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bq4050
SLUSC67B – MARCH 2016 – REVISED OCTOBER 2017
bq4050 CEDV Gas Gauge and Protection Solution for
1-Series to 4-Series Cell Li-Ion Battery Packs
1 Features
3 Description
•
The Texas Instruments bq4050 device, incorporating
Compensated End-of-Discharge Voltage (CEDV)
technology, is a highly integrated, accurate, 1-series
to 4-series cell gas gauge and protection solution,
enabling autonomous charger control and cell
balancing.
1
•
•
•
•
•
•
•
•
•
•
High-Side Protection N-CH FET Drive Enables
Serial Bus Communication During Fault
Conditions
Cell Balancing with Internal Bypass Optimizes
Battery Health
Diagnostic Lifetime Data Monitor and Black Box
Recorder for Failure Analysis
Full Array of Programmable Protection Features:
Voltage, Current, Temperature
JEITA Charge Algorithms Support Smart Charging
Analog Front End with Two Independent ADCs
– Simultaneous Current and Voltage Sampling
– High-Accuracy Coulomb Counter with Input
Offset Error < 1 μV (Typical)
Supports Battery Trip Point (BTP) Function for
Windows® Integration
LED Display for State of Charge and Battery
Status Indication
100-KHz SMBus v1.1 Communications Interface
for Programming and Data Access with Alternate
400-KHz Mode
SHA-1 Authentication Responder for Increased
Battery Pack Security
Compact 32-Pin VQFN Package (RSM)
The bq4050 device provides a fully integrated packbased solution with a flash programmable custom
reduced
instruction-set
CPU
(RISC),
safety
protection, and authentication for Li-Ion and LiPolymer battery packs.
The bq4050 gas gauge communicates via an SMBuscompatible interface and combines an ultra-low
power, high-speed TI bqBMP processor, highaccuracy analog measurement capabilities, integrated
flash memory, an array of peripheral and
communication ports, an N-CH FET drive, and a
SHA-1 Authentication transform responder into a
complete, high-performance battery management
solution.
Device Information(1)
PART NUMBER
bq4050
PACKAGE
BODY SIZE (NOM)
VQFN (32)
4.00 mm × 4.00 mm
(1) For all available packages, see the orderable addendum at
the end of this data sheet.
Simplified Schematic
2 Applications
VC4
PACK
VCC
DSG
CHG
PCHG
BAT
PTC
PACK +
Notebooks
Medical and Test Equipment
Portable Instrumentation
Cordless Vacuum Cleaners and Vacuum Robots
FUSE
•
•
•
•
LEDCNTLA
LEDCNTLB
LEDCNTLC
VC3
GND
nd
VDD
VC3
2 level
protector
OUT
VC2
Cell 3
VC2
DISP
Cell 2
VC1
SMBD
SMBC
PBI
VSS SRP SRN TS1 TS2 TS3 TS4 BTP PRES
VC1
Cell 1
SMBD
SMBC
PRES
BTP
PACK–
Copyright © 2017, Texas Instruments Incorporated
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
bq4050
SLUSC67B – MARCH 2016 – REVISED OCTOBER 2017
www.ti.com
Table of Contents
1
2
3
4
5
6
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
6.25 Electrical Characteristics: High-Frequency
Oscillator .................................................................. 14
6.26 Electrical Characteristics: Low-Frequency
Oscillator .................................................................. 15
6.27 Electrical Characteristics: Voltage Reference 1.... 15
6.28 Electrical Characteristics: Voltage Reference 2.... 15
6.29 Electrical Characteristics: Instruction Flash .......... 15
6.30 Electrical Characteristics: Data Flash ................... 15
6.31 Electrical Characteristics: OCD, SCC, SCD1, SCD2
Current Protection Thresholds ................................. 16
6.32 Timing Requirements: OCD, SCC, SCD1, SCD2
Current Protection Timing ........................................ 17
6.33 Timing Requirements: SMBus .............................. 17
6.34 Timing Requirements: SMBus XL......................... 18
6.35 Typical Characteristics .......................................... 19
1
1
1
2
3
7
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
Absolute Maximum Ratings ...................................... 7
ESD Ratings.............................................................. 7
Recommended Operating Conditions....................... 8
Thermal Information .................................................. 8
Electrical Characteristics: Supply Current................. 8
Electrical Characteristics: Power Supply Control...... 9
Electrical Characteristics: AFE Power-On Reset ...... 9
Electrical Characteristics: AFE Watchdog Reset and
Wake Timer................................................................ 9
6.9 Electrical Characteristics: Current Wake
Comparator ................................................................ 9
6.10 Electrical Characteristics: VC1, VC2, VC3, VC4,
BAT, PACK .............................................................. 10
6.11 Electrical Characteristics: SMBD, SMBC.............. 10
6.12 Electrical Characteristics: PRES, BTP_INT, DISP
................................................................................. 10
6.13 Electrical Characteristics: LEDCNTLA, LEDCNTLB,
LEDCNTLC ............................................................. 11
6.14 Electrical Characteristics: Coulomb Counter ........ 11
6.15 Electrical Characteristics: CC Digital Filter ........... 11
6.16 Electrical Characteristics: ADC ............................. 12
6.17 Electrical Characteristics: ADC Digital Filter ......... 12
6.18 Electrical Characteristics: CHG, DSG FET Drive . 12
6.19 Electrical Characteristics: PCHG FET Drive ......... 13
6.20 Electrical Characteristics: FUSE Drive.................. 13
6.21 Electrical Characteristics: Internal Temperature
Sensor...................................................................... 13
6.22 Electrical Characteristics: TS1, TS2, TS3, TS4 .... 14
6.23 Electrical Characteristics: PTC, PTCEN ............... 14
6.24 Electrical Characteristics: Internal 1.8-V LDO....... 14
7
Detailed Description ............................................ 22
7.1
7.2
7.3
7.4
8
Overview .................................................................
Functional Block Diagram ......................................
Feature Description.................................................
Device Functional Modes........................................
22
22
23
26
Applications and Implementation ...................... 27
8.1 Application Information .......................................... 27
8.2 Typical Applications ................................................ 28
9 Power Supply Recommendations...................... 42
10 Layout................................................................... 42
10.1 Layout Guidelines ................................................. 42
10.2 Layout Example .................................................... 44
11 Device and Documentation Support ................. 46
11.1
11.2
11.3
11.4
11.5
Documentation Support ........................................
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
46
46
46
46
46
12 Mechanical, Packaging, and Orderable
Information ........................................................... 46
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision A (April 2016) to Revision B
•
2
Page
Changed Applications............................................................................................................................................................. 1
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SLUSC67B – MARCH 2016 – REVISED OCTOBER 2017
5 Pin Configuration and Functions
BAT
CHG
PCHG
NC
DSG
PACK
VCC
FUSE
32
31
30
29
28
27
26
25
RSM Package
32-Pin VQFN with Exposed Thermal Pad
Top View
PBI
1
24
PTCEN
VC4
2
23
PTC
VC3
3
22
LEDCNTLC
VC2
4
21
LEDCNTLB
Thermal
Pad
14
15
16
NC
BTP_INT
PRES_or_SHUTDN
13
DISP
TS4
SMBD
17
12
18
8
11
7
TS3
NC
SRP
TS2
SMBC
10
LEDCNTLA
19
9
20
6
TS1
5
VSS
VC1
SRN
Pin Functions
PIN
NAME
NUMBER
TYPE
DESCRIPTION
PBI
1
P (1)
VC4
2
IA
Sense voltage input pin for the most positive cell, and balance current input for the most
positive cell
VC3
3
IA
Sense voltage input pin for the second most positive cell, balance current input for the
second most positive cell, and return balance current for the most positive cell
VC2
4
IA
Sense voltage input pin for the third most positive cell, balance current input for the third
most positive cell, and return balance current for the second most positive cell
VC1
5
IA
Sense voltage input pin for the least positive cell, balance current input for the least
positive cell, and return balance current for the third most positive cell
SRN
6
I
NC
7
—
SRP
8
I
Analog input pin connected to the internal coulomb counter peripheral for integrating a
small voltage between SRP and SRN where SRP is the top of the sense resistor.
Power supply backup input pin
Analog input pin connected to the internal coulomb counter peripheral for integrating a
small voltage between SRP and SRN where SRP is the top of the sense resistor.
Not internally connected. Connect to VSS.
VSS
9
P
Device ground
TS1
10
IA
Temperature sensor 1 thermistor input pin
TS2
11
IA
Temperature sensor 2 thermistor input pin
TS3
12
IA
Temperature sensor 3 thermistor input pin
TS4
13
IA
Temperature sensor 4 thermistor input pin
NC
14
—
Not internally connected. Connect to VSS.
