DS2784 Maxim Integrated Products, DS2784 Datasheet - Page 11

• Manufacturer Part Number: DS2784
• Description: 1-Cell Stand-Alone Fuel Gauge IC
• Manufacturer: Maxim Integrated Products

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Summary. All the protection conditions previously described are logic ANDed to affect the CC and DC outputs.
PROTECTION REGISTER FORMAT
The protection register reports events detected by the Li+ safety circuit on bits 2 to 7. Bits 0 and 1 are used to
disable the charge and discharge FET gate drivers. Bits 2 to 7 are set by internal hardware only. Bits 2 and 3 are
cleared by hardware only. Bits 4 to 7 are cleared by writing the register with a 0 in the bit position of interest. Writing
a 1 to bits 4 to 7 has no effect on the register. 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.
OV—Overvoltage Flag. OV is set to indicate that an overvoltage condition has been detected. The voltage on V
has persisted above the V
transition to Sleep mode.
UV—Undervoltage Flag. UV is a read-only mirror of the UVF flag located in the status register. UVF is set to
indicate that V
COC—Charge Overcurrent Flag. COC is set to indicate that an overcurrent condition has occurred during a charge.
The sense-resistor voltage has persisted above the V
cleared by a power-on reset, or transition to Sleep mode.
DOC—Discharge Overcurrent Flag. DOC is set to indicate that an overcurrent condition has occurred during a
discharge. The sense-resistor voltage has persisted above the V
to a 0, cleared by a power-on reset, or transition to Sleep mode.
CC—Charge Control Flag. CC indicates the logic state of the CC pin driver. CC flag is set to indicate CC high. CC
flag is cleared to indicate CC low. CC flag is read only.
DC—Discharge Control Flag. DC indicates the logic state of the DC pin driver. DC flag is set to indicate DC high.
DC flag is cleared to indicate DC low. DC flag is read only.
CE—Charge Enable Bit. 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
cleared, the CC pin is driven low to disable the charge FET.
DE—Discharge Enable Bit. 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
DE is cleared, the DC pin is driven low to disable the charge FET.
CC =
DC =
(Overvoltage) AND (Undervoltage) AND (Overcurrent, Charge Direction)
AND (Protection Register Bit CE)
(Undervoltage) AND (Overcurrent, Either Direction) AND (Short Circuit)
AND (Protection Register Bit DE )
IN
< V
BIT 7
OV
UV
. The UVF bit must be written to 0 to clear UV and UVF.
OV
DS2784: 1-Cell Stand-Alone Fuel Gauge IC with Li+ Protector and SHA-1 Authentication
BIT 6
UV
threshold for t
BIT 5
COC
OV
. OV remains set until written to a 0 or cleared by a power-on reset or
BIT 4
DOC
ADDRESS 00h
11 of 37
COC
threshold for t
BIT 3
CC
DOC
threshold for t
BIT 2
DC
OC
. COC remains set until written to a 0,
BIT 1
OC
CE
. DOC remains set until written
BIT 0
DE
CP
. If CE is
CP
. If
IN