for cell compensation and application parameters. Host side development of fuel-
gauging algorithms is eliminated. On-chip algorithms and convenient status reporting of operating conditions
reduce the serial polling required of the host processor.
Additionally, 16 bytes of EEPROM memory are made available for the exclusive use of the host system and/or
pack manufacturer. The additional EEPROM memory can be used to facilitate battery lot and date tracking and
non-volatile storage of system or battery usage statistics.
A Dallas 1-Wire interface provides serial communication at the standard 16kbps or overdrive 140kbps speeds
allows access to data registers, control registers and user memory. A unique, factory programmed 64-bit
registration number (8-bit family code + 48-bit serial number + 8-bit CRC) assures that no two parts are alike and
enables absolute traceability. The Dallas 1-Wire interface on the DS2781 supports multidrop capability so that
multiple slave devices may be addressed with a single pin.