LTC4065L_15_技术文档

LTC4065L/

LTC4065LX/LTC4065L-4.1

Standalone 250mA Li-Ion

Battery Charger in 2 × 2 DFN

FEATURES

DESCRIPTION

The LTC^®4065L is a complete constant-current/constant-

voltage linear charger for single-cell lithium-ion batteries.

Its small size and ability to accurately regulate low charge

currents make the LTC4065L especially well-suited for

portable applications using low capacity rechargeable

lithium-ion cells. Furthermore, LTC4065L is specifically

designed to work within USB power specifications.

n

Charge Current Programmable up to 250mA with

5% Accuracy

n

Complete Linear Charger in 2mm × 2mm DFN Package

n

C/10 Charge Current Detection Output

Timer Termination

n

No External MOSFET, Sense Resistor or Blocking

Diode Required

n

Preset Float Voltage with 0.6% Accuracy:

The CHRG pin indicates when charge current has dropped

to ten percent of its programmed value (C/10). An internal

timer terminates charging according to battery manufac-

turer specifications.

4.2V for LTC4065L/LTC4065LX

4.1V for LTC4065L-4.1

Constant-Current/Constant-Voltage Operation with

n

Thermal Feedback to Maximize Charging Rate

Without Risk of Overheating

TheLTC4065L-4.1featuresaconstant-voltagefloatvoltage

of 4.1V. This 4.1V version of the standard LTC4065L is in-

tendedforback-uporhighambienttemperatureapplications.

Under these conditions, a reduced float voltage will trade-

off initial cell capacity for the benefit of increased capacity

retention over the life of the battery. A reduced float voltage

also minimizes swelling in prismatic and polymer cells.

n

Charge Current Monitor Output for Gas Gauging

n

Automatic Recharge

n

Charges Single Cell Li-Ion Batteries Directly from

USB Port

n

20μA Supply Current in Shutdown Mode

n

Available Without Trickle Charge (LTC4065LX)

n

Tiny 6-Lead (2mm × 2mm) DFN Package

When the input supply (wall adapter or USB supply) is

removed,theLTC4065Lautomaticallyentersalowcurrent

state,droppingbatterydraincurrenttolessthan1μA.With

powerapplied,LTC4065Lcanbeputintoshutdownmode,

reducing the supply current to less than 20μA.

APPLICATIONS

n

Charger for Li-Ion Coin Cell Batteries

n

Portable MP3 Players, Wireless Headsets

n

Bluetooth Applications

Multifunction Wristwatches

The full-featured LTC4065L also includes automatic re-

charge,low-batterychargeconditioning(tricklecharging)

and soft-start (to limit inrush current).

n

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

Protected by U.S. Patents, including 6522118, 6700364.

Complete Charge Cycle (180mAh Battery)

LTC4065L and LTC4065LX

TYPICAL APPLICATION

110

Standalone Li-Ion Battery Charger

100

90 CONSTANT

CURRENT

4.3

4.1

3.9

3.7

3.5

3.3

100mA

V

IN

CONSTANT

VOLTAGE

V

BAT

LTC4065L

CHRG PROG

EN GND

80

70

60

50

40

30

20

10

0

CC

4.3V TO 5.5V

R1

510Ω

4.2V

C1

1μF

CHRG

TRANSITION

+

Li-Ion

BATTERY

R3

2k

4065L TA01

CHARGE

TERMINATION

V

= 5V

PROG

CC

R

= 2k

0

1

1.5

2

2.5

3

3.5

4

4.5

0.5

TIME (HOURS)

4065 TA02

4065lfb

1

LTC4065L/

LTC4065LX/LTC4065L-4.1

ABSOLUTE MAXIMUM RATINGS

PIN CONFIGURATION

(Note 1)

V

CC

TOP VIEW

t < 1ms and Duty Cycle < 1% ..................–0.3V to 7V

Steady State............................................. –0.3V to 6V

GND

CHRG

BAT

1

2

3

6

5

4

PROG

7

BAT, CHRG ...................................................–0.3V to 6V

EN, PROG.........................................–0.3V to V + 0.3V

EN

V

CC

BAT Short-Circuit Duration............................Continuous

BAT Pin Current ...................................................275mA

PROG Pin Current.............................................1.342mA

Junction Temperature (Note 6) ............................. 125°C

Operating Temperature Range (Note 2)....–40°C to 85°C

Storage Temperature Range................... –65°C to 125°C

DC PACKAGE

6-LEAD (2mm × 2mm) PLASTIC DFN

T

= 125°C, θ = 60°C/W (NOTE 3)

JA

EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB

JMAX

ORDER INFORMATION

LEAD FREE FINISH

LTC4065LEDC#PBF

LTC4065LXEDC#PBF

TAPE AND REEL

PART MARKING

LCBD

PACKAGE DESCRIPTION

TEMPERATURE RANGE

LTC4065LEDC#TRPBF

LTC4065LXEDC#TRPBF

6-Lead (2mm × 2mm) Plastic DFN

–40°C to 85°C

LCKS

LTC4065LEDC-4.1#PBF LTC4065LEDC-4.1#TRPBF LGGN

Consult LTC Marketing for parts specified with wider operating temperature ranges.

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/

LTC4065 Options

PART NUMBER

LTC4065

FLOAT VOLTAGE

CHARGE CURRENT RANGE PIN 5 IS EN OR ACPR?

TRICKLE CHARGE?

