bq24702
bq24703
www.ti.com
SLUS553E – MAY 2003 – REVISED OCTOBER 2007
MULTICHEMISTRY BATTERY CHARGER CONTROLLER AND
SYSTEM POWER SELECTOR
FEATURES
1
20
6
19
7
18
8
17
9
16
10
15
11
14
12
13
ACSET
VREF
ENABLE
BATSET
COMP
3
4
5
6
7
ACN
ACPRES
27
9
ACP
ACDET
26
10
NC
ACDRV
25
11
NC
BATDRV
24
12
BATP
NC
23
13
IBAT
VCC
22
14
NC
NC - No internal connection
15
5
8
SRN
21
28
16
4
ACSEL
SRP
22
17
3
ACDRV
BATDRV
VCC
PWM
VHSP
ALARM
VS
GND
SRP
SRN
IBAT
BATP
GND
23
18
24
2
VS
1
19
ACDET
ACPRES
ACSEL
BATDEP
SRSET
ACSET
VREF
ENABLE
BATSET
COMP
ACN
ACP
bq24703
RHD PACKAGE
(BOTTOM VIEW)
ALARM
bq24702, bq24703
PW PACKAGE
(TOP VIEW)
SRSET
•
VHSP
•
BATDEP
•
The bq24702/bq24703 uses a fixed frequency, pulse
width modulator (PWM) to accurately control battery
charge current and voltage. Charge current limits can
be programmed from a keyboard controller DAC or
by external resistor dividers from the precision 5-V,
±0.6%, externally bypassed voltage reference
(VREF), supplied by the bq24702/bq24703.
2
•
•
20
•
The bq24702/bq24703 uses dynamic power
management (DPM) to minimize battery charge time
by maximizing use of available wall-adapter power.
This is achieved by dynamically adjusting the battery
charge current based on the total system (adapter)
current.
1
•
•
The bq24702/bq24703 is a highly integrated battery
charge controller and selector tailored for notebook
and sub-notebook PC applications.
21
•
DESCRIPTION
Dynamic Power Management, DPM Minimizes
Battery Charge Time
Integrated Selector Supports Battery
Conditioning and Smart Battery Learn Cycle
Zero Volt Operation
Selector Feedback Circuit Ensures
Break-Before-Make Transition
±0.4% Charge Voltage Accuracy, Suitable for
Charging Li-Ion Cells
±4% Charge Current Accuracy
300-kHz Integrated PWM Controller for
High-Efficiency Buck Regulation
Depleted Battery Detection and Indication to
Protect Battery From Over Discharge
20-μA Sleep Mode Current for Low Battery
Drain
24-Pin TSSOP Package and 5 mm × 5 mm QFN
package (bq24703 only)
PWM
•
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 © 2003–2007, Texas Instruments Incorporated
bq24702
bq24703
www.ti.com
SLUS553E – MAY 2003 – REVISED OCTOBER 2007
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.
DESCRIPTION (CONTINUED)
The battery voltage limit can be programmed by using the internal 1.196-V, ±0.5% precision reference, making it
suitable for the critical charging demands of lithium-ion cells. Also, the bq24702/bq24703 provides an option to
override the precision reference and drive the error amplifier either directly from an external reference or from a
resistor divider off the 5 V supplied by the integrated circuit.
The selector function allows the manual selection of the system power source, battery or wall-adapter power.
The bq24702/bq24703 supports battery-conditioning and battery-learn cycles through the ACSEL function. The
ACSEL function allows manual selection of the battery or wall power as the main system power. It also provides
autonomous switching to the remaining source (battery or ac power) should the selected system power source
terminate (refer to Available Options table for the differences between the bq24702 and the bq24703). The
bq24702/bq24703 also provides an alarm function to indicate a depleted battery condition.
The bq24702/bq24703 PWM controller is ideally suited for operation in a buck converter for applications when
the wall-adapter voltage is greater than the battery voltage.
DISSIPATION RATINGS
MAXIMUM POWER DISSIPATION
(LOW K BOARD)
vs
FREE-AIR TEMPERATURE
MAXIMUM POWER DISSIPATION
(HIGH K BOARD)
vs
FREE-AIR TEMPERATURE
1.40
Maximum Power Dissipation (Low K Board) - W
Maximum Power Dissipation (High K Board) - W
1.60
MAX Pd (W) @ 500 LFM
1.40
MAX Pd (W) @ 250 LFM
1.20
MAX Pd (W) @ 150 LFM
MAX Pd (W) @ 0 LFM
1
0.80
0.60
0.40
θJA = 89.37 C/W @ 0 LFM,
θJA = 77.98 C/W @ 150 LFM,
θJA = 73.93 C/W @ 250 LFM,
θJA = 68.23 C/W @ 500 LFM
0.20
MAX Pd (W) @ 500 LFM
MAX Pd (W) @ 250 LFM
1
MAX Pd (W) @ 150 LFM
MAX Pd (W) @ 0 LFM
0.80
0.60
0.40
θJA = 150.17 C/W @ 0 LFM,
θJA = 110.95 C/W @ 150 LFM,
θJA = 99.81 C/W @ 250 LFM,
θJA = 86.03 C/W @ 500 LFM
0.20
0
0
25
2
1.20
50
70
TA - Free-Air Temperature - °C
85
25
50
70
A.
The JEDEC low K (1s) board design used to derive this data was a 3-inch × 3-inch, two layer board with 2 ounce
copper traces on top of the board.
B.
The JEDEC high K (1s) board design used to derive this data was a 3-inch × 3-inch, multilayer board with 1 ounce
internal power and ground planes and 2 ounce copper traces on top and bottom of the board.
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85
TA - Free-Air Temperature - °C
Copyright © 2003–2007, Texas Instruments Incorporated
Product Folder Link(s): bq24702 bq24703
bq24702
bq24703
www.ti.com
SLUS553E – MAY 2003 – REVISED OCTOBER 2007
AVAILABLE OPTIONS
SELECTOR OPERATION
CONDITION
20°C ≤ TJ ≤ 125°C
bq24702PW
bq24703RHD
BATTERY AS POWER SOURCE
Battery removal
Automatically selects ac + alarm
Automatically selects ac + alarm
Battery reinserted
Selection based on selector inputs
Adapter latched until adapter is removed or ac select toggles.