BTP_INT
15
O
Battery Trip Point (BTP) interrupt output
PRES or
SHUTDN
16
I
Host system present input for removable battery pack or emergency system shutdown
input for embedded packs
(1)
P = Power Connection, O = Digital Output, AI = Analog Input, I = Digital Input, I/OD = Digital Input/Output
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Pin Functions (continued)
PIN
NAME
NUMBER
TYPE
DESCRIPTION
DISP
17
—
SMBD
18
I/OD
SMBus data pin
SMBC
19
I/OD
SMBus clock pin
LEDCNTLA
20
—
LED display segment that drives the external LEDs depending on the firmware
configuration
LEDCNTLB
21
—
LED display segment that drives the external LEDs depending on the firmware
configuration
LEDCNTLC
22
—
LED display segment that drives the external LEDs depending on the firmware
configuration
PTC
23
IA
Safety PTC thermistor input pin. To disable, connect PTC and PTCEN to VSS.
PTCEN
24
IA
Safety PTC thermistor enable input pin. Connect to BAT. To disable, connect PTC and
PTCEN to VSS.
FUSE
25
O
Fuse drive output pin
VCC
26
P
Secondary power supply input
PACK
27
IA
Pack sense input pin
DSG
28
O
NMOS Discharge FET drive output pin
NC
29
—
Not internally connected. Connect to VSS.
PCHG
30
O
PMOS Precharge FET drive output pin
CHG
31
O
NMOS Charge FET drive output pin
BAT
32
P
Primary power supply input pin
4
Display control for LEDs
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SLUSC67B – MARCH 2016 – REVISED OCTOBER 2017
VC4
BAT
VCC
CDEN4
PACK
VC3
+
–
3.1 V
BATDET
ENVCC
CDEN3
PACK
Detector
VC2
PACKDET
PBI
Reference
System
Shutdown
Latch
1.8 V
Domain
VC1
BAT
Control
Power Supply Control
ADC
CDEN2
SHOUT
ENBAT
ADC Mux
SHUTDOWN
CDEN1
Cell Balancing
VCC
CHGEN
BAT
2 kΩ
CHG
Pump
CHG
8 kΩ
2 kΩ
PCHG
CHGOFF
PCHGEN
Pre-Charge Drive
PACK
BAT
DSGEN
BAT
DSG
Pump
ZVCD
2 kΩ
DSG
CHGEN
BAT
DSGOFF
CHG
Pump
VCC
ZVCHGEN
CHG, DSG Drive
Zero-Volt Charge
Figure 1. Pin Equivalent Diagram 1
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1.8 V
ADTHx
BAT
FUSEWKPUP
18 kΩ
2 kΩ
ADC Mux
TS1,2,3,4
ADC
FUSEEN
150 nA
2 kΩ
FUSE
1.8 V
1.8 V
100 kΩ
FUSEDIG
RCWKPUP
RCPUP
FUSE Drive
1 kΩ
RCIN
RCOUT
100 kΩ
SMBCIN
SMBC
Thermistor Inputs
SMBCOUT
SMBCEN
1 MΩ
PBI
100 kΩ
SMBDIN
RHOEN
SMBD
SMBDOUT
10 kΩ
PRES
SMBDEN
1 MΩ
SMBus Interface
RHOUT
100 kΩ
RHIN
High-Voltage GPIO
PTCEN
BAT
30 kΩ
PTC
Comparator
PTC
RLOEN
PTC
Counter
PTC
Latch
PTCDIG
290 nA
LED1, 2, 3
22.5 mA
RLOUT
100 kΩ
RLIN
LED Drive
PTC Detection
Figure 2. Pin Equivalent Diagram 2
6
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SLUSC67B – MARCH 2016 – REVISED OCTOBER 2017
10 Ω
VC4
CHANx
Φ2
3.8 kΩ
1.9 MΩ
SRP
ADC Mux
Φ1
ADC
Φ2
3.8 kΩ
0.1 MΩ
SRN
Comparator
Array
Φ1
Φ2
10 Ω
100 Ω
PACK
Φ1
Coulomb
Counter
Φ2
CHANx
100 Ω
Φ1
1.9 MΩ
ADC Mux
ADC
0.1 MΩ
OCD, SCC, SCD Comparators and Coulomb Counter
VC4 and PACK Dividers
Figure 3. Pin Equivalent Diagram 3
6 Specifications
6.1 Absolute Maximum Ratings
Over-operating free-air temperature range (unless otherwise noted) (1)
Supply voltage range, VCC
Input voltage range, VIN
Output voltage range, VO
MIN
MAX
UNIT
BAT, VCC, PBI
–0.3
30
V
PACK, SMBC, SMBD, PRES or SHUTDN, BTP_INT, DISP
–0.3
30
V
TS1, TS2, TS3, TS4
–0.3
VREG + 0.3
V
PTC, PTCEN, LEDCNTLA, LEDCNTLB, LEDCNTLC
–0.3
VBAT + 0.3
V
SRP, SRN
–0.3
0.3
V
VC4
VC3 – 0.3
VC3 + 8.5 V, or
VSS + 30
V
VC3
VC2 – 0.3
VC2 + 8.5 V, or
VSS + 30
V
VC2
VC1 – 0.3
VC1 + 8.5 V, or
VSS + 30
V
VC1
VSS – 0.3
VSS + 8.5 V, or
VSS + 30 V
V
CHG, DSG
–0.3
32
PCHG, FUSE
–0.3
30
V
50
mA
150
°C
300
°C
Maximum VSS current, ISS
TSTG
Storage temperature
–65
Lead temperature (soldering, 10 s), TSOLDER
(1)
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.
6.2 ESD Ratings
VALUE
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001
V(ESD)
(1)
(2)
Electrostatic discharge
Charged-device model (CDM), per JEDEC specification
JESD22-C101 (2)
(1)
UNIT
±2000
±500
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
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6.3 Recommended Operating Conditions
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
MIN
VCC
Supply voltage
BAT, VCC, PBI
VSHUTDOWN–
Shutdown voltage
VPACK < VSHUTDOWN–
VSHUTDOWN+
Start-up voltage
VPACK > VSHUTDOWN– + VHYS
VHYS
Shutdown voltage
hysteresis
VSHUTDOWN+ – VSHUTDOWN–
NOM
2.2
Input voltage range
UNIT
26
V
1.8
2.0
2.2
V
2.05
2.25
2.45
V
250
PACK, SMBC, SMBD, PRES, BTP_IN, DISP
VIN
MAX
mV
26
TS1, TS2, TS3, TS4
VREG
PTC, PTCEN, LEDCNTLA, LEDCNTLB, LEDCNTLC
VBAT
SRP, SRN
–0.2
0.2
VC4
VVC3
VVC3 + 5
VC3
VVC2
VVC2 + 5
VC2
VVC1
VVC1 + 5
VC1
VVSS
VVSS + 5
VO
Output voltage
range
CPBI
External PBI
capacitor
2.2
TOPR
Operating
temperature
–40
CHG, DSG, PCHG, FUSE
26
V
V
µF
85
°C
6.4 Thermal Information
bq4050
THERMAL METRIC
(1)
RSM (QFN)
UNIT
32 PINS
RθJA, High K
Junction-to-ambient thermal resistance
47.4
°C/W
RθJC(top)
Junction-to-case(top) thermal resistance
40.3
°C/W
RθJB
Junction-to-board thermal resistance
14.7
°C/W
ψJT
Junction-to-top characterization parameter
0.8
°C/W
ψJB
Junction-to-board characterization parameter
14.4
°C/W
RθJC(bottom)
Junction-to-case(bottom) thermal resistance
3.8
°C/W
(1)
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report, SPRA953.
