Not Recommended for New Designs

bq28550-R1

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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

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.

Table 8. Data Flash Access

Security Mode

SBS Commands

Data Flash

Device Programming

Standard and Extended

FULL ACCESS

R/W

Yes

Commands R/W

Standard and some Extended

UNSEALED

R/W

No

Commands R/W

SEALED

Standard Commands R/W

None

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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