BQ28550-R1 Datasheet, PDF (27/42 Pages) Texas Instruments – Single Cell Li-Ion Battery Gas Gauge

Not Recommended for New Designs
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bq28550-R1
SLUSAS4A – OCTOBER 2012 – REVISED SEPTEMBER 2014
7.6.5.7.6.2.1 Flash Updates
Data flash can only be updated if Voltage() ≥ Flash Update OK Voltage. Flash programming current can cause
an increase in LDO dropout. The value of Flash Update OK Voltage should be selected so that the bq28550-R1
V_CC voltage does not fall below its minimum of 2.4 V during flash write operations.
7.6.5.7.7 Manufacturer Information Blocks
The bq28550-R1 device contains 96 bytes of user-programmable data flash storage: Manufacturer Info Block
A, Manufacturer Info Block B, Manufacturer Info Block C. The method for accessing these memory locations
is slightly different, depending on whether the device is in FULL ACCESS, UNSEALED, or SEALED mode.
7.6.5.7.8 Access Modes
The bq28550-R1 device provides three security modes (FULL ACCESS, UNSEALED, and SEALED) that control
data flash access permissions. Data flash refers to those data flash locations that are accessible to the user, as
specified in Table 8.
Security Mode
FULL ACCESS
UNSEALED
SEALED
Table 8. Data Flash Access
SBS Commands
Standard and Extended
Commands R/W
Standard and some Extended
Commands R/W
Standard Commands R/W
Data Flash
R/W
R/W
None
Device Programming
Yes
No
No
7.6.6 Charging and Charge Termination Indication
7.6.6.1 Detection Charge Termination
For proper bq28550-R1 operation, the user must specify cell charging voltage. The default value for this variable
is in the data flash Charging Voltage.
The bq28550-R1 device detects charge termination when:
The battery current drops below the Taper Current for two consecutive Current Taper Window time periods
during charging AND battery voltage is equal to or higher than the Charging Voltage – Taper Voltage. Full
Charge is set when the taper condition is met.
7.6.6.2 Charge Suspend
The bq28550-R1 device suspends charging when:
• Temperature < JT1, OR
• Temperature > JT4 in CHARGE-SUSPEND mode, if the [CHGSUSP] bit in OperationConfiguration is set.
This will set the charging current to zero and the charging voltage to zero in the Safety Status Register. Also, the
CHG bit is reset in ControlStatus register. The bq28550-R1 device can indicate to resume charging if:
• Temperature ≥ JT1 + Temp Hys, AND
• Temperature ≤ JT3 – Temp Hys.
On resuming, the bq28550-R1 device sets the CHG bit in the ControlStatus Register, and sets ChargingCurrent
according to the appropriate charging mode entered. The bq28550-R1 device also leaves the charge-suspend
mode when the battery is removed in removable battery mode ([NR] = 0).
7.6.6.3 MANUFACTURER ACCESS(): 0x00/0x01
Issuing a Control() command requires a subsequent 2-byte subcommand. These additional bytes specify the
particular control function desired. The Control() command allows the system to control specific features of the
bq28550-R1 device during normal operation, and additional features when the device is in an access mode
(described in Table 9).
Copyright © 2012–2014, Texas Instruments Incorporated
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