6.5 Electrical Characteristics: Supply Current
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 20 V (unless otherwise noted)
PARAMETER
INORMAL
NORMAL mode
ISLEEP
SLEEP mode
ISHUTDOWN
SHUTDOWN mode
8
TEST CONDITIONS
CHG on. DSG on, no Flash write
MIN
TYP
336
CHG off, DSG on, no SBS communication
75
CHG off, DSG off, no SBS communication
52
1.6
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MAX
UNIT
µA
µA
µA
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6.6 Electrical Characteristics: Power Supply Control
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
VSWITCHOVER–
BAT to VCC
switchover
voltage
VBAT < VSWITCHOVER–
VSWITCHOVER+
VCC to BAT
switchover
voltage
VBAT > VSWITCHOVER– + VHYS
VHYS
Switchover
VSWITCHOVER+ – VSWITCHOVER–
voltage hysteresis
ILKG
RPD
Input Leakage
current
Internal pulldown
resistance
MIN
TYP
MAX
1.95
2.1
2.2
V
2.9
3.1
3.25
V
1000
mV
BAT pin, BAT = 0 V, VCC = 25 V, PACK = 25 V
1
PACK pin, BAT = 25 V, VCC = 0 V, PACK = 0 V
1
BAT and PACK terminals, BAT = 0 V, VCC = 0 V, PACK
= 0 V, PBI = 25 V
1
PACK
30
40
UNIT
50
µA
kΩ
6.7 Electrical Characteristics: AFE Power-On Reset
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
VREGIT–
Negative-going
voltage input
VREG
VHYS
Power-on reset
hysteresis
VREGIT+ – VREGIT–
tRST
Power-on reset
time
MIN
TYP
MAX
UNIT
1.51
1.55
1.59
V
70
100
130
mV
200
300
400
µs
6.8 Electrical Characteristics: AFE Watchdog Reset and Wake Timer
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
372
500
628
tWDT = 1000
744
1000
1256
tWDT = 2000
1488
2000
2512
tWDT = 4000
2976
4000
5024
tWAKE = 250
186
250
314
tWAKE = 500
372
500
628
tWAKE = 1000
744
1000
1256
tWAKE = 512
1488
2000
2512
409
512
614
tWDT = 500
tWDT
AFE watchdog
timeout
tWAKE
AFE wake timer
tFETOFF
FET off delay after
reset
tFETOFF = 512
UNIT
ms
ms
ms
6.9 Electrical Characteristics: Current Wake Comparator
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
VWAKE
Wake voltage
threshold
TEST CONDITIONS
MIN
TYP
MAX
VWAKE = ±0.625 mV
±0.3
±0.625
±0.9
VWAKE = ±1.25 mV
±0.6
±1.25
±1.8
VWAKE = ±2.5 mV
±1.2
±2.5
±3.6
VWAKE = ±5 mV
±2.4
±5.0
±7.2
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UNIT
mV
9
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Electrical Characteristics: Current Wake Comparator (continued)
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
VWAKE(DRIFT)
Temperature drift
of VWAKE accuracy
tWAKE
Time from
application of
current to wake
interrupt
tWAKE(SU)
Wake comparator
startup time
TEST CONDITIONS
MIN
TYP
MAX
0.5%
500
UNIT
°C
700
µs
1000
µs
6.10 Electrical Characteristics: VC1, VC2, VC3, VC4, BAT, PACK
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
0.1980
0.2000
0.2020
BAT–VSS, PACK–VSS
0.049
0.050
0.051
VREF2
0.490
0.500
0.510
VC1–VSS, VC2–VC1, VC3–VC2, VC4–VC3
K
Scaling factor
VC1–VSS, VC2–VC1, VC3–VC2, VC4–VC3
–0.2
5
BAT–VSS, PACK–VSS
–0.2
20
VIN
Input voltage range
ILKG
Input leakage current
VC1, VC2, VC3, VC4, cell balancing off, cell detach
detection off, ADC multiplexer off
RCB
Internal cell balance
resistance
RDS(ON) for internal FET switch at 2 V < VDS < 4 V
ICD
Internal cell detach
check current
VCx > VSS + 0.8 V
30
50
UNIT
—
V
1
µA
200
Ω
70
µA
6.11 Electrical Characteristics: SMBD, SMBC
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
VIH
Input voltage high
SMBC, SMBD, VREG = 1.8 V
1.3
VIL
Input voltage low
SMBC, SMBD, VREG = 1.8 V
0.8
VOL
Output low voltage
SMBC, SMBD, VREG = 1.8 V, IOL = 1.5 mA
0.4
CIN
Input capacitance
ILKG
Input leakage current
RPD
Pulldown resistance
V
5
0.7
UNIT
1.0
V
V
pF
1
µA
1.3
MΩ
6.12 Electrical Characteristics: PRES, BTP_INT, DISP
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
VIH
High-level input
VIL
Low-level input
VOH
Output voltage high
VOL
Output voltage low
CIN
Input capacitance
ILKG
Input leakage current
10
TEST CONDITIONS
MIN
TYP
MAX
1.3
V
0.55
VBAT > 5.5 V, IOH = –0 µA
3.5
VBAT > 5.5 V, IOH = –10 µA
1.8
V
V
IOL = 1.5 mA
0.4
5
V
pF
1
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UNIT
µA
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Electrical Characteristics: PRES, BTP_INT, DISP (continued)
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
Output reverse
resistance
RO
MIN
Between PRES or BTP_INT or DISP and PBI
TYP
MAX
UNIT
8
kΩ
6.13 Electrical Characteristics: LEDCNTLA, LEDCNTLB, LEDCNTLC
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
VIH
High-level input
VIL
Low-level input
MIN
TYP
MAX
UNIT
1.45
V
0.55
VOH
Output voltage high
VBAT > 3.0 V, IOH = –22.5 mA
VOL
Output voltage low
IOL = 1.5 mA
ISC
High level output
current protection
IOL
Low level output
current
VBAT > 3.0 V, VOH = 0.4 V
ILEDCNTLx
Current matching
between LEDCNTLx
VBAT = VLEDCNTLx + 2.5 V
CIN
Input capacitance
ILKG
Input leakage current
fLEDCNTLx
Frequency of LED
pattern
V
VBAT –
1.6
V
0.4
V
–30
–45
–6 0
mA
15.75
22.5
29.25
mA
±1%
20
pF
1
µA
124
Hz
6.14 Electrical Characteristics: Coulomb Counter
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
Input voltage range
Full scale range
Integral nonlinearity (1)
16-bit, best fit over input voltage range
Offset error
Offset error drift
Gain error
15-bit + sign, over input voltage range
Gain error drift
15-bit + sign, over input voltage range
TYP
MAX
0.1
–VREF1/10
VREF1/10
UNIT
V
V
±5.2
±22.3
16-bit, Post-calibration
±5
±10
µV
15-bit + sign, Post-calibration
0.2
0.3
µV/°C
±0.2%
±0.8%
Effective input resistance
(1)
MIN
–0.1
150
LSB
FSR
PPM/°C
2.5
N
MΩ
15
1 LSB = VREF1/(10 × 2 ) = 1.215/(10 × 2 ) = 3.71 µV
6.15 Electrical Characteristics: CC Digital Filter
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
Conversion time
Single conversion
Effective resolution
Single conversion
MIN
TYP
MAX
UNIT
250
15
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6.16 Electrical Characteristics: ADC
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
Input voltage range
Full scale range
Integral nonlinearity (1)
TEST CONDITIONS
MIN
TYP
MAX
Internal reference (VREF1)
–0.2
1
External reference (VREG)
–0.2
0.8 × VREG
VFS = VREF1 or VREG
–VFS
VFS
16-bit, best fit, –0.1 V to 0.8 × VREF1
±6.6
16-bit, best fit, –0.2 V to –0.1 V
±13.1
Offset error (2)
16-bit, Post-calibration, VFS = VREF1
±67
±157
Offset error drift
16-bit, Post-calibration, VFS = VREF1
0.6
3
Gain error
16-bit, –0.1 V to 0.8 × VFS
±0.2%
±0.8%
Gain error drift
16-bit, –0.1 V to 0.8 × VFS
150
Effective input resistance
(1)
(2)
N
8
UNIT
V
V
LSB
µV
µV/°C
FSR
PPM/°C
MΩ
15
1 LSB = VREF1/(2 ) = 1.225/(2 ) = 37.4 µV (when tCONV = 31.25 ms)
For VC1–VSS, VC2–VC1, VC3–VC2, VC4–VC3, VC4–VSS, PACK–VSS, and VREF1/2, the offset error is multiplied by (1/ADC
multiplexer scaling factor (K)).
