STMICROELECTRONICS STBC21FTR

STBC21
LI+ battery charger with thermal regulation
Datasheet − production data
Features
■
Programmable charge current up to 1.1 A
■
Floating voltage limitation outside the safety
temperature range
■
PSE fully compatible
■
Low battery voltage detection for pre-charge
setting
■
Automatic recharge
■
Two charge status output pins
■
Constant current / constant voltage operation
■
No external MOSFET, sense resistors or
blocking diode required
■
Reverse current blocking (50 µA max.)
■
Short-circuit protection and thermal shutdown
■
Less than 1 mA supply current in standby
mode
■
Reversed battery polarity protection
■
I²C interface for charging parameters
programming
■
ESD: HBM ± 2 kV, CDM 500 V on every pin
■
HTSSOP-14 (5 x 4.4 mm) package available
■
-25 °C to 125 °C operative junction
temperature
HTSSOP-14 (5 x 4.4 mm)
Description
The STBC21 is a constant current/constant
voltage charger for single cell Li-Ion batteries.
Most of the charging parameters, including
floating voltage, pre-charge and termination
current are programmable in NVM memory. While
fast charging current is programmed using an
external resistor. The constant current process is
split into three phases depending on the battery
voltage. If the battery voltage is below 3.0 V, the
charging current is set to a programmable value
below 200 mA. A timeout of 60 minutes is used in
this phase to detect faulty batteries. When the
battery voltage goes above 3.0 V, the charger
June 2012
This is information on a product in full production.
moves to the fast-charge procedure with a current
programmable by an external resistor up to 1.1 A.
When the battery reaches the value of the floating
voltage the charger enters “constant voltage”
mode. Even in this mode a protection timer is
active to avoid risks due to damaged batteries.
The charge cycle is automatically terminated
when the current flowing to the battery reaches
the value programmed in NVM. There is also a
programmable lag time after the termination to
maximize the battery charge. An internal block
regulates the battery floating voltage when its
temperature is outside the safety range between
10 °C and 45 °C, (JEITA/PSE regulation). The
floating voltage inside the safety range is set, by
default, at 4.2 V. If the external power supply is
removed, the STBC21 turns off and a 50 µA
(max.) current can flow from the battery to the
device. The device also has an undervoltage
lockout and automatic recharge capability which
can be enabled/disabled by setting a bit in NVM.
Two separate status pins allow a lot of information
to be gotten based also on flashing frequency and
duty cycle. The STBC21 also includes a reversed
battery polarity protection to prevent damage due
to incorrect battery insertion. The package is a
HTSSOP-14 (5 x 4.4).
Table 1.
Device summary
Order code
Package
Packaging
STBC21FTR
HTSSOP-14
Tape and reel
Doc ID 023256 Rev 1
1/54
www.st.com
54
Contents
STBC21
Contents
1
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5
Detailed description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6
5.1
Operation mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2
Battery connection detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.3
Start of charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.4
Fast-charge programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.5
Charge auto-limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.6
PHC pin functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.7
Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.8
Reversed battery polarity protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.9
Temperature protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.10
I²C data transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.10.1
Sequential registers write: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.10.2
Sequential registers read: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
ESD requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Appendix A Register configuration and access mode description . . . . . . . . . . 30
Appendix B Charging parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Appendix C Charging control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Appendix D Temperature thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Appendix E LED configurations diversified for customer
(each customer one pattern). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
2/54
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STBC21
Contents
Appendix F
LED display modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Appendix G NVM commands register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Appendix H Charger, battery and alarm status registers . . . . . . . . . . . . . . . . . . 47
H.1
Layout guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
7
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
8
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Doc ID 023256 Rev 1
3/54
List of tables
STBC21
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 8.
Table 9.
Table 10.
Table 11.
Table 12.
Table 13.
Table 14.
Table 15.
Table 16.
Table 17.
Table 18.
Table 19.
Table 20.
Table 21.
Table 22.
Table 23.
Table 24.
Table 25.
Table 26.
Table 27.
Table 28.
Table 29.
Table 30.
Table 31.
Table 32.
Table 33.
Table 34.
Table 35.
Table 36.
Table 37.
Table 38.
Table 39.
Table 40.
Table 41.
Table 42.
Table 43.
Table 44.
Table 45.
Table 46.
Table 47.
Table 48.
4/54
Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
External components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Electrical characteristics (DC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Start of charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Write single register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Read single register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Configuration registers map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Control registers map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Timer registers summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Timer-2 description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Timer-3 description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Charging current registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
SET1 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
ISET3 register description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Constant voltage register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
CV1 bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
CV2 bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
CV3 bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
CV4 bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Halving register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
ISET2 (CV1) bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
ISET2 (CV2) bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
ISET2 (CV3) bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
ISET2 (CV4) bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Charging control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Auto recharge bit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Temperature thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Th-h reg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Th reg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Tl reg. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Hys reg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
LED configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
LED display modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
LED frequency register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
LED duty cycle register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Address: 10H, Reset state: 00000000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
NVM commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Address: 11H, Reset state: 00000000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Address: 12H, Reset state: 00000000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Address: 13H, Reset state: 00000000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Digital charger status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Address: 14H, Reset state: 00000000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Battery temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
HTSSOP-14L (5 x 4.4 mm) mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Doc ID 023256 Rev 1
STBC21
List of figures
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Pin connections (top through view). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Charging process flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Battery connection detection flowcharts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Temperature ranges compatible with PSE, power safety electrical . . . . . . . . . . . . . . . . . . 18
V-I characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Battery temperature alarm after charging starts (at battery insertion
and at recharge) flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Battery temperature alarm during charge flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Temperature detector schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Charging process diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Charging process diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Battery alarm flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Charger alarm flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
LEDs control circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Junction shutdown temperature detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Layout board (top through view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Layout board (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Drawing dimension HTSSOP-14L (5 x 4.4 mm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Doc ID 023256 Rev 1
5/54
Block diagram
1
STBC21
Block diagram
Figure 1.
VCC
PHC
Block diagram
PWR
BAT
BIAS
CLAMP
BANDGAP
PWRSIS
VBAT_SNS
VCP
ISET
POWER
ICHARGE
VFLOAT
VCC
_
_
EOC
VREF
+
+
115°C/95°C
THERMAL
OCP
+
_
RES3
LED1
RES2
I2C
RES1
L
O
G
I
C
NVM
4.23V
_
VBAT
+
1.0V
+
_
BAT_LOW
+
_
FAST_CH
3.0V
VBAT
_
3.9V
+
BAT_OVP
LED2
TH_OFF
+
_
TH_H
+
_
0.75V
0.79V/1.002V
TH
VBAT
2.6V
TEMP
+
_
0.89V/1.1V
TL
RECHARGE
+
_
1.74V/1.95V
+
_
POR
+
_
VCC_OVP
TL_OFF
+
_
BAT_NO
+
_
VCC
2.128V
9.0V
VCC
VCC_OK
2.425V
2.8V
BAT_HOT
VCC
+
ASD
_
+
VBAT
0.505V
Voff
GND
AM10414v1
6/54
Doc ID 023256 Rev 1
STBC21
Block diagram
Figure 2.
Typical application schematic
STBC21A
VCC
VIN
BATTERY PACK
VBAT_SNS
VCC
VREF
R6
BAT
C1
VREF
R7
Li+
Protection
Circuit
C3
R3
RES1 (I2C Clock)
R4
RES2 (I2C Data)
TEMP
TEMP
RES3 (Reserved)
GND
R5
Li-Ion
Battery
BAT
C4
VREF
C5
NTC
GND
RLED1
LED1
D1
RLED2
D2
LED2
ISET
R1
PHC
VCP
VCC
R8
R2
C2
TO AC-DC
Table 2.
AM10434v2
External components
Symbol
Parameter
Min.
Typ.
Max.
Unit
10
µF
C1
Ceramic capacitor SMD
C2
Ceramic capacitor SMD
TBD
µF
C3
Ceramic capacitor SMD
0.1
µF
C4
Ceramic capacitor SMD
10
µF
C5
Ceramic capacitor SMD
TBD (1)
R1
Resistor
10 (2)
kΩ
R2
Resistor
TBD
kΩ
R3
Resistor
100
kΩ
R4
Resistor
0
Ω
1
(1)
R5
Resistor
R6
Resistor
4.7
kΩ
R7
Resistor
4.7
kΩ
R8
Resistor
TBD (3)
TBD
RLED1, RLED2 Resistor
90
D1
LED Kingbright L-934HD
D2
LED Kingbright L-934GD
Ω
1. Time constant R5*C5 must be less than 20 msec.
2. This value refers to a fast-charge current of 100 mA.
3. Time constant must be chosen taking into account compensation loop.
Doc ID 023256 Rev 1
7/54
Pin configuration
2
STBC21
Pin configuration
Figure 3.
