TI BQ77PL900 Five to ten series cell lithium-ion or lifthium-polymer battery protector and analog front end Datasheet

bq77PL900
www.ti.com ...................................................................................................................................................... SLUS844B – JUNE 2008 – REVISED JANUARY 2009
Five to Ten Series Cell Lithium-Ion or Lithium-Polymer Battery Protector
and Analog Front End
FEATURES
1
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•
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•
•
•
•
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•
5, 6, 7, 8, 9, or 10 Series-Cell Primary
Protection
PMOS FET Drive for Charge and Discharge
FETs
Capable of Operation with 1-mΩ Sense
Resistor
Supply Voltage Range from 7 V to 50 V
Low Supply Current of 450 µA Typical
Integrated 5-V, 25-mA LDO
Integrated 3.3-V, 25-mA LDO
Stand-Alone Mode
– Pack Protection Control and Recovery
– Individual Cell Monitoring
– Integrated Cell Balancing
– Programmable Threshold and Delay Time
for
– Overvoltage
– Undervoltage
– Overcurrent in Discharge
– Short Circuit in Discharge
– Fixed Overtemperature Protection
Host Control Mode
– I2C Interface to Host Controller
– Analog Interface for Host Cell Measurement
and System Charge/Discharge Current
– Host-Controlled Protection Recovery
– Host-Controlled Cell Balancing
APPLICATIONS
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•
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Cordless Power Tools
Power Assisted Bicycle/Scooter
Uninterruptible Power Supply (UPS) Systems
Medical Equipment
Portable Test Equipment
DESCRIPTION
The bq77PL900 is a five to ten series cell lithium-ion
battery pack protector. The integrated I2C
communications interface allows the bq77PL900 also
to be as an analog front end (AFE) for a Host
controller. Two LDOs, one 5-V, 25-mA and one 3.3-V,
25-mA, are also included and may be used to power
a host controller or support circuitry.
The bq77PL900 integrates a voltage translation
system to extract battery parameters such as
individual cell voltages and charge/discharge current.
Variables such as voltage protection thresholds and
detection delay times can be programmed by using
the internal EEPROM.
The bq77PL900 can act as a stand-alone
self-contained battery protection system (stand-alone
mode). It can alternatively be combined with a host
microcontroller to offer fuel gauge or other battery
management capabilities to the host system
(host-control mode).
The bq77PL900 provides full safety protection for
overvoltage, undervoltage, overcurrent in discharge,
and short circuit in discharge conditions. When the
EEPROM programmable safety thresholds are
reached, the bq77PL900 turns off the FET drive
autonomously. No external components are needed
to configure the protection features.
The analog front end (AFE) outputs allow a host
controller to observe individual cell voltages and
charge/discharge currents. The host controller’s
analog-to-digital
converter
connects
to
the
bq77PL900 to acquire these values.
Cell balancing can be performed autonomously, or
the host controller can activate it individually via a cell
bypass path integrated into the bq77PL900. Internal
control registers accessible via the I2C interface
configure this operation. The maximum balancing
bypass current is set via an external series resistor
and the internal FET-on resistance (typically 400 Ω).
Optionally, external bypass cell balance FETs can be
used for increased current capability.
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2008–2009, Texas Instruments Incorporated
bq77PL900
SLUS844B – JUNE 2008 – REVISED JANUARY 2009 ...................................................................................................................................................... www.ti.com
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
TYPICAL IMPLEMENTATION
Fuse
Pack +
Charge
bq77PL900
Discharge
PCH FET Drive
LDO, Thermal Output Drive
Overvoltage/
Undervoltage Protection
Cell Balance Drive
Serial Interface
RAM Registers
Overload Protection
Short-Circuit Protection
Pack –
Sense Resistor
B0323-01
Figure 1. Stand-Alone Mode
2
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Fuse
Pack +
bq77PL900
Microprocessor
PCH FET Drive
Thermal Measurement
Cell Balance Algorithm
and Control
RAM
ROM
Serial Interface
3.3 V or 5 V
NTC
LDO, Thermal Output Drive
XRST
Overvoltage/
Undervoltage Protection
Serial Interface
Voltage Output
Safety and Power
Management
Control
Cell Voltage Output, Cell Balance
Serial Interface
RAM Registers
Overload Protection
Battery Capacity Monitor
Short-Circuit Protection
Pack –
Sense Resistor
B0324-01
Figure 2. Host-Control Mode
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bq77PL900
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PIN DETAILS
Pin Out Diagram
DL Package
(Top View)
CPOUT
1
48
CHG
NC
2
3
47
46
PACK
45
NC
CP2
4
5
6
44
43
GPOD
CP1
NC
7
42
VREG1
DSG
8
GND
BAT
9
41
40
VC1
10
39
TOUT
VC2
11
38
TIN
VC3
37
GND
VC4
12
13
36
ZEDE
VC5
14
35
CNF2
VC6
15
34
CNF1
VC7
16
33
CNF0
VC8
32
VLOG
VC9
17
18
31
VOUT
VC10
19
30
GND
VC11
20
29
IOUT
GND
21
28
XRST
SRBGND
27
26
SCLK
SRPGND
22
23
EEPROM
24
25
XALERT
CP4
CP3
PMS
NC
VREG2
SDATA
P0084-01
TERMINAL FUNCTIONS
NAME
PIN #
DESCRIPTION
BAT
9
Power supply voltage
CHG
48
Charge FET gate drive
CNF0
33
Used cell for number determination in combination with CNF1 and CNF2
CNF1
34
Used cell for number determination in combination with CNF0 and CNF2
CNF2
35
Used cell for number determination in combination with CNF0 and CNF1
CP1
6
Charge pump capacitor 2 connection terminal
CP2
5
Charge pump capacitor 2 connection terminal
CP3
4
Charge pump capacitor 1 connection terminal
CP4
3
Charge pump capacitor 1 connection terminal (GND)
CPOUT
1
Charge pump output and internal power source.
DSG
8
Discharge FET gate drive
24
Active-high EEPROM write-enable pin. During normal operation, should be connected to GND
EEPROM
GND
21, 30, 37 Power-supply ground
GPOD
44
General-purpose N-CH FET open-drain output
GND
41
Should be connected to GND
IOUT
29
Amplifier output for charge/discharge current measurement
4
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TERMINAL FUNCTIONS (continued)
NAME
NC
PIN #
2, 7, 43,
45
DESCRIPTION
No connect (not electrically connected)
PACK
47
PACK positive terminal and alternative power source
PMS
46
Determines CHG output state for zero-volt charge
SCLK
27
Open-drain bidirectional serial interface clock with an internal 10-kΩ pullup to VLOG
SDATA
26
Open-drain bidirectional serial interface data with an internal 10-kΩ pullup to VLOG
SRBGND
22
Current sense terminal (Connect Battery to cell’s GND)
SRPGND
23
Current-sense positive terminal when discharging relative to SRNGND, current-sense negative terminal when
charging relative to SRGND. (Connect to pack GND)
TIN
38
Temperature sensing input
TOUT
39
Thermistor bias current source
VC1
10
Sense voltage input terminal for most positive cell, balance current input for most positive cell, and battery stack
measurement input
VC2
11
Sense voltage input terminal for second-most positive cell, balance current input for second-most positive cell, and
return balance current for most positive cell
VC3
12
Sense voltage input terminal for third-most positive cell, balance current input for third-most positive cell, and
return balance current for second-most positive cell
VC4
13
Sense voltage input terminal for fourth-most positive cell, balance current input for fourth-most positive cell, and
return balance current for third-most positive cell
VC5
14
Sense voltage input terminal for fifth-most positive cell, balance current input for fifth-most positive cell, and return
balance current for fourth-most positive cell
VC6
15
Sense voltage input terminal for sixth-most positive cell, balance current input for sixth-most positive cell, and
return balance current for fifth-most positive cell
VC7
16
Sense voltage input terminal for seventh-most positive cell, balance current input for seventh-most positive cell,
and return balance current for sixth-most positive cell
VC8
17
Sense voltage input terminal for eighth-most positive cell, balance current input for eighth-most positive cell, and
return balance current for seventh-most positive cell
VC9
18
Sense voltage input terminal for ninth-most positive cell, balance current input for ninth-most positive cell, and
return balance current for eighth-most positive cell
VC10
19
Sense voltage input terminal for tenth-most positive cell, balance current input for tenth-most positive cell, and
return balance current for ninth-most positive cell
VC11
20
Sense voltage input terminal for most negative cell, return balance current for least positive cell
VLOG
32
Data I/O voltage set by connecting either VREG1 or VREG2
VOUT
31
Amplifier output for cell voltage measurement
VREG1
42
Integrated 5-V regulator output
VREG2
40
Integrated 3.3-V regulator output
XALERT
25
Open-drain output used to indicate status register change. (Includes an internal 100-kΩ pullup to VLOG.)
XRST
28
Power-on-reset output. Active-low open-drain output with an internal 3-kΩ pullup to VLOG
ZEDE
36
Protection delay test pin. Minimizes protection delay times when connected to VLOG. Programmed delay times
used when pulled to GND, normal operation.
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5
6
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PACK–
CTHERM
RTHERM
0.98 V
3.3 V LDO
IOUT
CELL OUT
GPOD
ZEDE
PACK
EEPROM
State
Control
Thermal
Shutdown
PMS
Open Drain
Ooutput
SCD
CNF1
Control
SCC
CNF0
OLD/OLV
CNF2
OV/UV
Cell Bal
Output Ctl
Status
Registers
5 V LDO
CPOUT
EEPROM
XALERT
SCLK
SDATA
Buffer
Level
VLOG
XRST
TIN
TOUT
VREG2
VREG1
Charge Pump
Step Down
CP1 CP2 CP3 CP4
Serial
Interface
PACK+
PCH Gate
Driver
Delay
CHG
Short-Circuit
CELL1..10
Overload
Comparator
´10 or ´50
Short-Circuit
Comparator
Overcurrent
Cell AMP
Overvoltage
Undervoltage
PCH Gate
Driver
DSG
+
Cell
Selection
Switches
SRPGND
SRBGND
GND
VC11
VC10
VC9
VC8
VC7
VC6
VC5
VC4
VC3
VC2
VC1
BAT
Option
B0325-01
CELL 10
CELL 9
CELL 8
CELL 7
CELL 6
CELL 5
CELL 4
CELL 3
CELL 2
CELL 1
bq77PL900
SLUS844B – JUNE 2008 – REVISED JANUARY 2009 ...................................................................................................................................................... www.ti.com
FUNCTIONAL BLOCK DIAGRAM
Copyright © 2008–2009, Texas Instruments Incorporated
bq77PL900
www.ti.com ...................................................................................................................................................... SLUS844B – JUNE 2008 – REVISED JANUARY 2009
4 SAFETY STATE OVERVIEW
No Power Supply
Power Supply to PACK
Power Supply to PACK
Shutdown Mode
UVLO Mode
CHG: OFF
DSG: OFF
VREG1: OFF
VREG2: OFF
XRST: LOW
CHG: OFF
DSG: OFF
VREG1: OFF
VREG2: OFF
XRST: LOW
2
2
I C: Disabled
UV Protection: Disabled
OV Protection: Disabled
Current Protection: Disabled
Thermal Protection: Disabled
Internal VREG2 > 2.4 V
Current Protection Mode
Discharge Side
CHG: OFF
DSG: OFF
VREG1: ON
VREG2: ON
XRST: HIGH
2
I C: Enabled
UV Protection: Enabled
OV Protection: Enabled
Current Protection: Disabled
Thermal Protection: Enabled
Internal VREG2 < 2.3 V
No Supply to PACK
Normal Mode
VSR > VOC or VSC for a
period of tOC or tSC
2
I C: Enabled
UV Protection: Enabled
OV Protection: Enabled
Current Protection: Enabled
Thermal Protection: Enabled
VIN < 0.975 V
Vcell > VOV
VIN > 1.075 V
Undervoltage
Protection Mode
Vcell < VUV
CHG: ON
DSG: ON
VREG1: ON
VREG2: ON
XRST: HIGH
Attach a Charger
Overtemperature
Protection Mode
I C: Disabled
Current Protection: Disabled
VCELL: Disabled
Watchdog: Disabled
Thermal Protection: Disabled
All Cell Voltage > VUV + Δ VUV
(or Vpack – Vbat > 0.4 V and All
Cell Voltage > VUV)
CHG: ON
DSG: OFF
VREG1: ON
VREG2: ON
XRST: HIGH
2
I C: Enabled
UV Protection: Disabled
OV Protection: Enabled
Current Protection: Enabled
Thermal Protection: Enabled
All Cell Voltage < VOV – Δ VOV
Overvoltage
Protection Mode
CHG: OFF
DSG: OFF
VREG1: ON
VREG2: ON
XRST: HIGH
CHG: OFF
DSG: ON
VREG1: ON
VREG2: ON
XRST: HIGH
2
2
I C: Enabled
UV Protection: Enabled
OV Protection: Enabled
Current Protection: Enabled
Thermal Protection: Disabled
I C: Enabled
UV Protection: Enabled
OV Protection: Disabled
Current Protection: Enabled
Thermal Protection: Enabled
B0326-01
Figure 3. Stand-Alone Mode
Table 1. Stand-Alone STATUS Bit, XALERT and FET Transition Summary
MODE TRANSITION
STATUS BIT
XALERT
FET ACTIVITY
Normal to current protection
SCD or OCD = H to L
1
DSG and CHG off
Current protection to normal
SCD or OCD = L to H
0
DSG and CHG on
Normal to overvoltage protection
OVP = 1
H to L
CHG off
Overvoltage protection to normal
OVP = 0
L to H
CHG on
Normal to undervoltage protection (when VPACK goes down to 0 V, move to
shutdown mode)
UVP = 1
H to L
DSG off
Undervoltage protection to normal
UVP = 0
L to H
DSG on
Normal to overtemperature
OVT = 1
H to L
DSG and CHG off
Overtemperature to normal
OVT = 0
L to H
DSG and CHG on
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No Power Supply
Power Supply to PACK
Shutdown Mode
CHG: OFF
DSG: OFF
VREG1: OFF
VREG2: OFF
XRST: LOW
Power Supply to PACK
2
I C: Disabled
Current Protection: Disabled
VCELL: Disabled
Watchdog: Disabled
Thermal Protection: Disabled
UVLO Mode
CHG: OFF
DSG: OFF
VREG1: OFF
VREG2: OFF
XRST: LOW
Firmware Command
and No Supply to PACK
2
I C: Disabled
UV Protection: Disabled
OV Protection: Disabled
Current Protection: Disabled
Thermal Protection: Disabled
No Supply PACK
Voltage Mode
DSG: OFF
Any State
Internal VREG2 > 2.4 V
Current Protection Mode
Discharge Side
CHG: OFF
DSG: OFF
VREG1: ON
VREG2: ON
XRST: HIGH
2
I C: Enabled
UV Protection: Enabled
OV Protection: Enabled
Current Protection: Disabled
Thermal Protection: Enabled
VSR > VOC or VSC
or Firmware
for a period of
Command
tOC or tSC
Firmware Command
Turn On Tout and
VIN < 0.975 V
Internal VREG2 < 2.3 V
Normal Mode
CHG: OFF
DSG: OFF
VREG1: ON
VREG2: ON
XRST: HIGH
Turn On Tout and
VIN > 1.075 V,
then Firmware
Command
2
I C: Enabled
UV Protection: Enabled
OV Protection: Enabled
Current Protection: Enabled
Thermal Protection: Disabled
Vcell < VUV or Firmware
Command
CHG: ON
DSG: ON
VREG1: ON
VREG2: ON
XRST: HIGH
2
I C: Enabled
UV Protection: Enabled
OV Protection: Enabled
Current Protection: Enabled
Thermal Protection: Enabled
Vcell > VOV
Overtemperature
Protection Mode
Firmware
Command
All Cell Voltage > VUV + Δ VUV
(or Vpack – Vbat > 0.4 V and All
Cell Voltage < VUV), then
Firmware Command
Undervoltage
Protection Mode
CHG: ON
DSG: OFF
VREG1: ON
VREG2: ON
XRST: HIGH
2
I C: Enabled
UV Protection: Disabled
OV Protection: Enabled
Current Protection: Enabled
Thermal Protection: Enabled
All Cell Voltage < VOV, then
Firmware Command
Overvoltage
Protection Mode
CHG: OFF
DSG: ON
VREG1: ON
VREG2: ON
XRST: HIGH
2
I C: Enabled
UV Protection: Enabled
OV Protection: Disabled
Current Protection: Enabled
Thermal Protection: Enabled
B0327-01
Figure 4. Host-Control Mode
8
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Table 2. Host Control Summary