6.17 Electrical Characteristics: ADC Digital Filter
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
Conversion time
Resolution
Effective resolution
TEST CONDITIONS
MIN
TYP
Single conversion
31.25
Single conversion
15.63
Single conversion
7.81
Single conversion
1.95
No missing codes
16
With sign, tCONV = 31.25 ms
14
15
With sign, tCONV = 15.63 ms
13
14
With sign, tCONV = 7.81 ms
11
12
With sign, tCONV = 1.95 ms
9
10
MAX
UNIT
ms
Bits
Bits
6.18 Electrical Characteristics: CHG, DSG FET Drive
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
Output voltage
ratio
V(FETON)
V(FETOFF)
tR
12
MIN
TYP
MAX
RatioDSG = (VDSG – VBAT)/VBAT, 2.2 V < VBAT < 4.92 V,
10 MΩ between PACK and DSG
TEST CONDITIONS
2.133
2.333
2.433
RatioCHG = (VCHG – VBAT)/VBAT, 2.2 V < VBAT < 4.92 V,
10 MΩ between BAT and CHG
2.133
2.333
2.433
10.5
11.5
12
10.5
11.5
12
—
VDSG(ON) = VDSG – VBAT, 4.92 V ≤ VBAT ≤ 18 V, 10 MΩ
between PACK and DSG
Output voltage,
CHG and DSG on VCHG(ON) = VCHG – VBAT, 4.92 V ≤ VBAT ≤ 18 V, 10 MΩ
between BAT and CHG
V
VDSG(OFF) = VDSG – VPACK, 10 MΩ between PACK and
Output voltage,
DSG
CHG and DSG off
VCHG(OFF) = VCHG – VBAT, 10 MΩ between BAT and CHG
Rise time
–0.4
0.4
–0.4
0.4
VDSG from 0% to 35% VDSG(ON)(TYP), VBAT ≥ 2.2 V, CL =
4.7 nF between DSG and PACK, 5.1 kΩ between DSG
and CL, 10 MΩ between PACK and DSG
200
500
VCHG from 0% to 35% VCHG(ON)(TYP), VBAT ≥ 2.2 V, CL =
4.7 nF between CHG and BAT, 5.1 kΩ between CHG
and CL, 10 MΩ between BAT and CHG
200
500
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UNIT
V
µs
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Electrical Characteristics: CHG, DSG FET Drive (continued)
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
tF
TEST CONDITIONS
Fall time
TYP
MAX
VDSG from VDSG(ON)(TYP) to 1 V, VBAT ≥ 2.2 V, CL = 4.7 nF
between DSG and PACK, 5.1 kΩ between DSG and CL,
10 MΩ between PACK and DSG
MIN
40
300
VCHG from VCHG(ON)(TYP) to 1 V, VBAT ≥ 2.2 V, CL = 4.7
nF between CHG and BAT, 5.1 kΩ between CHG and
CL, 10 MΩ between BAT and CHG
40
200
UNIT
µs
6.19 Electrical Characteristics: PCHG FET Drive
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
V(FETON)
Output voltage,
PCHG on
VPCHG(ON) = VVCC – VPCHG, 10 MΩ between VCC and
PCHG
V(FETOFF)
Output voltage,
PCHG off
VPCHG(OFF) = VVCC – VPCHG, 10 MΩ between VCC and
PCHG
tR
Rise time
VPCHG from 10% to 90% VPCHG(ON)(TYP), VVCC ≥ 8 V, CL =
4.7 nF between PCHG and VCC, 5.1 kΩ between PCHG
and CL, 10 MΩ between VCC and CHG
tF
Fall time
VPCHG from 90% to 10% VPCHG(ON)(TYP), VCC ≥ 8 V, CL =
4.7 nF between PCHG and VCC, 5.1 kΩ between PCHG
and CL, 10 MΩ between VCC and CHG
MIN
TYP
MAX
6
7
8
V
0.4
V
40
200
µs
40
200
µs
–0.4
UNIT
6.20 Electrical Characteristics: FUSE Drive
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
VOH
Output voltage
high
VIH
High-level input
IAFEFUSE(PU)
Internal pullup
current
RAFEFUSE
Output impedance
CIN
Input capacitance
tDELAY
Fuse trip detection
delay
tRISE
Fuse output rise
time
MIN
TYP
MAX
VBAT ≥ 8 V, CL = 1 nF, IAFEFUSE = 0 µA
TEST CONDITIONS
6
7
8.65
VBAT < 8 V, CL = 1 nF, IAFEFUSE = 0 µA
VBAT – 0.1
1.5
VBAT ≥ 8 V, VAFEFUSE = VSS
2
UNIT
V
VBAT
2.0
2.5
V
150
330
nA
2.6
3.2
kΩ
5
128
VBAT ≥ 8 V, CL = 1 nF, VOH = 0 V to 5 V
5
pF
256
µs
20
µs
6.21 Electrical Characteristics: Internal Temperature Sensor
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
VTEMP
TEST CONDITIONS
MIN
TYP
MAX
Internal temperature VTEMPP
sensor voltage drift VTEMPP – VTEMPN, assured by design
–1.9
–2.0
–2.1
0.177
0.178
0.179
UNIT
mV/°C
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6.22 Electrical Characteristics: TS1, TS2, TS3, TS4
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
TS1, TS2, TS3, TS4, VBIAS = VREF1
–0.2
0.8 × VREF1
TS1, TS2, TS3, TS4, VBIAS = VREG
–0.2
0.8 × VREG
UNIT
VIN
Input voltage
range
RNTC(PU)
Internal pullup
resistance
TS1, TS2, TS3, TS4
14.4
18
21.6
kΩ
RNTC(DRIFT)
Resistance drift
over temperature
TS1, TS2, TS3, TS4
–360
–280
–200
PPM/°C
V
6.23 Electrical Characteristics: PTC, PTCEN
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
RPTC(TRIP)
PTC trip resistance
VPTC(TRIP)
PTC trip voltage
IPTC
Internal PTC
current bias
tPTC(DELAY)
PTC delay time
TEST CONDITIONS
MIN
TYP
MAX
UNIT
1.2
2.5
3.95
MΩ
VPTC(TRIP) = VPTCEN – VPTC
200
500
890
mV
TA = –40°C to 110°C
200
290
350
nA
TA = –40°C to 110°C
40
80
145
ms
6.24 Electrical Characteristics: Internal 1.8-V LDO
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
1.6
1.8
2.0
VREG
Regulator voltage
ΔVO(TEMP)
Regulator output
over temperature
ΔVREG/ΔTA, IREG = 10 mA
ΔVO(LINE)
Line regulation
ΔVREG/ΔVBAT, VBAT = 10 mA
–0 .6%
0.5%
ΔVO(LOAD)
Load regulation
ΔVREG/ΔIREG, IREG = 0 mA to 10 mA
–1.5%
1.5%
IREG
Regulator output
current limit
VREG = 0.9 × VREG(NOM), VIN > 2.2 V
20
ISC
Regulator shortcircuit current limit
VREG = 0 × VREG(NOM)
25
PSRRREG
Power supply
rejection ratio
ΔVBAT/ΔVREG, IREG = 10 mA ,VIN > 2.5 V, f = 10 Hz
VSLEW
Slew rate
enhancement
voltage threshold
VREG
UNIT
V
±0.25%
1.58
mA
40
55
mA
40
dB
1.65
V
6.25 Electrical Characteristics: High-Frequency Oscillator
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
fHFO
Operating frequency
fHFO(ERR)
Frequency error
tHFO(SU)
Start-up time
TEST CONDITIONS
TYP
MAX
16.78
–2.5%
±0.25%
2.5%
TA = –40°C to 85°C, includes frequency drift
–3.5%
±0.25%
3.5%
TA = –20°C to 85°C, oscillator frequency within
+/–3% of nominal
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UNIT
MHz
TA = –20°C to 70°C, includes frequency drift
oscillator frequency within +/–3% of nominal
14
MIN
4
ms
100
µs
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6.26 Electrical Characteristics: Low-Frequency Oscillator
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
fLFO
Operating frequency
fLFO(ERR)
Frequency error
fLFO(FAIL)
Failure detection
frequency
TEST CONDITIONS
MIN
TYP
MAX
UNIT
262.144
kHz
TA = –20°C to 70°C, includes frequency drift
–1.5%
±0.25%
1.5%
TA = –40°C to 85°C, includes frequency drift
–2.5
±0.25
2.5
30
80
100
kHz
6.27 Electrical Characteristics: Voltage Reference 1
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
VREF1
Internal reference
voltage
VREF1(DRIFT)
Internal reference
voltage drift
TEST CONDITIONS
TA = 25°C, after trim
MIN
TYP
MAX
UNIT
1.21
1.215
1.22
V
TA = 0°C to 60°C, after trim
±50
TA = –40°C to 85°C, after trim
±80
PPM/°C
6.28 Electrical Characteristics: Voltage Reference 2
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
VREF2
Internal reference
voltage
VREF2(DRIFT)
Internal reference
voltage drift
TEST CONDITIONS
TA = 25°C, after trim
MIN
TYP
MAX
UNIT
1.22
1.225
1.23
V
TA = 0°C to 60°C, after trim
±50
TA = –40°C to 85°C, after trim
±80
PPM/°C
6.29 Electrical Characteristics: Instruction Flash
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
Data retention
Flash programming
write cycles
MIN
TYP
MAX
UNIT
10
Years
1000
Cycles
tPROGWORD
Word programming
time
TA = –40°C to 85°C
40
µs
tMASSERASE
Mass-erase time
TA = –40°C to 85°C
40
ms
tPAGEERASE
Page-erase time
TA = –40°C to 85°C
40
ms
IFLASHREAD
Flash-read current
TA = –40°C to 85°C
2
mA
IFLASHWRITE
Flash-write current
TA = –40°C to 85°C
5
mA
IFLASHERASE
Flash-erase current
TA = –40°C to 85°C
15
mA
6.30 Electrical Characteristics: Data Flash
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
Data retention
Flash programming
write cycles
tPROGWORD
Word programming
time
TA = –40°C to 85°C
MIN
TYP
MAX
UNIT
10
Years
20000
Cycles
40
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Electrical Characteristics: Data Flash (continued)