Pin connections (top through view)
VCC
1
14
LED2
PHC
2
13
LED1
VCP
3
12
ISET
VREF
4
11
BAT
RES2
5
10
VBAT_SNS
RES1
6
9
TEMP
GND
7
8
RES3
AM10433v1
Table 3.
Pin description
Pin n°
Symbol
1
VCC
Input supply voltage
2
PHC
Photo coupler driver
3
VCP
Compensation pin
4
VREF
Voltage reference for external NTC
5
RES2
I²C bi-directional data - pulled high
6
RES1
I²C clock - pulled high
7
GND
Ground pin
8
RES3
Reserved
9
TEMP
Input from temperature sensor
10
VBAT_SNS
11
BAT
This pin provides an accurate output voltage and the charge current
following the charging algorithm. Only 50 µA reverse current can flow into
the device when in standby mode
12
ISET
Fast-charge current setting
13
LED1
Open drain. See Appendix E & F
14
LED2
Open drain. See Appendix E & F
EXPOSED
PAD
8/54
Function
Battery voltage sensing
Not connected
Doc ID 023256 Rev 1
STBC21
3
Maximum ratings
Maximum ratings
Table 4.
Absolute maximum ratings
Symbol
Value
Unit
Input supply voltage
From -0.3 to 10
V
Battery voltage
From -6.0 to 6.0
V
VPHC
PHC voltage
From -0.3 to 10
V
VVCP
VCP voltage
From -0.3 to 5.5
V
VREF
REF voltage
From -0.3 to 3.6
V
From -0.3 to VREF+0.3
V
From -0.3 to 3.6
V
1350
mA
Electrostatic discharge voltage
(according to HBM JESD22-A114D)
±2
kV
Electrostatic discharge voltage
(according to CDM JESD22-C101C)
500
V
VCC
VBAT,
VBAT_SNS
VLV
Parameter
TEMP, LED1, LED2, ISET
VRES
RES1, RES2, RES3
IBAT
Charging battery current
ESD
TSTG
Storage temperature range
–65 to 150
°C
TJ
Junction temperature range
–40 to 125
°C
300
°C
Lead
(soldering, 10 seconds)
temperature
Note:
Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these conditions is not implied. All values are referred to GND.
Table 5.
Symbol
RthJA (1)
Thermal data
Parameter
Thermal resistance junction-ambient
Value
Unit
37.6 (2)
ºC/W
1. Evaluated on 1S2P (1 signal, 2 plane layers) board, 4.4 x 5 mm body size, 3.0 x 3.0 mm pad size, 1.5 W
applied power.
2. By 0 velocity (linear feet per minute). This value drops to 30.2 °C/W by 500 velocity.
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Electrical characteristics
4
STBC21
Electrical characteristics
TJ = -25 °C to 85 °C unless otherwise specified. Refer to the typical application circuit.
Typical values are referred to TJ = 25 °C.
Table 6.
Electrical characteristics (DC)
Symbol
Parameter
Conditions
Typ.
2.6
VCC
VCC_USB
Min.
Minimum VCC to enable charging
without quasi-pulse
Max.
Unit
9.0
V
4.5
3.0
V
4.25
V
Fast charge
3.0 V<VCC<9.0 V
IBAT=100 mA
750
µA
Shutdown
2.6 V<VCC<2.85 V
80
µA
Standby
(charge terminated) 2.8
V<VCC<9.0 V
450
µA
0 V<VCC<9.0 V
VBAT=4.2 V
VTEMP=1.2 V
-50
µA
VBAT
(1)
ICC
ISTBY
IPRE_CH
IF_CH
ITERM
IBAT_OCP
Supply current
(excluding LEDs and
battery current)
IBAT standby current
(charge terminated)
Nominal pre-charge / 0V-charge
current
2.8 V<VCC<9.0 V
Nominal fast-charge current
Set by Ext. resistor
R1=1.25 kΩ
Charge termination current
10 mA steps
from 40 mA to 190 mA
4.5 V<VCC<9.0 V
VBAT=4.2 V, TIMER3=0
48
60
72
72
90
108
96
120
144
744
800
856
32
40
48
…
152
IBAT overcurrent protection
190
mA
mA
mA
228
1.35
A
IVREF
VREF current limit
5.0 V<VCC<9.0 V
30
mA
IPHC
Photo-coupler current
VCC=5.0 V, VBAT=3.0 V
10
mA
ILk_PHC
Photo-coupler leakage
VCC=5.0 V, VBAT=4.8 V,
VPHC=5.0 V
2
µA
ISINK
Sunk current during battery detection COUT=10 µF
1
mA
IDETECT
Sunk current during battery detection COUT=10 µF
1
mA
10
mA
ILED
VCC_POR
10/54
LED current
VREF=2.9 V, VFLED=2 V
RLED=90 kΩ
Power-on reset threshold
2.47
Doc ID 023256 Rev 1
2.6
2.73
V
STBC21
Table 6.
Electrical characteristics
Electrical characteristics (DC) (continued)
Symbol
Parameter
Conditions
VCC_OK
Charging start threshold –
VCC undervoltage alarm (VCC_UVLO)
VCC_ASD
VCC-VBAT threshold
VCC_OVP
VCC overvoltage protection
VPRE_CH
ΔVFLT
VFLT_OVP
Typ.
Max.
Unit
2.66
2.8
2.94
V
125
8.55
IODROP_QP Quasi-pulse VCC-VBAT drop
V0V_HD
±5%
Min.
9.0
IBAT=100 mA, IBAT=1.0A
0V-charge threshold
±5%
Pre-charge to fast-charge voltage
threshold
VCC = 5.0 V
Float voltage range tolerance
VFLT = 4.2 V, IBAT =1 mA
TJ = -10 °C to 85 °C
-0.7
Float voltage OVP
5.0 V < VCC < 9.0 V
TBAT = 0 °C to 60 °C
IBAT = 1.0 mA
TIMER-3 = 60 min.
4.21
mV
9.45
V
0.35
V
1
V
3.0
V
4.23
0.7
%
4.25
V
VCC_QP
Quasi-pulse minimum supply voltage
in pre-charge phase
3.1
V
VBAT_QP
Minimum battery voltage to start
quasi-pulse mode
2.8
V
3.9
V
Battery recharge threshold voltage
5.0 V < VCC < 9.0 V
VTEMP_UN
NTC voltage threshold
for battery unconnected
±2%
2.425
V
VTEMP_OT
NTC voltage threshold
for battery overtemperature
±2%
0.505
V
VREF
Reference voltage for NTC /
LED drive voltage
±5%
2.9
V
RDS-ON
Power MOS saturation resistance
0 °C < TJ < 85 °C
300
mΩ
TRECH
Battery recharge deglitching time
VCC = 5.0 V
100
ms
TFULL
Full charge detection deglitching time VCC = 5.0 V – TIMER-3
(after termination)
=0
100
ms
THV
Battery overvoltage detection
deglitching time
VCC = 5.0 V
100
ms
THl
Overcurrent detection deglitching
time
VCC = 5.0 V
100
ms
Deglitching time on VCC to start
charging (VCC=3.0 V)
VBAT = 2.8 V
10
ms
VRECH
THOLD_OFF
TBAT_HOT
Battery hot detection deglitching time VCC = 5.0 V
10
ms
TBAT_CON
Battery connection detection
deglitching time
VCC = 5.0 V
400
ms
TBAT_TLO
Battery TLO temperature detection
deglitching time
VCC = 5.0 V
100
ms
Doc ID 023256 Rev 1
11/54
Electrical characteristics
Table 6.
Symbol
STBC21
Electrical characteristics (DC) (continued)
Parameter
Conditions
Min.
Typ.
Max.