MODE TRANSITION
FUNCTION AND FIRMWARE PROCEDURE
Normal to current protection
Vsr > Voc or Vsc for period of toc or tsc
Automatically, DSG and CHG turn off, SCD or OCD status changes = 1, XALERT = L
Current protection to normal
1. Send commands to transition LTCLR from 0 to 1 to 0
2. Read status bit. XALERT would change to H.
3. Set CHG and DSG FET ON to enable normal operation
Normal to overvoltage protection
Vcell > Vov for period of tov
Automatically, CHG turns off, UV status changes = 1, XALERT = L
Overvoltage protection to normal
1. Confirm the OVP protection status is cleared
2. Send command LTCLR from 1 to 0
3. Read status bit. XALERT changes to H.
4. Set CHG FET ON to enable normal operation
UVFET_DIS = 0
Normal to undervoltage
protection
UVFET_DIS = 1
Undervoltage protection
to normal
Vcell < Vuv for period of tuv
Automatically, DSG turns off, UV status changes = 1, XALERT = L
1. Vcell < Vuv or for period of tuv, UV status changes = 1, XALERT = L
2. Send commands to turn off DSG.
1. Confirm the OVP protection status is cleared
UVFET_DIS = X
2. Send command LTCLR from 1 to 0
3. Set DSG FET ON to enable normal operation
4. Read status bit. XALERT changes to H.
Normal to overtemperature
1. Send commands to turn on TOUT
2. If TIN voltage < 0.975 V, DSG and CHG turn off, OVTEMP status changes = 1,
XALERT = L
Overtemperature to normal
1. Send commands to turn on TOUT (To return to normal mode, bq77PL900 must
acknowledge Vth > 1.075 V)
2. Send commands to transition LTCLR from 1 to 0
3. Set CHG and DSG FET ON
4. Read status bit. XALERT changes to H.
Any mode to shutdown
1. Set DSG FET OFF
2. Wait until PACK voltage decreases to 0 V
3. SET shutdown bit to 1
ORDERING INFORMATION
(1)
TA
PACKAGED
SSOP48
–40°C to 100°C
bq77PL900DL (1)
The bq77PL900 can be ordered in tape and reel by adding the suffix
R to the orderable part number, I.e., bq77PL900DLR.
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ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted) (1)
VMAX
Supply voltage range
VIN
Input voltage range
(2)
VALUE
UNIT
BAT, PACK
–0.3 to 60
V
VC1–VC10
–0.3 to 60
VC11
–0.3 to 0.3
VCn to VCn + 1, n = 1 to 10
–0.3 to 8
PMS
–0.3 to 60
SRP, SRN
–0.5 to 1
SDATA, SCLK, EEPROM, VLOG, ZEDE, CNF0, CNF1, CNF2, TIN
VO
Output voltage range
PACK – 20 to 60
DSG
BAT – 20 to 60
TOUT, VOUT, IOUT, XRST, XALERT, SDATA, SCLK
–0.3 to 7
CP1, CP2, CP3, CP4, CPOUT, GPOD
–0.3 to 60
VREG1
–0.3 to 8
VREG2
–0.3 to 3.6
Current for cell balancing
TSTG
Storage temperature range
TSOLDER
Lead temperature (soldering, 10 s)
(1)
(2)
–0.3 to 7
CHG
ICB
V
V
10
mA
–65 to 150
°C
300
°C
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating
Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
All voltages are with respect to ground of this device except VCn – VC(n+1), where n=1 to 10 cell voltage.
DISSIPATION RATINGS
10
PACKAGE
TA ≤ 25°C
POWER RATING
DERATING FACTOR
ABOVE TA ≥ 70°C
TA = 85°C
POWER RATING
TA = 100°C
POWER RATING
DL
1388 mW
11.1 mW/°C
720 mW
555 mW
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RECOMMENDED OPERATING CONDITIONS
MIN
Supply Voltage
PACK, BAT
VI(STARTUP)
Start-up voltage PACK
VLOG
7
Logic supply voltage
Input voltage range
VI
NOM
50
7.5
1.2 × VREG1
VC1 to VC10
0
BAT
VC11
0
0.5
–0.3
0.5
VCn – VC(n + 1), (n = 1 to 10)
0
Logic level input voltage high
Logic level input voltage low
Output voltage range
SCLK, SDATA, EEPROM, VLOG
(VLOG = VREG1 or VREG2)
VOUT, IOUT
0.8 × VLOG
VLOG
0
0.2 × VLOG
V
VLOG
VGAIN = High
1.2
VGAIN = Low
0.975
GPOD
V
45
RVCX
I(reg1 + reg2)
V
Ω
400
IREGOUT
V
50
XALERT, SDATA
VO
V
7
PACK, BAT
VIL
UNIT
V
0.8 × VREG2
SRP, SRN
VIH
MAX
25
mA
CREG1
External 5-V REG capacitor
2.2
µF
CREG2
External 3.3-V REG capacitor
2.2
µF
CCP1, CCP2
Charge pump flying capacitor
1
µF
CCPOUT
Charge pump output capacitor
4.7
µF
CVOUT
Output capacitance
0.1
µF
CIOUT
Output capacitance
0.1
IOL
fSCLK
GPOD, XRST
Input frequency
SCLK
EEPROM number of writes
µF
1
mA
100
kHz
3
TOPR
Operating temperature
–25
85
°C
TFUNC
Functional temperature
–40
100
°C
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ELECTRICAL CHARACTERISTICS
BAT = PACK = 7 V to 50 V, TA = –25°C to 85°C, typical values stated where TA = 25°C and BAT = PACK = 36 V (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
450
550
UNIT
SUPPLY CURRENT
TA = 25°C
Supply current 1
No load at REG1, REG2, TOUT, SCLK, SDIN,
XALERT, CELLAMP, CURRENTAMP = off
CHG, DSG = on, cell balance = off,
IREG1 = IREG2 = 0 mA,
Charge pump = off (1), BAT = PACK = 35 V
TA = 25°C
ICC2
Supply current 2
No load at REG1, REG2, TOUT, SCLK, SDIN,
XALERT, CELLAMP, CURRENTAMP = on,
CHG, DSG = on,
Cell balance = off, IREG1 = IREG2 = 0 mA,
Charge pump = off, BAT = PACK = 35 V
ISHUTDOWN
Shutdown mode
CHG, DSG = off, VREG1 = VREG2 = off,
PACK = 0 V, BAT = 35 V
ICC1
TA = –40°C to
100°C
600
650
TA = –40°C to
100°C
750
800
TA = 25°C
0.1
TA = –40°C to
100°C
µA
µA
1.2
2
µA
VREG1, INTEGRATED 5-V LDO
8.5 V < PACK or BAT ≤ 50 V, IOUT ≤ 25 mA
4.55
5
5.45
4.55
5
5.45
7 V < PACK or BAT ≤ 8.5 V, IOUT ≤ 3 mA
TA = –40°C to
100°C
Output temperature drift
PACK or BAT = 50 V, IOUT = 2 mA
TA = 25°C
±0.2%
Line regulation
10 V ≤ PACK or BAT ≤ 50 V, IOUT = 2 mA
TA = 25°C
10
20
7
15
40
100
35
75
125
5
20
35
3.05
3.3
3.55
3.05
3.3
3.55
–2%
3.3
2%
V(REG1)
Output voltage
ΔV(REG1)
ΔV(REG1LINE)
ΔV(REG1LOAD)
Load regulation
IREG1MAX
Current limit
PACK or BAT = 36 V, 0.2 mA ≤ IOUT ≤ 2 mA
PACK or BAT = 36 V, 0.2 mA ≤ IOUT ≤ 25 mA
PACK or BAT = 36 V, VREG1 = 4.5 V
PACK or BAT = 36 V, VREG1 = 0 V
TA = 25°C
TA = 25°C
V
mV
mV
mA
VREG2, INTEGRATED 3.3-V LDO
8.5 V < PACK or BAT ≤ 50 V, IOUT ≤ 25 mA
V(REG2)
Output voltage
7 V < PACK or BAT ≤ 8.5 V, IOUT ≤ 10 mA
TA = –40°C to
100°C
7 V < PACK or BAT ≤ 50 V, IOUT = 0.2 mA
ΔV(REG2)
Output temperature drift
PACK or BAT = 50 V, IOUT = 2 mA
TA = –40°C to
100°C
Line regulation
7 V ≤ PACK or BAT ≤ 50 V, IOUT = 2 mA
TA = 25°C
Load regulation
IREG2MAX
Current limit
PACK or BAT = 36 V, 0.2 mA ≤ IOUT ≤ 2 mA
PACK or BAT = 36 V, 0.2 mA ≤ IOUT ≤ 25 mA
PACK or BAT = 36 V, VREG2 = 3 V
PACK or BAT = 36 V, VREG2 = 0 V
±0.2%
10
20
7
15
40
100
25
50
100
10
20
30
TA = 25°C
TA = 25°C
V
mV
mV
mA
TOUT, THERMISTOR POWER SUPPLY
VTOUT
IOUT = 0 mA
TA = –40°C to
100°C
TA = –40°C to
100°C
3.05
3.55
V
50
100
Ω
RDS(ON)
Pass-element series
resistance
IOUT = –1 mA at TOUT pin, Ireg2 = –0.2 mA
RDS(ON) = (VREG2 – VTOUT)/1 mA
VTINS
Thermistor sense
voltage
TA = –40°C to 100°C
–5%
0.975
5%
V
VTINSHYS
Thermistor sense
hysteresis voltage
TA = –40°C to 100°C
50
100
150
mV
THERMAL SHUTDOWN
Ttherm
Shutdown threshold
PACK or BAT = 36 V (2)
150
°C
PMS, PRECHARGE MODE SELECT DISABLE
VPMSDISABLE
PMS disable threshold of
PACK = PMS = 20 V, VREG2 = 0 V, CHG = ON → OFF
BAT
8
13
16
VLOG = VREG1(5 V) V
3.85
4.05
4.25
VLOG = VREG2(3.3 V) V
2.45
2.65
2.8
V
POR, POWER-ON RESET
VPOR–
(1)
(2)
12
Negative-going voltage
input
V
Charge pump starts working when (IREG33 + IREG5) > 3 mA.
