LTC4150IMSTRPBF [Linear]
Coulomb Counter/ Battery Gas Gauge; 库仑计/电池电量监测计型号: | LTC4150IMSTRPBF |
厂家: | Linear |
描述: | Coulomb Counter/ Battery Gas Gauge |
文件: | 总14页 (文件大小:167K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
LTC4150
Coulomb Counter/
Battery Gas Gauge
FEATURES
DESCRIPTION
The LTC®4150 measures battery depletion and charging
in handheld PC and portable product applications. The
devicemonitorscurrentthroughanexternalsenseresistor
between the battery’s positive terminal and the battery’s
load or charger. A voltage-to-frequency converter trans-
forms the current sense voltage into a series of output
pulses at the interrupt pin. These pulses correspond to a
fixed quantity of charge flowing into or out of the battery.
The part also indicates charge polarity as the battery is
depleted or charged.
n
Indicates Charge Quantity and Polarity
n
±±50m Sense moltage Range
n
Precision Timer Capacitor or Crystal Not Required
n
2.7V to 8.5V Operation
High Side Sense
32.55Hz/V Charge Count Frequency
1.5μA Shutdown Current
10-Pin MSOP Package
n
n
n
n
APPLICATIONS
The LTC4150 is intended for 1-cell or 2-cell Li-Ion and
3-cell to 6-cell NiCd or NiMH applications.
L, LT, LTC, LTM, Linear Technology, the Linear logo, Burst Mode are registered trademarks and
ThinSOT and PowerPath are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
n
Battery Chargers
n
Palmtop Computers and PDAs
n
Cellular Telephones and Wireless Modems
TYPICAL APPLICATION
Integral Nonlinearity, % of Full Scale
0.5
0.4
CHARGER
R
SENSE
LOAD
0.3
+
0.2
4.7μF
0.1
R
R
L
L
0
–
+
SENSE SENSE
V
DD
+
–0.1
–0.2
–0.3
–0.4
–0.5
C
C
INT
F
4.7μF
CLR
LTC4150
GND
μP
CHG
–
DISCHG
F
POL
SHDN
4150 TA01a
–50
–25
0
25
50
CURRENT SENSE VOLTAGE (mV)
4150 TA01b
4150fc
1
LTC4150
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(Note 1)
Supply Voltage (V ) .................................. –0.3V to 9V
DD
Input Voltage Range
TOP VIEW
+
–
+
–
Digital Inputs (CLR, SHDN) ........–0.3V to (V + 0.3)
DD
SENSE
SENSE
1
2
3
4
5
10 INT
–
+
–
+
SENSE , SENSE , C , C .........–0.3V to (V + 0.3)
9
8
7
6
CLR
F
F
DD
C
C
V
GND
POL
F
F
DD
Output Voltage Range
SHDN
Digital Outputs (INT, POL) ....................... –0.3V to 9V
Operating Temperature Range
MS PACKAGE
10-LEAD PLASTIC MSOP
LTC4150CMS........................................... 0°C to 70°C
LTC4150IMS .......................................–40°C TO 85°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
T
= 125°C, θ = 160°C/W
JA
JMAX
ORDER INFORMATION
LEAD FREE FINISH
LTC4150CMS#PBF
LTC4150IMS#PBF
TAPE AND REEL
PART MARKING*
LTQW
PACKAGE DESCRIPTION
10-Lead Plastic MSOP
10-Lead Plastic MSOP
TEMPERATURE RANGE
0°C to 70°C
LTC4150CMS#TRPBF
LTC4150IMS#TRPBF
LTQW
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
te0perature range, otherwise specifications are at TA = 2±°C. mDD = 2.7m and 8.±m unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