4.2V

4.4V

4.2V

4.1V

40mA TO 750mA

8mA TO 250mA

EN

YES

NO

LTC4065A

ACPR

EN

LTC4065-4.4

LTC4065L

EN

LTC4065LX

LTC4065L-4.1

EN

YES

4065lfb

2

LTC4065L/

LTC4065LX/LTC4065L-4.1

ELECTRICAL CHARACTERISTICS ^Thel denotes specifications which apply over the full operating

temperature range, otherwise specifications are T_A= 25°C. V_CC= 5V, V_BAT= 3.8V, V_EN= 0V unless otherwise speciﬁed. (Note 2)

SYMBOL PARAMETER

Supply Voltage

CONDITIONS

MIN

TYP

MAX

5.5

250

40

UNITS

V

l

V

(Note 4)

3.75

CC

I

Quiescent V Supply Current

V

= 4.5V (Forces I and I = 0)

PROG

120

20

6

μA

CC

BAT

V

Supply Current in Shutdown

= 5V

μA

CCMS

CCUV

CC

EN

V

Supply Current in Undervoltage

< V , V = 3.5V, V = 4V

11

μA

CC

BAT CC

BAT

Lockout

V

Regulated Output Voltage

I

= 2mA

= 2mA, 0°C < T < 85°C

= 2mA (LTC4065L-4.1)

= 2mA, 0°C < T < 85°C (LTC4065L-4.1)

4.175

4.158

4.075

4.058

4.2

4.1

4.225

4.242

4.125

4.142

V

FLOAT

BAT

A

l

I

BAT Pin Current

R

= 13.3k (0.1%), Current Mode

= 1.33k (0.1%), Current Mode

13.5

148

15.5

155

17.5

162

mA

BAT

PROG

l

Battery Drain Current in Shutdown

Mode

V

= V

CC

–1

0

1

μA

BMS

BUV

EN

l

Battery Drain Current in Undervoltage

Lockout

V

= 3.5V, V = 4V

0

1

4

μA

CC

BAT

l

V

UVLO

V

PROG

V

ASD

V

Undervoltage Lockout Voltage

V

Rising

Falling

3.4

2.8

3.6

3.0

3.8

3.2

V

CC

l

PROG Pin Voltage

R

= 1.33k, I

= 13.3k, I

= 0.75mA

= 75μA

0.98

1

1.02

V

PROG

Automatic Shutdown Threshold Voltage (V – V ), V Low to High

60

15

80

30

100

45

mV

CC

BAT

CC

(V – V ), V High to Low

CC

BAT

CC

V

Manual Shutdown High Voltage

Manual Shutdown Low Voltage

EN Pin Input Resistance

V

Rising

1

V

MSH

EN

Falling

0.6

0.9

MSL

l

R

1.5

170

15.5

2.9

3.3

MΩ

μs

EN

t

I

Soft-Start Time

SS

TRKL

Trickle Charge Current

V

= 2V, R

= 1.33k (0.1%) (Note 7)

13

18

mA

V

BAT

PROG

V

Trickle Charge Threshold Voltage

Trickle Charge Hysteresis Voltage

Recharge Battery Threshold Voltage

Rising (Note 7)

2.7

3.05

TRKL

(Note 7)

– V

90

mV

TRHYS

ΔV

V

, 0°C < T < 85°C

70

100

130

RECHRG

FLOAT

RECHRG

A

ΔV

UVCL1

ΔV

UVCL2

(V – V ) Undervoltage Current

Limit

I

= 90%, R

= 10%, R

= 2k, Programmed Charge Current

150

80

190

125

300

150

mV

CC

BAT

PROG

I

BAT

l

t

Termination Timer

3

4.5

2.25

1.125

60

6

3

Hrs

mV

TIMER

Recharge Time

1.5

Low-Battery Trickle Charge Time

CHRG Pin Output Low Voltage

V

= 2.5V

0.75

1.5

105

BAT

V

I

= 5mA

CHRG

4065lfb

3

LTC4065L/

LTC4065LX/LTC4065L-4.1

ELECTRICAL CHARACTERISTICS ^Thel denotes specifications which apply over the full operating

temperature range, otherwise specifications are T_A= 25°C. V_CC= 5V, V_BAT= 3.8V, V_EN= 0V unless otherwise speciﬁed. (Note 2)

SYMBOL PARAMETER

CONDITIONS

= 4.5V, V

MIN

TYP

0

MAX

1

UNITS

μA

l

I

CHRG Pin Input Current

V

= 5V

CHRG

BAT

End of Charge Indication Current Level

R

= 1.33k (Note 5)

PROG

0.08

0.095

115

0.11

mA/mA

°C

C/10

T

LIM

Junction Temperature in Constant

Temperature Mode

R

Power FET “ON” Resistance

I

= 150mA

1.5

2

Ω

Hz

%

ON

BAT

(Between V and BAT)

CC

f

Defective Battery Detection CHRG

Pulse Frequency

BADBAT

D

Defective Battery Detection CHRG

75

BADBAT

Pulse Frequency Duty Ratio

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 4: Although the LTC4065L functions properly at 3.75V input, full

charge current requires an input voltage greater than the desired final bat-

tery voltage per the ΔV

specification.

UVCL1

Note 5: I

is expressed as a fraction of measured full charge current

C/10

Note 2: The LTC4065L is tested under pulsed load conditions such that

with indicated PROG resistor.

T ≈ T . The LTC4065L is guaranteed to meet performance specifica-

J

A

Note 6: This IC includes overtemperature protection that is intended

to protect the device during momentary overload conditions. Junction

temperature will exceed 125°C when overtemperature protection is active.