AC removal
Automatically selects battery
Automatically selects battery
AC reinserted
Selection based on selector inputs
Selection based on selector inputs
AC AS POWER SOURCE
DEPLETED BATTERY CONDITION
Battery as power source
Sends ALARM signal
Automatically selects ac Sends ALARM signal
AC as power source
Sends ALARM signal
Sends ALARM signal
Depleted battery condition
Depleted battery condition
ALARM SIGNAL ACTIVE
When selector input is not equal to selector
output (single pulse alarm)
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted)
VCC
TJ
Tstg
(1)
(2)
(1) (2)
VALUE
UNIT
Supply voltage range
–0.3 to 30
V
Battery voltage range: SRP, SRN
–0.3 to 30
V
Input voltage: ACN, ACP
–0.3 to 30
V
Virtual junction temperature range
–40 to 125
°C
Maximum source/sink current VHSP
50
mA
Maximum ramp rate for VCC
10
V/μs
Maximum sink current ACPRES, COMP, ALARM
2.5
mA
Maximum ramp rate for V(BAT)
10
V/μs
Maximum source/sink current BATDRV
10
mA
Maximum source/sink current ACDRV
10
mA
Maximum source/sink current PWM
50
mA
Maximum source/sink current pulsed ACDRV, (10-μs rise time, 10-μs fall time, 1-ms
pulse width, single pulse)
50
mA
Maximum source current VREF
30
mA
Maximum source current SRP
100
mA
Maximum difference voltage SRP–SRN
30
V
–65 to 150
°C
Storage temperature range
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. Currents are positive into and negative out of the specified terminals. Consult the Packaging
section of the data book for thermal limitations and considerations of the package.
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Copyright © 2003–2007, Texas Instruments Incorporated
Product Folder Link(s): bq24702 bq24703
3
bq24702
bq24703
www.ti.com
SLUS553E – MAY 2003 – REVISED OCTOBER 2007
RECOMMENDED OPERATING CONDITIONS
(TA = TOPR) all voltages relative to VSS
MIN
MAX
7
28
4.5
28
Negative ac current sense, (ACN)
7
28
V
Positive ac current sense, (ACP)
7
28
V
Negative battery current sense, (SRN)
5
28
V
Positive battery current sense, (SRP)
5
28
V
AC or adapter power detection (ACDET)
0
5
V
AC power indicator (ACPRES)
0
5
V
AC adapter power select (ACSEL)
0
5
V
Depleted battery level (BATDEP)
0
5
V
Battery charge current programming voltage (SRSET)
0
2.5
V
Charge enable (ENABLE)
0
5
V
External override to an internal 0.5% precision reference (BATSET)
0
2.5
V
Inverting input to the PWM comparator (COMP)
0
5
V
Battery charge regulation voltage measurement input to the battery—voltage gm amplifier (BATP)
0
5
V
Battery current differential amplifier output (IBAT)
0
5
V
System load voltage input pin (VS)
0
2.5
V
Depleted battery alarm output (ALARM)
0
5
V
VHSP
VCC
V
0
28
V
VHSP
VCC
V
0
2.5
V
-40
85
°C
Supply voltage, (VCC)
Analog and PWM operation
Selector operation
Gate drive output (PWM)
Battery power source select output (BATDRV)
AC or adapter power source selection output (ACDRV)
ACSET
Operating free-air temperature, TA
4
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UNIT
V
Copyright © 2003–2007, Texas Instruments Incorporated
Product Folder Link(s): bq24702 bq24703
bq24702
bq24703
www.ti.com
SLUS553E – MAY 2003 – REVISED OCTOBER 2007
ELECTRICAL CHARACTERISTICS
–40°C ≤ TJ ≤ 125°C, 7 VDC ≤ VCC ≤ 28 VDC, all voltages relative to VSS (unless otherwise specified)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
1
1.6
6
mA
22
28
μA
0.4
V
0.6
V
QUIESCENT CURRENT
IDD(OP)
Total chip operating current
ACPRES = High, EN = 0
IDD(SLEEP)
Total battery sleep current, ac not present
ACPRES = Low
LOGIC INTERFACE DC CHARACTERISTICS
VOL
Low-level output voltage (ACPRES, ALARM)
IOL = 1 mA
VIL
Low-level input voltage (ACSEL, ENABLE)
VIH
High-level input voltage (ACSEL, ENABLE)
I(SINK1)
Sink current (ACPRES)
VOL = 0.4
1.5
2
2.5
mA
I(SINK2)
Sink current (ALARM)
VOL = 0.4
1.5
2
2.5
mA
0°C ≤ TJ ≤ 85°C
280
300
340
–40°C ≤ TJ ≤ 125°C
240
300
350
1.8
V
PWM OSCILLATOR
fOSC(PWM)
Oscillator frequency
Maximum duty cycle
kHz
100%
Input voltage for maximum dc (COMP)
3.8
V
Minimum duty cycle
0%
Input voltage for minimum dc (COMP)
V(RAMP)
Oscillator ramp voltage (peak-to-peak)
VIK(COMP)
Internal input clamp voltage
(tracks COMP voltage for maximum dc)
IS(COMP)
Internal source current (COMP)
0.8
1.85
Error amplifier = OFF, V(COMP) = 1 V
70
V
2.15
2.30
3.8
4.5
110
140
μA
LEAKAGE CURRENT
IL(ACDET)
Leakage current, ACDET
V(ACDET) = 5 V
0.2
μA
IL(SRSET)
Leakage current, SRSET
V(SRSET) = 2.5 V
0.2
μA
IL(ACSET)
Leakage current, ACSET
V(ACSET) = 2.5 V
0.2
μA
IL(BATDEP)
Leakage current, BATDEP
V(BATDEP) = 5 V
0.2
μA
IL(VS)
Leakage current, VS
V(VS) = 5 V
0.2
μA
IL(ALARM)
Leakage current, ALARM
V(ALARM) = 5 V
0.2
μA
IL(ACSEL)
Leakage current, ACSEL
V(ACSEL) = 5 V
0.2
μA
IL(ENABLE)
Leakage current, ENABLE
V(ENABLE) = 5 V
0.2
μA
IL(ACPRES)
Leakage current, ACPRES
V(ACPRES) = 5 V
0.2
μA
IL(BATP)
Leakage current, BATP
V(BATP) = 5 V
0.2
μA
IL(BATSET)
Leakage current, BATSET
V(BATSET) = 2.5 V
0.2
μA
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Copyright © 2003–2007, Texas Instruments Incorporated
Product Folder Link(s): bq24702 bq24703
5
bq24702
bq24703
www.ti.com
SLUS553E – MAY 2003 – REVISED OCTOBER 2007
ELECTRICAL CHARACTERISTICS (Continued)
–40°C ≤ TJ ≤ 125°C, 7 VDC ≤ VCC ≤ 28 VDC, all voltages relative to VSS (unless otherwise specified)
PARAMETER
TEST CONDITIONS
MIN
TYP MAX
UNIT
120
mA/V
BATTERY CURRENT-SENSE AMPLIFIER
gm
Transconductance gain
75
(1)
CMRR
Common-mode rejection ratio
See
VICR
Common-mode input (SRP, SRN) voltage
range
VCC = SRN, SRP + 2 V
I(SINK)
Sink current (COMP)
COMP = 1 V, (SRP–SRN) = 10 mV
0.5
V(SRP) = 16 V, (SRP–SRN) = 100 mV,
SRSET = 2.5 V, VCC = 28
(SRP - SRN) = 100 mV, SRSET= 2.5 V,
VCC = 28 V, 0 ≤ TJ ≤ 125°C
Input bias current (SRP)
(2)
IIB
Input bias current accuracy (ISRP – ISRN)
V(SET)
AV
90
5
Battery current programming voltage (SRSET)
Total battery current-sense mid-scale accuracy
Total battery current-sense full-scale accuracy
dB
30
V
1.5
2.5
mA
70
85
110
–3
0
3
μA
0
0.65 V ≤ SRSET ≤ 2.5 V,
8 V ≤ SRN ≤ 16 V (3)
Battery current set gain
175
24
25
2.5
V
26
V/V
SRSET = 1.25 V, TJ = 25°C (4)
–5%
5%
SRSET = 1.25 V (4)
–6%
6%
SRSET = 2.5 V, TJ = 25°C (4)
–3%
3%
–4%
4%
SRSET = 2.5 V
(4)
(1)
(2)
Specified by design. Not production tested.