l
l
l
l
V
V
V
Digital Input Low Voltage, CLR, SHDN
Digital Input High Voltage, CLR, SHDN
Digital Output Low Voltage, INT, POL
Digital Output Leakage Current, INT, POL
Differential Offset Voltage (Note 4)
0.7
V
V
IL
1.9
IH
I
= 1.6mA, V = 2.7V
0.5
1
V
OL
OL
DD
I
V
V
= V = 8.5V
POL
0.01
μA
LEAK
INT
DD
V
= 4.0V
100
150
μV
μV
OS
l
l
V
V
= 8.0V
100
150
μV
μV
DD
DD
= 2.7V to 8.5V
150
200
μV
μV
l
l
l
V
V
Sense Voltage Common Mode Input Range
Sense Voltage Differential Input Range
Average Differential Input Resistance,
V
– 0.06
V + 0.06
DD
V
V
SENSE(CM)
DD
+
–
SENSE – SENSE
–0.05
155
0.05
390
SENSE
R
V
= 4.1V (Note 3)
Rising
270
2.5
kΩ
IDR
DD
+
–
Across SENSE and SENSE
l
V
Undervoltage Lockout Threshold
V
2.7
V
UVLO
DD
4150fc
2
LTC4150
The l denotes the specifications which apply over the full operating
ELECTRICAL CHARACTERISTICS
te0perature range, otherwise specifications are at TA = 2±°C. mDD = 2.7m and 8.±m unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Power Supply Current
l
l
I
I
Supply Current, Operating
Supply Current, Shutdown
V
V
= 8.5V
= 2.7V
115
80
140
100
μA
μA
DD
DD
DD
l
l
l
V
V
V
= 8.5V
= 5.5V
= 2.7V
10
22
10
1.5
μA
μA
μA
DD(SD)
DD
DD
DD
AC Characteristics
G
VF
Voltage to Frequency Gain
V
= 50mV to –50mV,
SENSE
32.0
31.8
32.55
33.1
33.3
Hz/V
Hz/V
l
2.7V ≤ V ≤ 8.5V
DD
Gain Variation with Supply
Gain Variation with Temperature
Integral Nonlinearity
2.7V ≤ V ≤ 8.5V
0
0.5
%/V
ΔG
ΔG
DD
VF(VDD)
l
l
(Note 2)
–0.03
0.03
%/ºC
VF(TEMP)
INL
–0.4
–0.5
0.4
0.5
%
%
t
t
CLR Pulse Width to Reset INT,
INT and CLR Not Connected
Figure 2
20
μs
CLR
INT
l
INT Low Time, INT Connected to CLR
Figure 3, C = 15pF
L
1
μs
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: Guaranteed by design and not tested in production.
Note 3: Measured at least 20ms after power on.
Note 4: Tested in feedback loop to SENSE and SENSE .
+
–
4150fc
3
LTC4150
TYPICAL PERFORMANCE CHARACTERISTICS TA = 2±°C, unless otherwise noted.
moltage to Frequency Gain
vs Supply moltage
moltage to Frequency Gain
vs Te0perature
Operating IDD vs mDD
+1.00
+0.75
+0.50
+0.25
0
+1.00
+0.75
+0.50
+0.25
0
140
120
100
80
V
= 50mV
SENSE
V
= 2.7V
DD
V
= 25mV
SENSE
V
= 8.5V
DD
V
= 50mV
SENSE
–0.25
–0.50
–0.75
–1.00
–0.25
–0.50
–0.75
–1.00
60
2
3
4
5
6
7
8
9
-50 -25
0
25
50
75 100 125
2
3
4
5
6
7
8
9
10
V
(V)
TEMPERATURE (°C)
V
(V)
DD
DD
4150 G01
4150 G02
4150 G03
Undervoltage Lockout Threshold
vs Te0perature
Shutdown IDD vs mDD
Digital Output Low moltage vs mDD
2.60
2.59
2.58
2.57
2.56
2.55
2.54
2.53
2.52
6
5
4
3
2
1
0
400
350
300
250
200
150
100
50
RISING EDGE
I
= 1.6mA
OL
POL PIN
INT PIN
0
-50 -25
0
25
50
75 100 125
2
3
4
5
6
7
8
9
10
2
3
4
5
6
7
8
9
TEMPERATURE (°C)
V
(V)
V
(V)
DD
DD
4150 G06
4150 G04
4150 G05
4150fc
4
LTC4150
PIN FUNCTIONS
+
SENSE (Pin 1): Positive Sense Input. This is the nonin-
POL (Pin 6): Battery Current Polarity Open-Drain Output.