Continuous operation above the specified maximum operating junction

temperature may impair device reliability.

tions from 0°C to 70°C. Specifications over the –40°C to 85°C operating

temperature range are assured by design, characterization and correlation

with statistical process controls.

Note 3: Failure to solder the exposed backside of the package to the PC

board ground plane will result in a thermal resistance much higher than

rated.

Note 7: This parameter is not applicable to the LTC4065LX.

4065lfb

4

LTC4065L/

LTC4065LX/LTC4065L-4.1

TYPICAL PERFORMANCE CHARACTERISTICS

Battery Regulation (Float) Voltage

vs Battery Charge Current

Battery Regulation (Float) Voltage

vs Temperature

Battery Regulation (Float) Voltage

vs Supply Voltage

4.24

4.22

4.20

4.18

4.16

4.14

4.12

4.10

4.08

4.06

4.24

4.22

4.20

4.18

4.16

4.14

4.12

4.10

4.08

4.06

4.24

4.22

4.20

4.18

4.16

4.14

4.12

4.10

4.08

4.06

V

A

R

= 5V

CC

T

I

= 25°C

= 2mA

PROG

A

BAT

R

T

= 25°C

= 800Ω

PROG

= 800Ω

LTC4065L

LTC4065L-4.1

5

LTC4065L-4.1

–25

0

50

75

100

–50

25

50

100

200

0

250

4

4.5

5.5

6

150

(mA)

TEMPERATURE (°C)

I

SUPPLY VOLTAGE (V)

BAT

4065L G02

4065L G01

4065L G03

Charge Current vs Temperature

with Thermal Regulation

(Constant Current Mode)

Charge Current vs Supply Voltage

(Constant Current Mode)

Charge Current vs Battery Voltage

30

25

20

15

10

5

300

250

300

250

200

150

100

50

V

T

= 5V

R

V

A

= 13.3k

CC

A

R

PROG

BAT

LTC4065L

= 25°C

= 3.8V

= 800Ω

T

= 25°C

PROG

200

150

THERMAL CONTROL

LOOP IN OPERATION

100

50

0

V

= 5V

CC

= 3.8V

BAT

R

= 800Ω

PROG

LTC4065L-4.1

0

4

4.5

5

5.5

6

0

1

2

3

4

5

100

–50

0

50

150

V

(V)

TEMPERATURE (°C)

SUPPLY VOLTAGE (V)

BAT

4065L G04

4065L G05

4065L G06

Power FET On Resistance

vs Temperature

PROG Pin Voltage vs Temperature

(Constant Current Mode)

PROG Pin Voltage

vs Charge Current

1.02

1.01

1.00

0.99

0.98

1.2

1.0

2.0

1.8

1.6

1.4

V

T

= 5V

V

I

= 4V

CC

BAT

V

= 5V

CC

A

R

CC

= 25°C

= 150mA

= 3.8V

BAT

= 800Ω

R

= 13.3k

PROG

0.8

0.6

0.4

0.2

0

1.2

1.0

50

TEMPERATURE (°C)

100

–50

–25

0

25

75

0

50

100

I

150

(mA)

200

250

–50

0

25

50

75

100

–25

TEMPERATURE (°C)

BAT

4065L G07

4065L G08

4065L G09

4065lfb

5

LTC4065L/

LTC4065LX/LTC4065L-4.1

TYPICAL PERFORMANCE CHARACTERISTICS

Manual Shutdown Threshold

Voltage vs Temperature

Manual Shutdown Supply Current

vs Temperature

Undervoltage Lockout Threshold

Voltage vs Temperature

1.0

0.9

0.8

0.7

0.6

0.5

4.00

3.75

3.50

3.25

3.00

2.75

2.50

40

30

20

10

V

= 5V

CC

EN

RISE

FALL

RISE

FALL

0

–50

0

25

50

75

100

50

TEMPERATURE (°C)

100

–25

–50

–25

0

25

75

–50

–25

0

25

50

75

100

TEMPERATURE (°C)

4065L G10

4065L G11

4065L G12

Trickle Charge Current vs Supply

Voltage (4065L and 4065L-4.1)

Trickle Charge Current vs

Temperature (4065L and 4065L-4.1)

EN Pin Current

30

25

20

15

10

5

30

25

20

15

4.0

3.5

3.0

2.5

V

T

= 2V

V

T

= 5V

V

= 5V

= 2V

BAT

A

CC

A

CC

BAT

= 25°C

R

= 800Ω

R

= 800Ω

PROG

2.0

1.5

10

5

1.0

0.5

0

R

= 13.3k

R

PROG

= 13.3k

PROG

0

50

TEMPERATURE (°C)

100

4

4.5

5

5.5

6

–50

–25

0

25

75

2.5

3

4

2

4.5

5

3.5

(V)

SUPPLY VOLTAGE (V)

V

EN

4065L G14

4065L G15

4065L G13

CHRG Pin Output Low Voltage

vs Temperature

Timer Accuracy vs Temperature

Timer Accuracy vs Supply Voltage

140

120

1

0

2.0

1.5

V

= 5V

= 5mA

CC

T = 25°C

A

V

= 5V

CC

I

CHRG

–1

–2

1.0

100

80

60

0.5

–3

–4

0

–0.5

–1.0

–1.5

–2.0

40

–5

–6

–7

20

0

50

TEMPERATURE (°C)

100

–50

–25

0

25

75

–25

0

50

4

4.5

5

5.5

6

–50

75

100

25

TEMPERATURE (°C)

SUPPLY VOLTAGE (V)

4065L G16

4065L G18

4065L G19

4065lfb

6

LTC4065L/

LTC4065LX/LTC4065L-4.1

PIN FUNCTIONS

GND (Pin 1, Exposed Pad Pin 7): Ground. The Exposed

Pad must be soldered to the PCB ground to provide both

electrical contact and rated thermal performance.

to 5.5V. This pin should be bypassed with at least a 1μF

capacitor. When V is within 32mV of the BAT pin volt-

CC

age, the LTC4065L enters shutdown mode, dropping I

BAT

to about 1μA.