I(SRP) = I(SRN) = (V(SRSET) / 50 kΩ) + ((V(SRP) - V(SRN) / 3 kΩ)
example: If (V(SRSET) = 2.5 V) , (V(SRP) - V(SRN) = 100 mV) Then I(SRP) = I(SRN) = 83 A
1
I
+ SRSET
BAT
R
A
SENSE
V
(3)
(4) Total battery-current set is based on the measured value of (SRP–SRN) = Δm, and the calculated value of (SRP–SRN) = ΔC, using the
(Dm * Dc)
SRSET
Dc +
, Total accuracy in % +
100, I (SRP) * I (SRN) + 0
Dc
A
V
measured gain, AV.
6
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Copyright © 2003–2007, Texas Instruments Incorporated
Product Folder Link(s): bq24702 bq24703
bq24702
bq24703
www.ti.com
SLUS553E – MAY 2003 – REVISED OCTOBER 2007
ELECTRICAL CHARACTERISTICS (Continued)
–40°C ≤ TJ ≤ 125°C, 7 VDC ≤ VCC ≤ 28 VDC, all voltages relative to VSS, (unless otherwise specified)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
75
130
175
mA/V
ADAPTER CURRENT-SENSE AMPLIFIER
gm
Transconductance gain
CMRR
Common-mode rejection ratio
VICR
Common-mode input voltage range (ACP)
I(SINK)
Sink current (COMP)
COMP = 1 V, (ACP – ACN) = 10 mV
0.5
Input bias current (ACP, ACN)
ACP = ACN = 28 V, VCC = 28 V, ACSET = 2.5
V
Input bias current accuracy ratio
(I(ACP), I(ACN))
ACP = ACN = 28 V, VCC = 28 V,
ACSET = 2.5 V, 0 ≤ TJ ≤ 125°C
IIB
See
(1)
V(SET)
AC current programming voltage (ACSET)
AV
AC current set gain
Total ac current-sense mid-scale accuracy
Total ac current-sense full-scale accuracy
90
7
V
1.5
2.5
mA
40
50
65
–3
0
3
2.5
V
25.3
26.5
V/V
A
0
0.65 V ≤ ACSET ≤ 2.5 V, 12 V ≤ ACP ≤ 20 V (1)
24.5
ACSET = 1.25 V, TJ = 25°C (2)
–5%
ACSET = 1.25 V
(2)
ACSET = 2.5 V, TJ = 25°C (2)
ACSET = 2.5 V (2)
dB
VCC
5%
–6%
6%
–3.5%
3.5%
–4%
4%
BATTERY VOLTAGE ERROR AMPLIFIER
gm
Transconductance gain
CMRR
Common-mode rejection ratio
VICR
BATSET common-mode input voltage
range
VIT
Internal reference override input threshold
voltage
I(SINK)
Sink current COMP
V(FB)
Error-amplifier precision reference voltage
(1)
(2)
75
See (1)
135
175
90
1
mA/V
dB
2.5
V
0.20
0.25
0.35
V
0.5
1.5
2.5
mA
TJ = 25°C
1.190
1.196
1.202
TJ = 0°C to 85°C
1.183
1.196
1.203
TJ = –40°C to 125°C
1.178
1.196
1.204
COMP = 1 V, (BATP–BATSET) = 10 mV,
BATSET = 1.25 V
V
1
I
+ ACSET
AC
R
A
SENSE
V
Calculation of the ac current:
Total ac-current set accuracy is based on the measured value of (ACP-ACN) = Δc, using the measured gain, AV.
(Dm * Dc)
ACSET
Dc +
, Total accuracy in % +
100, I(ACP) * I (ACN) + 0
Dc
A
V
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7
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bq24703
www.ti.com
SLUS553E – MAY 2003 – REVISED OCTOBER 2007
ELECTRICAL CHARACTERISTICS (Continued)
–40°C ≤ TJ ≤ 125°C, 7 VDC ≤ VCC ≤ 28 VDC, all voltages relative to VSS (unless otherwise specified)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
BATTERY CURRENT OUTPUT AMPLIFIER
G(TR)
Transfer gain
(SRP–SRN) = 5 mV (1)
VI(BAT)
Battery current readback output
voltage (IBAT)
(SRP–SRN) = 5 mV, SRP = 12 V,
VCC = 18 V, TJ = 25°C
Line rejection voltage
TJ = 25°C
20
V/V
100
mV
10
mV/V
CM
Common-mode input range (SRP)
5
28
V
VO(IBA
0
2.5
V
T)
Battery current output voltage
range (IBAT)
IS(O)
Output source current (IBAT)
9.4
mA
(SRP–SRN) = 100 mV
(SRP–SRN) = 50 mV, TJ = 25°C
Total battery current readback
full-scale accuracy
5
(1)
7.1
–3%
2.4%
(SRP–SRN) = 50 mV,
0°C ≤ TJ ≤ 85°C
–20%
20%
(SRP–SRN) = 100 mV,
TJ = 25°C (1)
–1.5%
1.2%
(SRP–SRN) = 100 mV,
0°C < TJ < 85°C
–6%
8.5%
5-V VOLTAGE REFERENCE
Vref
Output voltage (VREF)
TJ = 25°C
4.985
5
5.013
TJ = 0°C to 85°C
4.946
5
5.013
V
TJ = 40°C to 85°C
4.946
5
5.03
TJ = –40°C to 125°C
4.926
5
5.03
V
mV/V
V
Line regulation
ILOAD = 5 mA
0.1
0.37
Load regulation
1 mA ≤ ILOAD ≤ 5 mA
1.1
4
mV/mA
20
Short circuit current
8
5V REF output capacitor
Capacitance
Output capacitor equivalent
resistor
ESR
30
mA
2.2
10
μF
5
1000
mΩ
HALF SUPPLY REGULATOR
V(HSP)
(1)
8
Voltage regulation
I(SINK) = 20 mA, VCC = 18 V
I(SINK) = 1 mA, VCC = 7 V
VCC – 11
VCC – 10.2
VCC – 8.5
1.5
V
V
IBAT
G
+
(SRP * SRN)
Battery readback transfer gain TR
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bq24703
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SLUS553E – MAY 2003 – REVISED OCTOBER 2007
ELECTRICAL CHARACTERISTICS (Continued)
–40°C ≤ TJ ≤ 125°C, 7 VDC ≤ VCC ≤ 28 VDC , all voltages relative to VSS (unless otherwise specified)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
85
150
Ω
MOSFET GATE DRIVE
AC driver RDS(on) high
VCC = 18 V, I(ACDRV) = 1 mA
AC driver RDS(on) low
VCC = 18 V, I(ACDRV) = 1 mA
55
110
Ω
Battery driver RDS(on) high
VCC = 18 V, I(BATDRV) = 1 mA
315
600
Ω
Battery driver RDS(on) low
VCC = 18 V, I(BATDRV) = 1 mA
70
115
Ω
tda
Time delay from ac driver off to
battery driver on
ACSEL 2.4 V ^ 0.2 V
1.2
2
μs
tdb
Time delay from battery driver off to
ac driver on
ACSEL 0.2 V $ 2.4 V
2.4
3.3
μs
VOH
PWM driver high-level output
voltage
IO = –10 mA, VCC = 18 V
VCC –0.18
VCC –0.09
IO = –50 mA, VCC = 18 V
VCC –1.2