Unit
Battery THO temperature detection
deglitching time
VCC = 5.0 V
100
ms
TBAT_TL
Battery TL temperature detection
deglitching time
VCC = 5.0 V
100
ms
TBAT_TH
Battery TH temperature detection
deglitching time
VCC = 5.0 V
100
ms
TBAT_THH
Battery THH temperature detection
deglitching time
VCC = 5.0 V
100
ms
TSINK
Duration of battery connection
detection
COUT = 10 µF
100
ms
TDETECT
Duration of battery connection
detection
COUT = 10 µF
300
ms
TIMER-1
Pre-charge timer
± 10% @ 25 °C
±15% in temp range
60
min
TIMER-2
Fast-charge timer (programmable)
± 10% @ 25 °C
±15% in temp range
150
510
min
TIMER-3
Termination timer (programmable)
± 10% @ 25 °C
±15% in temp range
0
60
min
TIMER-4
0 V-charge timer
± 10% @ 25 °C
±15% in temp range
16
sec
Junction shutdown temperature
20 °C hysteresis
115
°C
TL
Lower limit of safety range
10 °C
1.74
1.95
V
TH
Upper limit of safety range
45 °C
0.89
1.10
V
THH
Intermediate safety range
50 °C
0.79
1.002
V
THO
Upper limit of functional range
60 °C
0.727
0.75
0.776
V
TLO
Lower limit of functional range
-2 °C
2.087
2.128
2.168
V
TBAT_THO
TJ_SH
2 °C
28
mV
5 °C
70
mV
Hysteresis
12/54
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STBC21
5
Detailed description
Detailed description
The STBC21 is designed to charge single-cell lithium-ion batteries using the constant
current/constant voltage algorithm. The charger can deliver up to 1.1 A (programmable) of
charge current with a final float voltage accuracy of 20 mV.
Once the battery is connected, the normal charge cycle begins when the voltage at the VCC
pin rises above the threshold (VCC_OK).
The process generally starts with a pre-charge phase in constant current mode, where a
reduced charge current (see Appendix B) is supplied to the battery. A programmable timer
(TIMER-1) during this phase allows possibly damaged batteries to be spotted in case the
voltage doesn't reach the expected value within a given time.
Note that, if the battery voltage is below 1.0 V, the charger first attempts to charge (0 Vcharge mode) for 16 seconds (TIMER-4) to test if the battery is dead. After the TIMER-4 has
elapsed, in case the voltage doesn't cross the 1.0 V threshold, a battery alarm is flagged.
Otherwise the charger keeps on charging.
When the battery voltage reaches 3.0 V, the charging current reaches its maximum value
(fast-charge phase) programmable by an external resistor.
When the battery voltage approaches the final float voltage (programmable, typ. 4.2 V), the
STBC21 enters constant voltage mode and the charge current decreases as the battery
becomes fully charged. The fast-charge and the following constant voltage phases have a
dedicated timer set through bits in NVM to make sure the current reaches its termination
value within a given time. If during this phase the battery voltage falls below VPRE_CH or
rises above 4.23 V (±20 mV), the operation is stopped and an alarm sounds.
The STBC21 terminates the constant voltage phase when the charging current reaches the
termination current threshold (value set in ISET3 register, see Appendix B). In addition, a
further step (end of charge) can be activated through bits in NVM. In this case, the charging
process in constant voltage mode continues for a predefined amount of time (TIMER-3): this
behavior is useful to increase the battery duration.
After charge termination the battery may be discharged by the leakage. When the battery
voltage reaches VRECH with a lag time of 100 ms the charge automatically restarts. This
feature can be disabled setting a bit in NVM.
If, during the charging phase, one of the timeouts elapses, the charge is stopped and a flag
is set. See Appendix B for more details on timers. The STBC21 charging process works as
depicted in Figure 4.
Doc ID 023256 Rev 1
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Detailed description
STBC21
Figure 4.
Charging process flowchart
YES
Insert Baery
NO
V BAT < 3.9V
Baery connecon
detecon at
beginning of charge
YES
NO
Terminaon
(without
Auto-recharge)
V BAT < 1.0V
Baery Connecon
Detecon
at the End of Charge
NO
Auto Recharge
ON
YES
YES
TIMER-3
elapsed
TIMER-4 ON
NO
0V-Charge Mode
Safe charge
NO
YES
V BAT > 1.0V
NO
TIMER-4
elapsed
YES
Baery alarm
Auto Recharge
ON
NO
YES
Safe charge
OFF
(TIMER-3=0 min)
TIMER-1 ON
Pre-Charge Mode
Baery Connecon
Detecon
at the End of Charge
YES
Terminaon
(without
Auto-recharge)
YES
NO
NO
IBAT < ISET3
V BAT > 3.0V
NO
TIMER-3 ON
NO
TIMER-1
elapsed
YES
TIMER-2
elapsed
Baery alarm
NO
YES
Baery Connecon
Detecon
at the End of Charge
Fast-Charge Mode
in constant voltage
TIMER-2 ON
NO
NO
Fast-Charge Mode
in constant current
YES
Terminaon
(without
Auto-recharge)
Baery Connecon YES
Detecon
at the End of Charge
TIMER-2
elapsed
YES
Terminaon
(without
Auto-recharge)
V BAT < V FLOAT
AM10415v1
Two outputs can be used to detect the status of charge. The functionality of these two pins
can be customized in NVM as outlined in Appendix E & Appendix F. This is to allow the final
customer to have different kinds of information depending on whether the output is ON, OFF,
or flickering. The flickering frequency is programmable both in frequency and duty cycle (see
Appendix E & Appendix F).
Note:
The device functionality is not guaranteed if the parameters are modified in NVM during the
charging cycle.
5.1
Operation mode
The STBC21 can work in standalone or driven by a microcontroller. If it works in standalone,
all device parameters are those stored in NVM. Otherwise, if it works driven by a
microcontroller, it is the microcontroller itself to program through I²C (SCL and SDA pins) the
device parameters.
14/54
Doc ID 023256 Rev 1
STBC21
5.2
Detailed description
Battery connection detection
The STBC21 includes a battery detection algorithm to avoid a wrong behavior of the charger
due to incorrect pin connection. This control is performed both at the beginning and at the
end of charge.
At the beginning of charge, the charger briefly (TDETECT) sources a small current (IDETECT)
to the battery: if the voltage remains below VRECH, the battery is definitely connected.
Otherwise, if the voltage reaches VRECH, a further control is added to be sure the battery is
not connected. The charger briefly sinks (TSINK) a small current (ISINK) from the battery. If
voltage falls below VPRE_CH, the battery is certainly absent.
Similarly, when the termination current is reached, the charger briefly (TSINK) sinks a small
current (ISINK) from the battery. After this period, if the battery voltage is above VPRE_CH, the
battery is present. Otherwise the battery is absent. The flowcharts in Figure 5 better explain
this algorithm.
Doc ID 023256 Rev 1
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Detailed description
STBC21
Figure 5.
Battery connection detection flowcharts
Insert baery
Start Terminaon
Sink ISINK from
baery and start TSINK
Wait for 400msec
(TWAIT)
Pin TEMP
connected
VBAT<3.0V
&
TSINK<100ms
NO
YES
NO
Terminaon
YES
Force IDETECT to
baery and start T DETECT
VBAT>3.9V
&
TDETECT<300ms
Baery alarm
YES
Baery
removed
NO
NO
YES
Baery unistallaon
LED SET
TDETECT ≥300ms
NO
END
YES
Baery connecon detecon at the End of Charge
VBAT>3.9V
NO
Start charging
YES
Sink ISINK from
baery and start T SINK
VBAT<3.0V
&
TSINK<100ms
NO
Start charging
YES
Baery alarm
Baery
removed
NO
YES
Baery unistallaon
LED SET
END
Baery connecon detecon at Beginning of Charge
5.3
AM10416v1
Start of charge
The STBC21 start of charge is subject to three variables: input voltage, battery connection
and battery temperature. The detection of these variables is filtered with different deglitching
as reported in Table 7:
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Doc ID 023256 Rev 1
STBC21
Detailed description
Table 7.
Start of charge
Item
Delay
Enabling condition
Battery connection detection
400 ms
VTEMP < 2.425 V
VCC voltage detection
10 ms
VCC > 2.8 V
Battery temperature detection
100 ms
0.75 V < VTEMP < 2.128 V
The charge starts if VCC exceeds 2.8 V, the battery is connected and its temperature is in
the safety range (see Section 5.5).
In addition, the charge cycle starts if the available supply voltage exceeds by VCC-ASD the
BAT pin voltage level.
The start of charge in case of a discharged battery is already described in a previous
paragraph. Meanwhile, if a fully charged battery is connected, the charge starts in constant
voltage mode with TIMER-2 associated.