Not 100% tested, assured by design up to 125°C
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ELECTRICAL CHARACTERISTICS (continued)
BAT = PACK = 7 V to 50 V, TA = –25°C to 85°C, typical values stated where TA = 25°C and BAT = PACK = 36 V (unless
otherwise noted)
PARAMETER
VPOR_HYS
Positive-going hysteresis
tRST
Reset delay time
TEST CONDITIONS
VLOG = 3.3 V
VLOG = 5 V
MIN
TYP
MAX
50
150
250
100
250
400
1
5
UNIT
mV
ms
CELL VOLTAGE MONITOR
VCELL
OUT
CELL output
VCn – VCn + 1 = 0 V , 20 V ≤ BAT ≤ 50 V, VGAIN = Low
0.925
0.975
1.025
VCn – VCn + 1 = 0 V , 20 V ≤ BAT ≤ 50 V, VGAIN = High
1.12
1.2
1.28
V
VCn – VCn + 1 = 4.5 V , 20 V ≤ BAT ≤ 50 V
0.3
REF 1
CELL output
Mode (3), 20 V ≤ BAT or PACK ≤ 50 V, VGAIN = Low
–2%
0.975
2%
V
REF 2
CELL output
Mode (4), 20 V ≤ BAT or PACK ≤ 50 V, VGAIN = High
–2%
1.2
2%
V
PACK
CELL output
Mode (5)
–5% PACK/50
5%
V
BAT
CELL output
Mode (6)
–5%
5%
CMRR
Common-mode rejection
CELL max to CELL min, 20 V ≤ BAT ≤ 50 V
K1
CELL scale factor 1
K2
CELL scale factor 2
BAT/50
40
V
dB
K = {CELL output (VC11 = 0 V, VC10 = 4.5 V) – CELL output
(VC11 = VC10 = 0 V)} / 4.5 (7)
0.147
0.15
0.153
K = {CELL output (VC2 = 40.5 V, VC1 = 45 V) – CELL output (VC2 = VC1
= 40.5 V)} / 4.5 (7)
0.147
0.15
0.153
K = {CELL output (VC11 = 0 V, VC10 = 4.5 V) – CELL output (VC11 =
VC10 = 0 V)} / 4.5 (8)
0.197
0.201
0.205
K = {CELL output (VC2 = 40.5 V, VC1 = 45 V) – CELL output (VC2 = VC1
= 40.5 V)} / 4.5 (8)
0.197
0.201
0.205
12
18
µA
–1
mV
IVCELLOUT
Drive current
VCn – VCn + 1= 0 V, Vcell = 0 V, TA = –40 to 100°C
VICR
CELL output offset error
CELL output (VC2 = 45 V, VC1 = 45 V) – CELL output (VC2 = VC1 = 0 V)
RBAL
Cell balance internal
resistance
RDS(ON) for internal FET switch at VDS = 2 V, BAT = PACK = 35 V
–50%
400
50%
Ω
CURRENT MONITOR
VIOUT
VOFFSET
Output voltage
Input offset voltage
DC gain, low
IIOUT
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
VSRP = VSRN = 0 V
(9)
1.2
V
VSRP = VSRN = 0 V (9), TA = 25°C
–3
3
VSRP = VSRN = 0 V (9), TA = –40°C to 100°C
–4
4
–100 mV < SRP < 100 mV
(10)
(11)
DC gain, high
–20 mV < SRP < 20 mV
Drive current
VIOUT = 0 V, TA = –40°C to 100°C
STATE_CONTROL [VGAIN] = 0, FUNCTION_CONTROL [VAEN] = 1, CELL_SEL[CAL2]
STATE_CONTROL [VGAIN] = 1, FUNCTION_CONTROL [VAEN] = 1, CELL_SEL[CAL2]
STATE_CONTROL [VGAIN] = X, FUNCTION_CONTROL [PACK] = 1, [VAEN] = 1
STATE_CONTROL [VGAIN] = X, FUNCTION_CONTROL [BAT] = 1, [VAEN] = 1
STATE_CONTROL [VGAIN] = 0, FUNCTION_CONTROL [VAEN] = 1, CELL_SEL[CAL2]
STATE_CONTROL [VGAIN] = 1, FUNCTION_CONTROL [VAEN] = 1, CELL_SEL[CAL2]
STATE_CONTROL [IGAIN] = X, FUNCTION_CONTROL [IAEN] = 1, [IACAL] = 1
STATE_CONTROL [IGAIN] = 0, FUNCTION_CONTROL [IAEN] = 1, [IACAL] = 0
STATE_CONTROL [IGAIN] = 1, FUNCTION_CONTROL [IAEN] = 1, [IACAL] = 0
–2%
10
2%
–2%
50
2%
12
18
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µA
= 0, [CAL0] = 1, [CAL0] = 1
= 0, [CAL0] = 1, [CAL0] = 1
= 0, [CAL0] = 0, [CAL0
= 0, [CAL0] = 0, [CAL0] = 0
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13
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ELECTRICAL CHARACTERISTICS (continued)
BAT = PACK = 7 V to 50 V, TA = –25°C to 85°C, typical values stated where TA = 25°C and BAT = PACK = 36 V (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
BATTERY PROTECTION THRESHOLDS
VOV
OV detection threshold
range
ΔVOV
OV detection threshold
program step
VOVH
OV detection hysteresis
voltage range
ΔVOVH
OV detection hysteresis
program step
VUV
UV detection threshold
range
ΔVUV
UV detection threshold
program step
VUVH
UV detection hysteresis
voltage
ΔVUVH
UV detection threshold
program step
VOCDT
OCD detection threshold
range
ΔVOCDT
OCD detection threshold
program step
VSCDT
SCD detection threshold
range
ΔVSCDT
SCD detection threshold
program step
VOV_acr
OV detection threshold
accuracy
Default (TA = 0°C to 85°C)
VUV_acr
UV detection threshold
accuracy
Default
VOCD_acr
OCD detection threshold
accuracy
VSCD_acr
SCD detection threshold
accuracy
Default
4.15
4.5
50
Default
0
mV
0.3
0.1
Default
1.4
2.9
0.2
1.2
10
85
60
mV
mV
135
5
VOCD = 10 mV or 15 mV
V
mV
5
Default
V
mV
200
Default
V
V
100
Default
V
mV
mV
–50
0
50
mV
–100
0
100
mV
mV
–4
0
4
VOCD > 20 mV
–20%
0
20%
Default
–20%
0
20%
Default
500
BATTERY PROTECTION DELAY TIMES
tOV
OV detection delay time
range
ΔtOV
OV detection delay time
step
tUV
UV detection delay time
range
ΔtUV
UV detection delay time
step
tOCD
OCD detection delay
time range
ΔtOCD
OCD detection delay
time step
tSCD
SCD detection delay
time range
ΔtSCD
SCD detection threshold
program step
tOV_acr
OV detection delay time
accuracy
Default
–15%
0%
15%
tUV_acr
UV detection delay time
accuracy
Default
–15%
0%
15%
tOC_acr
OC detection delay time
accuracy
Default
–15%
0%
15%
VSCD_acr
SC detection delay time
accuracy
tSCD Max
–15%
0%
15%
14
2250
250
Default
Default
Default
ms
0
8000
ms
1.25
1000
ms
20
1600
ms
20
100
ms
0
900
µs
µs
60
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ELECTRICAL CHARACTERISTICS (continued)
BAT = PACK = 7 V to 50 V, TA = –25°C to 85°C, typical values stated where TA = 25°C and BAT = PACK = 36 V (unless
otherwise noted)
PARAMETER
tSRC
TEST CONDITIONS
MIN
TYP
MAX
–15%
12.8 s
15%
1
1.4
2
V
0.05
0.1
0.3
V
VO(FETONDSG) = V(BAT) – V(DSG),
VGS connect 1 MΩ, BAT = PACK = 35 V
8
12
16
VO(FETONCHG) = V(PACK) – V(CHG),
VGS connect 1 MΩ, BAT = PACK = 35 V
8
12
16
OC/SC recovery timing
in stand-alone mode
UNIT
BATTERY PROTECTION RECOVERY
VRECSC
SC, OC recovery voltage
VRECUV
Undervoltage recover
voltage
VRECUV = VPACK– VBAT,
VUV + VUVH > VCELL > VUV
FET DRIVE
V(FETON)
Output voltage, charge
and discharge FETs on
V
V(FETOFF)
Output voltage, charge
and discharge FETs off
VO(FETOFFDSG) = V(PACK) – V(DSG), BAT = PACK = 35 V
0.2
VO(FETOFFCHG) = V(BAT) – V(CHG), BAT = PACK = 35 V
0.2
tr
Rise time
CL = 20 nF, BAT = PACK = 35 V
tf
Fall time
CL = 20 nF, BAT = PACK = 35 V
VDSG: 10% to 90%
5
15
VCHG: 10% to 90%
5
15
VDSG: 90% to 10%
90
140
VCHG: 90% to 10%
90
140
V
µs
µs
LOGIC
VOL
Logic-level output
voltage
XALERT, IOUT = 200 µA, TA = –40°C to 100°C
0.4
SDATA, SCLK, XRST, IOUT = 1 mA,
TA = –40°C to 100°C
0.4
GPOD, IOUT = 1 mA, TA = –40°C to 100°C
0.6
ILEAK
Leakage current
GPOD VOUT = 1 V, TA = –40°C to 100°C
VIH
SCLK (hysteresis input)
Hysteresis
RUP
Pullup resistance
XALERT, TA = –40°C to 100°C
IDOWN
Pulldown current
1
400
60
100
200
6
10
20
XRST, TA = –40°C to 100°C
1
3
6
2
4
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µA
mV
DATA, SCLK, TA = –40°C to 100°C
CNF0, CNF1, CNF2 = VREG2
V
kΩ
µA
15
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SLUS844B – JUNE 2008 – REVISED JANUARY 2009 ...................................................................................................................................................... www.ti.com
I2C COMPATIBLE INTERFACE
BAT = PACK = 7 V to 50 V, TA = –25°C to 85°C, typical values stated where TA = 25°C and BAT = PACK = 36 V (unless
otherwise noted)
MAX
UNIT
tr
SCLK, SDATA rise time
PARAMETER
MIN
1000
ns
tf
SCLK, SDATA fall time
300
tw(H)
SCLK pulse duration high
tw(L)
tsu(STA)
th(STA)
START condition hold time after which first clock pulse is generated
tsu(DAT)
Data setup time
250
ns
th(DAT)
Data hold time
0
µs
tsu(STOP)
Setup time for STOP condition
4
µs
tsu(BUF)
Time the bus must be free before new transmission can start
tV
Clock low to data-out valid
th(CH)
Data-out hold time after clock low
0
fSCL
Clock frequency
0
ns
4
µs
SCLK pulse duration low
4.7
µs
Setup time for START condition
4.7
µs
4
µs
tsu(STA)
tw(L)
tw(H)
µs
4.7
900
ns
100
kHz
ns
tr
tf
SCLK
tr
tf
SDATA
tsu(DAT)
SDA Input
th(DAT)
th(STA)
Stop Condition
SDA Change
Start Condition
SCLK
1
SDATA
MSB
2
th(ch)
3
7
8
9
ACK
tv
Start Condition
tsu(STOP)
SCLK
1
2
3
7
8
9
tsu(BUF)
SDATA
MSB
ACK
Stop Condition
T0369-01
Figure 5. I2C-Like I/F Timing Chart
16
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GENERAL OPERATIONAL OVERVIEW
Stand-Alone Mode and Host Control Mode
The bq77PL900 has two operational modes, stand-alone mode and host-control mode. The mode is switched by
STATE_CONTROL [HOST]. In stand-alone mode, the battery protection is managed by the bq77PL900 without
the need for any external control. In this mode, the CHG and DSG FETs are driven ON and OFF automatically
and cell balancing is processed by a fixed algorithm if enabled by OCDELAY[CBEN]). In this mode, I2C
communication is enabled, and a host can read the registers and set STATE_CONTROL [HOST] but cannot
control any output or function such as Vcell AMP enable.
In host control mode, a host microcontroller can obtain battery information such as voltage and current from the
bq77PL900 analog interface. This allows the host, such as a microcontroller, to calculate remaining capacity or
implement an alternative cell balancing algorithm. In this mode, the bq77PL900 still detects cell protection faults
and acts appropriately, although the recovery method is different from that in stand-alone mode. The host
controller has control over the recovery method and FET action after the protection state has been entered.
Table 3 contains further details of the protection action differences.
Table 3. Stand-Alone Mode and Host Control Mode Protection Summary
FUNCTION
OV protection
UV protection
Overtemperature
protection
Host-Control Mode
(HOST = H)
Detection
Automatic
The bq77PL900 detects an OV voltage and
turns OFF the CHG FET. Must turn off cell
balancing for correct voltage detection.