VCC –0.8
PWM driver RDS(on) high
VOL
PWM driver low-level output voltage
V
7
14
IO = 10 mA, VCC = 18 V
VHSP+0.1
VHSP+0.4
IO = 50 mA, VCC = 18 V
VHSP+0.6
VHSP+1.2
5
8.5
1.194
1.246
1.286
1.208
1.246
1.285
PWM driver RDS(on) low
Ω
V
Ω
SELECTOR
V(ACPRES)
AC presence detect voltage
VIT(ACPRES)
AC presence hysteresis
td(ACPRES)
Deglitch delay for adapter insertion
–40°C to 85°C
V
1%
μs
100
(1)
V(BATDEP)
Battery depletion ALARM trip
voltage
See
1.194
1.246
1.286
–40°C to 85°C
1.208
1.246
1.285
V(NOBAT)
No battery detect, switch to ACDRV
bq24702 only (1)
0.869
1
1.144
–40°C to 85°C
0.880
1
1.118
V
V
t(BATSEL)
Battery select time (ACSEL low to
BATDRV low)
VS < BATP, 50% threshold, ACSEL
2.4 V ↓ 0.2 V
1
2.5
3.5
μs
t(ACSEL)
AC select time (ACSEL high to
ACDRV low)
ACSEL 0.2 V ↑ 2.4 V
1
2.5
5
μs
V(VS)
VS voltage to enable BATDRV
BATP = 1 V
0.98
1
1.02
V
VIT(VS)
VS voltage hysteresis
VS > BATP
20
35
85
mV
5.3
8.7
Ω
ZERO VOLT OPERATION (2)
rDS(on)
Static drain source on-state
resistance
Zero volt operation threshold
(1)
(2)
VCC = 7 V, TJ = 125°C, IO = 100 mA
BATDEP increasing
0.743
0.794
0.840
BATDEP decreasing
0.570
0.62
0.656
V
Total battery current readback accuracy is based on the measured value of VIBAT, VIBATm, and the calculated value of VIBAT, VIBATc,
using the measured value of the transfer gain, GTR.
V
*V
IBATc 100
VIBATc + (SRP * SRN) GTR Total Accuracy in % + IBATm
V IBATm
See Table 1 to determine the logic operation of the bq24702 and the bq24703.
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10
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R10
Note1
VS 18
BATDRV 23
BATP 13
C10
180pF
C5
4.7 µF
Connect to GND
to Disable
C4
150pF
R16
100 Ω
C7
4.7 µF
35 V
U3
SI4435DY
R28
Note1
D5
Note 1
R19
Note1
D4
MBRD640CTT4
L1
33 µH
BAS16
R23
Note1
604 kΩ
R27
R25
Note1
R24
604 kΩ
C11 22 µF
Note1
35 V
R22
604 kΩ
R26 100K
D9
D6
Note 1
C8
Note1
R21
Note1
R20
0.025 Ω
U4
SI4435DY
Battery Plus
SYSTEM
SLUS553E – MAY 2003 – REVISED OCTOBER 2007
Note 1: R8 Sets AC Adapter Current Limit
R10 Sets Charge Current
R12 Sets AC ADAPTER Current Limit
R23 Sets the Battery Depleted Threshold
R25 Sets the Charge Regulation Voltage
R28 Sets System Break Before Make
R19 = R21, Sets Zero Volt Charge Current
C11 Optional, See Application Notes
C12 For Value, See Application Notes
C8 Value Depends on R21 and R19, See Application Notes
D5, D6 Refer to the Application Section
17 GND
6 ACSET
5 SRSET
9 BATSET
3 ACSEL
BATSET
PROCESSOR’S
POWER SUPPLY
SRN 15
COMP 10
8 ENABLE
4
BATDEP
7 VREF
14 IBAT
SRP 16
2 ACPRES
bq24702
bq24703
R2100 kΩ
PWM 21
1 ACDET
C6
D3 13 V
1 µF
16V
VHSP 20
VCC 22
12 ACP
11 ACN
24 ACDRV
D2
BAS16
ACPRES
R8
Note1
R18
10 Ω
R29 30 kΩ
C12
Note1
35V
R15
100 Ω
U2
SI4435DY
19 ALARM
C1
4.7 µF
C3
1 µF
R13
100 Ω
R14
0.025
ALARM
ACSEL
ENABLE
C13
1 nF
R12
Note1
R11
R6
100 kΩ Open
IBAT
AC Adapter
D1
MBRD640CTT4
bq24702
bq24703
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APPLICATION DIAGRAM
Copyright © 2003–2007, Texas Instruments Incorporated
bq24702
bq24703
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BLOCK DIAGRAM
VHSP
VCC
20
22
VREF
7
VREF
ACPRES
VHSP
REGULATOR
2
VOLTAGE
REFERENCE
ACPRES
ACPRES
HYST
ACDET
1
+
VCC
300 kHz
S
Q
R
Q
2V
VACPRES
OSC
PWM
LOGIC
LEVEL
SHIFT
HIGH-SIDE
DRIVE
21
PWM
13
BATP
+
VHSP
ACSEL
3
ENABLE
8
5V
100 µ A
BATDA
BATTERY
VOLTAGE
ERROR
AMPLIFIER
COMP
Zero Volt
Charging
5V
10
9
VCC
2 kΩ
ACP
+
VTBD
12
+
+
+
BATSET
0.25 V
VFB
ACN
11
ACSET
6
ac
CURRENT
ERROR
AMPLIFIER
+
SRN
2 kΩ
+
BATTERY
CURRENT
ERROR
AMPLIFIER
25
kΩ
0.8 x VNOBAT
VBATDEP
BATDEP
4
DEPLETED
BATTERY
COMPARATOR
BATP
VS
ALARM
18
SRN
5
SRSET
25
kΩ
ADAPTER
SELECT
DRIVE
24
ACDRV
23
BATDRV
17
GND
14
IBAT
VHSP
2
ACPRES
19
15
VCC
+
+
SWITCH TO
BATTERY
SRP
+
NO BATTERY
COMPARATOR
+
16
ACSEL
1
ACDRV
BATTERY
SELECT
DRIVE
VCC
SRP
1 bq24702 ONLY
VCC
BATTERY SELECT
LOGIC
AND
ANTI-CROSS
CONDUCT
ACSEL
+
A=20
SRN
2 bq24703 ONLY
UDG-00137
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Table 1. TERMINAL FUNCTIONS
TERMINAL
I/O
DESCRIPTION
bq24702
(PW)
bq24703
(QFN)
ACDET
1
26
I
AC or adapter power detection
ACDRV
24
25
O
AC or adapter power source selection output
ACN
11
8
I
Negative differential input
ACP
12
9
I
Positive differential input
ACPRES
2
27
O
AC power indicator
ACSEL
3
28
I
AC adapter power select
ACSET
6
3
I
Adapter current programming voltage
ALARM
19
19
O
Alarm output
BATDEP
4
1
I
Depleted battery level
BATDRV
23
24
O
Battery power source select output
BATP
13
12
I
Battery charge regulation voltage measurement input to the battery-voltage gm amplifier
BATSET
9
6
I
External override to an internal precision reference
COMP
10
7
O
Inverting input to the PWM comparator
ENABLE
8
5
I
Charge enable
GND
17
17
O
Supply return and ground reference
IBAT
14
13
O
Battery current differential amplifier output
PWM
21
21
O
Gate drive output
SRN
15
15
I
Negative differential battery current sense amplifier input
SRP
16
16
I/O