POLindicatesthemostrecentbatterycurrentpolaritywhen
INT is high. A low state indicates the current is flowing out
of the battery while high impedance means the current
is going into the battery. POL latches its state when INT
is asserted low. POL is an open-drain output and can be
pulled up to any logic supply up to 9V. In shutdown, POL
is high impedance.
+
verting current sense input. Connect SENSE to the load
and charger side of the sense resistor. Full-scale current
+
sense input is 50mV. SENSE must be within 60mV of
V
for proper operation.
DD
–
SENSE (Pin2):NegativeSenseInput.Thisistheinverting
–
current sense input. Connect SENSE to the positive bat-
tery terminal side of the sense resistor. Full-scale current
–
sense input is 50mV. SENSE must be within 60mV of V
for proper operation.
GND (Pin 7): Ground. Connect directly to the negative
battery terminal.
DD
+
C
(Pin 3): Filter Capacitor Positive Input. A capacitor
m
(Pin 8): Positive Power Supply. Connect to the load
F
DD
+
–
+
connected between C and C filters and averages
and charger side of the sense resistor. SENSE also con-
F
F
noise and fast battery current variations. A 4.7μF value
nects to V . V operating range is 2.7V to 8.5V. Bypass
V
DD DD
with 4.7μF capacitor.
DD
+
is recommended. If filtering is not desired, leave C and
F
–
C
unconnected.
F
CLR (Pin 9): Clear Interrupt Digital Input. When asserted
low for more than 20μs, CLR resets INT high. Charge
counting is unaffected. INT may be directly connected to
CLR. In this case the LTC4150 will capture each assertion
ofINTandwaitatleast1μsbeforeresettingit.Thisensures
that INT pulses low for at least 1μs but gives automatic
–
C
(Pin 4): Filter Capacitor Negative Input. A capacitor
F
+
–
connected between C and C filters and averages
F
F
noise and fast battery current variations. A 4.7μF value
+
is recommended. If filtering is not desired, leave C and
F
–
C
unconnected.
F
INT reset. In applications with a logic supply V > V ,
CC
DD
SHDN(Pin±):Shutdown Digital Input. When asser ted low,
SHDNforcestheLTC4150intoitslowcurrentconsumption
power-down mode and resets the part. In applications
a resistive divider must be used between INT and CLR.
See the Applications Information section.
with logic supply V > V , a resistive divider must be
INT (Pin 15): Charge Count Interrupt Open-Drain Output.
INT latches low every 1/(V
reset by a low pulse at CLR. INT is an open-drain output
and can be pulled up to any logic supply of up to 9V. In
shutdown INT is high impedance.
CC
DD
used between SHDN and the logic which drives it. See the
• G ) seconds and is
SENSE VF
Applications Information section.