5.4
Fast-charge programming
When the battery voltage reaches the pre-charge voltage threshold, the STBC21 starts the
fast-charge phase. In this phase, the device charges the battery with a constant current,
programmable by an external resistor that sets the charge current. The formula used to
select the RPRG is as follows:
Equation 1
K
RPRG = VSET × ( PRG )
ICHG
where VSET = 1.0 V and KPRG = 1000. During this phase, the battery voltage increases until
it reaches the programmed floating voltage or the safety timer expires and the alarm is
activated.
5.5
Charge auto-limitation
The STBC21 includes an auto-limitation algorithm to avoid explosion risks in the Li+ battery.
This algorithm makes sure that the battery is never charged at its maximum floating voltage
if the temperature is above 45 °C or below 10 °C.
Three more ranges are defined outside the safety range TL-TH (10 °C ~ 45 °C) as reported
in Figure 6.
Doc ID 023256 Rev 1
17/54
Detailed description
Figure 6.
STBC21
Temperature ranges compatible with PSE, power safety electrical
CV- 1
CV- 2
CV- 3 CV- 4
AM10417v1
NO CHARGE
NO CHARGE
V FLOAT
I CHARGE
I CHARGE
2
T LO
TL
T H T HH
T HO
Temperature
The new floating voltage in these ranges can be programmed to be 4.2 V, 4.1 V or 4.05 V (±
30 mV), as reported in Appendix B.
Once the reduced floating voltage is reached, the charge terminates only if the battery
temperature is in the 10 °C ~ 45 °C range. If the temperature is outside this range, the
charger holds and restarts once the temperature decreases.
This function can be enabled/disabled setting a bit in NVM.
There is also the possibility to halve the charging current (see Figure 6, blue dashed line) in
fast-charge in all temperature ranges.
In addition, all thresholds have an hysteresis: TLO and THO have a fixed hysteresis of 2 °C,
whereas TL, TH and THH have a programmable hysteresis of 2 °C or 5 °C (value set by a bit
in NVM).
If the temperature moves above TH or below TL, Vfloat is reduced. When the temperature
goes back inside the range TL-TH (with the associated hysteresis), Vfloat is replaced to its
maximum value.
At the beginning of the charge, when the battery pack is inserted, a check of battery
temperature is performed: if the temperature is outside the range 0 °C~45 °C, the charger
doesn't start charging and waits until the temperature goes back into the range (above 0 °C
or below 43 °C) (see Figure 8).
Similarly, if auto-recharge is active and battery voltage decreases below 3.9 V, but its
temperature is outside the range 0 °C ~ 45 °C, the charge is stopped and restarts only when
battery temperature goes into the range 0 °C ~ 43 °C. In this situation, LEDs continue to
show “charge completed”.
During charging, if battery temperature goes outside the functional range (-2 °C ~ 60 °C),
the charger must stop the operations regardless of the current state. In this case, the LEDs
show “Battery temperature alarm” but the timers keep on counting. If the temperature moves
back inside the range 0 °C ~ 43 °C, the charger restarts the operations restoring the status it
was in before the interruption.
In this case, if temperature goes above 60 °C twice, the charger stops, the LEDs show a
“charge completed” and it is necessary to remove the battery to restart the operations (see
Figure 9). With the battery uninstalled, the LED configuration is like that indicated in
Appendix E.
In summary, the STBC21 behavior can also be represented as the following V-I
characteristic:
18/54
Doc ID 023256 Rev 1
STBC21
Detailed description
Figure 7.
V-I characteristics
Battery voltage (V)
CV-- 1/2/3/4
CV-- 1/2/3/4
4. 20 V + 0.03V / - 0.06
4. 20 V + 0.03V / - 0.03
CV- 1/2/3/4
CV-- 1/2/3/4
4. 10 V + 0.03V / - 0.03
4. 10 V + 0.03V / - 0.06
CV- 1/2/3/4
4.05V
CV- 1/2/3/4
+ 0.03V / - 0.03
3V
AM10418v1
Figure 8.
+ 0.03V / - 0.06
4.05V
ISET1
ISET2
(Pr e --char ge cur r ent value)
(Fast - char
- ge cur r ent value)
Charging
current ( mA )
Battery temperature alarm after charging starts (at battery insertion and
at recharge) flowchart
Baery Temperature
Alarm Detecon / Aer
charging starts
Baery Temperature
Alarm occurrence
Charging doesn’t start
YES
Baery Temperature
> 45 °C
Baery Temp Alarm /
Aer charging starts
LED SET
NO
Baery Temperature
< 0°C
YES
NO
0°C < Baery Temperature < 4 3°C
NO
YES
Charge on going
LED SET
Charge on going
LED SET
Start charging
Start charging
AM10419v1
Doc ID 023256 Rev 1
19/54
Detailed description
Figure 9.
STBC21
Battery temperature alarm during charge flowchart
Baery Temperature
Alarm occurrence
Baery Temperature
Alarm Detecon /
During charge
Stop charging
Timers keep counng
Baery Temp Alarm /
During charge
YES
Baery Temperature >
60°C
NO
NO
Baery Temperature < 2°C
LED SET
Baery Temperature
> 60°C
YES
YES
Increase
alarm counter
NO
Charge on going
LED SET
NO
NO
Alarm asserons =2 mes
0°C < Baery Temperature < 43°C
Charge
YES
YES
Charging Compleon
LED SET
Charge on going
LED SET
Baery
removed
Restart charging from the
interrupted point
NO
YES
Baery Unistallaon
LED SET
END
AM10420v1
The chip also includes an NVM to allow the temperature thresholds above to be
programmable few times by the battery manufacturer.
The temperature thresholds are sensed by the NTC inside the battery pack. A reference
voltage is properly partitioned to translate the variable resistance in a variable voltage as
shown in Figure 10.
Figure 10. Temperature detector schematic
VREF
RPART2
R1
R3
+
TEMP
RPART1
NTC
R2
_
BATTERY PACK
STBC21
AM10421v1
20/54
Doc ID 023256 Rev 1
STBC21
Detailed description
Using an integrated resistor partition and a very low-offset comparator, it's possible to detect
a battery temperature value that doesn't depend on reference voltage, but is affected by an
internal resistor divider matching only.
As regards NTC, the components suggested are:
1.
NTC1 PANASONIC R25 = 100 kΩ ±1% B25/85=4700 K ±1% (code ERTJ0EV104F)
2.
NTC2 PANASONIC R25 = 10 kΩ ±1% B25/85=3435 K ±1% (code ERTJ0EG103FA)
Two resistor networks are proposed to implement linearization of these two NTCs, as written
below.
NTC1: R1 = 100 kΩ - R2 = 700 kΩ - R3 = 17.8 kΩ
NTC2: R1 = 9.1 kΩ - R2 = 160 kΩ - R3 = 0.22 kΩ
In this way, voltage thresholds of similar value for both NTCs are obtained. The STBC21
automatically recognizes these voltage thresholds.
5.6
TLO (-2 °C)
TL (10 °C)
TH (45 °C)
THH (50 °C)
THO (60 °C)
2.128 V
1.74 V - 1.95 V
0.89 V - 1.1 V
0.79 V - 1.002 V
0.75 V
PHC pin functionality
The time diagram of the charging process can be summarized in the image below:
Figure 11. Charging process diagram
As shown, in fast-charge phase the power dissipation can be important and supposing VIN =
9.0 V and IBAT = 1.1 A:
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Detailed description
STBC21
Equation 2
P = ( VIN − VOUT ) × IBAT = 6.6W
which is not compatible with the thermal specifications of the package used. In this situation
either the charging current must be reduced (increasing the charging time) or the STBC21
enters into thermal shutdown.
This effect can be seen even in pre-charge but is less critical because this phase generally
last few minutes and the current is lower but can become longer in case the chip goes into
thermal shutdown.
To allow a higher current capability during charging, the power dissipation must be reduced
acting on the voltage drop between input and output. To keep this difference at a minimum
value the STBC21 provides a pin to drive a controller downstream so that the input voltage
depends on the battery voltage.
The input voltage waveform is shaped as reported in Figure 12.
Figure 12. Charging process diagram
During pre-charge, until VBAT reaches 2.8 V (VBAT_QP threshold), the input voltage must be
regulated at VCC_QP. When VBAT goes over 2.8 V, VCC starts to increase, keeping a constant
voltage difference with VBAT (IODROP_QP).
5.7
Alarms
The STBC21 implements four kinds of alarms: battery alarm, charger alarm, ASD
(automatic shutdown) alarm and device temperature alarm.
