DS2777 MAXIM [Maxim Integrated Products], DS2777 Datasheet - Page 11

• Manufacturer Part Number: DS2777
• Description: 2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with Protector and Optional SHA-1 Authentication
• Manufacturer: MAXIM [Maxim Integrated Products]

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.
Protector and Optional SHA-1 Authentication
PMOD = 0
PMOD = 0
PMOD = 1
PMOD = 1
UVEN = 0
UVEN = 1
UVEN = 0
UVEN = 1
ACTIVE
ACTIVE
ACTIVE
ACTIVE
2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
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 and the OV
flag in the Protection register is set. The DC output
remains high during overvoltage to allow discharging.
When (V
charge-enable threshold, V
turn the charge FET on by driving CC high. The
DS2775–DS2778 drive CC high before [(V
and (V
sists with V
V
SS
)] < V
IN1
PMOD = 0
PMOD = 0
PMOD = 1
PMOD = 1
UVEN = 0
UVEN = 1
UVEN = 0
UVEN = 1
ACTIVE
ACTIVE
ACTIVE
ACTIVE
IN2
OV
- V
SNS
.
- V
SS
≥ 1.2mV and [(V
IN1
)] < 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
) and (V
PULL SDA AND SCL LOW
PULL SDA AND SCL LOW
CHARGER DETECT
V
CHARGER DETECT
CHARGER DETECT
V
CHARGER DETECT
CE
IN1
IN1
PULL PIO LOW
PULL PIO LOW
FOR t
FOR t
OR V
OR V
if a discharge condition per-
SLEEP
SLEEP
IN2
IN2
IN1
CE
IN2
< V
< V
UV
UV
, the DS2775–DS2778
OVD
- V
IN2
- V
Overvoltage (OV)
SS
IN1
, the CC pin is dri-
- V
) falls below the
OV
) or (V
IN1
PSPIO = 0
PSPIO = 0
PSPIO = 1
PSPIO = 1
PSDQ = X
PSDQ = X
PSDQ = X
PSDQ = X
, for a period
SLEEP
SLEEP
SLEEP
SLEEP
) and (V
IN2
IN1
- V
- V
IN1
IN1
SS
11
)
)
-