Positive differential battery current sense amplifier input
NAME
SRSET
5
2
I
Battery charge current programming voltage
VCC
22
22
I
Operational supply voltage
VHSP
20
20
O
Voltage source to drive gates of the external MOSFETs
VREF
7
4
O
Precision 5-V reference
VS
18
18
I
System (load) voltage input pin
PIN ASSIGNMENTS
ACDET: AC or adapter power detection. This input pin is used to determine the presence of the ac adapter.
When the voltage level on the ACDET pin is less than VACPRES, the bq24702/bq24703 is in sleep mode, the
PWM control is disabled, the BATDRV is driven low, and the ACDRV is driven high. This feature can be used to
automatically select battery as the system power source.
ACDRV: AC or adapter power source select output. This pin drives an external P-channel MOSFET used to
switch to the ac wall-adapter as the system power source. When the ACSEL pin is high while the voltage on the
ACDET pin is greater than VACPRES, the output ACDRV pin is driven low (VHSP). This pin is driven high (VCC)
when the ACDET is less than VACPRES.
ACN, ACP: Negative and positive differential inputs, respectively for ac-to-dc adapter current sense resistor.
ACPRES: This open-drain output pin is used to indicate the presence of ac power. A logic high indicates there is
a valid ac input. A low indicates the loss of ac power. ACPRES is high when the voltage level on the ACDET pin
is greater than VACPRES.
ACSEL: AC adapter power select. This input selects either the ac adapter or the battery as the power source. A
logic high selects ac power, while a logic low selects the battery.
ACSET: Adapter current programming voltage. This input sets the system current level at which dynamic power
management occurs. Adapter currents above this programmed level activate the dynamic power management
and proportionally reduce the available power to the battery.
12
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ALARM: Depleted battery alarm output. This open-drain pin indicates that a depleted battery condition exists. A
pullup on ALARM goes high when the voltage on the BATDEP pin is below VACPRES. On the bq24702, the
ALARM output also activates when the selector inputs do not match the selector state.
BATDEP: Depleted battery level. A voltage divider network from the battery to BATDEP pin is used to set the
battery voltage level at which depletion is indicated by the ALARM pin. See ALARM pin for more details. A
battery depletion is detected when BATDEP is less than VACPRES. A no-battery condition is detected when the
battery voltage is < 80% of the depleted threshold. In a no-battery condition, the bq24702 automatically selects
ac as the input source. If ENABLE = 1, the PWM remains enabled.
BATDRV: Battery power source select output. This pin drives an external P-channel MOSFET used to switch the
battery as the system's power source. When the voltage level on the ACDET pin is less than VACPRES, the output
of the BATDRV pin is driven low, GND. This pin is driven high (VCC) when ACSEL is high and ACDET > VACPRES.
BATP: Battery charge regulation voltage measurement input to the battery-voltage gm amplifier. The voltage on
this pin is typically derived from a voltage divider network connected across the battery. In a voltage loop, BATP
is regulated to the VFB precision reference of the battery voltage gm amplifier.
BATSET: An external override to an internal precision reference. When BATSET is > 0.25 V, the voltage level on
the BATSET pin sets the voltage charge level. When BATSET ≤ 0.25 V, an internal VFB reference is connected
to the inverting input of the battery error amplifier. To ensure proper battery voltage regulation with BATSET,
BATSET must be > 1.0 V. Simply ground BATSET to use the internal reference.
COMP: The inverting input to the PWM comparator and output of the gm amplifiers. A type II compensation
network between COMP and GND is recommended.
ENABLE: Charge enable. A high on this input pin allows PWM control operation to enable charging while a low
on this pin disables and forces the PWM output to a high state. Battery charging is initiated by asserting a logic 1
on the ENABLE pin.
GND: Supply return and ground reference
IBAT: Battery current differential amplifier output. The output of this pin produces a voltage proportional to the
battery charge current. This voltage is suitable for driving an ADC input.
PWM: Gate drive output pin drives the P-channel MOSFET for PWM control. The PWM control is active when
ACPRES, ACSEL, and ENABLE are high. PWM is driven low to VHSP and high to VCC.
SRN, SRP: Differential amplifier inputs for battery current sense. These pins feed back the battery charge current
for PWM control. SRN is tied to the battery terminal. SRP is the source pin for zero volt operation.
SRSET: Battery charge current programmed voltage. The level on this pin sets the battery charge current limit.
