DS2778 Maxim Integrated Products, DS2778 Datasheet - Page 12

• Manufacturer Part Number: DS2778
• Description: 2-Cell Stand-Alone Li+ Fuel-Gauge IC
• Manufacturer: Maxim Integrated Products

2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
Protector and Optional SHA-1 Authentication
Figure 1. Sleep-Mode State Diagram for DS2775/DS2776
During active mode, the DS2775–DS2778 constantly
monitor SNS, V
from overvoltage (overcharge), undervoltage (overdis-
charge), and excessive charge and discharge currents
(overcurrent, short circuit). Table 1 summarizes the
conditions that activate the protection circuit, the
response of the DS2775–DS2778, and the thresholds
that release the DS2775–DS2778 from a protection
state. Figure 3 shows Li+ protection circuitry example
waveforms.
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PMOD = 0
PMOD = 0
PMOD = 1
PMOD = 1
UVEN = 0
UVEN = 1
UVEN = 0
UVEN = 1
ACTIVE
ACTIVE
ACTIVE
ACTIVE
IN1
, V
Li+ Protection Circuitry
PULL DQ LOW FOR t
PULL DQ LOW FOR t
IN2
RISING EDGE ON DQ
RISING EDGE ON DQ
CHARGER DETECT
V
CHARGER DETECT
CHARGER DETECT
V
CHARGER DETECT
IN1
IN1
PULL PIO LOW
PULL PIO LOW
PULL DQ LOW
PULL DQ LOW
, and PLS to protect the battery
OR V
OR V
IN2
IN2
< V
< V
UV
UV
SLEEP
SLEEP
PSPIO = 0
PSPIO = 0
PSPIO = 1
PSPIO = 1
PSDQ = 0
PSDQ = 1
PSDQ = 0
PSDQ = 1
SLEEP
SLEEP
SLEEP
SLEEP
Figure 2. Sleep-Mode State Diagram for DS2777/DS2778
If either of the voltages on (V
exceeds the overvoltage threshold, V
longer than overvoltage delay, t
ven low to shut off the external charge FET. The DC out-
put remains high during overvoltage to allow
discharging. When (V
below the charge-enable threshold, V
DS2775–DS2778 turn the charge FET on by driving CC
high. The DS2775–DS2778 drive CC high before
[(V
condition persists with V
and (V
IN2
IN1
- V
PMOD = 0
PMOD = 0
PMOD = 1
PMOD = 1
UVEN = 0
UVEN = 1
UVEN = 0
UVEN = 1
ACTIVE
ACTIVE
ACTIVE
ACTIVE
IN1
- V
SS
) and (V
)] < V
RISING EDGE ON SDA OR SCL
RISING EDGE ON SDA OR SCL
RISING EDGE ON SDA OR SCL
RISING EDGE ON SDA OR SCL
PULL SDA AND SCL LOW
PULL SDA AND SCL LOW
OV
IN1
CHARGER DETECT
V
CHARGER DETECT
CHARGER DETECT
V
CHARGER DETECT
IN2
IN1
IN1
PULL PIO LOW
PULL PIO LOW
.
SNS
FOR t
FOR t
OR V
OR V
- V
- V
SLEEP
SLEEP
IN2
IN2
SS
≥ 1.2mV and [(V
IN1
IN2
< V
< V
)] < V
UV
UV
) and (V
OVD
- V
Overvoltage (OV)
IN1
, the CC pin is dri-
CE
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OV
) or (V
IN1
if a discharge
PSPIO = 0
PSPIO = 0
PSPIO = 1
PSPIO = 1
PSDQ = X
PSDQ = X
PSDQ = X
PSDQ = X
, for a period
SLEEP
SLEEP
SLEEP
SLEEP
- V
IN2
IN1
CE
SS
- V
- V
, the
) falls
IN1
SS
)
)