Recovery
Host Control
Detection
Host Control
The bq77PL900 detects a UV voltage but no
FET action is taken. Must turn off cell
balancing for correct voltage detection.
Recovery
OCD/SCD
protection
Stand-Alone Mode
(HOST = L)
MODE
Automatic
The bq77PL900 detects and recovers from
protection states and controls the FETs.
Host Control
Automatic
The bq77PL900 detects OCD and turns CHG
and DSG FETs OFF.
Detection
Recovery
Host Control
Detection
Host must turn ON.
Recovery
Host Control
CHG/DSG FET
control
—
Automatic
Host cannot drive the FETs
Host Control
The bq77PL900 cannot release from
protection state automatically.
Cell balancing
—
CBEN = 1: Automatic
CBEN = 0: No function
Host Control
The host can balance any cells at any time
CBEN = Don’t care
Zero-volt charge1
PMS = High,
ZVC = X
Automatic
(0-V charge current flows through CHG FET)
Automatic
Zero-volt charge2
PMS = Low,
ZVC = 0
No support for 0-V charge
PMS = Low,
ZVC = 1
Automatic
(0-V charge current flows through FET that is
driven by GPOD)
Zero-volt charge3
Host Control
Host should control precharge FET by using
GPOD pin.
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Normal Operation Mode
When all cell voltages are within the range of VUV to VOV, and the CHG and DSG FETs are turned ON, the cells
are charged and discharged at any time.
Pack+
On
On
Pack
Bat
Battery
bq77PL900
Load
Pack–
S0345-01
Figure 6. Normal Operation Mode
18
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Battery Protection
The bq77PL900 fully integrates battery protection circuits including cell overvoltage, undervoltage, and
overcurrent in discharge and short circuit in discharge detection. Each detection voltage can be adjusted by
programming the integrated EEPROM. Also, the detection delay time can be programmed as shown in Table 4.
CAUTION:
Only a maximum of three programming cycles should performed to ensure data
stability.
Table 4. Detection Voltage, Detection Delay Time Summary
PARAMETER
Voltage
Overvoltage
Undervoltage
Overcurrent in discharge
Short circuit in discharge
MIN
MAX
STEP
BITS
4.15 V
4.5 V
50 mV
3
Delay
0.5 s
2.25 s
0.25 s
3
Hysteresis
100 mV
400 mV
50 mV
2
Voltage
1.4 V
2.9 V
100 mV
4
Delay
0 ms
30 ms
1.25 ms–10 ms
4
1s
8s
1s
Hysteresis
100 mV
1200 mV
0.2 V, 0.4 V
2
Voltage
10 mV
85 mV
5 mV
4
Delay
20 ms
1600 ms
20 ms or 100 ms
5
Voltage
60 mV
135 mV
5 mV
4
Delay
0 µs
900 µs
60 µs
4
Cell Overvoltage and Cell Undervoltage Detection
The cell overvoltage and cell undervoltage detection circuit consists of a sample-and-hold (S/H) circuit and two
comparators.
The S/H period is about 120 µs for each cell, and S/H is performed sequentially on each cell. Once all of the
cells are checked, the bq77PL900 waits about 50 mS for the next S/H.
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Sample-and-Hold Circuit
OV/UV Comparator
OV Comparator
–
VC8
+
Delay
Counter
OVth
VC9
UV Comparator
VC10
+
–
–
+
VC11
Delay
Counter
UVth
120 ms ´ Number of Cells
/Monitor OV and UV
Sampling Sequence: 50 ms
S0346-01
Figure 7. Cell Voltage Monitoring Circuit
Cell Overvoltage Detection and Recovery
Cell overvoltage detection is the same as host control mode for the FET OFF state, but the recovery conditions
are different. The CHG FET is turned OFF if any one of the cell voltages remains higher than VOV for a period
greater than tOV. As a result, the cells are protected from an overcharge condition. Also XLAERT changes from
High to Low. Both VOV and tOV can be programmed in the internal EEPROM.
Recovery in Host Control Mode
The recovery condition is as follows:
1. All cell voltages become lower than VOV (ΔVOVH is ignored).
2. Additionally, the host must send a sequence of firmware commands to the bq77PL900 to turn ON the CHG
FET.
The command sequence required is as follows:
1. The host must toggle LTCLR from 0 to 1 and then back to 0.
2. Then set the CHG control bit to 1. To reset XLAERT high, the host must read the status register.
Figure 8 illustrates the circuit schematic in overvoltage protection mode in Host Control Mode. Figure 9 illustrates
the timing of this protection mode.
20
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Pack+
On
Off
Pack
Bat
Cell Voltage
VOV
Battery
Overvoltage
Detect Comparator
Charger
bq77PL900
Pack–
S0347-01
Figure 8. Overvoltage in Host-Control Mode
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OV Detect
All Cell Voltage < VOV
BAT
Disconnect
Charger
Connect
Load
PACK
DSG
Host Turns on CHG FET
CHG
Host Reads STATUS Register
XALERT
T0370-01
Figure 9. OV and OV Recovery Timing in Host-Control Mode
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Recovery in Stand-Alone Mode
The recovery condition occurs when all cell voltages become lower than (VOV – ΔVOVH).
Figure 10 illustrates the circuit schematic in overvoltage protection mode in stand-alone mode. Figure 11
illustrates the timing of this protection mode.
Pack+
On
Off
Pack
Bat
Cell Voltage
VOV – DVOVH
Battery
Overvoltage
Detect Comparator
Charger
bq77PL900
Pack–
S0348-01
Figure 10. Cell Overvoltage Protection Mode in Stand-Alone Mode
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OV Detect
All Cell Voltage < (VOV – DVOVH)
BAT
Disconnect
Charger
Connect
Load
PACK
DSG
CHG
XALERT
T0371-01
Figure 11. OV and OV Recovery Timing in Stand-Alone Mode
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7.14.1 Cell Undervoltage Detection and Recovery
When any one of the cell voltages falls below VUV for a period of tUV, the bq77PL900 enters the undervoltage
mode. At this time, the DSG FET is turned OFF and XALERT driven low. Both VUV and tUV can be programmed
in the internal EEPROM.
Pack+
Off
On
Pack
Bat
Battery
Charge Currrent
Detect Comparator
Load
Undervoltage
Detect Comparator
bq77PL900
Pack–
S0349-01
Figure 12. Cell Undervoltage Protection Mode in Host Mode and Stand-Alone Mode (Attaching a Charger)
In Host-Control Mode
Cell undervoltage protection recovery conditions are when:
1. All cell voltages become higher than (VUV + ΔVUVH), or
2. All cell voltages are higher than VUV AND a charger is connected between PACK+ and PACK–, noting that
PACK+ voltage must be higher than BAT due to the diode forward voltage.
The bq77PL900 monitors the voltage difference between the PACK+ and BAT pins. When a difference higher
than 0.4V (typ.) is seen, it is interpreted that a charger has been connected.
Figure 12 illustrates the circuit schematic in undervoltage protection mode.
In some applications, it is required not to turn OFF the DSG FET suddenly. In these cases, by setting UVLEVLE
[UVFET_DIS] = 1, only XALERT is driven low in response to entering an undervoltage condition. The host can
turn OFF the DSG FET to protect the undervoltage condition. When the bq77PL900 recovery condition is
satisfied, the host must send a sequence of firmware commands to the bq77PL900. The firmware command
sequence to turn ON the DSG FET is as follows:
1. The host must toggle LTCLR from 0 to 1 and back to 0.
2. Then the host must set the DSG ON bit to 1.
3. Then the host can read the status register to reset XALERT high.
Figure 13 and Figure 14 illustrate the timing chart of protection mode.
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BAT
UV Detection
Connect a Charger
All Cell Voltage > (VUV + DVUVH) or
All Cell Voltage > VUV
and Detecting (PACK+) – VBAT > 0.1 V
PACK
Host Turns On DSG FET
DSG
CHG
Host Read Status Register
XALERT
T0372-01
Figure 13. UV and UV Recovery Timing Host-Control Mode (UVFET_DIS = 0)
BAT
UV Detection
Connect a Charger
All Cell Voltage > (VUV + DVUVH) or
All Cell Voltage > VUV
and Detecting (PACK+) – VBAT > 0.1 V
PACK
DSG Not
Turning Off
DSG
Host Turns on DSG FET
Host Turns Off DSG FET
CHG
Host Read Status Register
XALERT
T0373-01
Figure 14. UV and UV Recovery Timing Host Control Mode (UVFET_DIS = 1)
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In Stand-Alone Mode
On detecting entry to undervoltage mode, the bq77PL900 moves to the shutdown power mode.
When a charger is attached, the bq77PL900 wakes up from shutdown mode. If cell voltages are lower than the
undervoltage condition, the DSG FET is turned OFF and XALERT driven low. During periods when a charger is
attached, the bq77PL900 never changes to shutdown mode.
When the undervoltage recovery condition is satisfied, the DSG FET turns ON and XLAERT is reset high.
UV Detection
BAT
UV Detection
PACK
Connect a Charger
All Cell Voltage > (VUV + DVUVH) or
All Cell Voltage > VUV
and Detecting (PACK+) – VBAT > 0.1 V
DSG
CHG
Change to Shutdown
Wake Up
REG1/REG2
T0374-01
Figure 15. UV and UV Recovery in Stand-Alone Mode
Overcurrent in Discharge (OCD) Detection
The overcurrent in discharge detection feature detects abnormal currents in the discharge direction via
measuring the voltage across the sense resistor (VOCD) and is used to protect the pass FETs, cells, and any
other inline components from abnormal discharge current conditions. The detection circuit also incorporates a
blanking delay period (tOCD) before turning OFF the pass FETs. Both VOCD and tOCD can be programmed in
internal EEPROM.
Short Circuit in Discharge (SCD) Detection
The short circuit in discharge detection feature detects severe discharge current via measuring the voltage
across the sense resistor (VSCD) and is used to protect the pass FETs, cells, and any other inline components
from severe current conditions. The detection circuit also incorporates a blanking delay period (tSCD) before
turning OFF the pass FETs. Both VSCD and tSCD can be programmed in the internal EEPROM.
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7.14.1 Overcurrent in Discharge and Short Circuit in Discharge Recovery
In host-control mode, the host must send a sequence of firmware commands to the bq77PL900 to recover from
overcurrent and short-circuit currents. The command sequence to turn ON the DSG and CHG FETs is as follows:
1. The host must toggle LTCLR from 0 to 1 and back to 0.
2. Then set the DSG and CHG control bits to 1. To reset XALERT high, the STATUS register must be read.
In stand-alone mode, the bq77PL900 has two methods to recover from overcurrent and short-circuit conditions
by setting the SOR bit of OCD_CFG.
SOR = 0: Recover comparator is active after 12.8 s. An internal comparator monitors the PACK+ voltage and
when the PACK+ voltage reaches VRECSC, the overcurrent in discharge recovers. When the bq77PL900
detects a charger is attached, the DSG and CHG FETs turn ON and XALERT is reset High.
SOR = 1: After 12.8 s, the bq77PL900 automatically recovers from OC and SC. The DSG and CHG FETs
turn ON and XALERT is reset high. If the OC or SC condition is still present, OC and SC is detected again
and the recovery/detection cycle continues until the fault is removed.
Pack+
Off
Off
Pack
Bat
Battery
OL/SC Release
Comparator
Load
bq77PL900
Pack–
S0350-01
Figure 16. Overcurrent and Short-Circuit Protection Modes
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Table 5. Detection and Recovery Condition Summary (Stand-Alone Mode)
CELL OVERVOLTAGE
CELL UNDERVOLTAGE
OVERCURRENT IN
DISCHARGE
SHORT CIRCUIT IN
DISCHARGE
Detection condition
Any cell voltage > VOV
Any cell voltage < VUV
(VSRP – VSRN) > VOCD
(VSRP – VSRN) > VSCD
CHG FET
ON → OFF
ON
ON → OFF
ON → OFF
DSG FET
ON
ON → OFF
ON → OFF
ON → OFF
Recovery condition 1
All cell voltage <
(VOV – ΔVOVH)
All cell voltages >
(VUV + ΔVUVH)
SOR = 0: Attach a
charger
SOR = 1: OC condition is
released
SOR = 0: Attach a
charger
SOR = 1: SC condition is
released
All cell voltages > VUV
AND
PACK+ – VBAT > 0.1 V
Recovery condition 2
CHG FET
OFF → ON
ON
OFF → ON
OFF → ON
DSG FET
ON
OFF → ON
OFF → ON
OFF → ON
Table 6. Detection and Recovery Condition Summary (Host-Control Mode)
CELL OVERVOLTAGE
CELL UNDERVOLTAGE
OVERCURRENT IN
DISCHARGE
SHORT CIRCUIT IN
DISCHARGE
Detection condition
Any cell voltage > VOV
Any cell voltage < VUV
(VSRP – VSRN) > VOCD
(VSRP – VSRN) > VSCD
CHG FET
ON → OFF
ON
ON → OFF
ON → OFF
DSG FET
ON
ON → OFF
(UVFET_DIS = 0)
ON → OFF
ON → OFF
Recovery condition 1
All cell voltage < VOV
(ignore the hysteresis)
All cell voltage >
(VUV + ΔVUVH)
None
None
All cell voltage > VUV
AND
VPACK – VBAT > 0.1 V
Recovery condition 2
(1)
CHG FET (1)
OFF → ON
ON
OFF → ON
OFF → ON
DSG FET (1)
ON
OFF → ON
OFF → ON
OFF → ON
Host is required to set and clear LTCLR, then turn on the FETs.
