BQ24157S Datasheet, PDF (24/45 Pages) Texas Instruments – Full USB Compliance and USB-OTG Support

Not Recommended for New Designs
bq24157S
SLUSB76B – FEBRUARY 2013 – REVISED MAY 2015
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S SLAVE ADDRESS
R/W
‘0’ (Write)
A REGISTER ADDRESS A DATA
Data Transferred
(n Bytes + Acknowledge)
A/A ^P
From master to IC
From IC to master
A = Acknowledge (SDA LOW)
A = Not acknowledge (SDA
HIGH)
S = START condition
Sr = Repeated START condition
P = STOP condition
(a) F/S-Mode
F/S-Mode
HS-Mode
F/S-Mode
S HS-MASTER CODE
A ^{Sr SLAVE ADDRESS R/W}
‘0’ (write)
A REGISTER ADDRESS A DATA
Data Transferred
(n Bytes + Acknowledge)
A/A ^P
HS-Mode
Continues
(b) HS- Mode
Figure 26. Data Transfer Format In F/S Mode And HS Mode
Sr Slave A.
8.3.16.4 Slave Address Byte
The slave address byte is the first byte received following the START condition from the master device.
MSB
LSB
X
1
1
0
1
0
1
1
8.3.16.5 Register Address Byte
Following the successful acknowledgment of the slave address, the bus master will send a byte to the IC, which
contains the address of the register to be accessed. The IC contains five 8-bit registers accessible through a
bidirectional I²C-bus interface. Among them, four internal registers have read and write access; and one has only
read access.
MSB
LSB
0
0
0
0
0
D2
D1
D0
8.4 Device Functional Modes
8.4.1 Charge Mode Operation
8.4.1.1 Charge Profile
When a good battery with voltage below the recharge threshold has been inserted and a good adapter is
attached, the bq24157S enters charge mode. In charge mode, the IC has five control loops to regulate input
voltage, input current, charge current, charge voltage, and device junction temperature. During the charging
process, all five loops are enabled and the one that is dominant takes control. The IC supports a precision Li-ion
or Li-polymer charging system for single-cell applications. Figure 27 (a) indicates a typical charge profile without
input current regulation loop. It is the traditional CC/CV charge curve, while Figure 27 (b) shows a typical charge
profile when input current limiting loop is dominant during the constant current mode. In this case, the charge
current is higher than the input current, so the charge process is faster than the linear chargers. The input
voltage threshold for DPM loop, input current limits, charge current, termination current, and charge voltage are
all programmable using I²C interface.
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