CHRG (Pin 2): Open-Drain Charge Status Output. The

charge status indicator pin has three states: pull-down,

pulse at 2Hz and high impedance state. This output can

be used as a logic interface or as an LED driver. When the

battery is being charged, the CHRG pin is pulled low by

an internal N-channel MOSFET. When the charge current

drops to 10% of the full-scale current, the CHRG pin is

forced to a high impedance state. If the battery voltage

remains below 2.9V for one quarter of the charge time, the

battery is considered defective and the CHRG pin pulses

at a frequency of 2Hz.

EN (Pin 5): Enable Input Pin. Pulling this pin above the

manual shutdown threshold (V is typically 0.82V) puts

MS

the LTC4065L in shutdown mode. In shutdown mode, the

LTC4065Lhaslessthan20μAsupplycurrentandlessthan

1μA battery drain current. Enable is the default state, but

the pin should be tied to GND if unused.

PROG (Pin 6): Charge Current Program and Charge Cur-

rent Monitor Pin. Connecting a 1% resistor, R

, to

PROG

ground programs the charge current. When charging in

constant-currentmode,thispinservosto1V.Inallmodes,

the voltage on this pin can be used to measure the charge

current using the following formula:

BAT (Pin 3): Charge Current Output. Provides charge cur-

renttothebatteryandregulatesthefinalfloatvoltage(4.2V

for LTC4065L/LTC4065LX and 4.1V for LTC4065L-4.1).

An internal precision resistor divider on this pin sets the

float voltage and is disconnected in shutdown mode.

V

PROG

I_BAT

=

• 205

R_PROG

V

(Pin 4): Positive Input Supply Voltage. This pin pro-

CC

Floating the PROG pin sets the charge current to zero.

vides power to the charger. V can range from 3.75V

CC

4065lfb

7

LTC4065L/

LTC4065LX/LTC4065L-4.1

SIMPLIFIED BLOCK DIAGRAM

V

CC

4

V

CC

T

+

–

DIE

D3

TA

+

–

115°C

UVLO

BAT

C2

M2

1×

M1

205×

3.6V

EN

5

+

R

SHUTDOWN

ENB

C1

D1

D2

0.82V

–

3

+

–

+

MA

R1

R2

1.2V

REF

CA

VA

PROG

0.1V

–

+

–

+

R3

1V

–

+

1.2V

MP

C/10

R4

R5

0.1V

CHARGE CONTROL

LOGIC

CHRG

2

COUNTER

ENABLE

–

2.9V

LOBAT

+

SHUTDOWN

BAT

OSCILLATOR

PROG

GND

6

1

4056L F01

TRICKLE CHARGE DISABLED ON THE LTC4065LX

R

PROG

Figure 1. LTC4065L Block Diagram

4065lfb

8

LTC4065L/

LTC4065LX/LTC4065L-4.1

OPERATION

TheLTC4065Lisalinearbatterychargerdesignedprimar-

ily for charging single cell lithium-ion batteries. Featuring

an internal P-channel power MOSFET, the charger uses a

constant-current/constant-voltage charge algorithm with

programmablecurrent.Chargecurrentcanbeprogrammed

up to 250mA with a final float voltage accuracy of 0.6%.

The CHRG open-drain status output indicates if C/10 has

been reached. No blocking diode or external sense resis-

tor is required; thus, the basic charger circuit requires

only two external components. An internal termination

timer and trickle charge low-battery conditioning adhere

to battery manufacturer safety guidelines (Note: The

LTC4065LX does not include this trickle charge feature).

Furthermore, the LTC4065L is capable of operating from

a USB power source.

When the BAT pin approaches the final float voltage (4.2V

forLTC4065L/LTC4065LXor4.1VforLTC4065L-4.1), the

LTC4065L enters constant-voltage mode and the charge

current begins to decrease. When the current drops to

10% of the full-scale charge current, an internal compara-

tor turns off the N-channel MOSFET on the CHRG pin and

the pin assumes a high impedance state.

An internal timer sets the total charge time, t

(typi-

TIMER

cally 4.5 hours). When this time elapses, the charge cycle

terminates and the CHRG pin assumes a high impedance

state. To restart the charge cycle, remove the input voltage

and reapply it or momentarily force the EN pin above V

MS

(typically0.82V).Thechargecyclewillautomaticallyrestart

if the BAT pin voltage falls below V (typically 4.1V).

RECHRG

When the input voltage is not present, the battery drain

currentisreducedtolessthan4μA.TheLTC4065Lcanalso

be shut down by pulling the EN pin above the shutdown

threshold voltage. This reduces input quiescent current to

less than 20μA and battery drain current to less than 1μA.

An internal thermal limit reduces the programmed charge

current if the die temperature attempts to rise above a

presetvalueofapproximately115°C. Thisfeatureprotects

the LTC4065L from excessive temperature and allows the

usertopushthelimitsofthepowerhandlingcapabilityofa

givencircuitboardwithoutriskofdamagingtheLTC4065L

or external components. Another benefit of the LTC4065L

thermal limit is that charge current can be set according

to typical, not worst-case, ambient temperatures for a

given application with the assurance that the charger will

automaticallyreducethecurrentinworst-caseconditions.