Low-Dropout Regulators (REG1 and REG2)
The bq77PL900 has two low dropout (LDO) regulators that provide power to both internal and external circuitry.
The inputs for these regulators can be derived from the PACK or BAT terminals (see the Initialization section for
further details). The output of REG1 is typically 5 V, with a minimum output capacitance of 2.2 µF required for
stable operation. It is also internally current-limited. During normal operation, the regulator limits the output
current, typically to 25 mA. The output of REG2 is typically 3.3 V, also with a minimum output capacitance of 2.2
µF for stable operation, and it is also internally current-limited.
Until the internal regulator circuit is correctly powered, the DSG and CHG FETs are driven OFF.
Initialization
From a shutdown situation, the bq77PL900 requires a voltage greater that the start-up voltage (VSTARTUP) applied
to the PACK pin to enable its integrated regulator and provide the regulator power source. Once the REG1 and
REG2 outputs become stable, the power source of the regulator is switched to BAT.
After the regulators have started, they then continue to operate through the BAT input. If the BAT input is below
the minimum operating range, then the bq77PL900 does not operate until the supply to the PACK input is
applied.
If the voltage at REG2 falls, the internal circuit turns off the CHG and DSG FETs and disables all controllable
functions, including the REG1, REG2, and TOUT outputs.
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Series Configuration of Five to Ten Cells
Unused cell inputs are required to be shorted to the uppermost-voltage-connected terminal. For example, in a
five-cell configuration, VC1 to VC5 are shorted to VC6. In a 9-cell configuration, VC1 is shorted to VC2.
The CNF0, CNF1, and CNF2 pins should be connected to VLOG = logic 1 (through a10-kΩ resistance) or GND =
logic 0 (directly) according to the desired cell configuration as seen in Table 7.
Table 7. Cell Configuration
CNF2 PIN
CNF1 PIN
CNF0 PIN
CELL
CONFIGURATION
0
0
0
10-cell
0
0
1
9-cell
0
1
0
8-cell
0
1
1
7-cell
1
0
0
6-cell
1
0
1
5-cell
All other combinations
10-cell
Delay Time Zero
The ZEDE pin enables EEPROM-programmed detection delay times when connected with GND (normal
operation). The detection delay time is set to 0 when this pin is connected with VLOG. This is typically used in
battery manufacturing test only.
Cell Voltage Measurement
The cell voltage is translated to allow a host controller to measure individual series elements of the battery. The
series element voltage is presented on the VOUT terminal. The cell voltage amplifier gain can be selected as
one of the following two equations. The VOUT voltage gain is selected by STATE_CONTROL [VGAIN]. VOUT is
internally connected to ground when disabled.
VOUT1 = 0.975 – {(Cell voltage) × 0.15} when VGAIN = 0
or
VOUT 2 = 1.2 – {(Cell voltage) × 0.20} when VGAIN = 1
The total pack voltage can also be monitored. The PACK voltage output is enabled or disabled by
FUNCTION_CONTROL [PACK].
VOUT3 = (Total pack voltage) × 0.02 when PACK = 1
The total pack voltage can also be monitored. The BAT voltage output is enabled or disabled by
FUNCTION_CONTROL [BAT].
VOUT4 = (Total battery voltage) × 0.02 when BAT = 1
Cell Voltage Measurement Calibration
The bq77PL900 cell-voltage monitor consists of a sample-and-hold (S/H) circuit and differential amplifier.
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Sample-and-Hold Circuit
VC8
Differential Amp Circuit
VC9
VC10
+
–
VOUT
–
+
VC11
REF = 2.5 V
VREF = 0.975 V or 1.2 V
Calibration
S0351-01
Figure 17. Cell Voltage Monitoring Circuit
To calibrate the VCELL output, it must measure a 2.5-V signal, but 2.5 V is beyond the ADC input range of most
analog-to-digital converters used in these applications. The bq77PL900 is designed to measure the 2.5 V
through a differential amplifier first, which is where the calibration procedure starts.
VOUT
VOUT
Step 1 Vd OUT(0V)
Step 5 Vout(VREF_m)
Step 3 VdOUT(VREF_m)
Step 6 Vout(2.5V)
Step 4 VdOUT(2.5V)
KdACT
Step 2 VREF_m
Step 2 VREF_m
Calculate
CalculateVREF_2.5V
VREF_2.5V from
fromStep
Step
1–4
1-4
0V
VREF_2.5V
VC(n + 1) – VCn
VREF_m(0.975V or 1.2V)
0V
VREF_2.5V
VREF_m(0.975V or 1.2V)
Differential Amp
Input
M0122-01
Figure 18. Calibration Method
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Step 1
Set CAL2 = 0, CAL1 = 0, CAL0 = 1, CELL[4:1] = 0, VAEN = 1
Measure the output voltage of the differential amplifier at 0-V input (both inputs of the differential amplifier are
connected to GND). The output voltage includes the offset and is represented by:
VdOUT(0V) = measured output voltage of differential amplifier at 0-V input
(This value includes an offset voltage (VOS) and a reference voltage.)
Step 2
Set CAL2 = 0, CAL1 = 1, CAL0 = 1, VAEN = 1
VREF is trimmed to 0.975 V or 1.2 V within ±2%. Then measure internal reference voltage VREF directly from
VOUT:
VREF_m = measured reference voltage (0.975 V or 1.2 V)
Step 3
Set CAL2 = 0, CAL1 = 1, CAL0 = 0, CELL[4:1] = 0, VAEN = 1
Measure the scaled REF voltage through the differential amplifier.
VdOUT(VREF_m) = The output voltage, including the scale factor error and offset
= VREF + (1 + K) × VOS – K × VREF
= VREF_m + (1 + KdACT) × VOS – KdACT × VREF_m
where: VREF_m + (1 + KdACT) × VOS = VdOUT(0V)
KdACT = ( VdOUT(0V) – VdOUT(VREF_m)) / VREF_m
= (measured value at step 1 – measured value at step 3)/ measured value at step 2
Calibrated differential voltage is calculated by:
Vdout = VREF + (1 + K) × VOS – K × Vdin
= VdOUT(0V) – KdACT × Vdin
Where: Vdin = input voltage of differential amp lifier
Step 4
Set CAL2 = 1, CAL1 = 0, CAL0 = 0, CELL[4:1] = 0, VAEN = 1
Measure scaled REF(2.5V) though differential amp,
Some TI-Benchmarq gas gauges cannot measure 2.5 V directly, because the ADC input voltage is 1 V. So to
measure the 2.5-V internal reference voltage, use a differential amplifier as a method to scale down the
measurement value.
Vdout(2.5V) = measured differential amp output voltage at the 2.5-V input
Already, differential amplifier calibration was performed in steps 1, 2, and 3.
So VREF_2.5V is presented by
VREF_2.5V = { VdOUT(0V) – Vdout(2.5V)}/KdACT
Step 5
Set CAL2 = 1, CAL1 = 0, CAL0 = 1, CELL2 = 0, CELL1 = 0, VAEN = 1
Vout(0.975V or 1.2V) = Measure scaled REF (0.975-V or 1.2-V) output voltage S/H and differential amplifier.
Step 6
Set CAL2 = 1, CAL1 = 1, CAL0 = 0, CELL[4:1] = 0, VAEN = 1
Vout(2.5V) = Measure scaled REF (2.5-V) output voltage S/H and differential amp.
Scale factor
KACT = –(VOUT(2.5V) – VOUT(0.975V or 1.2V)/(VREF_2.5V – VREF_m)
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Vout(0V) = VOUT(2.5V) + KACT × VREF_2.5V
OR
Vout(0V) = VOUT(0.975V or 1.2V) + KACT × VREF_m
Cell voltage is calculated by as follows:
VCn – VC(n + 1) = {Vout(0V) – VOUT} / KACT
Current Monitor
Discharge and charge currents are translated to allow a host controller to measure accurately current, which
measurement can then be used for additional safety features or calculating the remaining capacity of the battery.
The sense resistor voltage is converted using the following equation. The typical offset voltage is VCELL_OFF
(1.2 V typical), although it can be presented on the IOUT pin for measurement, if required.
The output voltage increases when current is positive (discharging) and decreases when current is negative
(charging).
VCURR = 1.2 + (IPACK × RSENSE) × (IGAIN)
where
State_Control [IGAIN] = 1 then IGAIN = 50
State_Control [IGAIN] = 0 then IGAIN = 10
The current monitor amplifier can present the offset voltage as shown in Table 8. The IOUT pin is enabled or
disabled by FUNCTION_CONTROL [IACAL, IAEN] and has a default state of OFF. IOUT is internally connected
to ground when disabled.
Table 8. IACAL and IAEN Configuration
IACAL
IAEN
CONDITION
0
1
NORMAL
1
1
OFFSET
X
0
OFF
Cell Balance Control
The integrated cell balance FETs allow a bypass path to be enabled for any one series element. The purpose of
this bypass path is to reduce the current into any one cell during charging to bring the series elements to the
same voltage. Series resistors placed between the input pins and the positive series element nodes limits the
bypass current value. Series input resistors between 500 Ω and 1 kΩ are recommended for effective cell
balancing.
In host-control mode, individual series element selection is made via CELL_BALANCE [CBAL1, CBAL2, CBAL3,
CBAL4, CBAL5, CBAL6, CBAL7, and CBAL8] and FUNCTION_CONTROL [CBAL9, CBAL10].
In stand-alone mode, cell balancing works as shown in Figure 19. When a certain cell (cell A) voltage reaches
cell overvoltage, the battery charging stops and then cell balance starts working at ta. The cell-A voltage
decreases by the bypass current until the voltage reaches (VOV – ΔVOVH). Cell-B voltage does not change during
the period because cell balancing works only for the cell that reached VOV. At tb, battery charging starts again.
Cell A and cell B have been charged in this period until cell-A voltage reaches VOV again. The voltage difference
between cell A and cell B becomes smaller when the bq77PL900 repeats the foregoing cycle. The bq77PL900
stops cell balance when cell overvoltage protection has released.
The bq77PL900 is designed to prevent cell balancing on adjacent cells or on every other cell. For example, if cell
overvoltage happened to cell 8, cell 7 (cell 7 is next to cell 8) and cell 3 (cell 3 is not next to cell 8 or cell 7), then
cell balancing starts for cell 8 and cell 3 first. When the cell-8 voltage is back to normal, then cell balancing starts
for cell 7.
While the bq77PL900 monitors the overvoltage and undervoltage, cell balancing is automatically turned off. This
configuration is supported for both modes (host-control and stand-alone modes).
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Vdiffb
VOV
VOV – DVOVH
Cell A
Vdiffa
Cell B
ta
tb
tc
td
te
tf
T0375-01
Figure 19. Cell Balancing Timing Chart (Automatic)
Thermistor Drive Circuit (TOUT), Thermistor Input (TIN)
The TOUT pin is powered by REG2, can be enabled via FUNCTION_CONTROL [TOUT] to drive an external
thermistor, and is OFF by default. A 10-kΩ, 25°C NTC (e.g., Semitec 103AT) thermistor is typical. The maximum
output impedance is 100 Ω.
The bq77PL900 monitors the battery temperature as shown in Figure 20. A voltage divided by the NTC
thermistor and reference resistor is connected to TIN. The bq77PL900 compares the TIN voltage with the internal
reference voltage (0.975V), and when VTIN < VREF the bq77PL900 turns OFF the CHG and DSG FETs and sets
STATUS [OVTEMP].
In host-control mode, the host should enable and disable TOUT.
RTHERM
TOUT
3.3 V
TIN
VREF
CTHERM
S0352-01
Figure 20. Temperature Monitoring Circuit
General-Purpose Open-Drain Drive (GPOD)
The GPOD output is enabled or disabled by OUTPUT_CONTROL [GPOD] and has a default state of OFF.
In stand-alone mode, this pin is used for driving the 0-V/precharge FET for zero-voltage battery charging by
OCD_CFG [ZVC] = 1.
Alerting the Host (XALERT)
In both modes, the XALERT pin is available and is driven low when faults are detected. The method to clear the
XALERT pin is different in stand-alone mode than in host-control mode. In stand-alone mode, XLAERT is cleared
when all of the faults are cleared. In host-control mode, the host must toggle (from 0, set to 1, then reset to 0)
OUTPUT_CONTROL [LTCLR] and then read the STATUS register.
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Alerting the Host (LTCLR)
In host-control mode, when a protection fault occurs, the state is latched. The fault flag is unlatched by toggling
(from 0, set to 1 then reset to 0) OUTPUT_CONTROL [LTCLR]. The OCD, SCD, OV, and UV bits are unlatched
by this function. Now the FETs can be controlled by programming the OUTPUT_CONTROL register, and the
XALERT output can be cleared by reading the STATUS register. When detecting overvoltage or undervoltage
faults, LTCTR changes are ignored. After a period of 1 ms, it must send an LTCLR command.
