National Semiconductor LP3945, LP3946 Technical data

LP3945/LP3946
Battery Charge Management System

LP3945/LP3946 Battery Charge Management System

October 2003

General Description

The LP3945 and LP3946 are complete charge management
systems that safely charge and maintain a Li-Ion battery or a
four-cell Ni-MH (LP3945 only) battery pack. The LP3945
offers the flexibility of programming charge current, battery
regulation voltage (4.1V/4.2V), battery type (Li-Ion/Ni-MH),
and End Of Charge (EOC) termination through the use of I
interface. On the LP3946, these parameters are pro­grammed at the factory per customer specification.

The pass transistor, charge current sensing resistor and
charge current setting resistors are all integrated inside the
LP3945 and LP3946. This eliminates the use of external
components and significantly reduces design time and board
space.

The LP3945 and LP3946 operate in four modes: pre­qualification, constant current, constant voltage and mainte­nance modes. The LP3945 features Ni-MH charging mode
as well. The charger has under-voltage and over-voltage
protection as well as an internal 5.6 hr timer to prevent
overcharging the battery. There are two open drain outputs
for status indication.An internal amplifier readily converts the
charge current into a voltage. Also, the charger can operate
in an LDO mode providing up to 1 Amp to the load.

2

Features

n Integrated pass transistor
n Does not require external charge current setting or

sensing resistors

2

n I

C interface (LP3945 only) — programmable charge

current, EOC current and battery regulation voltage

C

n Near-depleted battery preconditioning
n Built-in 5.6 hour timer
n Under voltage and over voltage lockout on adaptor
n Charge status indicators
n Charge current monitor analog output
n LDO mode operation can source 1 amp
n Continuous over current/temperature protection

Key Specifications

n 1% charger voltage accuracy over 0˚C ≤ TJ≤ 85˚C
n 4.5V to 6.0V input voltage range
n LLP package power dissipation: 2.7W at T

Applications

n Cellular phones
n PDAs
n Digital cameras
n USB powered devices
n Programmable current sources

= 25˚C

A

Typical Application Circuit

20066502

20066501

© 2003 National Semiconductor Corporation DS200665 www.national.com

LP3945/LP3946 LLP14 Package Drawing

LP3945/LP3946

(TOP VIEW)

20066503

See NS Package Number LDA14A

LP3945/LP3946 Pin Description

Pin # LP3945 LP3946 Description

1 EN EN Charger Enable Input. Internally pulled high to CHG-IN pin.

2 SCL GND Serial Interface Clock Input for LP3945. Ground in LP3946.

3 SDA GND Serial Interface DATA Input/Output for LP3945. Ground in LP3946.

4 BATT BATT Battery supply input terminal. Must have 10 µF ceramic capacitor to GND.

5V

6VB

BG

SENSE

7 GND GND Digital Ground

8 Diff-Amp Diff-Amp Charge current monitoring differential amplifier output. Voltage output representation

9 BIPB BIPB Battery in Place Bar. Input signal to indicate presence/absence of the battery.

10 EOC EOC Active Low Open Drain Output to drive Green LED. Active when wall adaptor is

11 GND GND Analog Ground

12 CHG CHG Active Low Open Drain Output to drive Red LED. Active when wall adaptor is

13 StopModeEN StopModeEN For normal operation, this pin must be left floating. Pulling this pin to ground will

14 CHG-IN CHG-IN Charger input from a regulated, current limited power source. Must havea1µF

V

VB

BG

SENSE

Bandgap Voltage Reference (1.225V). Factory test point. Must be left floating.

Battery Voltage Sense connected to the + terminal of the battery.

of the charge current.

Internally pulled high to CHG-IN. Pulled low by the Battery ID resistor. Absence of
the ID resistor (BIPB signal high) indicates no battery. Pulling BIPB pin high sets the
device to LDO mode.

connected and battery is fully charged. Regardless of the battery chemistry, this
signal is available whenever a battery is attached.

connected and battery is being charged. Regardless of the battery chemistry, this
signal is available whenever a battery is attached.

bypass the 5.6 Hrs safety timer in constant current mode. See "StopModeEN PIN"
Section for more detail.

WARNING! Disabling the timer is not a recommended operating condition
since it disables the safety timer function. User must provide protection
against continuously charging a defective battery.

ceramic capacitor to GND.

Ordering Information

LP3945 supplied as 1000 units Tape and Reel LP3945 supplied as 4500 units Tape and Reel Package Marking

LP3945ILD LP3945ILDX L00011B

LP3946 supplied as 1000 units Tape and Reel LP3946 supplied as 4500 units Tape and Reel Package Marking

LP3946ILD LP3946ILDX L00030B

The LP3946 has default values of I
Semiconductor Sales Office.

www.national.com 2

=500mA, V

CHG

=4.1V and EOC=0.1C. For other default options, please contact National

BATT

Block Diagram

LP3945/LP3946

LP3945 Functional Block Diagram

20066530

www.national.com3

Absolute Maximum Ratings (Notes 1,

2)

If Military/Aerospace specified devices are required,

ESD (Note 4)

Human Body Model
Machine Model

please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

LP3945/LP3946

CHG-IN −0.3V to +6.5V

BATT, VB

CHG, EN, BIPB, StopModeEN −0.3V to +6V

Junction Temperature 150˚C

Storage Temperature −65˚C to +150˚C

Power Dissipation (Note 3) 1.76W

, SDA, SCL, EOC,

SENSE

Operating Ratings (Notes 1, 2)

