BQ2063_15 Datasheet, PDF (17/60 Pages) Texas Instruments – SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

Not Recommended For New Designs
bq2063
SBS v1.1ĆCOMPLIANT LiĆION GASĆGAUGE IC
WITH PROTECTOR INTERFACE
SLUS468E− MAY 2001 − REVISED APRIL 2002
Li-Ion protector control
The bq2063 provides a secondary level of protection for lithium Ion batteries, as shown in Table 8. The bq2063
uses the CTL2 output to communicate battery conditions to the S-8243A/B Protector IC. When the CVOV or
CVUV condition occurs the bq2063 changes the state of the CTL2 pin according to Table 8.
The cell overvoltage threshold should be set higher than the overvoltage threshold of the S-8243 protector,
establishing a secondary overvoltage protection limit. The cell undervoltage threshold should be set somewhat
higher than the overdischarged threshold of the S-8243 protector, establishing the primary undervoltage limit.
There is no secondary undervoltage limit if the cell undervoltage threshold is set lower, because the S-8243
goes into a power-down mode and removes V_CC to the bq2063 when it detects the overdischarged limit. It is
also recommended that the bq2063 protection control be validated by two successive measurements by setting
PDLY=1 in Pack Programming.
The bq2063 asserts CVOV to turn off the charge FET if cell overvoltage, battery overvoltage, or
overtemperature conditions exist, or if AverageCurrent( ) ≥ Fast-Charging Current + Overcurrent Margin
(Prolonged Overcurrent condition in Table 5). It returns control to the S-8243 when overvoltage and
overtemperature conditions no longer exist, AverageCurrent( ) < 256 mA (if Prolonged Current generated the
fault condition), or Current( ) < 0.
The bq2063 asserts CVUV to turn off the discharge FET if a cell undervoltage condition exists, or if
AverageCurrent( ) ≤ −Overload current (Overload). It returns control to the S−8243 when the undervoltage
condition no longer exists and AverageCurrent( ) ≥ −256mA (if Overload generated the fault condition), or
Current( ) > 0.
Table 8. bq2063 to S-8243A/B Interface (FET Protection Control)
Battery State (Table 5)
CVOV = 1: Prolonged Overcurrent, Overvoltage, Overtemperature
CVOV = CVUV = 0
CVUV = 1: Overload, Overdischarged
NOTE: State determined by S-8243A/B
OUTPUT
CTL2
High
Open
Low
INSTRUCTION TO S-8243A/B (CTL1 = LOW)
DISCHARGING FET CHARGING FET
Normal (see Note) Off
Normal (see Note) Normal (see Note)
Off
Normal (see Note)
SAFETY output
The SAFETY output of the bq2063 provides an additional level of safety control. The active low safety output
can be used to blow fuse or control another switch based on temperature or a programmable pack-voltage level.
The safety temperature threshold is programmable in Safety Overtemperature in EE 0x08 and the voltage level
is programmable in Safety Overvoltage in EE 0x1f. The bq2063 SAFETY is allowed to go low only after the
CVOV bit is set 2 seconds before either Voltage( ) > Safety Overvoltage or Temperature( ) ≥ Safety
Overtemperature. If the SAFETY output activates, the bq2063 sets the SOV bit in Pack Status. SOV remains
set until the bq2063 is reset or the bit is overwritten.
An example circuit using the SAFETY output to blow a fuse is shown in Figure 7.
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