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STBC21
Detailed description
Battery alarm occurs when:
●
TIMER-1 during pre-charge phase elapses;
●
TIMER-4 during 0V-charge phase elapses;
●
Overvoltage on the BAT pin occurs (VBAT > 4.23 V ± 20 mV, infringement of JEITA/PSE
regulation);
●
Undervoltage, during fast-charge or end of charge, on the BAT pin occurs (VBAT < 3.0
V);
●
Undervoltage on the TEMP pin occurs (VTEMP < 0.505 V, battery overheating);
●
Battery connection detection error occurs.
In all these cases the charge stops, the LEDs show a “Battery alarm” and a battery removal
is required to reset the charger. The battery removal is spotted because the voltage on the
TEMP pin rises above 2.425 V.
The battery alarm's flowchart is presented in Figure 13.
Charger alarm occurs when:
●
Overvoltage on the VCC pin occurs (VCC > 9.0 V);
●
Undervoltage on the VCC pin occurs (VCC < 2.8 V, except for the power-up transition
when the charger is switched on);
●
Current increases over 1.1 A.
In these cases the charge is stopped, LEDs show a “charger alarm” and it's kept in this state
even if the battery is removed. A VCC removal is required to reset the charger.
The charger alarm's flowchart is depicted in Figure 14.
Other alarms occur when:
●
VCC and VBATT are very close (VCC_ASD is lower than threshold);
●
Die temperature increases over 115 °C (thermal shutdown).
In these cases the battery charge is stopped, the LEDs continue to show “charge ongoing” if
the charger was in charge, and “end of charge” if the charger was in the termination phase
and the timers keep on counting. Once the alarm condition is removed, the charger restarts
the operations restoring the status it was in before the interruption.
During this phase, all other alarms (battery alarms and charger alarms) are active.
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Detailed description
STBC21
Figure 13. Battery alarm flowchart
Baery alarm detecon
YES
TIMER-4
expired
YES
VBAT < 1.0V
NO
NO
YES
TIMER-1
expired
NO
Baery
YES
Connecon Detecon
error
Charging Stop
NO
Fast-Charge
or
End of Charge
YES
UVLO on VBAT
VBAT < 3.0V
NO
YES
Baery Alarm
LED SET
NO
NO
Baery removal
YES
OVP on VBAT
VBA T > 4.25V
YES
NO
Baery unistallaon
LED SET
YES
Baery hot
VTEMP < 0.3V
END
NO
AM10422v1
Figure 14. Charger alarm flowchart
Charger alarm detecon
YES
OVP on VCC
VCC > 9.0V
NO
UVLO on VCC
VCC < 2.8V
NO
Charging Stop
YES
Power UP
2.8V Transion
YES
NO
Charger Alarm
LED SET
NO
Over Current
IBAT > 1.1A
YES
POWER OFF
YES
NO
END
AM10423v1
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Doc ID 023256 Rev 1
STBC21
Detailed description
The alarms are reported by two different LEDs driven from the high side with 10 mA current
capability, as reported in Figure 15. The LED current is not internally limited.
Figure 15. LEDs control circuit
VCC
Charging
MODE
LDO
LDO
2.9V
2.9
V
7mode
10mA
LED
LED
Control
Control
LED
display
VREF
9bit
10mA
LED
display
flickering
OSC
OSC
3bit
ON/0.625/㧞
ON/0.625/2/2.5/3/4
/2.5/3/4
CK
LED
display
ON duty
2bit
ON(100%)
ON
ON duty
duty
30/50/80/100
30/50/80/100
AM10424v1
See Appendix E for possible LED configurations.
As regards RLED calculation, taking into account ILED = 10 mA and VFLED = 2 V, we obtain:
Equation 3
R LED =
5.8
( VREF − VFLED ) ( 2 . 9 − 2 )
=
= 90 Ω
ILED
0 . 01
Reversed battery polarity protection
The STBC21 includes a reversed battery polarity protection to prevent damage due to an
incorrect insertion of the battery in the cradle.
If the battery is able to supply 2 mA, charge doesn't start and no alarm is set.
If the battery is protected against overvoltage, undervoltage, etc. and it is in protection mode
(represented as an open circuit) it is not able to supply 2 mA. In this condition, the battery
connection detection alarm is set. Even in this case the charge does not start.
If the battery is not protected against overvoltage, undervoltage, etc. and battery voltage is
below 1.0 V, battery connection detection is unable to start. In this case, for a time
corresponding to TIMER-4 (16 sec), the battery is discharged with a pre-charge current. But
when TIMER-4 elapses the battery alarm is flagged and the discharge is stopped.
5.9
Temperature protection
The STBC21 has a further protection when the dye temperature reaches 115 °C. In this
condition the charge is stopped and restarts after the temperature decreases to 95 °C.
During this “idle” state, LEDs continue to show “charge ongoing” if the charger was in
charge, “end of charge” if the charger was in termination phase and the timers keep on
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Detailed description
STBC21
counting. Once the charger exits “idle” state (temperature decrease to 95 °C), it restarts the
operations restoring the status it was in before the interruption.
The flowchart in Figure 16 shows junction shutdown temperature detection.
Figure 16. Junction shutdown temperature detection
Juncon shutdown
temperature detecon
YES
Juncon temperature
>115°C
During charge
YES
Charging Stop
NO
NO
Charge on going
LED SET
Timers keep counng
Juncon temperature
<95°C
NO
YES
Charge restart from the
interrupted point
AM10425v1
5.10
I²C data transfer
A standard I²C interface, mapped in pins RES1 (SCL) and RES2 (SDA), is used to
read/write the non-volatile memory integrated into the chip. Both read and write operations
can be always done based on registers or in one operation starting from a given address till
the bottom of the memory.
Table 8.
S
Write single register
SLAVE ADDRESS
R/W
Master
A
REGISTER ADDRESS
A
DATA
A/An
Slave (STBC21)
S = START condition (from Master to STBC21)
SLAVE ADDRESS= 6BH
R/W = '0' Write / '1' Read
A = Acknowledge (SDA low from STBC21)
REGISTER ADDRESS = From 00H to 17H (8 bits from MSB to LSB)
DATA = 8 bits data register (from MSB to LSB)
An = Acknowledge/Not Acknowledge (SDA left high from STBC21)
P = STOP condition (from Master to STBC21)
Example: Write into Reg 01H (Customer Register) in order to set the pre-charge current
(ISET1) to 90 mA and end-charge current (ISET3) to 100 mA.
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Doc ID 023256 Rev 1
P
STBC21
Detailed description
S
6BH
Table 9.
0
00000001
A
xx011001
A/An
A
SEND DATA
P
Read single register
SLAVE ADDRESS
S
A
R/W
A
Master
REGISTER ADDRESS
A/An
P
Slave (STBC21)
S = START condition (from Master to STBC21)
SLAVE ADDRESS= 6BH
R/W = '0' Write / '1' Read
A = Acknowledge (SDA low from STBC21)
REGISTER ADDRESS = From 00H to 17H (8 bits from MSB to LSB)
SEND DATA =
8 bits data coming from internal addressed Register of STBC21 (from
MSB to LSB)
A/An = Acknowledge/Not Acknowledge (SDA left high from Master)
P = STOP condition (from Master to STBC21)
Example: Read data from Reg 12H (charger status register) in order to know the status of
the charger.
S
6BH
1
A
00010010
A
xxxxxxxx
A/An
P
The I²C interface also performs sequential write and sequential read in order to write/read all
the STBC21STBC21 registers in a single step. An internal pointer starts from the first
addressed register and then returns to the first internal address (00H) when it has achieved
the last internal address (17H).
5.10.1
S
Sequential registers write:
SLAVE
ADDRESS
R/W
(0)
Master
A
REGISTER
ADDRESS
A
DATA (Regx)
A
DATA (Regx+1)..
A/An
P
Slave (STBC21)
S = START condition (from Master to STBC21)
SLAVE ADDRESS= 6BH
R/W = '0' Write / '1' Read
A = Acknowledge (SDA low from STBC21)
REGIST. ADDR. = First Register address (8 bits from 00H to 17H and from MSB to LSB)
DATA (Regx) = 8 bits data of the first addressed register (from MSB to LSB)
DATA (Regx+1) = 8 bits data of the next addressed register (from MSB to LSB)
A/An = Acknowledge/Not Acknowledge (SDA left high from STBC21)
P = STOP condition (from Master to STBC21)
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Detailed description
5.10.2
Sequential registers read:
SLAVE
ADDRESS
S
STBC21
R/W
(1)
Master
A
REGISTER
ADDRESS
A
SEND DATA
(Regx)
A
SEND DATA
(Regx+1)...