Programming Charge Current

The charge current is programmed using a single resistor

from the PROG pin to ground. The battery charge current

is 205 times the current out of the PROG pin. The program

resistor and the charge current are calculated using the

following equations:

The charge cycle begins when the following conditions

1V

I_BAT

205V

R_PROG

are met: the voltage at the V pin exceeds 3.6V and ap-

CC

R_PROG= 205 •

,I_BAT=

proximately 80mV above the BAT pin voltage, a program

resistor is present from the PROG pin to ground and the

EN pin is pulled below the shutdown threshold (typically

0.82V).

The charge current out of the BAT pin can be determined

at any time by monitoring the PROG pin voltage and using

the following equation:

If the BAT pin voltage is below 2.9V, the charger goes into

trickle charge mode, charging the battery at one-tenth the

programmed charge current to bring the cell voltage up

to a safe level for charging (Note: The LTC4065LX does

not include this trickle charge feature). If the BAT pin volt-

age is above 4.1V for LTC4065L/LTC4065LX or 4.0V for

LTC4065L-4.1, the charger will not charge the battery as

the cell is near full capacity. Otherwise, the charger goes

into the fast charge constant-current mode.

V

PROG

I_BAT

=

•205

R_PROG

4065lfb

9

LTC4065L/

LTC4065LX/LTC4065L-4.1

OPERATION

Undervoltage Lockout (UVLO)

falls 100mV below the float voltage (which corresponds

to 80% to 90% battery capacity), a new charge cycle is

initiated and a 2.25 hour timer begins. This ensures that

the battery is kept at, or near, a fully charged condition and

eliminates the need for periodic charge cycle initiations.

TheCHRGoutputassumesastrongpull-downstateduring

recharge cycles until C/10 is reached when it transitions

to a high impendance state.

Aninternalundervoltagelockoutcircuitmonitorstheinput

voltageandkeepsthechargerinundervoltagelockoutuntil

V

rises above 3.6V and approximately 80mV above the

CC

BAT pin voltage. The 3.6V UVLO circuit has a built-in hys-

teresisofapproximately0.6Vandtheautomaticshutdown

thresholdhasabuilt-inhysteresisofapproximately50mV.

Duringundervoltagelockoutconditions,maximumbattery

draincurrentis4μAandmaximumsupplycurrentis11μA.

Trickle Charge and Defective Battery Detection

Shutdown Mode

At the beginning of a charge cycle, if the battery voltage

is low (below 2.9V), the charger goes into trickle charge,

reducing the charge current to 10% of the full-scale cur-

rent (Note: The LTC4065LX has full charge current at

low-battery voltage). If the low-battery voltage persists

for one quarter of the total time (1.125 hour), the battery

is assumed to be defective, the charge cycle is terminated

and the CHRG pin output pulses at a frequency of 2Hz with

a 75% duty cycle. If for any reason the battery voltage

rises above 2.9V, the charge cycle will be restarted. To

restart the charge cycle (i.e., when the defective battery

is replaced with a discharged battery), simply remove the

input voltage and reapply it or temporarily pull the EN pin

above the shutdown threshold.

The LTC4065L can be disabled by pulling the EN pin

above the shutdown threshold (approximately 0.82V).

In shutdown mode, the battery drain current is reduced

to less than 1μA and the supply current to about 20μA.

Timer and Recharge

The LTC4065L has an internal termination timer that

starts when an input voltage greater than the undervolt-

age lockout threshold is applied to V_CC, or when leaving

shutdown the battery voltage is less than the recharge

threshold.

At power-up or when exiting shutdown, if the battery volt-

age is less than the recharge threshold, the charge time is

set to 4.5 hours. If the battery voltage is greater than the

rechargethresholdatpower-uporwhenexitingshutdown,

the timer will not start and charging is prevented since the

battery is at or near full capacity.

CHRG Status Output Pin

The charge status indicator pin has three states: pull-

down, pulse at 2Hz (see Trickle Charge and Defective

Battery Detection) and high impedance. The pull-down

state indicates that the LTC4065L is in a charge cycle. A

high impedance state indicates that the charge current

has dropped below 10% of the full-scale current or the

LTC4065L is disabled. Figure 2 shows the CHRG status

under various conditions.

Once the charge cycle terminates, the LTC4065L continu-

ously monitors the BAT pin voltage using a comparator

with a 2ms filter time. When the average battery voltage

4065lfb

10

LTC4065L/

LTC4065LX/LTC4065L-4.1

OPERATION

Charge Current Soft-Start and Soft-Stop

loop, whichever is trying to reduce the charge current

the most. The output of the other amplifier saturates low

which effectively removes its loop from the system. When

in constant-current mode, CA servos the voltage at the

PROG pin to be precisely 1V. VA servos its inverting input

to an internal reference voltage when in constant-voltage

mode and the internal resistor divider, made up of R1 and

R2, ensures that the battery voltage is maintained at 4.2V

for LTC4065L/LTC4065LX or 4.1V for LTC4065L-4.1. The

PROGpinvoltagegivesanindicationofthechargecurrent

during constant-voltage mode as discussed in “Program-

ming Charge Current”.