4150fc
5
LTC4150
BLOCK DIAGRAM
CHARGER
LOAD
REFHI
1.7V
V
DD
+
INT
10
S3
8
1
+
–
OFLOW/
UFLOW
S
Q
100pF
SENSE
R
S1
2k
2k
COUNTER
200k
CLR
9
6
–
+
200k
C
F
UP/DN
CONTROL
LOGIC
AMPLIFIER
CHARGE
3
4
R
SENSE
C
F
+
POL
POLARITY
DETECTION
+
–
–
–
C
F
DISCHARGE
200k
S2
I
BAT
2
7
SENSE
GND
REFLO
0.95V
5
SHDN
4150 F01
Figure 1. Block Diagra0
TIMING DIAGRAMS
50% 50%
CLR
INT
t
CLR
50% 50%
INT
t
4150 F02
INT
4150 F03
Figure 2. CLR Pulse Width to Reset INT,
CLR and INT Not Connected
Figure 3. INT Mini0u0 Pulse Width, CLR and INT Connected
4150fc
6
LTC4150
OPERATION
Charge is the time integral of current. The LTC4150 mea-
suresbatterycurrentbymonitoringthevoltagedeveloped
acrossasenseresistorandthenintegratesthisinformation
inseveralstagestoinfercharge.TheBlockDiagramshows
the stages described below. As each unit of charge passes
into or out of the battery, the LTC4150 INT pin interrupts
an external microcontroller and the POL pin reports the
polarity of the charge unit. The external microcontroller
then resets INT with the CLR input in preparation for the
next interrupt issued by the LTC4150. The value of each
charge unit is determined by the sense resistor value and
CHARGE COUNTING
First, the current measurement is filtered by capacitor C
F
+
–
connected across pins C and C . This averages fast
F
F
changes in current arising from ripple, noise and spikes
in the load or charging current.
Second, the filter’s output is applied to an integrator with
the amplifier and 100pF capacitor at its core. When the
integratoroutputrampstoREFHIorREFLOlevels,switches
S1 and S2 reverse the ramp direction. By observing the
condition of S1 and S2 and the ramp direction, polarity is
determined. The integrating interval is trimmed to 600μs
at 50mV full-scale sense voltage.
the sense voltage to interrupt frequency gain G of the
VF
LTC4150.
Third, a counter is incremented or decremented every
time the integrator changes ramp direction. The counter
effectively increases integration time by a factor of 1024,
greatly reducing microcontroller overhead required to
service interrupts from the LTC4150.
Power-On and Start-Up Initialization
When power is first applied to the LTC4150, all internal
circuitryisreset.Afteraninitializationinterval,theLTC4150
begins counting charge. This interval depends on V and
DD
the voltage across the sense resistor but will be at least
5ms. It may take an additional 80ms for the LTC4150 to
accuratelytrackthesensevoltage.Aninternalundervoltage
At each counter under or overflow, the INT output latches
low, flagging a microcontroller. Simultaneously, the POL
output is latched to indicate the polarity of the observed
charge. With this information, the microcontroller can
total the charge over long periods of time, developing
an accurate estimate of the battery’s condition. Once the
interruptisrecognized,themicrocontrollerresetsINTwith
a low going pulse on CLR and awaits the next interrupt.
Alternatively, INT can drive CLR.
lockout circuit monitors V and resets all circuitry when
DD
V
falls below 2.5V.
DD
Asserting SHDN low also resets the LTC4150’s internal
circuitry and reduces the supply current to 1.5μA. In this
condition, POL and INT outputs are high impedance. The
LTC4150 resumes counting after another initialization
interval. Shutdown minimizes battery drain when both
the charger and load are off.
4150fc
7
LTC4150
APPLICATIONS INFORMATION
SENSE mOLTAGE INPUT AND FILTERS
Coulo0b Counting
The LTC4150’s transfer function is quantified as a volt-
Since the overall integration time is set by internally trim-
mingtheLTC4150,noexternaltimingcapacitorortrimming
is necessary. The only external component that affects
the transfer function of interrupts per coulomb of charge
age to frequency gain G , where output frequency is the
VF
number of interrupts per second and input voltage is the
+
–
differential drive V
across SENSE and SENSE . The
SENSE
number of interrupts per second will be:
is the sense resistor, R
. The common mode range
SENSE
+
–
for the SENSE and SENSE pins is V
60mV, with a
DD
f = G • ⏐V
⏐
SENSE
(2)
(3)
(4)
VF
+
maximum differential voltage range of 50mV. SENSE is
where
normally tied to V , so there is no common mode issue
DD
–
when SENSE operates within the 50mV differential limit
V
= I
• R
SENSE
BATTERY SENSE
+
relative to SENSE .