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
tMASSERASE
Mass-erase time
TA = –40°C to 85°C
40
ms
tPAGEERASE
Page-erase time
TA = –40°C to 85°C
40
ms
IFLASHREAD
Flash-read current
TA = –40°C to 85°C
1
mA
IFLASHWRITE
Flash-write current
TA = –40°C to 85°C
5
mA
IFLASHERASE
Flash-erase current
TA = –40°C to 85°C
15
mA
6.31 Electrical Characteristics: OCD, SCC, SCD1, SCD2 Current Protection Thresholds
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
PARAMETER
OCD detection
threshold voltage range VOCD = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 0
VOCD
OCD detection
threshold voltage
program step
ΔVOCD
SCC detection
threshold voltage
program step
ΔVSCC
SCD1 detection
threshold voltage
program step
ΔVSCD1
SCD2 detection
threshold voltage
program step
ΔVSCD2
VOFFSET
OCD, SCC, and SCDx
offset error
VSCALE
OCD, SCC, and SCDx
scale error
–100
–8.3
–50
mV
44.4
200
22.2
100
mV
VSCC = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 1
22.2
VSCC = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 0
11.1
mV
–44.4
–200
–22.2
–100
mV
VSCD1 = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 1
–22.2
VSCD1 = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 0
–11.1
mV
–44.4
–200
–22.2
–100
mV
VSCD2 = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 1
–22.2
VSCD2 = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 0
–11.1
No trim
Post-trim
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UNIT
mV
–2.78
Post-trim
MAX
–16.6
VOCD = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 0
VSCD2 = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 1
SCD2 detection
threshold voltage range VSCD2 = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 0
VSCD2
TYP
–5.56
VSCD1 = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 1
SCD1 detection
threshold voltage range VSCD1 = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 0
VSCD1
MIN
VOCD = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 1
VSCC = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 1
SCC detection
threshold voltage range VSCC = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 0
VSCC
16
TEST CONDITIONS
VOCD = VSRP – VSRN, AFE PROTECTION
CONTROL[RSNS] = 1
mV
–2.5
2.5
–10%
10%
–5%
5%
mV
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6.32 Timing Requirements: OCD, SCC, SCD1, SCD2 Current Protection Timing
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
MIN
NOM
MAX
tOCD
OCD detection
delay time
ΔtOCD
OCD detection
delay time
program step
tSCC
SCC detection
delay time
ΔtSCC
SCC detection
delay time
program step
tSCD1
SCD1 detection
delay time
AFE PROTECTION CONTROL[SCDDx2] = 0
0
915
AFE PROTECTION CONTROL[SCDDx2] = 1
0
1850
SCD1 detection
delay time
program step
AFE PROTECTION CONTROL[SCDDx2] = 0
61
ΔtSCD1
AFE PROTECTION CONTROL[SCDDx2] = 1
121
tSCD2
SCD2 detection
delay time
AFE PROTECTION CONTROL[SCDDx2] = 0
0
458
AFE PROTECTION CONTROL[SCDDx2] = 1
0
915
SCD2 detection
delay time
program step
AFE PROTECTION CONTROL[SCDDx2] = 0
30.5
ΔtSCD2
AFE PROTECTION CONTROL[SCDDx2] = 1
61
tDETECT
Current fault
detect time
VSRP – VSRN = VT – 3 mV for OCD, SCD1, and SC2,
VSRP – VSRN = VT + 3 mV for SCC
tACC
Current fault
delay time
accuracy
Max delay setting
1
31
2
0
ms
ms
915
61
µs
µs
µs
µs
µs
µs
160
–10%
UNIT
µs
10%
6.33 Timing Requirements: SMBus
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
MIN
NOM
10
MAX
UNIT
100
kHz
fSMB
SMBus operating frequency SLAVE mode, SMBC 50% duty cycle
fMAS
SMBus master clock
frequency
tBUF
Bus free time between start
and stop
4.7
µs
tHD(START)
Hold time after (repeated)
start
4.0
µs
tSU(START)
Repeated start setup time
4.7
µs
tSU(STOP)
Stop setup time
4.0
µs
tHD(DATA)
Data hold time
300
ns
tSU(DATA)
Data setup time
250
ns
tTIMEOUT
Error signal detect time
25
tLOW
Clock low period
4.7
tHIGH
Clock high period
4.0
tR
Clock rise time
tF
Clock fall time
tLOW(SEXT)
Cumulative clock low slave
extend time
tLOW(MEXT)
Cumulative clock low
master extend time
MASTER mode, no clock low slave extend
51.2
kHz
35
ms
µs
50
µs
10% to 90%
1000
ns
90% to 10%
300
ns
25
ms
10
ms
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6.34 Timing Requirements: SMBus XL
Typical values stated where TA = 25°C and VCC = 14.4 V, Min/Max values stated where TA = –40°C to 85°C and VCC =
2.2 V to 26 V (unless otherwise noted)
MIN
SLAVE mode
NOM
MAX
UNIT
400
kHz
fSMBXL
SMBus XL operating
frequency
tBUF
Bus free time between start
and stop
4.7
µs
tHD(START)
Hold time after (repeated) start
4.0
µs
tSU(START)
Repeated start setup time
4.7
µs
tSU(STOP)
Stop setup time
4.0
tTIMEOUT
Error signal detect time
tLOW
tHIGH
40
µs
5
20
ms
Clock low period
20
µs
Clock high period
20
µs
TtR
tSU(STOP)p
TtF
TtF
tHD(START)
TtBUFT
SMBC
SMBC
SMBD
SMBD
P
TtR
TtHIGHT
TtLOWT
S
tHD(DATA)T
Start and Stop Condition
TtSU(DATA)
Wait and Hold Condition
tSU(START)T
TtTIMEOUT
SMBC
SMBC
SMBD
SMBD
S
Timeout Condition
Repeated Start Condition
Figure 4. SMBus Timing Diagram
18
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6.35 Typical Characteristics
0.15
8.0
Max CC Offset Error
Min CC Offset Error
6.0
ADC Offset Error (µV)
CC Offset Error ( V)
0.10
0.05
0.00
±0.05
±0.10
4.0
2.0
0.0
±2.0
±4.0
±6.0
±0.15
Max ADC Offset Error
Min ADC Offset Error
±8.0
±40
±20
0
20
40
60
80
100
Temperature (ƒC)
120
±40
Figure 5. CC Offset Error vs. Temperature
20
40
60
80
100
120
C003
Figure 6. ADC Offset Error vs. Temperature
264
Low-Frequency Oscillator (kHz)
Reference Voltage (V)
0
Temperature (°C)
1.24
1.23
1.22
1.21
1.20
262
260
258
256
254
252
250
±40
0
±20
20
40
60
80
Temperature (ƒC)
100
±40
0
±20
20
40
60
80
Temperature (ƒC)
C006
Figure 7. Reference Voltage vs. Temperature
100
C007
Figure 8. Low-Frequency Oscillator vs. Temperature
16.9
±24.6
OCD Protection Threshold (mV)
High-Frequency Oscillator (MHz)
±20
C001
16.8
16.7
16.6
±24.8
±25.0
±25.2
±25.4
±25.6
±25.8
±40
±20
0
20
40
60
Temperature (ƒC)
80
100
120
±40
±20
0
20
40
60
80
100
Temperature (ƒC)
C008
120
C009
Threshold setting is –25 mV.
Figure 9. High-Frequency Oscillator vs. Temperature
Figure 10. Overcurrent Discharge Protection Threshold vs.
Temperature
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Typical Characteristics (continued)
±86.0
SCD 1 Protection Threshold (mV)
SCC Protection Threshold (mV)
87.4
87.2
87.0
86.8
86.6
86.4
86.2
±86.2
±86.4
±86.6
±86.8
±87.0
±87.2
±40
±20
0
20
40
60
80
100
Temperature (ƒC)
120
±40
±20
0
C010
Threshold setting is 88.85 mV.
20
40
60
80
100
Temperature (ƒC)
120
C011
Threshold setting is –88.85 mV.
Figure 11. Short Circuit Charge Protection Threshold vs.
Temperature
Figure 12. Short Circuit Discharge 1 Protection Threshold
vs. Temperature
±172.9
Over-Current Delay Time (mS)
SCD 2 Protection Threshold (mV)
11.00
±173.0
±173.1
±173.2
±173.3
±173.4
±173.5
10.95
10.90
10.85
10.80
10.75
10.70
±173.6
±40
±20
0
20
40
60
80
100
Temperature (ƒC)
120
±40
Threshold setting is –177.7 mV.
20
40
60
80
100
120
C013
Threshold setting is 11 ms.
Figure 14. Overcurrent Delay Time vs. Temperature
480
452
450
SC Discharge 1 Delay Time ( S)
SC Charge Current Delay Time ( S)
0
Temperature (ƒC)
Figure 13. Short Circuit Discharge 2 Protection Threshold
vs. Temperature
448
446
444
442
440
438
436
434
432
460
440
420
400
±40
±20
0
20
40
60
Temperature (ƒC)
80
100
120
±40
±20
0
20
40
60
80
Temperature (ƒC)
C014
Threshold setting is 465 µs.
100
120
C015
Threshold setting is 465 µs (including internal delay).
Figure 15. Short Circuit Charge Current Delay Time vs.