The LTC4065L includes a soft-start circuit to minimize

the inrush current at the start of a charge cycle. When a

charge cycle is initiated, the charge current ramps from

zerotothefull-scalecurrentoveraperiodofapproximately

170μs.Likewise,internalcircuitryslowlyrampsthecharge

current from full-scale to zero when the charger is shut off

or self terminates. This has the effect of minimizing the

transient current load on the power supply during start-up

and charge termination.

Constant-Current/Constant-Voltage/

Constant-Temperature

Thetransconductanceamplifier,TA,limitsthedietempera-

turetoapproximately115°Cwheninconstant-temperature

mode. DiodeD3ensuresthatTAdoesnotaffectthecharge

current when the die temperature is below approximately

115°C. The PROG pin voltage continues to give an indica-

tion of the charge current.

The LTC4065L use a unique architecture to charge a bat-

tery in a constant-current, constant-voltage and constant-

temperature fashion. Figure 1 shows a simplified block

diagram of the LTC4065L. Three of the amplifier feedback

loops shown control the constant-current, CA, constant-

voltage,VA,andconstant-temperature,TAmodes.Afourth

amplifierfeedbackloop,MA,isusedtoincreasetheoutput

impedanceofthecurrentsourcepair;M1andM2(notethat

M1 is the internal P-channel power MOSFET). It ensures

that the drain current of M1 is exactly 205 times greater

than the drain current of M2.

In typical operation, the charge cycle begins in constant-

currentmodewiththecurrentdeliveredtothebatteryequal

. If the power dissipation of the LTC4065L

PROG

to 205V/R

results in the junction temperature approaching 115°C,

the amplifier (TA) will begin decreasing the charge current

to limit the die temperature to approximately 115°C. As

the battery voltage rises, the LTC4065L either returns to

constant-current mode or enters constant-voltage mode

straight from constant-temperature mode. Regardless of

mode, the voltage at the PROG pin is proportional to the

current delivered to the battery.

Amplifiers CA and VA are used in separate feedback loops

to force the charger into constant-current or constant-

voltage mode, respectively. Diodes D1 and D2 provide

priority to either the constant-current or constant-voltage

4065lfb

11

LTC4065L/

LTC4065LX/LTC4065L-4.1

OPERATION

ENABLE

UVLO

IF V > 3.6V AND

UVLO MODE

NO

POWER

IS EN > SHUTDOWN

THRESHOLD?

CHRG HIGH IMPEDANCE

CC

ON

V

CC

> V

BAT

+ 80mV?

YES

SHUTDOWN MODE

CHRG HIGH IMPEDANCE

V

> 4.1V (LTC4065L/LTC4065LX)

> 4.0V (LTC4065L-4.1)

BAT

V

≤ 2.9V

2.9V < V

< 4.1V (LTC4065L/LTC4065LX)

< 4.0V (LTC4065L-4.1)

BAT

2.9V < V

FAST CHARGE MODE

FULL CHARGE CURRENT

TRICKLE CHARGE MODE*

STANDBY MODE

1/10 FULL CHARGE CURRENT

NO CHARGE CURRENT

CHRG STRONG PULL-DOWN

CHRG HIGH IMPEDANCE

1/4 CHARGE CYCLE

(1.125 HOURS)

NO

CHARGE CYCLE

(4.5 HOURS)

NO

DEFECTIVE BATTERY

< 2.9V?

RECHARGE

IS V

< 4.1V? (LTC4065L/LTC4065LX)

< 4.0V? (LTC4065L-4.1)

BAT

YES

BAD BATTERY MODE

YES

RECHARGE MODE

NO CHARGE CURRENT

FULL CHARGE CURRENT

CHRG PULSES (2Hz)

CHRG STRONG PULL-DOWN

V

< 3V

CC

1/2 CHARGE CYCLE

(2.25 HOURS)

OR

EN > SHDN

THRESHOLD

4065L F02

*LTC4065L and LTC4065L-4.1 ONLY; LTC4065LX HAS FULL CHARGE CURRENT.

Figure 2. State Diagram of LTC4065L Operation

4065lfb

12

LTC4065L/

LTC4065LX/LTC4065L-4.1

APPLICATIONS INFORMATION

Undervoltage Charge Current Limiting (UVCL)

The LTC4065L includes undervoltage charge (ΔV

current limiting that prevents full charge current until the

inputsupplyvoltagereachesapproximately200mVabove

the battery voltage. This feature is particularly useful if the

LTC4065L is powered from a supply with long leads (or

any relatively high output impedance).

USB and Wall Adapter Power

)

Although the LTC4065L allows charging from a USB port,

a wall adapter can also be used to charge Li-Ion batteries.

Figure 3 shows an example of how to combine wall adapter

and USB power inputs. A P-channel MOSFET, MP1, is

used to prevent back conducting into the USB port when a

wall adapter is present and Schottky diode, D1, is used to

preventUSBpowerlossthroughthe1kpull-downresistor.

UVCL1

For example, USB-powered systems tend to have highly

variablesourceimpedances(dueprimarilytocablequality

and length). A transient load combined with such imped-

ance can easily trip the UVLO threshold and turn the

charger off unless undervoltage charge current limiting

is implemented.

Stability Considerations

TheLTC4065Lcontainstwocontrolloops:constant-voltage

and constant-current. The constant-voltage loop is stable

without any compensation when a battery is connected

withlowimpedanceleads.Excessiveleadlength,however,

may add enough series inductance to require a bypass

capacitor of at least 1μF from BAT to GND. Furthermore,

a 4.7μF capacitor with a 0.2Ω to 1Ω series resistor from

BAT to GND is required to keep ripple voltage low when

the battery is disconnected.

