DS2760

6

POWER MODES

The DS2760 has two power modes: Active and Sleep. While in Active Mode, the DS2760 continually

measures current, voltage and temperature to provide data to the host system and to support current

accumulation and Li+ safety monitoring. In Sleep Mode, the DS2760 ceases these activities. The

DS2760 enters Sleep Mode when any of the following conditions occurs:

§ the PMOD bit in the Status Register has been set to 1 and the DQ line is low for longer than

2 seconds (pack disconnection)

§ the pack is disabled through the issuance of a SWAP command (SWEN bit =1)

The DS2760 returns to Active Mode when any of the following occurs:

§ the PMOD bit has been set to 1 and the SWEN bit is set to 0 and the DQ line is pulled high

(pack connection)

§ the voltage on PLS becomes greater than the voltage on VIN (charger connection) with the SWEN bit

set to 0

§ the pack is enabled through the issuance of a SWAP command (SWEN bit =1)

The DS2760 defaults to Sleep Mode when power is first applied.

LI+ PROTECTION CIRCUITRY

During Active Mode, the DS2760 constantly monitors cell voltage and current to protect the battery from

overcharge (overvoltage), overdischarge (undervoltage) and excessive charge and discharge currents

(overcurrent, short circuit). Conditions and DS2760 responses are described in the sections below and

summarized in Table 2 and Figure 3.

LI+ PROTECTION CONDITIONS AND DS2760 RESPONSES Table 2

Activation

Condition

Name

Threshold

Delay

Response

Release

Threshold

Overvoltage

Undervoltage

Sleep Mode

(1)

(charger connected)

Overcurrent, Charge

(2)

(3)

Overcurrent, Discharge

(2)

(4)

Short Circuit

(4)

references current delivered from pin SNS.

(2) for the internal sense resistor configuration, the overcurrent thresholds are expressed in terms of