Temperature
20
±20
C012
Figure 16. Short Circuit Discharge 1 Delay Time vs.
Temperature
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Typical Characteristics (continued)
3.49825
2.4984
2.49835
3.4982
Cell Voltage (V)
Cell Voltage (V)
2.4983
2.49825
2.4982
2.49815
2.4981
3.49815
3.4981
3.49805
2.49805
3.498
2.498
±40
±20
0
20
40
60
80
100
Temperature (ƒC)
120
±40
±20
0
20
40
60
80
100
Temperature (ƒC)
C016
120
C017
This is the VCELL average for single cell.
Figure 17. VCELL Measurement at 2.5-V vs. Temperature
Figure 18. VCELL Measurement at 3.5-V vs. Temperature
4.24805
Measurement Current (mA)
99.25
Cell Voltage (V)
4.248
4.24795
4.2479
4.24785
4.2478
99.20
99.15
99.10
99.05
99.00
±40
±20
0
20
40
60
Temperature (ƒC)
80
100
120
±40
0
20
40
60
80
100
Temperature (ƒC)
C018
This is the VCELL average for single cell.
±20
120
C019
ISET = 100 mA
Figure 19. VCELL Measurement at 4.25-V vs. Temperature
Figure 20. I Measured vs. Temperature
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7 Detailed Description
7.1 Overview
The bq4050 device, incorporating Compensated End-of-Discharge Voltage (CEDV) technology, provides cell
balancing while charging or at rest. This fully integrated, single-chip, pack-based solution, including a diagnostic
lifetime data monitor and black box recorder, provides a rich array of features for gas gauging, protection, and
authentication for 1-series, 2-series, 3-series, and 4-series cell Li-Ion and Li-Polymer battery packs.
Cell Detach
Detection
Wake
Comparator
PCHG
DSG
CHG
PBI
VCC
BAT
VSS
Cell, Stack,
Pack
Voltage
PACK
VC2
VC1
VC4
Cell
Balancing
VC3
7.2 Functional Block Diagram
Power Mode
Control
High Side
N-CH FET
Drive
P-CH
FET Drive
Power On
Reset
Zero Volt
Charge
Control
PTC
Overtemp
Short Circuit
Comparator
PTCEN
PTC
FUSE
Control
FUSE
High
Voltage
I/O
PRES or SHUTDN
SRP
SRN
Over
Current
Comparator
Voltage
Reference2
NTC Bias
Random
Number
Generator
Watchdog
Timer
Internal
Temp
Sensor
LED Display
Drive I/O
TS1
TS2
TS3
ADC/CC
FRONTEND
ADC MUX
DISP
LEDCNTLC
LEDCNTLB
LEDCNTLA
TS4
Voltage
Reference1
BTP_INT
AFE Control
Low
Frequency
Oscillator
1.8V LDO
Regulator
AFE COM
Engine
SBS High
Voltage
Translation
I/O &
Interrupt
Controller
AFE COM
Engine
SBS COM
Engine
SMBD
SMBC
High
Frequency
Oscillator
Low Voltage
I/O
I/O
ADC/CC
Digital Filter
Data (8bit)
bqBMP
CPU
PMInstr
(8bit)
Timers &
PWM
DMAddr (16bit)
PMAddr
(16bit)
Program
Flash
EEPROM
Data Flash
EEPROM
Data
SRAM
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7.3 Feature Description
7.3.1 Primary (1st Level) Safety Features
The bq4050 gas gauge supports a wide range of battery and system protection features that can easily be
configured. See the bq4050 Technical Reference Manual (SLUUAQ3) for detailed descriptions of each protection
function.
The primary safety features include:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Cell Overvoltage Protection
Cell Undervoltage Protection
Overcurrent in Charge Protection
Overcurrent in Discharge Protection
Overload in Discharge Protection
Short Circuit in Charge Protection
Short Circuit in Discharge Protection
Overtemperature in Charge Protection
Overtemperature in Discharge Protection
Undertemperature in Charge Protection
Undertemperature in Discharge Protection
Overtemperature FET protection
Precharge Timeout Protection
Host Watchdog Timeout Protection
Overcharge Protection
Overcharging Voltage Protection
Overcharging Current Protection
Over Precharge Current Protection
7.3.2 Secondary (2nd Level) Safety Features
The secondary safety features of the bq4050 gas gauge can be used to indicate more serious faults via the
FUSE pin. This pin can be used to blow an in-line fuse to permanently disable the battery pack from charging or
discharging. See the bq4050 Technical Reference Manual (SLUUAQ3) for detailed descriptions of each
protection function.
The secondary safety features provide protection against:
• Safety Overvoltage Permanent Failure
• Safety Undervoltage Permanent Failure
• Safety Overtemperature Permanent Failure
• Safety FET Overtemperature Permanent Failure
• Fuse Failure Permanent Failure
• PTC Permanent Failure
• Voltage Imbalance at Rest (VIMR) Permanent Failure
• Voltage Imbalance Active (VIMA) Permanent Failure
• Charge FET Permanent Failure
• Discharge FET Permanent Failure
• AFE Register Permanent Failure
• AFE Communication Permanent Failure
• Second Level Protector Permanent Failure
• Instruction Flash Checksum Permanent Failure
• Open Cell Connection Permanent Failure
• Data Flash Permanent Failure
• Open Thermistor Permanent Failure
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Feature Description (continued)
7.3.3 Charge Control Features
The bq4050 gas gauge charge control features include:
•
•
•
•
•
•
•
Supports JEITA temperature ranges. Reports charging voltage and charging current according to the active
temperature range
Handles more complex charging profiles. Allows for splitting the standard temperature range into two
subranges and allows for varying the charging current according to the cell voltage
Reports the appropriate charging current needed for constant current charging and the appropriate charging
voltage needed for constant voltage charging to a smart charger using SMBus broadcasts
Reduces the charge difference of the battery cells in fully charged state of the battery pack gradually using a
voltage-based cell balancing algorithm during charging. A voltage threshold can be set up for cell balancing to
be active. This prevents fully charged cells from overcharging and causing excessive degradation and also
increases the usable pack energy by preventing premature charge termination.
Supports precharging/0-volt charging
Supports charge inhibit and charge suspend if the battery pack temperature is out of temperature range
Reports charging fault and also indicates charge status via charge and discharge alarms
7.3.4 Gas Gauging
The bq4050 gas gauge uses the Compensated End-of-Discharge Voltage (CEDV) algorithm to measure and
calculate the available capacity in battery cells. The bq4050 device accumulates a measure of charge and
discharge currents, estimates self-discharge of the battery, and adjusts the self-discharge estimation based on
temperature. See the bq4050 Technical Reference Manual (SLUUAQ3) for further details.
7.3.5 Configuration
7.3.5.1 Oscillator Function
The bq4050 gas gauge fully integrates the system oscillators and does not require any external components to
support this feature.
7.3.5.2 System Present Operation
The bq4050 gas gauge checks the PRES pin periodically (1 s). If PRES input is pulled to ground by the external
system, the bq4050 device detects this as system present.
7.3.5.3 Emergency Shutdown
For battery maintenance, the emergency shutdown feature enables a push button action connecting the
SHUTDN pin to shut down an embedded battery pack system before removing the battery. A high-to-low
transition of the SHUTDN pin signals the bq4050 gas gauge to turn off the CHG and DSG FETs, disconnecting
the power from the system to safely remove the battery pack. The CHG and DSG FETs can be turned on again
by another high-to-low transition detected by the SHUTDN pin or when a data flash configurable timeout is
reached.
7.3.5.4 1-Series, 2-Series, 3-Series, or 4-Series Cell Configuration
In a 1-series cell configuration, VC4 is shorted to VC, VC2, and VC1. In a 2-series cell configuration, VC4 is
shorted to VC3 and VC2. In a 3-series cell configuration, VC4 is shorted to VC3.
7.3.5.5 Cell Balancing
The device reduces the charge difference of the battery cells in a fully charged state of the battery pack by
gradually using a voltage-based cell balancing algorithm during charging. A voltage threshold can be set up for
cell balancing to be active. This prevents fully charged cells from overcharging and causing excessive
degradation, and increases the usable pack energy by preventing premature charge termination.
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Feature Description (continued)
7.3.6 Battery Parameter Measurements
7.3.6.1 Charge and Discharge Counting
The bq4050 gas gauge uses an integrating delta-sigma analog-to-digital converter (ADC) for current
measurement, and a second delta-sigma ADC for individual cell and battery voltage and temperature
measurement.
The integrating delta-sigma ADC measures the charge/discharge flow of the battery by measuring the voltage
drop across a small-value sense resistor between the SRP and SRN terminals. The integrating ADC measures
bipolar signals from –0.1 V to 0.1 V. The bq4050 gauge detects charge activity when VSR = V(SRP) – V(SRN) is
positive, and discharge activity when VSR = V(SRP) – V(SRN) is negative. The bq4050 gas gauge continuously
integrates the signal over time, using an internal counter. The fundamental rate of the counter is 0.26 nVh.
