Detailed Description

The DS2726 provides the protection features for a

5-cell to 10-cell Li+ battery pack. The Li+ protection cir-

cuit allows for pin-configured selection of OV threshold

and the cell-balancing threshold. DOC and SC thresh-

olds and delays are component programmable.

Sleep Mode

Sleep Mode is a low-power state where the FETs are

open and the IC is not monitoring voltages. During

Wake Mode, the IC measures voltages and drives the

FETs to the appropriate state.

Upon initial connection to cells, the DS2726 enters

Sleep Mode. The IC also enters Sleep Mode if a UV

condition is detected. Sleep Mode can be initiated any

time by pulling the SLEEP pin low while a charger-

detect condition does not exist. During Sleep Mode

there is a pulldown current from PKP to GND.

exit wake from Sleep Mode.

tion, the part measures all cells for undervoltage and

overvoltage. Then the IC begins controlling the CC and

DC FETs as shown in Table 1. Care should be taken to

ensure that the SLEEP pin is not held low during a wake

condition.

Charger Detect

The DS2726 has two different methods for detecting a

charger connection. The methods are pin programma-

ble at the CBCFG pin. If CBCFG is pulled to GND, then

when the SLEEP pin is driven to a logic-high state.

Li+ Protection Circuitry

In Active Mode, the DS2726 constantly monitors V00–

V10 to protect the battery from overvoltage and under-

voltage. The voltage on the SNS pin is monitored and

compared to the voltages on RDOC and RSC to protect

against excessive discharge currents (discharge over-

current and short circuit). Table 1 summarizes the con-

ditions that activate the protection circuit, the response

of the DS2726, and the thresholds that release it from a

protection state.

5- to 10-Cell Li+ Protector with Cell Balancing

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9

ACTIVATION

CONDITION*

THRESHOLD

DELAY

RESPONSE

RELEASE THRESHOLD

Overvoltage (OV)

CC Off

Undervoltage (UV)

(Note 15)

CC Off, DC Off,

Sleep Mode

Discharge Overcurrent

(DOC) (Note 15)

DC Off

Short Circuit (SC)

DC Off

Table 1. Li+ Protection Conditions and DS2726 Responses

Note 13:

Note 14:

Note 15:

If a DOC condition persists indefinitely and a UV condition is reached, the IC does not enter Sleep Mode.