Fault Timeout
Expired
STATUS Register
Read
FET Control Access by Host
Fault Flag Set
LTCLR Bit
XALERT Output
T0376-01
Figure 21. LTCLR and XLAERT Clear Timing (Host-Control Mode)
POR
The XRST open-drain output pin is triggered on activation of the VREG1 or VREG2 output. This holds the host
controller in reset for tRST, allowing VVREG1 or VVREG2 to stabilize before the host controller is released from reset.
The XRST output and monitoring voltage is supplied by the source of VLOG. When VLOG is connected to
VREG1, the XRST output level is VVREG1 and monitors the activation of VREG1. When VLOG is connected to
VREG2, the XRST output level is VVREG2 and monitors the activation of VREG2.
When VVREG1 or VVREG2 voltage is below the output specifications, XRST is active-low (0.8 × VLOG). When VBAT
is below 7 V, VREG1 and VREG2 stop, then XRST goes low. If a host has a problem with a sudden reset signal,
it is recommended monitoring the battery voltage to avoid it, e.g., burnout detection.
VREGTH+
VREGTH–
REG Output
tRST
VLOG
XRST Output
T0377-01
Figure 22. XRST Timing Chart – Power Up and Power Down
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EEPROM Write Sequence
The bq77PL900 has integrated configuration EEPROM for OV, UV, OCD, and SCD thresholds and delays. The
appropriate configuration data is programmed to the configuration registers, and then 0xe2 is sent to the
EEPROM register to enable the programming supply voltage. By driving the EEPROM pin (set high and then
low), the data is written to the EEPROM.
When supplying BAT, care should be taken not to exceed VCn – VC(n + 1), (n = 1 to 10) > 5 V. If BAT and VC1
are connected onboard, it is recommended that all cell-balance FETs be ON where each input voltage is divided
with the internal cell-balance ON resistance.
The recommended voltage at BAT or PACK for EEPROM writing is 20 V. When supplying VBAT, care is needed
to ensure VBAT does not exceed the VCn – VC(n + 1), (n = 1 to 10) absolute maximum voltage. If BAT and VC1
are connected onboard, supplying 7.5 V is recommended to activate the bq77PL900 and turn ON all cell-balance
FETs.
Then increase the power supply up to 20 V. By this method, each input voltage is divided with the internal
cell-balance ON resistance.
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EEPROM
Programming
Start
Set
BAT Voltage or
PACK Voltage = 20 V
Confirm the Status
Register VGOOD = 1
2
Send I C command
OV/UV/SC/OL
Register = Desired Value
Set EEPROM Pin =
VLOG Voltage (3.3 V
or 5.5 V)
2
Send I C Command
EEPROM Register
= 0110 0010
Verify the
OV/UV/OL/SC Value
Wait 100 ms
2
Send I C Command
EEPROM Register
= 0000 0000
2
Send I C Command
EEPROM Register
= 0100 0001
Wait 1 ms
Set EEPROM Pin = GND
Verify the
OV/UV/OL/SC Value
EEPROM
Programming
Finish
F0038-01
Figure 23. EEPROM Data-Writing Flow Chart
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Power Modes
The bq77PL900 has two power modes, normal and shutdown. Table 9 outlines the operational functions during
the two power modes.
Table 9. Power Modes
POWER
MODE
TO ENTER
NORMAL MODE
MODE DESCRIPTION
The battery is in normal operation with protection, power management, and battery monitoring
functions available and operating. The supply current of this mode varies, as the host can enable and
disable various features.
Normal
Shutdown
Add supply at the
VPACK < VWAKE
When undervoltage is detected in stand-alone mode, or shutdown command at host-control mode, the
bq77PL900 goes into shutdown: all outputs and interfaces are OFF and memory is not valid.
Shutdown Mode
In host-control mode, the bq77PL900 enters shutdown mode when it receives the shutdown command,
STATE_CONTROL [SHDN] set. First, the DSG FET is turned OFF, and then after the pack voltage goes to 0 V,
the bq77PL900 enters shutdown mode, which stops all functions of the bq77PL900.
In stand-alone mode the bq77PL900 enters shutdown when the battery voltage falls and UV is detected. It turns
the DSG FET OFF, and after the pack voltage goes to 0 V, the bq77PL900 enters shutdown mode, which stops
all functions.
Exit From Shutdown
If a voltage greater than VSTARTUP is applied to the PACK pin, then the bq77PL900 exits from shutdown and
enters normal mode.
Parity Check
The bq77PL900 uses EEPROM for storage of protection thresholds, delay times, etc. The EEPROM is also used
to store internal trimming data. For safety reasons, the bq77PL900 uses a column parity error checking scheme.
If the column parity bit is changed from the written value, then OUT_CONTROL [PFALT] is set to 1 and XALERT
driven low. In stand-alone mode, both DSG and CHG outputs are driven high, turning OFF the DSG and CHG
FETs. The GPOD output is also turned off.
In host-control mode, only OUT_CONTROL [PFALT] and the XALERT output are changed, allowing the
microprocessor host to control bq77PL900 operation.
Communications
The I2C-like communication provides read and write access to the bq77PL900 data area. The data is clocked via
separate data (SDATA) and clock (SCLK) pins. The bq77PL900 acts as a slave device and does not generate
clock pulses. Communication to the bq77PL900 can be provided from the GPIO pins of a host controller. The
slave address for the bq77PL900 is 7 bits and the value is 0010 000.
I2C Address + R/W Bit
(MSB)
Write
Read
0
(LSB)
I2C Address
(MSB)
0
1
0
(LSB)
0
0
0
0
1
The bq77PL900 does NOT have the following functions compatible with the I2C specification.
• The bq77PL900 is always regarded as a slave.
• The bq77PL900 does not support the general code of the I2C specification and therefore does not return an
ACK, but may return a NACK.
• The bq77PL900 does not support the address auto-increment, which allows continuous reading and writing.
• The bq77PL900 allows data to be written to or read from the same location without resending the location
address.
38
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SCLK
•••
SDATA
A6
A5
A4
•••
•••
A0 R/W ACK
0
Start
R7
R6
R5
•••
•••
R0 ACK
0
D7
D6
D5
D0 ACK
•••
0
0
Register Address
Slave Address
Data
Stop
T0378-01
2
Figure 24. I C-Bus Write to bq77PL900
SCLK
•••
SDATA
A6
A5
•••
•••
A0 R/W ACK
0
R7
•••
R0 ACK
0
A6
0
•••
A0 R/W ACK
1
Slave Address
Register Address
Slave
Start
R6
•••
•••
0
D7
D6
D0 NACK
•••
Master
Drives
NACK and
Stop
Slave Drives
the Data
Repeated
Start
Stop
T0379-01
2
Figure 25. I C-Bus Read From bq77PL900: Protocol A
SCLK
SDATA
•••
A6
A5
•••
•••
A0 R/W ACK
R7
R6
•••
•••
R0 ACK
A6
A5
•••
•••
A0
R/W ACK
0
Start
Slave
Register Address
Stop
Start
Slave Address
D7
•••
D0
Slave
Drives
the Data
NACK
Master
Drives
NACK and
Stop
Stop
T0380-01
2
Figure 26. I C-Bus Read From bq77PL900: Protocol B
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Register Set
The bq77PL900 has 12 addressable registers. These registers provide status, control, and configuration
information for the battery protection system.
Table 10. Register Descriptions
TEST
PIN
ADDR
MEMORY
R/W
STATUS
X
0x00
Read
R
OUTPUT_CONTROL
X
0x01
RAM
R/W
Output pin control from system host-control mode and external pin
status
STATE_CONTROL
X
0x02
RAM
R/W
State control from system host and external pin status
FUNCTION_CONTROL
X
0x03
RAM
R/W
Function control from system host and external pin status
CELL BALANCE
X
0x04
RAM
R/W
Battery cell select for balance bypass
CELL _SEL
X
0x05
RAM
R/W
Battery cell select for balance bypass and for analog output voltage
NAME
DESCRIPTION
Status register
(1)
OV CFG
X
0x06
EEPROM
R/W
UV LEVEL
X
0x07
EEPROM
R/W (1)
Undervoltage level register
OCV & UV DELAY
X
0x08
EEPROM
R/W (1)
Overload voltage level and undervoltage delay time register
OCDELAY
X
0x09
EEPROM
R/W (1)
Overload delay time register
(1)
SCD CFG
X
0x0a
EEPROM
EEPROM
X
0x0b
RAM
(1)
R/W
R/W
Overvoltage level and delay time register
Short-circuit in discharge current level and delay time register
EEPROM read and write enable register
Write and read data will be match after write EEPROM writing procedure.
Table 11. Register Map
NAME
2
I C ADDR
B7
STATUS
0x00
OUTPUT_CONTROL
0x01
STATE_CONTROL
0x02
IGAIN
VGAIN
0
0
FUNCTION_CONTROL
[Cell(9,10) balance register]
0x03
CBAL10
CBAL9
TOUT
BAT
CELL_BALANCE
0x04
CBAL8
CBAL7
CBAL6
CBAL5
CELL_SEL
0x05
0
CAL2
CAL1
CAL0
OV_CFG
0x06
OVD2
OVD1
OVD0
UV_CFG
0x07
0
UVFET_DIS
OCV&UV_DELAY
0x08
UVD3
UVD2
OCD_CFG
0x09
CBEN
SCD_CFG
0x0a
SCDD3
0
Read-writing
EEPROM
Writing (0x41)
0x0b
Reading (except above)
40
B6
B5
B4
CHG
DSG
VGOOD
OVTEMP
FS
PFALT
0
0
B2
B1
UV
OV
OCD
SCD
GPOD
CHG
DSG
LTCLR
0
0
HOST
SHDN
PACK
IACAL
IAEN
VAEN
CBAL4
CBAL3
CBAL2
CBAL1
CELL4
CELL3
CELL2
CELL1
OVH1
OVH0
OV2
OV1
OV0
UVH1
UVH0
UV3
UV2
UV1
UV0
UVD1
UVD0
OCD3
OCD2
OCD1
OCD0
ZVC
SOR
OCDD4
OCDD3
OCDD2
OCDD1
OCDD0
SCDD2
SCDD1
SCDD0
SCD3
SCD2
SCD1
SCD0
1
1
0
0
0
1
0
0
1
0
0
0
0
0
1
0
0
0
0
0
0
0
0
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Register Control
0x01 to 0x05 should be controlled during host-control mode.
STATUS: Status Register
7
CHG
6
DSG
5
VGOOD
STATUS REGISTER (0x00)
4
3
OVTEMP
UV
2
OV
1
OCD
0
SCD
The STATUS register provides information about the current state of the bq77PL900.
STATUS b0 (SCD):
This bit indicates a short-circuit in discharge condition.
0 = Current is below the short-circuit in discharge threshold (default).
1 = Current is greater than or equal to the short-circuit in discharge threshold.
STATUS b1 (OCD):
This bit indicates an overload condition.
0 = Current is less than or equal to the overload threshold (default).
1 = Current is greater than the overload threshold.
STATUS b2 (OV): This bit indicates an overvoltage condition.
0 = Voltage is less than or equal to the overvoltage threshold (default).
1 = Voltage is greater than the overvoltage threshold.
STATUS b3 (UV):
This bit indicates an undervoltage condition.
0 = Voltage is greater than or equal to the undervoltage threshold (default).
1 = Voltage is less than the undervoltage threshold.
STATUS b4 (OVTEMP):
This bit indicates an overtemperature condition.
0 = Temperature is lower than or equal to the overtemperature threshold (default).
1 = Temperature is higher than the overtemperature threshold.
STATUS b5 (VGOOD):
This bit indicates a valid EEPROM power-supply voltage condition.
0 = Voltage is smaller than specified EEPROM power-supply voltage (default).
1 = Voltage is greater than or equal to the specified EEPROM power-supply voltage.
STATUS b6 (DSG): This bit reports the external discharge FET state.
0 = Discharge FET is off.
1 = Discharge FET is on.
STATUS b7 (CHG): This bit reports the external charge FET state.
0 = Charge FET is off.
1 = Charge FET is on.
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OUTPUT_CONTROL: Output Control Register
7
FS
6
PFALT
5
0
OUTPUT_CONTROL REGISTER (0x01)
4
3
0
GPOD
2
CHG
1
DSG
0
LTCLR
The OUPTUT_CONTROL register controls some of the outputs of the bq77PL900 and can show the state of the
external pin corresponding to the control.
OUTPUT_ CONTROL b0 (LTCLR): When a fault is latched, this bit releases the fault latch when toggled
(default).
0→1→0 clears the fault latches, allowing STATUS to be cleared on its next read.
OUTPUT_ CONTROL b1 (DSG): This bit controls the external discharge FET.
0 = Discharge FET is OFF in host-control mode.
1 = Discharge FET is ON in host-control mode.
OUTPUT_ CONTROL b2 (CHG): This bit controls the external charge FET.
0 = Charge FET is OFF in host-control mode.
1 = Charge FET is ON in host-control mode.