7.3.7 Battery Trip Point (BTP)
Required for WIN8 OS, the battery trip point (BTP) feature indicates when the RSOC of a battery pack has
depleted to a certain value set in a DF register. This feature enables a host to program two capacity-based
thresholds that govern the triggering of a BTP interrupt on the BTP_INT pin and the setting or clearing of the
OperationStatus[BTP_INT] on the basis of RemainingCapacity().
An internal weak pullup is applied when the BTP feature is active. Depending on the system design, an external
pullup may be required to put on the BTP_INT pin. See Electrical Characteristics: PRES, BTP_INT, DISP for
details.
7.3.8 Lifetime Data Logging Features
The bq4050 gas gauge offers lifetime data logging for several critical battery parameters. The following
parameters are updated every 10 hours if a difference is detected between values in RAM and data flash:
• Maximum and Minimum Cell Voltages
• Maximum Delta Cell Voltage
• Maximum Charge Current
• Maximum Discharge Current
• Maximum Average Discharge Current
• Maximum Average Discharge Power
• Maximum and Minimum Cell Temperature
• Maximum Delta Cell Temperature
• Maximum and Minimum Internal Sensor Temperature
• Maximum FET Temperature
• Number of Safety Events Occurrences and the Last Cycle of the Occurrence
• Number of Valid Charge Termination and the Last Cycle of the Valid Charge Termination
• Number of Shutdown Events
• Cell Balancing Time for Each Cell
(This data is updated every 2 hours if a difference is detected.)
• Total FW Runtime and Time Spent in Each Temperature Range
(This data is updated every 2 hours if a difference is detected.)
7.3.9 Authentication
The bq4050 gas gauge supports authentication by the host using SHA-1.
7.3.10 LED Display
The bq4050 gas gauge can drive a 3-, 4-, or 5- segment LED display for remaining capacity indication and/or a
permanent fail (PF) error code indication.
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Feature Description (continued)
7.3.11 Voltage
The bq4050 gas gauge updates the individual series cell voltages at 0.25-s intervals. The internal ADC of the
bq4050 device measures the voltage, and scales and calibrates it appropriately. This data is also used to
calculate the impedance of the cell for the CEDV gas gauging.
7.3.12 Current
The bq4050 gas gauge uses the SRP and SRN inputs to measure and calculate the battery charge and
discharge current using a 1-mΩ to 3-mΩ typ. sense resistor.
7.3.13 Temperature
The bq4050 gas gauge has an internal temperature sensor and inputs for four external temperature sensors. All
five temperature sensor options can be individually enabled and configured for cell or FET temperature usage.
Two configurable thermistor models are provided to enable monitoring of the cell temperature in addition to the
FET temperature, which use a different thermistor profile.
7.3.14 Communications
The bq4050 gas gauge uses SMBus v1.1 with MASTER mode and packet error checking (PEC) options per the
SBS specification.
7.3.14.1 SMBus On and Off State
The bq4050 gas gauge detects an SMBus off state when SMBC and SMBD are low for two or more seconds.
Clearing this state requires that either SMBC or SMBD transition high. The communication bus will resume
activity within 1 ms.
7.3.14.2 SBS Commands
See the bq4050 Technical Reference Manual (SLUUAQ3) for further details.
7.4 Device Functional Modes
The bq4050 gas gauge supports three power modes to reduce power consumption:
• In NORMAL mode, the bq4050 gauge performs measurements, calculations, protection decisions, and data
updates in 250-ms intervals. Between these intervals, the bq4050 gauge is in a reduced power stage.
• In SLEEP mode, the bq4050 gauge performs measurements, calculations, protection decisions, and data
updates in adjustable time intervals. Between these intervals, the bq4050 gauge is in a reduced power stage.
The bq4050 gauge has a wake function that enables exit from SLEEP mode when current flow or failure is
detected.
• In SHUTDOWN mode, the bq4050 gauge is completely disabled.
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8 Applications and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The bq4050 gas gauge has primary protection support to be used with a 1-series to 4-series Li-Ion/Li Polymer
battery pack. To implement and design a comprehensive set of parameters for a specific battery pack, users
need the Battery Management Studio (bqStudio) graphical user-interface tool installed on a PC during
development. The firmware installed on the bqStudio tool has default values for this product, which are
summarized in the bq4050 Technical Reference Manual (SLUUAQ3). Using the bqStudio tool, these default
values can be changed to cater to specific application requirements during development once the system
parameters, such as fault trigger thresholds for protection, enable/disable of certain features for operation,
configuration of cells, chemistry that best matches the cell used, and more are known. This data is referred to as
the "golden image."
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bq4050
4P
J1
1
2
3
1
2
1
R11
100
R13
1K
R14
0.1uF
C4
C5
0.1uF
1
2
3
4
CD 7
VSS 6
V1 5
U2
BQ2947xyDSG
VDD
OUT 8
V4
V3
V2
1
FUSE
C7
0.1uF 0.1uF
C6
F1
2
SFDxxxx
4P
10M
R2
300
R1
FUSEPIN
R6
0.1uF
C3
R16
5.1K
C13
51K
Q5
Si1406DH
3
BAT
D1
BAT54HT1
AGND
BAT
3
R17
5.1K
3
Q2
Si7116DN
R7
5.1K
CHG
SRP
NC
SRN
VC 1
VC 2
VC 3
VC 4
2.2uF
1 PBI
2
3
4
5
6
7
8
C1
0.1uF
C2
R9
2
0.1uF
Q1
FDN358P
R5
10M
R8
100
3
DSG
5.1K
RT3
GND
Q3
Si7116DN
R10
5.1K
10M
R3
23
24
10K
R12
PTCEN
PTC
20
21
22
19
17
18
Q4
2N7002K
1
10K
R4
C12
RT1
D8
LED2
D6
LED4
BAT
CHGND
D5
LED3
D7
LED1
0.1uF
2
10K
D9
LED5
4P
BAT
10K
R32
S1
Wake
PACK+
A
A'
5
4
3
2
1
B
B'
For Thumbus-SMB
SMBD
I2C_VOUT
CHGND
SMBC
CHGND
1K
R29
100
R25
D4
R24
D3
100
R27
D2
200
R26
200
2001
2
A
B
A'
B'
J7
S2
LED DISPLAY
GND
R28
B
B'
SHUTDOWN
A
A'
S3
DISP
SMBD
SMBC
LEDCNTLA
LEDCNTLB
LEDCNTLC
TP12
RT5
GND
RT4
10K
GND
10K
GND
J6
SMBC
SMBD
4
3
2
PACK+
J2
1
CHGND
C8
0.1uF
C10
0.1uF
SMBD
VSS
SMBC
2
1
3
2
1
J4
J3
PACK+
PACK+
Sys Pres
PACK-
PACK-
PACK+
CHGND
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1K
R15
GND
C15
C16
0.1uF
C17
GND
RT2
10K
GND
10K
GND
CHGND
GND SIDE
6
7
2
3
GND
MM3ZxxVyC
Copyright © 2017, Texas Instruments Incorporated
SMBD
C9
0.1uF
C11
0.1uF
0.1uF
C14
0.1uF
0.1uF
TP3
SRN
DNP
C20
C21
DNP
GND SIDE
1
GND SIDE
1K
R22
100
R23
C18
0.1uF
R31
25
4
100
GND
1
2
1
2
R18
R21
100
SRP
R30
R19
0.001
CHGND
1
1
1K
R20
100
100
GND
C19
DNP 100
GND
1
1
3P
2P
1P J5
1N
NT1
Net-Tie
IC ground should be connected to the 1N cell tab.
Replace D1 and R9 with a 10 ohm resistor for single cell applications
Place RT1 close to Q2 and Q3.
DSG
28
1
SMBC
SMBC
SMBD
1
2
1
2
GND SIDE
30
NC
29
CHG
3
2
1
FUSE
1 16 PRES or SHUTDN
VCC
1
4P
AGND GND
1
3
MM3ZxxVyC
5
PCHG
1
2
3
1
5
1
1
1
10 TS1
11 TS2
4
27
26
1
32
12 TS3
13 TS4
PACK
14 NC
15 BTP_INT
31
33
BAT
1
1
PWPD
VSS
9
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2
MM3ZxxVyC
1
1
1
1
1
1
3
6
4
1
1
1
EP
9
5
2
1
1
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8.2 Typical Applications
Figure 21. Application Schematic
bq4050
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Typical Applications (continued)
8.2.1 Design Requirements
Table 1 shows the default settings for the main parameters. Use the bqStudio tool to update the settings to meet
the specific application or battery pack configuration requirements.
The device should be calibrated before any gauging test. Follow the information in the bqStudio Calibration
page to calibrate the device, and use the bqStudio Chemistry page to update the match chemistry profile to the
device.