Consider a situation where the LTC4065L is operating

under normal conditions and the input supply voltage

begins to droop (e.g., an external load drags the input

supplydown). IftheinputvoltagereachesV_BAT+ΔV_UVCL1

(approximately 220mV above the battery voltage), un-

dervoltage charge current limiting will begin to reduce

the charge current in an attempt to maintain ΔV_UVCL1

between the V_CCinput and the BAT output of the IC. The

LTC4065L will continue to operate at the reduced charge

current until the input supply voltage is increased or volt-

age mode reduces the charge current further.

High value capacitors with very low ESR (especially ce-

ramic)mayreducetheconstant-voltageloopphasemargin.

Ceramic capacitors up to 22μF may be used in parallel

with a battery, but larger ceramics should be decoupled

with 0.2Ω to 1Ω of series resistance.

I

5V WALL

ADAPTER

BAT

3

6

SYSTEM

LOAD

BAT

LTC4065L

D1

4

USB

POWER

V

CC

MP1

+

Li-Ion

BATTERY

PROG

1k

800Ω

4065L F03

Figure 3. Combining Wall Adapter and USB Power

4065lfb

13

LTC4065L/

LTC4065LX/LTC4065L-4.1

APPLICATIONS INFORMATION

In constant-current mode, the PROG pin is in the feedback

loop,notthebattery.Becauseoftheadditionalpolecreated

bythePROGpincapacitance,capacitanceonthispinmust

be kept to a minimum. With no additional capacitance on

the PROG pin, the charger is stable with program resistor

values as high as 25k. However, additional capacitance on

this node reduces the maximum allowed program resis-

tor. The pole frequency at the PROG pin should be kept

above 100kHz. Therefore, if the PROG pin is loaded with

battery current as shown in Figure 4. A 10k resistor has

been added between the PROG pin and the filter capacitor

to ensure stability.

Power Dissipation

Due to the low charge currents, it is unlikely that the

LTC4065L will reduce charge current through thermal

feedback. Nonetheless, the LTC4065L power dissipation

can be approximated by:

a capacitance, C

, the following equation should be

PROG

P = (V – V ) • I

BAT

D

CC

BAT

usedtocalculatethemaximumresistancevalueforR

:

PROG

Where P is the power dissipated, V is the input supply

D

CC

1

R_PROG

≤

voltage, V is the battery voltage and I is the charge

2π •10⁵•C_PROG

BAT

current. It is not necessary to perform any worst-case

power dissipation scenarios because the LTC4065L will

automatically reduce the charge current to maintain the

die temperature at approximately 115°C. However, the

approximate ambient temperature at which the thermal

feedback begins to protect the IC is:

Average,ratherthaninstantaneous,batterycurrentmaybe

of interest to the user. For example, if a switching power

supply operating in low current mode is connected in

parallel with the battery, the average current being pulled

out of the BAT pin is typically of more interest than the

instantaneous current pulses. In such a case, a simple RC

filter can be used on the PROG pin to measure the average

T = 115°C – P • θ

JA

A

D

T = 115°C – (V – V ) • I • θ

A

CC

BAT

JA

LTC4065L

CHARGE

10k

CURRENT

MONITOR

CIRCUITRY

PROG

GND

R

C

FILTER

PROG

4065L F04

Figure 4. Isolating Capacitive Load on the PROG Pin and Filtering

4065lfb

14

LTC4065L/

LTC4065LX/LTC4065L-4.1

APPLICATIONS INFORMATION

Example: Consider an LTC4065L operating from a 5.5V

wall adapter providing 250mA to a 3V Li-Ion battery. The

ambienttemperatureabovewhichtheLTC4065Lwillbegin

to reduce the 250mA charge current is approximately:

Board Layout Considerations

In order to deliver maximum charge current under all

conditions, it is critical that the exposed metal pad on

the backside of the LTC4065L package is soldered to

2

T = 115°C – (5.5V – 3V) • (250mA) • 60°C/W

A

the PC board ground. Correctly soldered to a 2500mm

double-sided 1 oz. copper board the LTC4065L has a

thermal resistance of approximately 60°C/W. Failure to

make thermal contact between the Exposed Pad on the

backside of the package and the copper board will result

in thermal resistances far greater than 60°C/W.

T = 115°C – 0.625W • 60°C/W = 115°C – 37.5°C

A

T = 77.5°C

A

Chargingatsuchhighambienttemperaturesisnotrecom-

mended by battery manufacturers.

Furthermore, the voltage at the PROG pin will change

proportionally with the charge current as discussed in

the Programming Charge Current section.

V

Bypass Capacitor

CC

Many types of capacitors can be used for input bypassing;

however,cautionmustbeexercisedwhenusingmulti-layer

ceramic capacitors. Because of the self-resonant and high

Qcharacteristicsofsometypesofceramiccapacitors,high

voltage transients can be generated under some start-up

conditions, such as connecting the charger input to a live

power source. For more information, refer to Application

Note 88.

It is important to remember that LTC4065L applications

do not need to be designed for worst-case thermal

conditions since the IC will automatically reduce power

dissipation when the junction temperature reaches ap-

proximately 115°C.

4065lfb

15

LTC4065L/

LTC4065LX/LTC4065L-4.1

PACKAGE DESCRIPTION

Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.