VCC: Operational supply voltage.
VHSP: The VHSP pin is connected to a 1-μF capacitor (close to the pin) to provide a stable voltage source to
drive the gates of the external MOSFETs. VHSP = VCC – 10 V for VCC > 10.5 V and VHSP = VCC – 0.5 V for
VCC 1 V
Figure 4. Battery Error Amplifier Input Multiplexing Scheme
18
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PROGRAMMING THE BATTERY CHARGE CURRENT
The battery charge current is programmed via a voltage on the SRSET pin. This voltage can be derived from a
resistor divider from the 5-V VREF or by means of an DAC. The voltage is converted to a current source that is
used to develop a voltage drop across an internal offset resistor at one input of the SR gmamplifier. The charge
current is then a function of this voltage drop and the sense resistor (RS), refer to Figure 5.
RS
COMP 10
SRP
2 kΩ
16
+
VREF
SRN
15
SRSET
5
+
25 kΩ
UDG-00117
Figure 5. Battery Charge Current Input Threshold Function
The battery charge current can be defined as:
V
I
+ SRSET
BAT
25 R
S
(2)
where VSRSET is the programming voltage on the SRSET pin. VSRSET maximum is 2.5 V.
PROGRAMMING THE ADAPTER CURRENT
Like the battery charge current described previously, the adapter current is programmed via a voltage on the
ACSET pin. That voltage can either be from an external resistor divider from the 5-V VREF or from an external
DAC. The adapter current is defined as:
V
I
+ ACSET
ADPT
25 R
S2
(3)
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COMPONENT SELECTION
MOSFET Selection
MOSFET selection depends on several factors, namely, gate-source voltage, input voltage, and input current.
The MOSFET must be a P-channel device capable of handling at least 15-V gate-to-source with a drain-source
breakdown of VBV~ VIN+1 V. The average input current can be approximated by:
I (avg) + D
Ichg A
IN
D = Duty cycle
Ichg = Charge current
(4)
The RMS current through the MOSFET is defined as:
ǸD A
I (RMS) + Ichg
IN
RMS
(5)
The rise/fall times for pin PWM for the selected MOSFET should be greater than 40 nsec.
Schottky Rectifier (Freewheeling)
The freewheeling Schottky rectifier must also be selected to withstand the input voltage, VIN. The average current
can be approximated from:
I (avg) + Ichg (1 * D) A
D1
(6)
Choosing an Inductance
Low inductance values result in a steep current ramp or slope. Steeper current slopes result in the converter
operating in the discontinuous mode at a higher power level. Steeper current slopes also result in higher output
ripple current, which may require a higher number or more expensive capacitors to filter the higher ripple current.
In addition, the higher ripple current results in an error in the sensed battery current particularly at lower charging
currents. It is recommended that the ripple current not exceed 20% to 30% of full scale dc current.
D
L+
ǒVIN * VBATǓ
F
Ichg Ripple
S
Ripple = % Ripple allowed (Ex.: 0,2 for 20% ripple)
(7)
Too large an inductor value results in the current waveform of Q1 and D1 in Figure 2 approximating a
squarewave with an almost flat current slope on the step. In this case, the inductor is usually much larger than
necessary, which may result in an efficiency loss (higher DCR) and an area penalty.
20
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Selecting an Output Capacitor
For this application the output capacitor is used primarily to shunt the output ripple current away from the battery.
The output capacitor should be sized to handle the full output ripple current as defined as:
I c (RMS) +
ǒVIN * VBATǓ
F
D
A
L
S
RMS
(8)
Selecting an Input Capacitor
The input capacitor is used to shunt the converter ripple current on the input lines. The capacitor(s) must have a
ripple current (RMS) rating of:
I
RMS
+
Ǹ[Ichg
(1–D)]
2
D ) [Ichg
D]
2
(1–D)
A
RMS
(9)
In addition to shunting the converter input ripple when the PWM is operating, the input capacitor also acts as part
of an LC filter, where the inductance component is defined by the ac adapter cable inductance and board trace
inductance from adapter connector to filter capacitor. Overshoot conditions can be observed at VCC line during
fast load transients when the adapter powers the load or when the adapter is hot-plugged .
Increasing the input capacitor value decreases the overshoot at VCC. Avoid overshoot voltages at VCC in excess
of the absolute maximum ratings for that pin.
Compensating the Loop
For the bq24702/bq24703 used as a buck converter, the best method of compensation is to use a Type II
compensation network from the output of the transconductance amplifiers (COMP pin) to ground (GND) as
shown in Figure 2. A Type II compensation adds a pole-zero pair and an additional pole at dc.
The Type II compensation network places a zero at
F +1
Z
2
ǒ
1
p
R
COMP
C
Z
Ǔ
Hz
Ǔ
Hz
(10)
and a pole at
F +1
P
2
ǒ
p
1
R
COMP
C
P
(11)
For this battery charger application the following component values: CZ = 4.7 μF, CP = 150 pF, and RCOMP = 100
Ω, provides a closed loop response with more than sufficient phase margin, as long as the LC pole [1/2 × PI ×
sqrt (l×c)] is set below 10 kHz. The SRP/SRN filter (R19, R21, C8) and ACP/ACN filter (R13/R15/C3) are
required to filter noise associated with the PWM switching. To avoid adding secondary poles to the PWM closed
loop system those filters should be set with cutoff frequencies higher than 1 kHz.
SELECTOR OPERATION
The bq24702/bq24703 allows the host controller to manually select the battery as the system's main power
source, without having to remove adapter power. This allows battery conditioning through smart battery learn
cycles. In addition, the bq24702/bq24703 supports autonomous supply selection during fault conditions on either
supply. The selector function uses low RDS(on) P-channel MOSFETs for reduced voltage drops and longer battery
run times.
NOTE:
Selection of battery power whether manual or automatic results in the suspension of
battery charging.
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ADAPTER SELECT SWITCH
ADAPTER
INPUT
SYSTEM
LOAD
(bq24702)
PWM
BATTERY
CHARGER
BAT
ACDRV
(bq24702) 24
BATTERY
SELECTOR
BATDRV
CONTROL 23
BATTERY
SELECT
SWITCH
UDG-00119
Figure 6. Selector Control Switches
AUTONOMOUS SELECTION OPERATION
Adapter voltage information is sensed at the ACDET pin via a resistor divider from the adapter input. The voltage
on the ACDET pin is compared to an internally fixed threshold. An ACDET voltage less than the set threshold is
considered as a loss of adapter power regardless of the actual voltage at the adapter input. Information
concerning the status of adapter power is fed back to the host controller through ACPRES. The presence of
adapter power is indicated by ACPRES being set high. A loss of adapter power is indicated by ACPRES going
low regardless of which power source is powering the system. During a loss of adapter power, the
bq24702/bq24703 obtains operating power from the battery through the body diode of the P-channel battery
select MOSFET. Under a loss of adapter power, ACPRES (normally high) goes low, if adapter power is selected
to power the system, the bq24702/bq24703 automatically switches over to battery power by commanding
ACDRV high and BATDRV low. During the switch transition period, battery power is supplied to the load via the
body diode of the battery select P-channel MOSFET. When adapter power is restored, the bq24702/bq24703
configures the selector switches according to the state of signals; ACSEL, and ACPRES. If the ACSEL pin is left
high when ac power is restored, the bq24702/bq24703 automatically switches back to ac power. To remain on
battery power after ac power is restored, the ACSEL pin must be brought low.