Therefore,
f = G • ⏐I
ChooseR
to provide 50mV drop at maximum charge
SENSE
• R ⏐
SENSE
VF
BATTERY
or discharge current, whichever is greater. Calculate
from:
R
SENSE
Since I • t = Q, coulombs of battery charge per INT pulse
can be derived from Equation 4:
50mV
IMAX
RSENSE
=
(1)
1
One INT =
Coulombs
(5)
GVF •RSENSE
The sense input range is small ( 50mV) to minimize the
loss across R . To preserve accuracy, use Kelvin
SENSE
Battery capacity is most often expressed in ampere-
hours.
connections at R
.
SENSE
The external filter capacitor, C , operates against a total
F
1Ah = 3600 Coulombs
(6)
(7)
(8)
on-chip resistance of 4k to form a lowpass filter that
averages battery current and improves accuracy in the
presence of noise, spikes and ripple. 4.7μF is recom-
mended for general applications but can be extended to
higher values as long as the capacitor’s leakage is low.
A 10nA leakage is roughly equivalent to the input offset
error of the integrator. Ceramic capacitors are suitable
for this use.
Combining Equations 5 and 6:
1
One INT =
[Ah]
3600 •GVF •RSENSE
or
1Ah = 3600 • G • R
Interrupts
VF
SENSE
The charge measurement may be further scaled within
the microcontroller. However, the number of interrupts,
coulombs or Ah all represent battery charge.
Switching regulators are a particular concern because
they generate high levels of current ripple which may flow
+
through the battery. The V and SENSE connection to
DD
the charger and load should be bypassed by at least 4.7μF
at the LTC4150 if a switching regulator is present.
The LTC4150’s transfer function is set only by the value
of the sense resistor and the gain G . Once R
is
VF
SENSE
selected using Equation 1, the charge per interrupt can
The LTC4150 maintains high accuracy even when Burst
Mode® switching regulators are used. Burst pulse “on”
levels must be within the specified differential input volt-
be determined from Equation 5 or 7.
Note that R
is not chosen to set the relationship
SENSE
+
–
age range of 50mV as measured at C and C . To retain
between ampere-hours of battery charge and number of
interruptsissuedbytheLTC4150.Rather,R ischosen
F
F
accurate charge information, the LTC4150 must remain
SENSE
enabled during Burst Mode operation. If the LTC4150
to keep the maximum sense voltage equal to or less than
the LTC4150’s 50mV full-scale sense input.
shuts down or V drops below 2.5V, the part resets and
DD
charge information is lost.
4150fc
8
LTC4150
APPLICATIONS INFORMATION
INT, POL and CLR
Interfacing to INT, POL, CLR and SHDN
INT asserts low each time the LTC4150 measures a unit
of charge. At the same time, POL is latched to indicate
the polarity of the charge unit. The integrator and counter
continuerunning,sothemicrocontrollermustserviceand
clear the interrupt before another unit of charge accumu-
lates. Otherwise, one measurement will be lost. The time
available between interrupts is the reciprocal of
The LTC4150 operates directly from the battery, while in
most cases the microcontroller supply comes from some
separate, regulatedsource. ThisposesnoproblemforINT
and POL because they are open-drain outputs and can
be pulled up to any voltage 9V or less, regardless of the
voltage applied to the LTC4150’s V .
DD
CLR and SHDN inputs require special attention. To drive
them, the microcontroller or external logic must generate
a minimum logic high level of 1.9V. The maximum input
Equation 2:
1
GVF •⏐VSENSE
level for these pins is V + 0.3V. If the microcontroller’s
Time per INT Assertion =
(9)
DD
⏐
supply is more than this, resistive dividers must be used
on CLR and SHDN. The schematic in Figure 6 shows an
At 50mV full scale, the minimum time available is 596ms.