OUTPUT_CONTROL b3 (GPOD): This bit enables or disables the GPOD output.
0 = GPOD output is high impedance (default).
1 = GPOD output is active (GND).
OUTPUT_CONTROL b6 (PFALT): This bit indicates a parity error in the EEPROM. This bit is read-only.
0 = No parity error (default)
1 = A parity error has occurred.
OUTPUT_CONTROL b7 (FS): This bit selects the undervoltage detection sampling time.
0 = Sampling time is 50 ms/cell (typ) (default).
1 = Sampling time is 100 µs/cell (typ)
OUTPUT_CONTROL b6-b4:
42
These bits are not used and should be set to 0.
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STATE_CONTROL: State Control Register
7
IGAIN
6
VGAIN
STATE_CONTROL REGISTER (0x02)
4
3
0
0
5
0
2
0
1
HOST
0
SHDN
The STATE_CONTROL register controls the states of the bq77PL900.
STATE_CONTROL b0 (SHDN):
This bit enables or disables the shut down mode in host mode.
0 = Disable shutdown mode (default).
1 = Enable shutdown mode (if PACK voltage = 0 V).
STATE_CONTROL b1 (HOST):
This bit selects stand-alone mode or host-control mode.
0 = Stand-alone mode (default)
1 = Host control mode
STATE_CONTROL b6 (VGAIN):
This bit controls the cell amplifier scale.
0 = SCALE is 0.15 (default).
1 = SCALE is 0.2.
STATE_CONTROL b7 (IGAIN):
This bit controls the current monitor amplifier gain.
0 = GAIN is 10 (default).
1 = GAIN is 50.
STATE_CONTROL b5-b2:
These bits are not used and should be set to 0.
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FUNCTION_CONTROL: Function Control Register, [Cell (9, 10) Balance Register]
7
CBAL10
6
CBAL9
5
TOUT
FUNCTION CONTROL REGISTER (0x03)
4
3
2
BAT
PACK
IACAL
1
IAEN
0
VAEN
The FUNCTION_CONTROL register controls some features of the bq77PL900.
FUNCTION_ CONTROL b0 (VAEN): This bit controls the internal cell-voltage amplifier.
0 = Disable cell-voltage amplifier (default).
1 = Enable cell-voltage amplifier.
FUNCTION _CONTROL b1 (IAEN): This bit controls the internal current-monitor amplifier.
0 = Disable current-monitor amplifier (default).
1 = Enable current-monitor amplifier.
FUNCTION_CONTROL b2 (IACAL): This bit controls the internal current-monitor amplifier offset-voltage output.
0 = Disable offset voltage output (default).
1 = Enable offset voltage output.
FUNCTION_CONTROL b3 (PACK): When VAEN = 1, PACK input is divided by 50 and presented on VCELL
0 = Disable pack total voltage output (default).
1 = Enable pack total voltage output.
FUNCTION_ CONTROL b4 (BAT): When VAEN = 1, BAT input is divided by 50 and presented on VCELL.
0 = Disable pack total voltage output (default).
1 = Enable pack total voltage output.
This bit priority is higher than PACK(b3).
FUNCTION _CONTROL b5 (TOUT): This bit controls the power to the thermistor.
0 = Thermistor power is off in host-control mode (default).
1 = Thermistor power is on in host-control mode.
FUNCTION _CONTROL b7–b6 (CELL10–9): This bit enables or disables the cell 9 and cell 10 balance charge
bypass path
0 = Disable bottom series cell 9 or cell 10 balance charge bypass path (default).
1 = Enable bottom series cell 9 or cell 10 balance charge bypass path.
44
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CELL_BALANCE: Cell (1 to 8) Balance Register
7
CBAL8
6
CBAL7
5
CBAL6
CELL_BALANCE REGISTER (0x04)
4
3
CELL5
CBAL4
2
CBAL3
1
CBAL2
0
CBAL1
The CELL_BALANCE register controls cell balancing of the bq77PL900.
CELL_BALANCE b7(CBAL8): This bit enables VC3–VC4 cell balance charge bypass path.
CELL_BALANCE b6(CBAL7): This bit enables VC4–VC5 cell balance charge bypass path.
CELL_BALANCE b5(CBAL6): This bit enables VC5–VC6 cell balance charge bypass path.
CELL_BALANCE b4(CBAL5): This bit enables VC6–VC7 cell balance charge bypass path.
CELL_BALANCE b3(CBAL4): This bit enables VC7–VC8 cell balance charge bypass path.
CELL_BALANCE b2(CBAL3): This bit enables VC8–VC9 cell balance charge bypass path.
CELL_BALANCE b1(CBAL2): This bit enables VC9–VC10 cell balance charge bypass path.
CELL_BALANCE b0(CBAL1): This bit enables VC10–VC11 cell balance charge bypass path.
0 = Disable series cell balance charge bypass path (default).
1 = Enable series cell balance charge bypass path.
CELL_SEL: Cell Translation Selection and Cell Translation Status Register
7
0
6
CAL2
CELL_SEL REGISTER (0x05)
4
3
CAL0
CELL4
5
CAL1
2
CELL3
1
CELL2
0
CELL1
The CELL_SEL register determines the cell selection for voltage measurement and translation. The register also
determines operation mode of the cell voltage monitoring.
The CELL_SEL b6–b4 (CAL2–CAL0) bits should be 0 when VAEN(b0) in register 3 is changed from 0 to 1 or the
VOUT pin will not go active.
This register is don’t care when either BAT(b4) or PACK(b3) is set or VAEN(b0) is cleared in register 3.
CELL_SEL b3–b0 (CELL4–1):
These four bits select the series cell for voltage measurement translation.
These are don’t care when CAL2–0 are not equal to 0x0.
CELL4
CELL3
CELL2
CELL1
0
0
0
0
VC10–VC11, Bottom series element (default)
0
0
0
1
VC9–VC10, Second-lowest series element
0
0
1
0
VC8–VC9, Third-lowest series element
0
0
1
1
VC7–VC8, Fourth-lowest series element
0
1
0
0
VC6–VC7, Fifth-lowest series element
0
1
0
1
VC5–VC6, Sixth-highest series element
0
1
1
0
VC4–VC5, Seventh-highest series element
0
1
1
1
VC3–VC4, Eighth-highest series element
1
0
0
0
VC2–VC3, Ninth-highest series element
1
0
0
1
VC1–VC2, Top series element
Other
SELECTED CELL
VC10–VC11, Bottom series element
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CELL_SEL b6–b4 (CAL2–0):
These three bits determine the mode of the voltage monitor block.
CAL2 CAL1 CAL0
(1)
CELL_SEL b7:
SELECTED MODE
0
0
0
Cell translation for selected cell (default), VOUT output depends on CELL4–1.
0
0
1
Monitor offset of differential amplifier (both inputs of differential amplifier are
connected to GND).
0
1
0
Monitor the scaled VREF (1) value.
0
1
1
Monitor VREF (1) directly.
1
0
0
Monitor the scaled 2.5-V value to the measured 2.5 V.
1
0
1
Monitor VREF–0 V, through the sample-and-hold circuit. (1)
1
1
0
Monitor 2.5 V–0 V through the sample-and-hold circuit.
1
1
1
Monitor 2.5 V–1.2 V through the sample-and-hold circuit.
When VGAIN = 0, VREF = 0.975 V; when VGAIN = 1, VREF = 1.2 V.
These bits are not used and should be set to 0.
OV_CFG: Overvoltage Delay Time, Hysteresis, and Threshold Configuration Register
7
OVD2
6
OVD1
5
OVD0
OV CFG REGISTER (0x06)
4
3
OVH1
OVH0
2
OV2
1
OV1
0
OV0
The OV register determines cell overvoltage threshold, hysteresis voltage, and detection delay time.
OV_CFG b2–b0 (OV2–0) configuration bits with corresponding voltage threshold with a default of 000.
Resolution is 50 mV.
0x00
4.15 V
0x02
4.25 V
0x04
4.35 V
0x06
4.45 V
0x01
4.2 V
0x03
4.3 V
0x05
4.4 V
0x07
4.5 V
OV_CFG b4–b3 (OVH1–0) configuration bits with corresponding hysteresis voltage with a default of 00.
Resolution is 100 mV.
0x00
0.1 V
0x01
0.2 V
0x02
0.3 V
0x03
0V
OV_CFG b7–b5 (OVD2–0) configuration bits with corresponding delay time for overvoltage with a default of 000.
Resolution is 250 ms.
46
0x00
0.5 s
0x02
1s
0x04
1.5 s
0x06
2s
0x01
0.75 s
0x03
1.25 s
0x05
1.75 s
0x07
2.25 s
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UV_CFG: Undervoltage Hysteresis and Threshold Configuration Register
7
0
6
UVFET _-DIS
UV LEVEL REGISTER (0x07)
4
3
UVH0
UV3
5
UVH1
2
UV2
1
UV1
0
UV0
The UV register determines the cell undervoltage threshold, hysteresis voltage, and detection delay time.
UV_CFG b2–b0 (UV3–0) configuration bits with corresponding voltage threshold with a default of 000. Resolution
is 100 mV.
0x00
1.4 V
0x04
1.8 V
0x08
2.2 V
0x0c
2.6 V
0x01
1.5 V
0x05
1.9 V
0x09
2.3 V
0x0d
2.7 V
0x02
1.6 V
0x06
2V
0x0a
2.4 V
0x0e
2.8 V
0x03
1.7 V
0x07
2.1 V
0x0b
2.5 V
0x0f
2.9 V
UV_CFG b5–b4 (UVH1–0) configuration bits with corresponding hysteresis voltage with a default of 00.
Resolution is 200 mV.
0x00
0.2 V
0x01
0.4 V
0x02
0.8 V
0x03
1.2 V
When the undervoltage threshold and the hysteresis values are high, then undervoltage recovery may not occur.
To avoid this, Table 12 should be used for assistance in configuration.
Table 12. Combination of UV Release Voltage vs Hysteresis
HYSTERESIS
Cell undervoltage (V)
UV_CFG b6 (UVFET_DIS):
host-control mode.
0.2 V
0.4 V
0.8 V
1.2 V
1.4
1.6
1.8
2.2
2.6
1.5
1.7
1.9
2.3
2.7
1.6
1.8
2
2.4
2.8
1.7
1.9
2.1
2.5
2.9
1.8
2
2.2
2.6
3
1.9
2.1
2.3
2.7
3.1
2
2.2
2.4
2.8
3.2
2.1
2.3
2.5
2.9
3.3
2.2
2.4
2.6
3
3.3
2.3
2.5
2.7
3.1
3.3
2.4
2.6
2.8
3.2
3.3
2.5
2.7
2.9
3.3
3.3
2.6
2.8
3
3.3
3.3
2.7
2.9
3.1
3.3
3.3
2.8
3
3.2
3.3
3.3
2.9
3.1
3.3
3.3
3.3
This bit disable automatically turns off the DSG output when UV is detected in
0 = DSG output changes to OFF when UV is detected (default).
1 = DSG output does not change to OFF when UV is detected.
But the UV bit of the status register (0x00) is changed, even if this bit = 1.
UV_CFG b7:
This bit should be set to 0, so that the bq77PL900 protects battery cell safety.
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OC&UV_DELAY: Overcurrent and Undervoltage Delay Register
7
UVD3
6
UVD2
5
UVD1
OC&UVDELAY REGISTER (0x08)
4
3
UVD0
OCD3
2
OCD2
1
OCD1
0
OCD0
The FUNCTION and OCDV CFG register determines overcurrent in discharge voltage threshold and controls
functions.
OC&UV_DELAY b3–b0 (OCD3–0) configuration bits with corresponding voltage threshold. Resolution is 5 mV.
0x00
10 mV
0x04
30 mV
0x08
50 mV
0x0c
70 mV
0x01
15 mV
0x05
35 mV
0x09
55 mV
0x0c
75 mV
0x02
20 mV
0x06
40 mV
0x0a
60 mV
0x0e
80 mV
0x03
25 mV
0x07
45 mV
0x0b
65 mV
0x0f
85 mV
OC&UVDELAY b7–hb4 (UVD3–0) configuration bits with corresponding delay time for undervoltage with a
default of 000. Resolution is 1 s when the FS bit = 0.
OC&UVDELAY
b7-b4 (UVD3-0)
FS bit (OUTPUT_CONTROL b7 )
0x00
1
0
See the following table.
1s
0x01
2s
0x02
3s
0x03
4s
0x04
5s
0x05
6s
0x06
7s
0x07
48
8s
0x08
1s
1s
0x09
2s
2s
0x0a
3s
3s
0x0b
4s
4s
0x0c
5s
5s
0x0d
6s
6s
0x0e
7s
7s
0x0f
8s
8s
UVD<3:0>
Internal Count
0x00
DELAY TIME (ms), FS = 1
5 Cells
6 Cells
7 Cells
8 Cells
9 Cells
10 Cells
0
0
0
0
0
0
0
0x01
2
1.25
1.5
1.75
2
2.25
2.5
0x02
4
2.5
3
3.5
4
4.5
5
0x03
8
5
6
7
8
9
10
0x04
10
6.25
7.5
8.75
10
11.25
12.5
0x05
12
7.5
9
10.5
12
13.5
15
0x06
16
10
12
14
16
18
20
0x07
24
15
18
21
24
27
30
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OCD_CFG: Overcurrent in Discharge Configuration Register
7
CBEN
6
ZVC
5
SOR
OCD_CFG REGISTER (0x09)
4
3
OCDD4
OCDD3
2
OCDD2
1
OCDD1
0
OCDD0
The FUNCTION & OCD_CFG register determines function and overload-detection delay time.
