Datasheet

4 SAFETY STATE OVERVIEW
UVLO Mode
Shutdown Mode
Power Supply to PACK
Internal V
REG2
> 2.4 V Internal V
REG2
< 2.3 V
Power Supply to PACK
NoPowerSupply
CHG: OFF
DSG: OFF
VREG1: OFF
VREG2: OFF
XRST:LOW
I C: Disabled
UVProtection:Disabled
OV Protection: Disabled
Current Protection: Disabled
Thermal Protection: Disabled
2
CHG: OFF
DSG: OFF
VREG1: OFF
VREG2: OFF
XRST:LOW
I C: Disabled
Current Protection: Disabled
VCELL: Disabled
Watchdog: Disabled
Thermal Protection: Disabled
2
NoSupplytoPACK
AttachaCharger
CHG: OFF
DSG: OFF
VREG1: ON
VREG2: ON
XRST:HIGH
I C:Enabled
UVProtection:Enabled
OV Protection: Enabled
Current Protection: Disabled
Thermal Protection: Enabled
2
CHG: ON
DSG: OFF
VREG1: ON
VREG2: ON
XRST:HIGH
I C:Enabled
UVProtection:Disabled
OV Protection: Enabled
Current Protection:Enabled
Thermal Protection: Enabled
2
CHG: ON
DSG: ON
VREG1: ON
VREG2: ON
XRST:HIGH
I C:Enabled
UVProtection:Enabled
OV Protection: Enabled
Current Protection:Enabled
Thermal Protection: Enabled
2
CurrentProtection Mode
DischargeSide
CHG: OFF
DSG: OFF
VREG1: ON
VREG2: ON
XRST:HIGH
I C:Enabled
UVProtection:Enabled
OV Protection: Enabled
Current Protection:Enabled
Thermal Protection: Disabled
2
Overtemperature
Protection Mode
CHG: OFF
DSG: ON
VREG1: ON
VREG2: ON
XRST:HIGH
I C:Enabled
UVProtection:Enabled
OV Protection: Disabled
Current Protection:Enabled
Thermal Protection: Enabled
2
Overvoltage
Protection Mode
Undervoltage
Protection Mode
Normal Mode
V >V orV fora
periodoft ort
SR OC SC
OC SC
V <V
cell UV
V >V
cell OV
AllCell Voltage> V + V
(or V – V >0.4Vand All
CellVoltage> V )
UV UV
pack bat
UV
Δ
AllCell Voltage< V – V
OV OV
Δ
V <0.975V
IN
B0326-01
V >1.075V
IN
bq77PL900
www.ti.com ...................................................................................................................................................... SLUS844B – JUNE 2008 – REVISED JANUARY 2009
Figure 3. Stand-Alone Mode
Table 1. Stand-Alone STATUS Bit, XALERT and FET Transition Summary
MODE TRANSITION STATUS BIT XALERT FET ACTIVITY
Normal to current protection SCD or OCD = H to L DSG and CHG off
1
Current protection to normal SCD or OCD = L to H DSG and CHG on
0
Normal to overvoltage protection OVP = 1 H to L CHG off
Overvoltage protection to normal OVP = 0 L to H CHG on
Normal to undervoltage protection (when VPACK goes down to 0 V, move to UVP = 1 H to L DSG off
shutdown mode)
Undervoltage protection to normal UVP = 0 L to H DSG on
Normal to overtemperature OVT = 1 H to L DSG and CHG off
Overtemperature to normal OVT = 0 L to H DSG and CHG on
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