Table 1. Design Parameters
(1)
DESIGN PARAMETER
EXAMPLE
Cell Configuration
3s1p (3-series with 1 Parallel) (1)
Design Capacity
4400 mAh
Device Chemistry
1210 (LiCoO2/graphitized carbon)
Cell Overvoltage at Standard Temperature
4300 mV
Cell Undervoltage
2500 mV
Shutdown Voltage
2300 mV
Overcurrent in CHARGE Mode
6000 mA
Overcurrent in DISCHARGE Mode
–6000 mA
Short Circuit in CHARGE Mode
0.1 V/Rsense across SRP, SRN
Short Circuit in DISCHARGE Mode
0.1 V/Rsense across SRP, SRN
Safety Overvoltage
4500 mV
Cell Balancing
Disabled
Internal and External Temperature Sensor
External Temperature Sensors are used.
Undertemperature Charging
0°C
Undertemperature Discharging
0°C
BROADCAST Mode
Disabled
Battery Trip Point (BTP) with active high interrupt
Disabled
When using the device the first time, if the a 1-s or 2-s battery pack is used, then a charger or power supply should be connected to the
PACK+ terminal to prevent device shutdown. Then update the cell configuration (see the bq4050 Technical Reference Manual
(SLUUAQ3) for details) before removing the charger connection.
8.2.2 Detailed Design Procedure
8.2.2.1 High-Current Path
The high-current path begins at the PACK+ terminal of the battery pack. As charge current travels through the
pack, it finds its way through protection FETs, a chemical fuse, the lithium-ion cells and cell connections, and the
sense resistor, and then returns to the PACK– terminal (see Figure 22). In addition, some components are
placed across the PACK+ and PACK– terminals to reduce effects from electrostatic discharge.
8.2.2.1.1 Protection FETs
Select the N-CH charge and discharge FETs for a given application. Most portable battery applications are a
good match for the CSD17308Q3. The TI CSD17308Q3 is a 47A, 30-V device with Rds(on) of 8.2 mΩ when the
gate drive voltage is 8 V.
If a precharge FET is used, R1 is calculated to limit the precharge current to the desired rate. Be sure to account
for the power dissipation of the series resistor. The precharge current is limited to (VCHARGER – VBAT)/R1 and
maximum power dissipation is (Vcharger – Vbat)2/R1.
The gates of all protection FETs are pulled to the source with a high-value resistor between the gate and source
to ensure they are turned off if the gate drive is open.
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Capacitors C1 and C2 help protect the FETs during an ESD event. Using two devices ensures normal operation
if one becomes shorted. To have good ESD protection, the copper trace inductance of the capacitor leads must
be designed to be as short and wide as possible. Ensure that the voltage ratings of C1 and C2 are adequate to
hold off the applied voltage if one of the capacitors becomes shorted.
C1
R1
0.1 F
C2
0.1 F
300
Q1
FDN358P
Q3
Si7114DN
Q2
Si7114DN
R2
10M
R5
R3
10M
Q4
2N7002K
10M
R4
10K
R7
5.1K
R8
5.1K
R9
100
R10
5.1K
Copyright © 2016, Texas Instruments Incorporated
Figure 22. bq4050 Protection FETs
8.2.2.1.2 Chemical Fuse
The chemical fuse (Dexerials, Uchihashi, and so on) is ignited under command from either the bq294700
secondary voltage protection IC or from the FUSE pin of the gas gauge. Either of these events applies a positive
voltage to the gate of Q5, shown in Figure 23, which then sinks current from the third terminal of the fuse,
causing it to ignite and open permanently.
It is important to carefully review the fuse specifications and match the required ignition current to that available
from the N-CH FET. Ensure that the proper voltage, current, and Rds(on) ratings are used for this device. The
fuse control circuit is discussed in detail in FUSE Circuitry.
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4P
F1
DNP
1
2
6
5
2
1
3
Q5
Si1406DH
4
3
R6
51K
to 2nd Level Protector
R16
C3
0.1 F
5.1K
R17
5.1K
to FUSE Pin
Copyright © 2016, Texas Instruments Incorporated
Figure 23. FUSE Circuit
8.2.2.1.3 Lithium-Ion Cell Connections
The important part to remember about the cell connections is that high current flows through the top and bottom
connections; therefore, the voltage sense leads at these points must be made with a Kelvin connection to avoid
any errors due to a drop in the high-current copper trace. The location marked 4P in Figure 24 indicates the
Kelvin connection of the most positive battery node. The connection marked 1N is equally important. The VC5
pin (a ground reference for cell voltage measurement), which is in the older generation devices, is not in the
bq4050 device. Therefore, the single-point connection at 1N to the low-current ground is needed to avoid an
undesired voltage drop through long traces while the gas gauge is measuring the bottom cell voltage.
Figure 24. Lithium-Ion Cell Connections
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8.2.2.1.4 Sense Resistor
As with the cell connections, the quality of the Kelvin connections at the sense resistor is critical. The sense
resistor must have a temperature coefficient no greater than 50 ppm in order to minimize current measurement
drift with temperature. Choose the value of the sense resistor to correspond to the available overcurrent and
short-circuit ranges of the bq4050 gauge. Select the smallest value possible to minimize the negative voltage
generated on the bq4050 VSS node(s) during a short circuit. This pin has an absolute minimum of –0.3 V. Parallel
resistors can be used as long as good Kelvin sensing is ensured. The device is designed to support a 1-mΩ to 3mΩ sense resistor.
The ground scheme of bq4050 gauge is different from the older generation devices. In previous devices, the
device ground (or low current ground) is connected to the SRN side of the Rsense resistor pad. The bq4050
gauge, however, it connects the low-current ground on the SRP side of the Rsense resistor pad close to the
battery 1N terminal (see Lithium-Ion Cell Connections). This is because the bq4050 gauge has one less VC pin
(a ground reference pin VC5) compared to the previous devices. The pin was removed and was internally
combined to SRP.
R19
0.001
50 ppm
Copyright © 2016 , Texas Instruments Incorporated
Figure 25. Sense Resistor
8.2.2.1.5 ESD Mitigation
A pair of series 0.1-μF ceramic capacitors is placed across the PACK+ and PACK– terminals to help in the
mitigation of external electrostatic discharges. The two devices in series ensure continued operation of the pack
if one of the capacitors becomes shorted.
Optionally, a tranzorb such as the SMBJ2A can be placed across the terminals to further improve ESD immunity.
8.2.2.2 Gas Gauge Circuit
The gas gauge circuit includes the bq4050 gauge and its peripheral components. These components are divided
into the following groups: Differential Low-Pass Filter, PBI, system present, SMBus Communication, FUSE
circuit, and LED.
8.2.2.2.1 Coulomb-Counting Interface
The bq4050 gauge uses an integrating delta-sigma ADC for current measurements. Add a 100-Ω resistor from
the sense resistor to the SRP and SRN inputs of the device. Place a 0.1-µF (C18) filter capacitor across the SRP
and SRN inputs. Optional 0.1-µF filter capacitors (C19 and C20) can be added for additional noise filtering if
required for a circuit.
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C18
0.1 µF
C19
DNP
C20
DNP
R31
100
R30
100
R19
0.001
50 ppm
Copyright © 2016, Texas Instruments Incorporated
Figure 26. Differential Filter
8.2.2.2.2 Power Supply Decoupling and PBI
The bq4050 gauge has an internal LDO that is internally compensated and does not require an external
decoupling capacitor.
25
FUSE
27
VCC 26
PACK
DSG 28
29
NC
PCHG 30
BAT
PWPD
CHG 31
32
33
The PBI pin is used as a power supply backup input pin providing power during brief transient power outages. A
standard 2.2-µF ceramic capacitor is connected from the PBI pin to ground as shown in Figure 27.
1 PBI
C13
2.2 μF
PTCEN
24
23
2
VC4
PTC
3
VC3
LEDCNTL3
22
4
VC2
LEDCNTL2
21
5
VC1
LEDCNTL1 20
6 SRN
SMBC
7
SMBD
NC
19
18
DISP 17
PRES
16
1 5 NC
NC
14
TS4
13
TS2
TS3
12
11
TS1
10
9
vss
8 SRP
Copyright © 2016 , Texas Instruments Incorporated
Figure 27. Power Supply Decoupling
8.2.2.2.3 System Present
The system present signal is used to inform the gas gauge whether the pack is installed into or removed from the
system. In the host system, this pin is grounded. The PRES pin of the bq4050 gauge is occasionally sampled to
test for system present. To save power, an internal pullup is provided by the gas gauge during a brief 4-μs
sampling pulse once per second. A resistor can be used to pull the signal low and the resistance must be 20 kΩ
or lower to ensure that the test pulse is lower than the VIL limit. The pullup current source is typically 10 µA to
20 µA.
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bq4050
16
PRES
BTP_IN
15
NC
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14
13
TS4
SLUSC67B – MARCH 2016 – REVISED OCTOBER 2017
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