A/An
Slave (STBC21)
S = START condition (from Master to STBC21)
SLAVE ADDR. = 6BH
R/W = '0' Write / '1' Read
A = Acknowledge (SDA low from STBC21)
REG. ADDR. = First Register address (8 bits from 00H to 17H and from MSB to LSB)
SEND DATA (Regx)
= 8 bits of data coming from the first addressed register of STBC21 (from MSB to LSB)
SEND DATA
(Regx+1) = 8 bits of data coming from the next addressed register of STBC21 (from MSB to LSB)
A/An = Acknowledge/Not Acknowledge (SDA left high from Master)
P = STOP condition (from Master to STBC21)
28/54
Doc ID 023256 Rev 1
P
STBC21
6
ESD requirements
ESD requirements
HBM ± 2 kV, CDM ± 500 V
ESD sensitivity of the electrical components must be tested using the following standards
for each required model:
Charged device model (CDM)
●
JESD22-C101-C
●
ESD-STM5.3.1-1999
Human body model (HBM)
●
JESD22-A114-B
●
IEC6134-3-1:2002
●
ESD-STM5.1-2001
●
MIL-STD-883E 3015.7.
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Register configuration and access mode description
Appendix A
Table 10.
Register configuration and access mode
description
Configuration registers map
REG/BIT
B7
B6
B5
00H
AMR
TIMER-3
01H
Reserved
Reserved
02H
CV-4
03H
Th
04H
Reserved
05H
LF45
LD7
06H
Reserved
LD6
07H
Reserved
Table 11.
STBC21
B4
B3
B2
B1
B0
TIMER-2
ISET3
ISET1
CV-3
CV-2
CV-1
Th-h
Hys
Tl
LD45
LD3
CV4-Iset2
LD2
LF267
DUTY mode
CV3-Iset2
CV2-Iset2
CV1-Iset2
Control registers map
REG/
BIT
B7
B6
10H
NVM Busy
NVM
check
11H
VCC_uvlo
VCC_ovp IBAT_ocp Batt_ovp
Batt_uvlo
12H
ASD_Mode
Thermal Batt temp Batt temp
protection
alarm
alarm
Batt_temp_soc
13H
Customer_ en
14H
CE
Batt_temp_range
B5
B4
B3
B2
B1
B0
NVM command
Batt_hot Batt_detect_KO
Batt_no_
conn
Timer2
expired
0V_Chrg
_alarm
Reserved Reserved SW_chrg_alarm
Reserved
Iset2_half
Timer1 expired
SW_chrg_status
Vfloat_05
Vfloat_10
Vfloat_20
The STBC21 has two different access modes to the internal registers: user mode and
customer mode.
User mode
At power-on the STBC21 enters user mode. Only Reg11H and Reg12H are fully accessible
in read-mode while Reg13H is accessible in limited write-mode (only 'customer_mode' and
'CE' bits can be written) and fully accessible in read-mode.
Customer mode
The STBC21 enters customer mode when bit7, in Reg13H, is set to '1'. In this mode the
configuration of the internal system registers is:
30/54
●
Reg00H to Reg07H are accessible in read/write mode;
●
Reg10H has limited write access (NVM interface commands);
●
Reg11H and Reg12H are accessible only in read mode;
●
Reg13H has limited write access (commands bits only);
●
Reg14H is accessible only in read mode.
Doc ID 023256 Rev 1
STBC21
Charging parameters
Appendix B
Table 12.
Charging parameters
Timer registers summary
Timer name
Charging
phase
Setting range
Min. unit
TIMER-1
Pre-charge
60 min.
FIX
TIMER-2
Fast-charge
150 min. to 510 min.
30 min.
(1)
10 min.
TIMER-3
End of charge
TIMER-4
0V-charge
0 min. to 60 min.
16 sec
Accuracy
±10% @ 25°C
± 15% in temp
FIX
Step
Bit
-
-
12
4
7
3
-
-
Total
7
1. 0 min. means timer disabled.
Table 13.
Timer-2 description
TIMER-2 Reg 00H
Bit3
Bit2
Bit1
Bit0
150
min.
0
0
0
0
180
min.
0
0
0
1
210
min.
0
0
1
0
240
min.
0
0
1
1
270
min.
0
1
0
0
300
min.
0
1
0
1
330
min.
0
1
1
0
360
min.
0
1
1
1
390
min.
1
0
0
0
420
min.
1
0
0
1
450
min.
1
0
1
0
480
min.
1
0
1
1
510
min.
1
1
0
0
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Charging parameters
Table 14.
STBC21
Timer-3 description
TIMER-3 Reg 00H
Bit6
Bit5
Bit4
0
min.
0
0
0
10
min.
0
0
1
20
min.
0
1
0
30
min.
0
1
1
40
min.
1
0
0
50
min.
1
0
1
60
min.
1
1
0
1
1
1
-
Table 15.
Charging current registers
Name
Charging phase
Setting range
Min. unit
Accuracy
Step
Bit
ISET1
Pre-charge/0V-charge
current value
60 mA / 90 mA / 120 mA
30 mA
± 20%
3
2
ISET2
Fast-charge current value
100 mA to 1100 mA (1)
-
± 7% @ 800
mA
ISET3
End of charge current
value
40 mA to 190 mA (1)
10 mA
± 20%
Setting with
external resistor
16
4
1. End of charge current is always less than fast-charge current.
Table 16.
SET1 register description
ISET1 Reg 01H
32/54
Bit1
Bit0
60
mA
0
0
90
mA
0
1
120
mA
1
0
Doc ID 023256 Rev 1
Total
6
STBC21
Table 17.
Charging parameters
ISET3 register description
ISET3 Reg 01H
Table 18.
Bit5
Bit4
Bit3
Bit2
40
mA
0
0
0
0
50
mA
0
0
0
1
60
mA
0
0
1
0
70
mA
0
0
1
1
80
mA
0
1
0
0
90
mA
0
1
0
1
100
mA
0
1
1
0
110
mA
0
1
1
1
120
mA
1
0
0
0
130
mA
1
0
0
1
140
mA
1
0
1
0
150
mA
1
0
1
1
160
mA
1
1
0
0
170
mA
1
1
0
1
180
mA
1
1
1
0
190
mA
1
1
1
1
Constant voltage register
Name
Temperature range
Setting range
Accuracy
Step
Bit
Total
CV-1
TLO to TL
-2 °C - 10 °C
4.10 V / 4.20 V / 4.05 V
±0.03 V
3
2
8
CV-2
TL to TH
10 °C - 45 °C
4.10 V / 4.20 V / 4.05 V
3
2
CV-3
TH to THH
45 °C - 50 °C
4.10 V / 4.20 V / 4.05 V
3
2
CV-4
THH to THO
50 °C - 60 °C
4.10 V / 4.20 V / 4.05 V
3
2
Table 19.
CV1 bit description
CV1 Reg 02H
Bit1
Bit0
4.05
V
0
0
4.10
V
0
1
4.20
V
1
0
1
1
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Charging parameters
Table 20.
STBC21
CV2 bit description
CV2 Reg 02H
Bit2
4.05
V
0
0
4.10
V
0
1
4.20
V
1
0
1
1
Bit5
Bit4
-
Table 21.
Bit3
CV3 bit description
CV3 Reg 02H
4.05
V
0
0
4.10
V
0
1
4.20
V
1
0
1
1
Bit7
Bit6
-
Table 22.
CV4 bit description
CV4 Reg 02H
4.05
V
0
0
4.10
V
0
1
4.20
V
1
0
1
1
-
Table 23.
Halving register
Name
Notes
Bit
Total
ISET CV-1
Iset2 x 50% in CV-1
1
4
ISET CV-2
Iset2 x 50% in CV-2
1
ISET CV-3
Iset2 x 50% in CV-3
1
ISET CV-4
Iset2 x 50% in CV-4
1
Table 24.
ISET2 (CV1) bit description
CV1-Iset2 Reg 07H
Bit0
34/54
ISET2 x 50% ON
1
ISET2 x 50% OFF
0
Doc ID 023256 Rev 1
STBC21
Charging parameters
Table 25.
ISET2 (CV2) bit description
CV2-Iset2 Reg 07H
Bit1
Table 26.
ISET2 x 50% ON
1
ISET2 x 50% OFF
0
ISET2 (CV3) bit description
CV3-Iset2 Reg 07H
Bit2
Table 27.
ISET2 x 50% ON
1
ISET2 x 50% OFF
0
ISET2 (CV4) bit description
CV4-Iset2 Reg 07H
Bit3
ISET2 x 50% ON
1
ISET2 x 50% OFF
0
Doc ID 023256 Rev 1
35/54
Charging control
STBC21
Appendix C
Charging control
Table 28.
