DS2778 Maxim Integrated Products, DS2778 Datasheet - Page 29

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

The overcurrent thresholds are set in the upper nibble of the RSGAIN register. The OC1 and OC0 bits set the over-
current thresholds for the charge and discharge thresholds. The short-circuit threshold is set by the SC0 bit (see
Tables 6 and 7, respectively, for overcurrent and short-circuit threshold values). The DS2775–DS2778 have a built-in
fixed delay of t
read a value greater than the overcurrent threshold for longer than t
for longer than t
are ignored.
Figure 20. Overcurrent and Short-Circuit Threshold Bits Format
Table 6. COC, DOC Programmability
All register bits are read and write accessible with default values specified in each bit definition.
Bits 7 to 2: Reserved.
Bit 1: SHA Idle Bit (SHA_IDLE). For the DS2777/DS2778, this bit reads logic 1 while an SHA calculation is in
progress and reads logic 0 when the calculation is complete.
Bit 0: PIO Pin Sense and Control Bit (PIOB). Writing a 0 to the PIOB bit activates the PIO pin open-drain output
driver, forcing the PIO pin low. Writing a 1 to PIOB disables the output driver, allowing the PIO pin to be pulled high
or used as an input. Reading PIOB returns the logic level forced on the PIO pin. Note that if the PIO pin is left uncon-
nected with PIOB set, a weak pulldown current source pulls the PIO pin to V
PIOB is also set in sleep mode to ensure the PIO pin is high-impedance in sleep mode. Note: Do not write PIOB to 0
if PSPIO is enabled.
OC[1:0] BIT FIELD
BIT 7
X
Protector and Optional SHA-1 Authentication
0 0
0 1
1 0
1 1
2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
OCD
SCD
______________________________________________________________________________________
BIT 6
for overcurrent events and t
before turning off the FET. Overcurrent and short-circuit events less than their respective delays
X
V
COC
-25
-38
-50
-75
(mV)
MSb
X
BIT 5
X
SC0
V
DOC
100
OC1
38
50
75
(mV)
SCD
BIT 4
X
ADDRESS 78h
OC0
for short-circuit events. This means that the current ADC must
X
Table 7. SC Programmability
BIT 3
Special Feature Register Format
X
2
0
SC0 BIT FIELD
OCD
2
and greater than the short-circuit threshold
-1
0
1
Special Feature Register (15h)
BIT 2
Overcurrent Thresholds
LSb
2
SS
X
-2
. PIOB is set to a 1 on power-up.
SHA_IDLE
BIT 1
V
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SC
150
300
(mV)
BIT 0
PIOB
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