To be conservative and accommodate for small, unex-
pectedexcursionsabovethe50mVsensevoltagelimit,the
microcontroller should process the interrupt and polarity
information and clear INT within 500ms.
application with INT driving CLR and microcontroller V
CC
> V . The resistive dividers on CLR and SHDN keep the
DD
voltages at these pins within the LTC4150’s V range.
DD
Choose R2 and R1 so that:
(R1 + R2) ≥ 50R
(12)
(13)
L
Toggling CLR low for at least 20μs resets INT high and
unlatchesPOL.SincetheLTC4150’sintegratorandcounter
operate independently of the INT and POL latches, no
charge information is lost during the latched period or
while CLR is low. Charge/discharge information contin-
ues to accumulate during those intervals and accuracy
is unaffected.
R1
1.9V ≤
VCC ≤ VDD (Minimum)
R1+R2
Equation 13 also applies to the selection of R3 and R4.
The minimum V is the lowest supply to the LTC4150
DD
when the battery powering it is at its lowest discharged
voltage.
Once cleared, INT idles in a high state and POL indicates
real-timepolarityofthebatterycurrent.POLhighindicates
charge flowing into the battery and low indicates charge
flowing out. Indication of a polarity change requires at
least:
When the battery is removed in any application, the CLR
and SHDN inputs are unpredictable. INT and POL outputs
may be erratic and should be ignored until after the bat-
tery is replaced.
If desired, the simple logic of Figure 4 may be used to
derive separate charge and discharge pulse trains from
INT and POL.
2
tPOL
=
(10)
GVF •1024 •⏐VSENSE
⏐
where V
is the smallest sense voltage magnitude
SENSE
CHARGE
INT
before and after the polarity change.
CLR
Open-drain outputs POL and INT can sink I = 1.6mA
OL
LTC4150
at V = 0.5V. The minimum pull-up resistance for these
OL
DISCHARGE
pins should be:
POL
R > (V – 0.5)/1.6mA
(11)
L
CC
4150 F04
where V is the logic supply voltage. Because speed isn’t
Figure 4. Unravelling Polarity—
Separate Charge and Discharge Outputs
CC
an issue, pull-up resistors of 10k or higher are adequate.
4150fc
9
LTC4150
APPLICATIONS INFORMATION
AUTOMATIC CHARGE COUNT INTERRUPT AND CLEAR
use Figure 6. The resistor dividers on CLR and SHDN keep
thevoltagesatthesepinswithintheLTC4150’sV range.
DD
InapplicationswhereaCLRpulse is unavailable, it ’s easy to
Choose an R value using Equation 11 and R1-R4 values
L
maketheLTC4150runautonomously, asshowninFigures
using Equation 13. In either application, the LTC4150 will
capture the first assertion of INT and wait at least 1μs
before resetting it. This insures that INT pulses low for at
least 1μs but gives automatic INT reset.
5 and 6. If the microcontroller V is less than or equal to
CC
the battery V , INT may be directly connected to CLR, as
DD
inFigure5.Theonlyrequirementisthatthemicrocontroller
should be able to provide a high logic level of 1.9V to SHDN.