Charging control
Control
Notes
Bit
Total
Auto-recharge
Default is enabled
1
1
Table 29.
Auto recharge bit description
AMR Reg 00H
Bit7
36/54
Automatic recharge ON
1
Automatic recharge OFF
0
Doc ID 023256 Rev 1
STBC21
Temperature thresholds
Appendix D
Table 30.
Temperature thresholds
Name
Battery temperature
detection
Hysteresis range
Table 31.
Temperature thresholds
Temp
thresholds
Setting range
Minimum
unit
Accuracy
Step
Bit
THO 60 °C
0.75 V
FIX
±1% on voltage
Thresholds
-
-
THH 50 °C
0.79 V -1.002 V
0.014 V
16
4
TH 45 °C
0.89 V -1.10 V
0.014 V
16
4
TL 10 °C
1.74 V -1.95 V
0.014 V
16
4
TLO - 2 °C
2.128 V
FIX
-
-
THH, TH, TL
2 °C - 5 °C
3 °C
1
1
2 °C = 28 mV
5 °C = 70 mV
Total
FTP/
OTP
12
1 Time
Th-h reg
Th-h Reg 03H
Bit3
Bit2
Bit1
Bit0
0.792
V
0
0
0
0
0.806
V
0
0
0
1
0.820
V
0
0
1
0
0.834
V
0
0
1
1
0.848
V
0
1
0
0
0.862
V
0
1
0
1
0.876
V
0
1
1
0
0.890
V
0
1
1
1
0.904
V
1
0
0
0
0.918
V
1
0
0
1
0.932
V
1
0
1
0
0.946
V
1
0
1
1
0.960
V
1
1
0
0
0.974
V
1
1
0
1
0.988
V
1
1
1
0
1.002
V
1
1
1
1
Doc ID 023256 Rev 1
37/54
Temperature thresholds
Table 32.
STBC21
Th reg
Th Reg 03H
38/54
Bit7
Bit6
Bit5
Bit4
0.890
V
0
0
0
0
0.904
V
0
0
0
1
0.918
V
0
0
1
0
0.932
V
0
0
1
1
0.946
V
0
1
0
0
0.960
V
0
1
0
1
0.974
V
0
1
1
0
0.988
V
0
1
1
1
1.002
V
1
0
0
0
1.016
V
1
0
0
1
1.030
V
1
0
1
0
1.044
V
1
0
1
1
1.058
V
1
1
0
0
1.072
V
1
1
0
1
1.086
V
1
1
1
0
1.100
V
1
1
1
1
Doc ID 023256 Rev 1
STBC21
Temperature thresholds
Table 33.
Tl reg
Tl Reg 04H
Bit3
Bit2
Bit1
Bit0
1.740
V
0
0
0
0
1.754
V
0
0
0
1
1.768
V
0
0
1
0
1.782
V
0
0
1
1
1.796
V
0
1
0
0
1.810
V
0
1
0
1
1.824
V
0
1
1
0
1.838
V
0
1
1
1
1.852
V
1
0
0
0
1.866
V
1
0
0
1
1.880
V
1
0
1
0
1.894
V
1
0
1
1
1.908
V
1
1
0
0
1.922
V
1
1
0
1
1.936
V
1
1
1
0
1.950
V
1
1
1
1
Table 34.
Hys reg
Hys Reg 04H
Bit4
2
°C
0
5
°C
1
Doc ID 023256 Rev 1
39/54
LED configurations diversified for customer (each customer one pattern)
Appendix E
Table 35.
Pattern
STBC21
LED configurations diversified for customer
(each customer one pattern)
LED configurations
LED-flickering
timing
Battery charger mode
LED-Red
LED-Green
1.Battery uninstallation
Off
Off
2.Charging control
On
Off
3.Charging completion
Off
On
1
4.Charger alarm
f = 3 Hz
Flickering
Off
5.Battery alarm
f = 3 Hz
Flickering
Off
6.Temperature waiting control
Off
Off
1.Battery uninstallation
Off
Off
2.Charging control
On
Off
3.Charging completion
Off
On
2
4.Charger alarm
f = 2.5 Hz
Flickering
Off
5.Battery alarm
f = 2.5 Hz
Flickering
Off
6.Temperature waiting control
On
Off
1.Battery uninstallation
Off
Off
2.Charging control
On
Off
3.Charging completion
Off
On
3
4.Charger alarm
f = 2.5 Hz
Flickering
Off
5.Battery alarm
f = 2.5 Hz
Flickering
Off
f = 0.625 Hz
Flickering
Off
Off
Off
Flickering
Flickering
On
On
6.Temperature waiting control
1.Battery uninstallation
2.Charging control
f = 0.625 Hz
3.Charging completion
4
4.Charger alarm
f = 2.5 Hz
Flickering
Flickering
5.Battery alarm
f = 2.5 Hz
Flickering
Flickering
f = 0.625 Hz
Flickering
Flickering
7.Temperature waiting control/during
charging
On
On
1.Battery uninstallation
Off
Off
2.Charging control
On
Off
3.Charging completion
Off
On
4.Charger alarm
Off
Off
5.Battery alarm
Off
Off
6.Temperature waiting control
On
Off
6.Temperature waiting control/charging start
5
40/54
Doc ID 023256 Rev 1
STBC21
Table 35.
Pattern
LED configurations diversified for customer (each customer one pattern)
LED configurations (continued)
Battery charger mode
LED-Flickering
timing
LED-Red
LED-Green
1.Battery uninstallation
Off
Off
2.Charging control
On
Off
3.Charging completion
Off
On
4.Charger alarm
Off
Off
5.Battery alarm
Off
Off
6.Temperature waiting control
Off
Off
1.Battery uninstallation
Off
Off
2.Charging control
On
Off
3.Charging completion
Off
On
4.Charger alarm
Off
Off
5.Battery alarm
Off
Off
Flickering
Off
Off
Off
6
7
6.Temperature waiting control
f = 0.625 Hz
1.Battery uninstallation
2.Charging control
f = 2 Hz
Flickering
Flickering
3.Charging completion
f = 4 Hz
Off
Flickering
4.Charger alarm
f = 2 Hz
Flickering
Off
5.Battery alarm
f = 2 Hz
Flickering
Off
6.Temperature waiting control
f = 2 Hz
Flickering
Flickering
8
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LED display modes
STBC21
Appendix F
LED display modes
As a consequence of the configuration reported in Appendix E there are 7 possible modes:
Table 36.
LED display modes
Function
Condition
LED modes
Mode
Bit
1.Battery uninstallation
OFF
1
0
2.Charging control
1.ON / 2.FL
2
1
3.Charging completion
1.OFF /2.ON /3.OFF
3
2
1.FL /2.FL /3.OFF
3
2
5
3
2
1
Total
4.Charger alarm
LED
display
6.Temperature waiting
1.OFF/ 2.ON/3.OFF/ 4.FL/5.FL
control / after charging starts
7.Temperature waiting
control / during charging
Table 37.
1.ON/ 2. Same ilLumination MODE 6
6.Temperature waiting control / (after
charging starts)
LED frequency register
Function
Parameter
1.Battery uninstallation
2.Charging control
Range
FIXED
#
Step
#
Bit
1
0
-
±10%
2
1
4 Hz
-
±10%
1
0
4.Charger alarm
2 Hz, 2.5 Hz, 3 Hz, 4 Hz
-
±10%
4
2
5.Battery alarm
2 Hz, 2.5 Hz, 3 Hz, 4 Hz
-
±10%
4
(1)
6.Temperature waiting control
/ after charging starts
0.625 Hz, 2 Hz
-
±10%
2
(2)
7.Temperature waiting control
/ during charging
0.625 Hz, 2 Hz
-
±10%
2
(2)
1. Same as mode 4.
2. Same as mode 2.
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Minimum Accuracy
0.625 Hz, 2 Hz
3.Charging completion
Flickering
frequency
9
5.Battery alarm
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Total
3
STBC21
Table 38.
