DS2755: High-Accuracy Battery Fuel Gauge with Snapshot

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DESCRIPTION (CONTINUED)

The DS2755 performs temperature, voltage, and current measurement to a resolution sufficient to support process-

monitoring applications such as battery charge control and remaining capacity estimation. Temperature is

measured using an on-chip sensor, eliminating the need for a separate thermistor. Bidirectional current

measurement supporting current accumulation (coulomb counting) is accomplished using an external current

sense resistor.

The host system can configure the DS2755 to signal critical conditions to reduce polling overhead. The interrupt

fires when programmable upper and lower thresholds of temperature or coulomb count are crossed. The user can

select either the DQ pin or PIO pin as the interrupt signal.

The programmable I/O pin allows the host system to sense and control other electronics in the pack, including

switches, vibration motors, speakers, and LEDs, or the I/O pin can be configured as an interrupt output.

Three types of memory are provided on the DS2755 for battery information storage: EEPROM, lockable EEPROM,

and SRAM. EEPROM memory saves important battery data in true NV memory that is unaffected by severe battery

depletion, accidental shorts, or ESD events. Lockable EEPROM becomes ROM when locked to provide additional

security for unchanging battery data. SRAM provides inexpensive storage for temporary data.

Figure 1. APPLICATION EXAMPLE

5.6V

(1)

2.5V

102

150

1k

104

(1)

(1)

5.6V

103

500

Protection IC

(Li+/Polymer)

1 Cell Li+

150

DS2755

SNS

VDD

VIN

DQ

IS2

PIO

VSS

IS1

5.6V

(1)

PACK+

PIO

DATA

PACK -

SNS

DS2755

IS2

IS1

ADC

Input

(1) Optional component(s) for robust ESD performance