If the microcontroller V is greater than the battery V ,
CC
DD
POWER-DOWN
SWITCH
LOAD
C
L
PROCESSOR
47μF
V
CC
R
L
R
L
1
10
+
SENSE
INT
9
8
LTC4150
R
SENSE
CLR
2
3
–
V
DD
SENSE
C2
4.7μF
+
2.7V TO 8.5V
BATTERY
+
7
C
F
GND
μP
C
F
4.7μF
4
5
–
C
F
6
SHDN
POL
4150 F05
Figure ±. Application with INT Direct Drive or CLR and Separate Microprocessor Supply mCC ≤ mDD
POWER-DOWN
SWITCH
LOAD
C
L
PROCESSOR
47μF
V
CC
R
L
R
L
1
10
9
+
SENSE
INT
LTC4150
R
CLR
SENSE
R2
R1
8
2
3
–
V
DD
SENSE
C2
4.7μF
+
+
7
6
C
BATTERY
< V
F
GND
μP
V
C
BATTERY
CC
F
4.7μF
4
5
–
C
F
SHDN
POL
SHUTDOWN
R4
R3
4150 F06
Figure 6. Application with INT Driving CLR and Separate Microprocessor Supply mCC > mDD
4150fc
10
LTC4150
APPLICATIONS INFORMATION
PC BOARD LAYOUT SUGGESTIONS
TO CHARGER
Keep all traces as short as possible to minimize noise
and inaccuracy. The supply bypass capacitor C2 should
be placed close to the LTC4150. The 4.7μF filter capacitor
PIN 1
R
SENSE
LTC4150
+
–
C should be placed close the C and C pins and should
F
F
F
be a low leakage, unpolarized type. Use a 4-wire Kelvin
sense connection for the sense resistor, locating it close
4150 F07
+
TO BATTERY
to the LTC4150 with short sense traces to the SENSE and
–
SENSE pins and longer force lines to the battery pack
Figure 7. Kelvin Connection on SENSE Resistor
and powered load, see Figure 7.
TYPICAL APPLICATIONS
Figure 8 shows a typical application designed for a single
celllithium-ionbatteryand500mAmaximumloadcurrent.
With a microcontroller supply = 5V, Equation 11 gives
L
R > 2.875k. The nearest standard value is 3k.
Use Equation 1 to calculate R
= 0.05V/0.5A = 0.1Ω.
SENSE
From Equation 12, R = 3k gives R1 + R2 equal to 150.5k.
L
With R
= 0.1Ω, Equation 7 shows that each interrupt
A single cell lithium-ion battery can discharge as low as
SENSE
corresponds to 0.085mAh. Equation 14, derived from
2.7V.
Equation2,givesthenumberofINTassertionsforaverage
battery current, I
From Equation 13, select R1 = 75k; the nearest standard
value for R2 is 76.8k.
, over a time, t, in seconds:
BATT
INT Assertions = G • I
• R
• t
(14)
VF BATT
SENSE
Also from Equation 13, we choose R3 = 75k and R4 =
76.8k.
Loading the battery so that 51.5mA is drawn from it over
600secondsresultsin100INTassertions.Foran800mAh
battery, this is (51.5mA • 1/6h) / 800mAh = 11% of the
battery’s capacity.
POWER-DOWN
SWITCH
LOAD
C
L
5.0V
47μF
R
R
L
3k
L
3k
1
10
9
+
SENSE
INT
R
SENSE
0.1Ω
R2
76.8k
LTC4150
CLR
8
2
3
–
V
DD
SENSE
C2
4.7μF
SINGLE-CELL
Li-Ion
3.0V ~ 4.2V
+
7
6
+
C
R1
75k
F
GND
μP
C
F
4.7μF
4
5
–
C
F
SHDN
POL
SHUTDOWN
R4
76.8k
R3
75k
4150 F08
Figure 8. Typical Application, Single Cell Lithiu0-Ion Battery
4150fc
11
LTC4150
PACKAGE DESCRIPTION
MS Package
15-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1661 Rev E)
0.889 p 0.127
(.035 p .005)
5.23
(.206)
MIN
3.20 – 3.45
(.126 – .136)
3.00 p 0.102
(.118 p .004)
(NOTE 3)
0.497 p 0.076
(.0196 p .003)
REF
0.50
0.305 p 0.038
(.0120 p .0015)
TYP
(.0197)
10 9
8
7 6
BSC
RECOMMENDED SOLDER PAD LAYOUT
3.00 p 0.102
(.118 p .004)
(NOTE 4)
4.90 p 0.152
(.193 p .006)
DETAIL “A”
0.254
(.010)
0o – 6o TYP
GAUGE PLANE
1
2
3
4 5
0.53 p 0.152
(.021 p .006)
0.86
(.034)
REF
1.10
(.043)
MAX
DETAIL “A”
0.18
(.007)
SEATING
PLANE
0.17 – 0.27
(.007 – .011)
TYP
0.1016 p 0.0508
(.004 p .002)
0.50
(.0197)
BSC
MSOP (MS) 0307 REV E
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
4150fc
12
LTC4150
REVISION HISTORY (Revision history begins at Rev C)
REm
DATE
DESCRIPTION
PAGE NUMBER
C
2/10
Added Conditions to Power Supply Current in Electrical Characteristics
3
4150fc
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However,noresponsibilityisassumedforitsuse.LinearTechnologyCorporationmakesnorepresenta-
t ion t h a t t he in ter c onne c t ion o f i t s cir cui t s a s de s cr ib e d her ein w ill no t in fr inge on ex is t ing p a ten t r igh t s.
