Datasheet

DS2775/DS2776/DS2777/DS2778
2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
Protector and Optional SHA-1 Authentication
______________________________________________________________________________________ 25
Protection, Status, and Control Registers
Protection Register Format
The Protection register reports events detected by the Li+ safety circuit on bits [3:2]. Bits 0 and 1 are used to disable
the charge and discharge FET gate drivers. Bits [3:2] are set by internal hardware only. Bits 2 and 3 are cleared by
hardware only. Bits 0 and 1 are set on power-up and a transition from sleep to active modes. While in active mode,
these bits can be cleared to disable the FET gate drive of either or both FETs. Setting these bits only turns on the
FETs if there are no protection faults.
Protection Register (00h)
Bits 7 to 4: Reserved.
Bit 3: Charge Control Flag (CC). CC indicates the logic state of the CC pin driver. The CC flag is set to indicate CC
high and is cleared to indicate CC low. The CC flag is read-only.
Bit 2: Discharge Control Flag (DC). DC indicates the logic state of the DC pin driver. DC flag is set to indicate DC
high and is cleared to indicate DC low. DC flag is read-only.
Bit 1: Charge-Enable Bit (CE). CE must be set to allow the CC pin to drive the charge FET to the on state. CE acts
as an enable input to the safety circuit. If all safety conditions are met and CE is set, the CC pin drives to V
CP
. If CE
is cleared, the CC pin is driven low to disable the charge FET. The power-up default state of CE is 1.
Bit 0: Discharge-Enable Bit (DE). DE must be set to allow the DC pin to drive the discharge FET to the on state. DE
acts as an enable input to the safety circuit. If all safety conditions are met and DE is set, the DC pin drives to V
CP
. If
DE is cleared, the DC pin is driven low to disable the discharge FET. The power-up default state of DE is 1.
BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
X X X X CC DC CE DE