Conversely, if the battery is removed while the system is running on battery power and adapter power is present,
the bq24702/bq24703 automatically switches over to adapter power by commanding BATDRV high and ACDRV
low.
NOTE:
For the bq24702 any fault condition that results in the selector MOSFET switches not
matching their programmed states is indicated by the ALARM pin momentarily going
high. Refer to Battery Depletion Detection Section for more information on the ALARM
discrete.
When switching between the ac adapter and battery the internal logic monitors the voltage at pins ACDRV and
BATDRV to implement a break-before-make function, with typical dead time on the order of 150 nsec.
The turnon times for the external ac/battery switches can be increased to minimize inrush peak currents; that can
be accomplished by adding external resistors in series with the MOSFET gates (R18 and R26). Note, however,
that adding those resistors effectively disables the internal break-before-make function for ac/battery-switches, as
the MOSFET gate voltages can not be monitored directly. If external resistors are added to increase the rise/fall
times for battery/ac switches the break-before-make has to be implemented with discrete external components,
to avoid shoot-through currents between ac adapter and battery pack. This functionality can be implemented by
adding diodes (D2/D9) that bypass the external resistors when turning off the external FETs.
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SMART LEARN CYCLES WHEN ADAPTER POWER IS PRESENT
Smart learn cycles can be conducted when adapter power is present by asserting and maintaining the ACSEL
pin low. The adapter power can be reselected at the end of the learn cycle by a setting ACSEL to a logic high,
provided that adapter power is present. Battery charging is suspended while selected as the system power
source.
NOTE:
On the bq24703 the ac adapter is switched to the load when the battery voltage
reaches the battery depleted threshold; it can be used when the learn cycle does not
require the battery voltage to go below the battery depleted threshold. If the learn
cycle algorithm requires the battery voltage to go lower than the battery depleted
voltage, the bq24702 should be used, as it does not switch the ac adapter to load
upon battery depleted detection.
SYSTEM BREAK BEFORE MAKE FUNCTION
When selecting the battery as the system primary power source, the adapter power select MOSFET turns off, in
a break-before-make fashion, before the battery select MOSFET turns on. To ensure that this happens under all
load conditions, the system voltage (load voltage) can be monitored through a resistor divider on the VS pin. This
function provides protection against switching over to battery power if the adapter selector switch were shorted
and adapter power present. Setting the VS resistive divider gain with the same gain selected for the BATP
resistive divider assures the battery switch is turned on only when the system voltage is equal or less than the
battery voltage. This function can be eliminated by grounding the VS pin.
The ACDET function senses the adapter voltage via a resistive divider (refer to application circuit).The divider
can be connected either to the anode of the input blocking diode (directly to the adapter supply) or to the cathode
of the input blocking diode (bq24702/3 VCC pin). When the divider is connected to the adapter supply, the
adapter power removal is immediately identified and the sleep mode is entered, disabling the break-before-make
function for system voltage (see section for system power switching) and coupling system voltage to the battery
line. In normal operation with a battery present, the battery low impedance prevents any over-voltage conditions.
However, if a pack is not present or the pack is open, the battery line voltage has a transient equal to the adapter
voltage. The bq24703 SRP/SRN pins are designed to withstand this over-voltage condition, but avoid connection
to the battery line of any external devices that are not rated to withstand the adapter voltage.
Connecting the ACDET resistive divider input to the VCC node keeps the system break-before-make function
enabled until the voltage at pin VS is lower than the voltage at pin BATP. However, note that when using this
topology the VCC pin voltage can be held by capacitive loads at either the VCC or system (ac switch is on)
nodes when the ac adapter is removed. As the ACDET divider is connected to the VCC line there is a time delay
from ac adapter removal to ac adapter removal detection by the IC. This time is dependent on load conditions
and capacitive load values at VCC and system lines.
BATTERY DEPLETION DETECTION
The bq24702/bq24703 provides the host controller with a battery depletion discrete, the ALARM pin, to alert the
host when a depleted battery condition occurs. The battery depletion level is set by the voltage applied to the
BATDEP pin through a voltage divider network. The ALARM output asserts high and remains high as long as the
battery deplete condition exists, regardless of the power source selected.
For the bq24702, the host controller must take appropriate action during a battery deplete condition to select the
proper power source. The bq24702 remains on the selected power source. The bq24703, however, automatically
reverts over to adapter power, provided the adapter is present, during a deep discharge state. The battery is
considered as being in a deep discharge state when the battery voltage is less than (0.8 × depleted level).
Feature sets for the bq24702 and bq24703 are detailed in the Available Options table.
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SELECTOR/ALARM TIMING EXAMPLE
The selector and ALARM timing example in Figure 7 illustrates the battery conditioning support.
NOTE:
For manual selection of wall power as the main power source, both the ACPRES and
ACSEL signals must be a logic high.
ACPRES
ACSEL
ACDRV
BATDRV
ALARM
BATTERY
DEPLETE
CONDITION
bq24703 ONLY
UDG-00122
ACSEL
(ACPRES)
tBATSEL
ACDRV
tACSEL
BATDRV
BATDEP< 1 V
t
ACSEL
BATDRV
tBATSEL
ACDRV
UDG-00120
Figure 7. Battery Selector and ALARM Timing Diagram
24
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PWM SELECTOR SWITCH GATE DRIVE
Because the external P-channel MOSFETs (as well as the internal MOSFETs) have a maximum gate-source
voltage limitation of the input voltage, VCC, cannot be used directly to drive the MOSFET gate under all input
conditions. To provide safe MOSFET-gate-drive at input voltages of less than an intermediate gate drive voltage
rail was established (VSHP). Where VHSP = VCC – 10 V. This ensures adequate enhancement voltage across all
operating conditions.
An external zener diode (D3) connected between VCC and VHSP is required for transient protection; its
breakdown voltage should be above the maximum value for internal VHSP/VCC clamp voltage for all operating
conditions.