13
LTC4150
TYPICAL APPLICATION
CHARGER
LOAD
+
SENSE
INT
CD40110B
CD40110B
CD40110B
CD40110B
CD40110B
LTC4150
CLR
1.2Ω
1.1Ω
100mΩ
–
SENSE
+
SENSE RESISTANCE = 0.0852Ω
= 588mA
I
MAX
10,000 PULSES = 1Ah
4150 F09
Figure 9. A0pere-Hour Gauge
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1732
Lithium-Ion Linear Battery Charger Controller
Simple Charger uses External FET, Features Preset Voltages, C/10 Charger
Detection and Programmable Timer, Input Power Good Indication
LTC1733
LTC1734
LTC1734L
LTC1998
LTC4006
Monolithic Lithium-Ion Linear Battery Charger
Lithium-Ion Linear Battery Charger in ThinSOT
Lithium-Ion Linear Battery Charger in ThinSOT
Lithium-Ion Low Battery Detector
Standalone Charger with Programmable Timer, Up to 1.5A Charge Current
Simple ThinSOT Charger, No Blocking Diode, No Sense Resistor Needed
Low Current Version of LTC1734
™
1% Accurate 2.5μA Quiescent Current, SOT-23
Small, High Efficiency, Fixed Voltage,
Lithium-Ion Battery Charger
Constant-Current/Constant Voltage Switching Regulator with Termination
Timer, AC Adapter Current Limit and Thermistor Sensor in a Small 16-Pin
Package
LTC4050
Lithium-Ion Linear Battery Charger Controller
Simple Charger uses External FET, Features Preset Voltages, C/10 Charger
Detection and Programmable Timer, Input Power Good Indication,
Thermistor Interface
LTC4052
LTC4053
LTC4054
Monolithic Lithium-Ion Battery Pulse Charger
No Blocking Diode or External Power FET Required, Safety Current Limit
USB Compatible Monolithic Lithium-Ion Battery Charger Standalone Charger with Programmable Timer, Up to 1.25A Charge Current
800mA Standalone Linear Lithium-Ion Battery Charger
with Thermal Regulation in ThinSOT
No External MOSFET, Sense Resistor or Blocking Diode Required, Charge
Current Monitor for Gas Gauging, C/10 Charge Termination
LTC4410
LTC4412
USB Power Manager
For Simultaneous Operation of USB Peripheral and Battery Charging from
USB Port, Keeps Current Drawn from USB Port Constant, Keeps Battery
Fresh, Use with the LTC4053, LTC1733, LTC4054
™
PowerPath Controller in ThinSOT
More Efficient Diode OR’ing, Automatic Switching Between DC Sources,
Simplified Load Sharing, 3V ≤ V ≤ 28V
IN
4150fc
LT 0210 REV C • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
14
●
●
© LINEAR TECHNOLOGY CORPORATION 2003
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
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