LED display modes
LED duty cycle register
Function
Condition
Range
1.Battery uninstallation
Minimum
Accuracy
#
Step
#
Bits
1
0
FIXED
Total
2.Charging control
3.Charging completion
Flickering duty
cycle
4.Charger alarm
30%, 50%,
80%
5.Battery alarm
2
30%
± 2%
6.Temperature waiting control
/ after charging starts
7.Temperature waiting control
/ during charging
LED display configurations
CHARGE RUNNING Reg 05H
Bit0
ON-OFF
0
FL-FL
1
CHARGE COMPLETE Reg 05H
Bit2
Bit1
OFF-ON
0
0
ON-ON
0
1
OFF-FL
1
0
Reserved
1
1
BATTERY/CHARGER ALARM Reg 05H
Bit4
Bit3
FL-OFF
0
0
FL-FL
0
1
OFF-OFF
1
0
Reserved
1
1
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LED display modes
STBC21
BATTERY TEMP. CONTROL (charge start mode) Reg 06H
Bit5
Bit4
Bit3
OFF-OFF
0
0
0
ON-OFF
0
0
1
OFF-FL
0
1
0
FL-FL
0
1
1
FL-FL
1
0
0
Reserved
1
0
1
Reserved
1
1
0
Reserved
1
1
1
BATTERY TEMP. CONTROL (charge running mode) Reg 05H
Bit5
ON-ON
0
Same as in “charge start mode”
1
LED display flickering frequency
BATTERY/CHARGER ALARM Reg 05H
Bit7
Bit6
2 Hz
0
0
2.5 Hz
0
1
3.0 Hz
1
0
4.0 Hz
1
1
CHARGE RUNNING AND TEMPERATURE CONTROL Reg 06H
Bit2
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0.625 Hz
0
2.0 Hz
1
Doc ID 023256 Rev 1
STBC21
LED display modes
DUTY CYCLE MODES Reg 06H
Bit1
Bit0
30%
0
0
50%
0
1
80%
1
0
Reserved
1
1
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NVM commands register
Appendix G
Table 39.
STBC21
NVM commands register
Address: 10H, Reset state: 00000000
Bit
Name
Read/Write
B7(MSB)
NVM busy
Read
1: NVM activity; 0: NVM free
B6
NVM check flag
Read
1: NVM data check failed; 0: NVM data check OK
B5
Read/Write
B4
Read/Write
B3
Read/Write
NVM commands (seeTable 40)
NVM command
B2
Read/Write
B1
Read/Write
B0(LSB)
Read/Write
Table 40.
Function
NVM commands
100 000
U (1)
Erase partial memory
001 000
U
Write partial memory array
011 000
U
Write partial complementary memory array
010 000
110 000
U
Read partial memory
1. NVM commands classified as 'U' are User allowed [permitted if customer_en=1 (Reg13H, B7)].
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STBC21
Charger, battery and alarm status registers
Appendix H
Table 41.
Charger, battery and alarm status registers
Address: 11H, Reset state: 00000000
Bit
Name
Read/Write
Function
B7(MSB)
VCC_uvlo
Read
1: VCC undervoltage protection, valid only after initialization.
Cleared at reset or sw_alarms_clr=Reg13H(5).
B6
VCC_ovp
Read
1: VCC over protection. Cleared at reset or sw_alarms_clr.
B5
IBAT_ocp
Read
1: IBAT over protection. Cleared at reset or sw_alarms_clr.
B4
Batt_ovp
Read
1: Battery overvoltage protection always active. Cleared at
battery disconnection or sw_alarms_clr, disabled by
Reg19H(6).
B3
Batt_uvlo
Read
1: Battery undervoltage protection valid only in fast-charge.
Cleared at battery disconnection or sw_alarms_clr.
B2
Batt_hot
Read
1: Battery temperature too high. Cleared at battery
disconnection or sw_alarms_clr.
B1
Batt_detect_KO
Read
1: Battery detection failed. Cleared at battery disconnection
or sw_alarms_clr.
B0(LSB)
Batt_no_conn
Read
1: Battery disconnected
Table 42.
Address: 12H, Reset state: 00000000
Bit
Name
Read/Write
Function
B7(MSB)
ASD_mode
Read
1: Automatic shutdown mode.
B6
Thermal protection
Read
1: Chip temperature over 115 ºC.
B5
Batt_temp_alarm
(T>60 ºC)
Read
1: Battery temp. is out of range during charge. At the first
occurrence it can be cleared if the battery temp. returns
again in a good range; after the first one, a battery
disconnection or sw_alarms_clr is needed.
B4
Batt_temp_alarm
(T>60 ºC or T<0 °C)
Read
1: Battery temp. is out of range during charge. Cleared if
battery temp. returns in a good range or at battery
disconnection or sw_alarm_clr.
B3
Batt_temp_soc
(at batt. insertion)
Read
1: Battery temp. is out of range at start of charge (battery
connection). Cleared at battery disconnection or
sw_alarms_clr or when temperature returns in good range.
B2
Timer2_expired
Read
1: Timer2 expired. Active only during fast-charge. Cleared
at battery disconnection or sw_alarms_clr.
B1
Timer1_expired
Read
1: Timer1 expired. Active only during pre-charge. Cleared
at battery disconnection or sw_alarms_clr.
B0(LSB)
0 V-Chrg_alarm
Read
1: Timer4 expired and battery still under 1 V. Cleared at
battery disconnection or sw_alarms_clr.
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Charger, battery and alarm status registers
Table 43.
Address: 13H, Reset state: 00000000
Bit
Name
Read/Write
B7 (MSB)
customer_en
Read/Write
1: Enable customer functions; 0: Disable
B6
CE
Read/Write
0: Charger enabled (default value); 1: Charger
disabled.
B5
Reserved
B4
Reserved
B3
SW_chrg_alarm
B2
B1
Table 44.
Table 45.
Bit
SW_chrg_status
1: Digital charger alarm during IDLE.
Read
Digital charger status (seeTable 44).
Read
Digital charger status
000
IDLE
001
Battery detection (force)
010
Battery detection (1st)
011
Pre-charge
100
Fast-charge
101
Safe-charge
110
Battery detection (2nd)
111
Termination
Address: 14H, Reset state: 00000000
Name
B7 (MSB)
B6
Read
Function
Read
B0 (LSB)
Read/Write
Function
Read
Batt_temp_range
B5
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STBC21
Read
Battery temperature range (see Table 46)
Read
B4
Reserved
B3
Iset2_half
Read
1: Iset2 (fast-charge current) set to 50%
B2
Vfloat_05
Read
1: Vfloat set to 4.05 V
B1
Vfloat_10
Read
1: Vfloat set to 4.10 V
B0 (LSB)
Vfloat_20
Read
1: Vfloat set to 4.20 V
Doc ID 023256 Rev 1
STBC21
Charger, battery and alarm status registers
Table 46.
H.1
Battery temperature range
000
No battery
001
Battery temperature > 60 ºC
010
Battery temperature > 50 ºC
011
Battery temperature > 45 ºC
100
Battery temperature > 10 ºC
101
Battery temperature > 0 ºC
110
Battery temperature < 0 ºC
111
Battery temperature < 0 ºC
Layout guidelines
The layout of the application board for the STBC21 is very critical due to the high precision
required on charging parameters which can be met only by minimizing the voltage drops
across the connecting tracks and the noise in the ground plane.
For these reasons the following guidelines are strongly suggested:
1.
Input and output decoupling capacitor should be placed as close as possible to the
STBC21 with short trace runs to both IN, OUT.
2.
All low current GND connections should be kept separate from the high current charge
or discharge paths from the battery.
3.
Use a single-point ground technique incorporating both the small signal ground path
and the power ground path.
4.
The high current charge paths into the IN pin and from the OUT pin must be sized
appropriately in order to avoid voltage drops in these traces.
5.
VBAT_SNS must be connected to VBAT as near as possible to the battery pin.
The layout of the board is reported below.
Figure 17. Layout board (top through view)
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Charger, battery and alarm status registers
Figure 18. Layout board (top view)
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STBC21
STBC21
7
Package mechanical data
Package mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK
specifications, grade definitions and product status are available at: www.st.com. ECOPACK
is an ST trademark.
Table 47.
HTSSOP-14L (5 x 4.4 mm) mechanical data
mm.
Dim.
Min.
Typ.
Max.
A
1.20
A1
0.15
A2
0.80
1.00
1.05
b
0.19
0.30
c
0.09
0.20
D
4.90
D1
1.70
E
5.00
5.10
6.20
6.40
6.60
E1
4.30
4.40
4.50
E2
1.50
e
L
0.65
0.45
L1
k
0.60
0.75
1.00
0
aaa
8
0.10
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Package mechanical data
STBC21
Figure 19. Drawing dimension HTSSOP-14L (5 x 4.4 mm)
7256412_C
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STBC21
8
Revision history
Revision history
Table 48.
Document revision history
Date
Revision
07-Jun-2012
1
Changes
Initial release
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STBC21
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