TRANSIENT CONDITIONS AT SYSTEM, OVER-VOLTAGE AT SYSTEM TERMINAL
Overshoot conditions can be observed at the system terminal due to fast load transients and inductive
characteristics of the system terminal to load connection. An overshoot at the system terminal can be directly
coupled to the VCC and VBAT nodes, depending on the switch mode of operation. If the capacitors at VBAT and
VCC can not reduce this overshoot to values below the absolute maximum ratings, it is recommended that an
additional capacitor is added to the system terminal to avoid damage to IC or external components due to
voltage overstress under those transient conditions.
AC ADAPTER COLLAPSING DUE TO TRANSIENT CONDITIONS
The ac adapter voltage collapses when the ac switch is on and a current load transient at the system exceeds
the adapter current limit protection. Under those conditions the ac switch is turned off when the ac adapter
voltage falls below the ac adapter detection threshold. If the system terminal to load impedance has an inductive
characteristic, a negative voltage spike can be generated at the system terminal and coupled into the battery line
via the battery switch backgate diode.
In normal operation, with a battery present, this is not an issue, as the low battery impedance holds the voltage
at battery line. However, if a battery is not present or the pack protector switches are open the negative spike at
the system terminal is directly coupled to the SRP/SRN pins via the R19/R21 resistors.
Avoid damage to the SRP/SRN pins if this transient condition happens in the application. If a negative voltage
spike happens at system terminal and R19/R21 limit the current sourced from the pin to less than –50 mA (Ipin =
Vsystem/R19), the pins SRP/SRN are not damaged and the external protection schottky diodes are not required.
However, if the current under those transient conditions exceeds –50 mA, external schottky diodes must be
added to clamp the voltage at pins SRP/SRN so they do not exceed the absolute maximum ratings specified
(-0.3 V).
IBAT AMPLIFIER
A filter with a cutoff frequency smaller than 10 kHz should be added to the IBAT output to remove switching
noise.
POWER DISSIPATION CALCULATION
During PWM operation, the power dissipated internally to the IC increases as the internal driver is switching the
PWM FET on/off. The power dissipation figures are dependent on the external FET used, and can be calculated
using the following equation:
Pd(max) = [IDDOP + Qg × Fs(max)] × VADAP
where:
Qg = Total gate charge for selected PWM MOSFET
IDDOP = Maximum quiescent current for IC
VADAP = Maximum adapter voltage
Fs(max) = Maximum PWM switching frequency
The maximum junction temperature for the IC must be limited to 125°C, under worst case conditions.
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25
bq24702
bq24703
www.ti.com
SLUS553E – MAY 2003 – REVISED OCTOBER 2007
TYPICAL CHARACTERISTICS
ERROR AMPLIFIER REFERENCE
vs
JUNCTION TEMPERATURE
BYPASSED 5-V REFERENCE
vs
JUNCTION TEMPERATURE
5.1
1.215
5.08
1.21
1.205
1.2
1.195
1.19
1.185
5.04
5.02
5
4.98
4.96
4.94
1.18
4.92
1.175
−40
10
60
TJ − Junction Temperature − _C
4.9
−40
110 125
10
60
TJ − Junction Temperature − _C
Figure 8.
Figure 9.
TOTAL SLEEP CURRENT
vs
JUNCTION TEMPERATURE
OSCILLATOR FREQUENCY
vs
JUNCTION TEMPERATURE
26
110 125
335
VCC = 18 V
VCC = 18 V
325
24
f − Oscillator Frequency − kHz
I SLEEP − Battery Sleep Current − µ A
VCC = 18 V
5.06
VREF − 5 -V Reference − V
VFB − Error Amplifier Reference − V
VCC = 18 V
22
20
18
315
305
295
285
275
265
255
16
245
14
−40
10
60
TJ − Junction Temperature − _C
110 125
235
−40
Figure 10.
26
Submit Documentation Feedback
10
60
TJ − Junction Temperature − _C
Figure 11.
110 125
Copyright © 2003–2007, Texas Instruments Incorporated
Product Folder Link(s): bq24702 bq24703
bq24702
bq24703
www.ti.com
SLUS553E – MAY 2003 – REVISED OCTOBER 2007
TYPICAL CHARACTERISTICS (continued)
BATTERY CURRENT SET ACCURACY
vs
BATTERY CURRENT SET VOLTAGE
AC CURRENT SET ACCURACY
vs
AC CURRENT SET VOLTAGE
25
20
SRSET Full Scale = 2.5 V
= Max Programmed Current
TJ = 25°C
AC Current Set Accuracy − %
Battery Current Set Accuracy − %
25
15
10
20
ACSET Full Scale = 2.5 V
= Max Programmed Current
TJ = 25°C
15
10
5
5
0
0.25 0.5 0.75
1 1.25 1.5 1.75 2 2.25 2.5
VSRSET − Battery Current Set Voltage − V
0
0.25 0.5
Figure 12.
0.75 1
1.25 1.5 1.75 2
2.25 2.5
VACSET − AC Current Set Voltage − V
Figure 13.
BOARD LAYOUT GUIDELINES
Recommended Board Layout
Follow these guidelines when implementing the board layout:
1. Do not place lines and components dedicated to battery/adapter voltage sensing (ACDET,BATDEP, VS),
voltage feedback loop (BATP, BATSET if external reference is used) and shunt voltage sensing
(SRP/SRN/ACP/ACN) close to lines that have signals with high dv/dt (PWM, BATDRV, ACDRV, VHSP) to
avoid noise coupling.
2. Add filter capacitors for SRP/SRN (C8) and ACP/ACN (C3) close to IC pins
3. Add Reference filter capacitor C1 close to IC pins
4. Use an isolated, clean ground for IC ground pin and resistive dividers used in voltage sensing; use an
isolated power ground for PWM filter cap and diode (C11/D4). Connect the grounds to the battery PACKand adapter GND.
5. Place C7 close to VCC pin.
6. Place input capacitor C12 close to PWM switch (U3) source and R14.
7. Position ac switch (U2) to minimize trace length from ac switch source to input capacitor C12.
8. Minimize inductance of trace connecting PWM pin and PWM external switch U3 gate
9. Maximize power dissipation planes connected to PWM switch
10. Maximize power dissipation planes connected to SRP resistor if steady state in zero volt mode is possible
11. Maximize power dissipation planes connected to D1
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27
PACKAGE OPTION ADDENDUM
www.ti.com
13-Aug-2021
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
BQ24702PW
ACTIVE
TSSOP
PW
24
60
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
24702PW
BQ24702PWG4
ACTIVE
TSSOP
PW
24
60
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
24702PW
BQ24702PWR
ACTIVE
TSSOP
PW
24
2000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
24702PW
BQ24703PW
ACTIVE
TSSOP
PW
24
60
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
24703PW
BQ24703PWR
ACTIVE
TSSOP
PW
24
2000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
24703PW
BQ24703RHDR
ACTIVE
VQFN
RHD
28
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
24703
(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)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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