OCD_CFG b4–b0 (OCDD4–0) configuration bits with corresponding delay time. Units are in ms and resolution is
20 ms or 100 ms.
0x00
20 ms
0x08
180 ms
0x10
100 ms
0x18
900 ms
0x01
40 ms
0x09
200 ms
0x11
200 ms
0x19
1000 ms
0x02
60 ms
0x0a
220 ms
0x12
300 ms
0x1a
1100 ms
0x03
80 ms
0x0b
240 ms
0x13
400 ms
0x1b
1200 ms
0x04
100 ms
0x0c
260 ms
0x14
500 ms
0x1c
1300 ms
0x05
120 ms
0x0d
280 ms
0x15
600 ms
0x1d
1400 ms
0x06
140 ms
0x0e
300 ms
0x16
700 ms
0x1e
1500 ms
0x07
160 ms
0x0f
320 ms
0x17
800 ms
0x1f
1600 ms
OCD_CFG b5 (SOR): Recover condition from SC and OC with stand-alone mode
0 = Recover by attaching a charger. Recover comparator is active after 12.8 s for OC/SC
detection (default).
1 = Recover by SC/OC condition released. Recovery from OC/SC after 12.8 s.
OCD_CFG b6 (ZVC): This bit controls the 0-V/precharge of the GPOD output.
0 = Disable the GPOD output 0-V/precharge mode with stand-alone (default).
1 = Enable the GPOD output 0-V/precharge mode with stand-alone.
OCD_CFG b7 (CBEN): This bit controls cell balancing.
0 = Disable the cell balancing function (default)
1 = Enable the cell balancing function.
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SCD_CFG: Short-Circuit in Discharge Configuration Register
7
SCDD3
6
SCDD2
5
SCDD1
SCD_CFG REGISTER (0x0a)
4
3
SCDD0
SCD3
2
SCD2
1
SCD1
0
SCD0
The SCD_CFG register determines the short-circuit voltage threshold and detection delay time.
SCD_CFG b3–b0 (SCD3–0): These lower-nibble bits select the value of the short-circuit in discharge voltage
threshold with 0000 as the default, units in mV, and a resolution of 5 mV.
0x00
60 mV
0x04
80 mV
0x08
100 mV
0x0c
120 mV
0x01
65 mV
0x05
85 mV
0x09
105 mV
0x0d
125 mV
0x02
70 mV
0x06
90 mV
0x0a
110 mV
0x0e
130 mV
0x03
75 mV
0x07
95 mV
0x0b
115 mV
0x0f
135 mV
SCD_CFG b7-b4 (SCDD3-0): These upper nibble bits select the value of the short circuit in discharge delay time.
0000 is the default, units of µs and a resolution of 60µs.
0x00
0 µs
0x04
240 µs
0x08
480 µs
0x0c
720 µs
0x01
60 µs
0x05
300 µs
0x09
540 µs
0x0d
780 µs
0x02
120 µs
0x06
360 µs
0x0a
600 µs
0x0e
840 µs
0x03
180 µs
0x07
420 µs
0x0b
660 µs
0x0f
900 µs
2
EEPROM2
1
EEPROM1
0
EEPROM0
EEPROM: EEPROM Write Enable and Configurati0n Register
7
EEPROM7
6
EEPROM6
5
EEPROM5
EEPROM REGISTER (0x0b)
4
3
EEPROM4
EEPROM3
EEPROM b7–b0 (EEPROM7–0):
These bits enable data write to EEPROM(0x06-0x9a) with 0100 0001 (0x41).
Prewriting data is available by setting these bits with 0110 0010 (0x62).
Default is 0000 0000 (0x00).
Zero-Volt Charging
In order to charge cells, the CHG FET must be turned on to create a current path. When the battery voltage
(VBAT) is low and the CHG is ON, the pack voltage (VPACK) is as low as the battery voltage. In cases where the
level is below the supply voltage for the bq77PL900 is too low to operate, there are two configurations to provide
the appropriate 0-V/precharge function.
Common FET mode does not require a dedicated 0-V/precharge FET. The CHG FET is ON. This method is
suitable for a charger that has a 0-V/precharge function. The second mode is to use a 0-V/precharge FET which
establishes a dedicated 0-V/precharge current path by using an additional open drain (GPOD output) for driving
an external FET (PCHG FET). This configuration sustains the PACK+ voltage level. Any type of charger can be
used with this configuration.
Table 13. 0-V Charge Summary
PROTECTION
MODE
0-V CHARGE TYPE
Host-control mode
Stand-alone mode
50
DEMANDED CHARGE
FUNCTION
APPLICATION CIRCUIT
Common FET (1)
Fast charge
Precharge
PMS = PACK
GPOD output not used
0-V/precharge FET (2)
Fast charge
PMS = GND
GPOD output: Drives 0-V charge FET (PCHG FET)
Common FET (1)
Fast charge
Precharge
PMS = PACK
GPOD output not used
0-V/precharge FET (2)
Fast charge
PMS = GND
GPOD output: Drives 0-V charge FET (PCHG FET)
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Common FET
In this mode, the PMS pin is connected to PACK+. In this configuration, the charger must have a 0-V/precharging
function which is typically controlled as follows:
• The cell voltage is lower than a certain constant voltage (normally about 3 V/cell).
– Apply 0-V/precharging current.
• The cell voltage is higher than a certain constant voltage (normally about 3 V/cell).
– Apply fast-charging current.
When the charger is connected and VPMS is greater than or equal to 0.7 V, the CHG FET is turned ON. The
charging current flows through the CHG FET and the back diode of the DSG.
VPACK+ = VBAT + 0.7 V (VF: forward voltage of a DSG-FET back diode) + VDS(CHG-FET)
Charger
DSG-FET
CHG-FET
CC
I-PC
PACK+
BAT
CHG
DSG
I-QC
PACK
bq77PL900
Battery
CV
PMS
REG
GPOD
Open
I-PC: Precharge Current
I-QC: Quick-Charge Current
S0353-01
Figure 27. Common FET Circuit Diagram
When the PACK pin voltage is maintained at higher than 0.7 V and the precharging current is maintained, the
PACK voltage and BAT voltage are under the minimum bq77PL900 supply voltage, so the regulator is inactive.
When the BAT voltage rises and the PACK pin voltage reaches the bq77PL900 minimum supply voltage, an
internal 3.3-V regulator is turned ON. Then, the CHG FET state is controlled by UVP and OVP functions. When
the all the cell voltages reach fast-charge voltage (about 3 V per cell), the charger starts the fast-charging mode.
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PACK
Operating Voltage
0V
3.3 V
0V
REG2
PMS
0V
CHG = L by 0 V Charge Control
L
0V
CHG
DSG = L by 0 V Charge Control
DSG
L
Battery Voltage
0 V Charge Disable Voltage
0V
Quick-Charge Current
Charge Current
0-V and Prechg Current
0A
OV Charge and
Precharge Mode
QuickCharge
Mode
T0381-01
Figure 28. Signal Timing of Pins During 0-V/Precharging
8.22.2 0-V/Precharge FET in Host Control Mode
In this configuration, the charger does not have a requirement to support a precharge function. Thus, the host
controller and bq77PL900 must limit the fast charging current to a suitable 0-V/precharge level.
The PMS pin is connected to GND and a 0-V/precharge current flows through a dedicated 0-V/precharge FET
(PCHG FET).
52
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PCHG-FET
R(PCHG)
Charger
DSG-FET
CHG-FET
CC
PACK+
BAT
I-QC
DSG
CHG
CV
PACK
Battery
GPOD
bq77PL900
I-QC: Quick-Charge Current
PMS
REG
S0354-01
Figure 29. 0-V/Precharge FET Circuit in Host-Control Mode
The 0-V/precharge FET is driven by the GPOD output. By setting the GPOD bit to 1, the GPOD output turns ON,
and then the PCHG FET. The 0-V/precharge current is limited by the 0-V/precharge FET (PCHG FET) and a
series resistor (R(PCHG)) as follows.
I0V/PCHG = ID = ( VPACK+ – VBAT – VDS ) / RP
A load curve of the PCHG FET is shown in Figure 30. When the gate-source voltage (VDS) is high enough, the
FET operates in the linear region and has low resistance. By approximating VDS as 0 V, the 0-V/precharge
current (I0V/PCHG) is expressed as follows.
I0V/PCHG = (VPACK+ – VBAT) / RP
ID
ID = (VPACK)
VDS
M0123-01
Figure 30. 0V/PCHG FET ID and VDS Characteristics
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During the 0-V/precharge, the CHG FET is turned OFF and the PCHG FET is turned ON. When the host
controller detects that all the cell voltages have reached the fast-charge threshold, it then turns ON the CHG FET
and turns OFF the PCHG FET. The signal timing is shown in Figure 31.
The CHG, DSG and PCHG FETs are turned OFF when the charger is connected. Then, the charger applies its
maximum output voltage (constant-voltage-mode output voltage) to the PACK+ pin. Then, the bq77PL900 3.3-V
regulator becomes active and supplies power to the host controller. As the host controller starts up, it turns on
the GPOD output and the 0-V/precharge current begins to flow.
In this configuration, attention is needed to control high power consumption at the PCHG FET and the series
resistor (RP). The highest power is consumed at 0-V cell voltage (highest voltage between PACK+ and BAT pins)
and it results in highest heat generation. For example, the power consumption in 10 series batteries with 42-V
fast charge voltage and 1-kΩ RP is expressed as follows.
IOV/PCHG = (42 V – 0 V) /1 kΩ = 42 mA
(Power consumption at RP) = 42 V × 42 mA = 1.6 W
It is recommended to combine the resistor (RP) and the thermistor to reduce the consumption. Once the cell
voltage reaches the fast-charge threshold, the host controller turns ON the CHG and DSG FETs and also turns
OFF the PCHG FET.
Charge CV
PACK
0V
uP: Active
3.3 V
0V
REG2
PCHG FET = ON
OFF
OFF
GPOD
0V
CHG
CHG-FET = OFF
CHG-FET = ON
L
DSG-FET = ON by uC
DSG
L
Battery Voltage
0V
Quick-Charge Current
Charge Current
0-V and Prechg Current
0A
OV Charge and
Precharge Mode
QuickCharge
Mode
T0382-01
Figure 31. Signal Timing of Pins During 0-V Charging and Precharging (Precharge FET) With
Host-Control Mode
54
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0-V/Precharge FER in Stand-Alone Mode
The circuit configuration is the same as 0-V/precharge FET in host-control mode, although in stand-alone mode
the bq77PL900 automatically turns on the GPOD output. When the battery voltage reaches 0 V, the charger
disable voltage (= PMS disable voltage), the GPOD output is turned OFF, and then the DSG and CHG FETs are
controlled by an internal UV comparator function. To activate this mode, set OCDELAY register [ZVC].
PCHG-FET
R(PCHG)
Charger
DSG-FET
CHG-FET
CC
PACK+
BAT
I-QC
DSG
CHG
PACK
CV
Battery
GPOD
bq77PL900
I-QC: Quick-Charge Current
PMS
REG
S0354-01
Figure 32. 0-V/Precharge FET Circuit Diagram In Stand-Alone Mode
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Charge CV
PACK
0V
uP: Active
3.3 V
0V
REG2
PCHG FET = ON
OFF
GPOD
0V
CHG
CHG-FET = OFF
CHG-FET = ON
L
DSG-FET = ON by uC
DSG
L
0 V Charge Disable Voltage
Battery Voltage
0V
Quick-Charge Current
Charge Current
0-V and Prechg Current
0A
OV Charge and
Precharge Mode
QuickCharge
Mode
T0383-01
Figure 33. Signal Timing of Pins During 0-V/Precharging (PCHG FET) In Stand-Alone Mode
56
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PACKAGE OPTION ADDENDUM
www.ti.com
18-Feb-2010
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
BQ77PL900DL
ACTIVE
SSOP
DL
48
25
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
BQ77PL900DLG4
ACTIVE
SSOP
DL
48
25
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
BQ77PL900DLR
ACTIVE
SSOP
DL
48
1000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
BQ77PL900DLRG4
ACTIVE
SSOP
DL
48
1000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-2-260C-1 YEAR
Lead/Ball Finish
MSL Peak Temp (3)
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS
compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is
provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the
accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take
reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on
incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited
information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI
to Customer on an annual basis.
Addendum-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
17-Feb-2010
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
BQ77PL900DLR
Package Package Pins
Type Drawing
SSOP
DL
48
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
1000
330.0
32.4
Pack Materials-Page 1
11.35
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
16.2
3.1
16.0
32.0
Q1
PACKAGE MATERIALS INFORMATION
www.ti.com
17-Feb-2010
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
BQ77PL900DLR
SSOP
DL
48
1000
346.0
346.0
49.0
Pack Materials-Page 2
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