DC Package

6-Lead Plastic DFN (2mm × 2mm)

(Reference LTC DWG # 05-08-1703)

R = 0.115

TYP

0.56 0.05

(2 SIDES)

0.38 0.05

4

6

0.675 0.05

2.50 0.05

2.00 0.10

(4 SIDES)

0.61 0.05

(2 SIDES)

1.15 0.05

PIN 1 BAR

TOP MARK

(SEE NOTE 6)

PIN 1

PACKAGE

OUTLINE

CHAMFER OF

EXPOSED PAD

(DC6) DFN 1103

3

1

0.25 0.05

0.50 BSC

0.75 0.05

0.200 REF

1.37 0.05

(2 SIDES)

1.42 0.05

(2 SIDES)

BOTTOM VIEW—EXPOSED PAD

0.00 – 0.05

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

NOTE:

1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WCCD-2)

2. DRAWING NOT TO SCALE

3. ALL DIMENSIONS ARE IN MILLIMETERS

4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE

MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE

5. EXPOSED PAD SHALL BE SOLDER PLATED

6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE

TOP AND BOTTOM OF PACKAGE

4065lfb

16

LTC4065L/

LTC4065LX/LTC4065L-4.1

REVISION HISTORY ^{(Revision history begins at Rev B)}

REV

DATE

DESCRIPTION

PAGE NUMBER

B

05/12 Added new part number LTC4065L-4.1

Added Options Table & Updated Order Information Table

Clarified Note 2 testing conditions

Throughout

2

4

Clarified State Diagram

12

4065lfb

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-

tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

17

LTC4065L/

LTC4065LX/LTC4065L-4.1

RELATED PARTS

PART NUMBER

Battery Chargers

LTC1734

DESCRIPTION

COMMENTS

TM

Lithium-Ion Linear Battery Charger in ThinSOT

Lithium-Ion Linear Battery Charger Controller

Simple ThinSOT Charger, No Blocking Diode, No Sense Resistor Needed

LTC1734L

Low Current Version of LTC1734, 50mA ≤ I

≤ 180mA

CHRG

LTC4050

Features Preset Voltages, C/10 Charger Detection and Programmable

Timer, Input Power Good Indication, Thermistor Interface

LTC4054

LTC4054L

LTC4057

Standalone Linear Li-Ion Battery Charger

with Integrated Pass Transistor in ThinSOT

Thermal Regulation Prevents Overheating, C/10 Termination,

C/10 Indicator, Up to 800mA Charge Current

Standalone Linear Li-Ion Battery Charger

with Integrated Pass Transistor in ThinSOT

Low Current Version of LTC4054, Charge Current Up to 150mA

Lithium-Ion Linear Battery Charger

Up to 800mA Charge Current, Thermal Regulation, ThinSOT Package

LTC4059/

LTC4059A

900mA Linear Lithium-Ion Battery Charger

2mm × 2mm DFN Package, Thermal Regulation, Charge Current Monitor

Output. A Version has ACPR Function

LTC4061

Standalone Li-Ion Charger with Thermistor Interface

4.2V, 0.35% Float Voltage, Up to 1A Charge Current, 3mm × 3mm DFN

LTC4061-4.4

4.4V (Max), 0.4% Float Voltage, Up to 1A Charge Current,

3mm × 3mm DFN

LTC4062

LTC4063

Standalone Linear Li-Ion Battery Charger with

Micropower Comparator

4.2V, 0.35% Float Voltage, Up to 1A Charge Current, 3mm × 3mm DFN

Up to 1A Charge Current, 100mA, 125mV LDO, 3mm × 3mm DFN

LI-Ion Charger with Linear Regulator

Standalone Li-Ion Battery Chargers

LTC4065/

LTC4065A

4.2V, 0.6% Float Voltage, Up to 750mA Charge Current,

2mm × 2mm DFN; “A” Version Has ACPR Function

Power Management

LTC3405/

LTC3405A

300mA (I ), 1.5MHz, Synchronous Step-Down

95% Efficiency, V : 2.7V to 6V, V

= 0.8V, I = 20μA, I < 1μA,

OUT Q SD

OUT

IN

DC/DC Converter

ThinSOT Package

LTC3406/

LTC3406A

600mA (I ), 1.5MHz, Synchronous Step-Down

95% Efficiency, V : 2.5V to 5.5V, V

= 0.6V, I = 20μA, I < 1μA,

Q SD

OUT

IN

OUT

DC/DC Converter

ThinSOT Package

LTC3411

1.25A (I ), 4MHz, Synchronous Step-Down

95% Efficiency, V : 2.5V to 5.5V, V

= 0.8V, I = 60μA, I < 1μA,

Q SD

OUT

IN

DC/DC Converter

MS Package

LTC3440

600mA (I ), 2MHz, Synchronous Buck-Boost

95% Efficiency, V : 2.5V to 5.5V, V

= 2.5V, I = 25μA, I < 1μA,

Q SD

OUT

IN

DC/DC Converter

MS Package

TM

LTC4411/LTC4412 Low Loss PowerPath Controller in ThinSOT

Automatic Switching Between DC Sources, Load Sharing,

Replaces ORing Diodes

LTC4413

Dual Ideal Diode in DFN

2-Channel Ideal Diode ORing, Low Forward ON Resistance, Low Regulated

Forward Voltage, 2.5V ≤ V ≤ 5.5V

IN

ThinSOT and PowerPath are trademarks of Linear Technology Corporation.

4065lfb

LT 0512 REV B • PRINTED IN THE USA

LinearTechnology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

18

●

(408) 432-1900 FAX: (408) 434-0507 www.linear.com


型号：	LTC4065L_15
厂家：	Linear
描述：	Standalone 250mA Li-Ion Battery Charger 电池
文件：	总18页 (文件大小：200K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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