DS2761

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POWER MODES

The DS2761 has two power modes: active and sleep. While in active mode, the DS2761 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 DS2761 ceases these activities. The DS2761

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

2s (pack disconnection)

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

The DS2761 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)

set to 0

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

The DS2761 defaults to sleep mode when power is first applied.

Li+ PROTECTION CIRCUITRY

During active mode, the DS2761 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 DS2761 responses are described in the sections below and

summarized in Table 2 and Figure 3.

Table 2. Li+ PROTECTION CONDITIONS AND DS2761 RESPONSES

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)

delivered from pin SNS.