CHG-IN 3.0V to 6.0V

EN, BIPB, StopModeEN 0V to (V

Junction Temperature, T

Operating Temperature, T

Thermal Resistance, θ

Maximum Power Dissipation

(TA= 85˚C, (Note 5) ) 1.08W

Electrical Characteristics

Unless otherwise noted, V
mal type apply for T

= −40˚C to +85˚C. (Notes 6, 7, 8)

T

J

= 25˚C. Limits appearing in boldface type apply over the entire junction temperature range for operation,

J

Symbol Parameter Conditions Typical

V

SUPPLY

CC

V

CHG-IN

I

BATT

V

OK−TSHD

V

UVLO−TSHD

V

OVLO−TSHD

Input Voltage Range 4.5 6

Operating Range Battery Connected 4.5 6

Battery Leakage Current

Adapter OK Trip Point (CHG-IN)

Under Voltage Lock-out Trip
Point

Over Voltage Lock-out Trip Point

Thermal Shutdown Temperature

Thermal Shutdown Hysteresis 20 ˚C

BATTERY CHARGER — Li ION MODE (MODE = LOW)

Fast Charge Current Range 500 950 mA

I

CHG

Fast Charge Current Accuracy −10 +10 %

Programmable Charging Current
Step

I

PRE-CHG

I

EOC

Pre-Charge Current V

End Of Charge Current Accuracy For I

Battery Regulation Voltage
(For 4.1V Cell) (Default State)

V

BATT

Battery Regulation Voltage
(For 4.2V Cell)

V

CHG-Q

Full Charge Qualification
Threshold

CHG-IN

= 5V, V

BATT

= 4V, C

V

CHG-IN

= 1µF, C

CHG-IN

≤ 4V 2 20 µA

EOC = Low, adaptor connected,
V

= 4.1V

BATT

V

CHG-IN-VBATT

V

CHG-IN-VBATT

V

V

V

V

(Rising) 4.15 3.8 4.5 V

CHG-IN

(Falling) 3.95 3.6 4.3 V

CHG-IN

(Rising) 5.9

CHG-IN

(Falling) 5.7

CHG-IN

(Note 7)

=2V 50 65 mA

BATT

= 0.1C, 0.15C or 0.2C +20 −20 %

EOC

T

= 0˚C to +85˚C

J

I

CHARGE

T
I

CHARGE

T
I

CHARGE

T
I

CHARGE

V

= 10 mA, Mode = Low

= −40˚C to +85˚C

J

= 10 mA, Mode = Low

= 0˚C to +85˚C

J

= 10 mA, Mode = Low

= −40˚C to +85˚C

J

= 10 mA, Mode = Low

Rising, Transition from

BATT

Pre-Charge to Full Current

= 10µF. Typical values and limits appearing in nor-

BATT

(Rising) 60 mV

(Falling) 50 mV

200V

+0.3V)

CHG-IN

J

A

JA

Min Max

−40˚C to +125˚C

−40˚C to +85˚C

Limit

37˚C/W

Units

50 150 µA

160 ˚C

50 mA

4.1 4.059 4.141

4.1 4.038 4.162

4.2 4.158 4.242

4.2 4.137 4.263

3.0 V

2kV

V

V

V

www.national.com 4

Electrical Characteristics (Continued)

Unless otherwise noted, V
mal type apply for T

= −40˚C to +85˚C. (Notes 6, 7, 8)

T

J

= 25˚C. Limits appearing in boldface type apply over the entire junction temperature range for operation,

J

Symbol Parameter Conditions Typical

BATTERY CHARGER — Li ION MODE (MODE = LOW)

Restart Threshold Voltage

V

BAT-RST

(For 4.1V Cell)

Restart Threshold Voltage
(For 4.2V Cell)

Internal Current Sense

R

SENSE

Resistance

Internal Current Sense Resistor
Load Current

ICHG

t

EOC

MON

Diff-Amp Output

Time to EOC State

BATTERY CHARGER — NI-MH MODE (MODE = HIGH, LP3945 ONLY)

V

BATT-MAX

Battery Over Voltage Protection

LDO MODE (BIPB=HIGH)

V

OUT

Output Voltage Regulation

LOGIC LEVELS

V

IL

V

IH

I

IL

Low Level Input Voltage EN 0.4 V

High Level Input Voltage EN 2.0 V

Enable Pin Input Current

CHG-IN

= 5V, V

= 4V, C

BATT

V

BATT

EOC, to Pre-Qualification State

V

BATT

EOC, to Pre-Qualification State

= 1µF, C

CHG-IN

BATT

Falling, Transition from

Falling, Transition from

= 10µF. Typical values and limits appearing in nor-

3.9 3.77 4.02

4.00 3.86 4.12

(Note 7) 120 mΩ

(Note 7) 1.2 A

= 50 mA 0.583

I

CHG

= 500 mA 1.333

CHG

I

= 950 mA 2.090

CHG

0˚C to +85˚C (Note 7) 5.625 4.78 6.42

−40˚C to +85˚C (Note 7) 5.625 4.5 6.75

(Charging Current Decreases to
0 mA when V
Voltage), V

=50mA 4.10

I

LOAD

I

=950mA 4.06

LOAD

BATT

CHG-IN

is above this

= 5.6V

5.4 5.292 5.508 V

EN = LOW −10 +10

EN = HIGH −5 +5

Limit

Min Max

LP3945/LP3946

Units

V

VI

Hrs

V

µA

Electrical Characteristics, I2C Interface (LP3945 Only)

Unless otherwise noted, V
Limits appearing in boldface type apply over the entire junction temperature range for operation, T
6, 7, 8)

Symbol Parameter Conditions Typical

V

V

V

V

F

t

HOLD

IL

IH

OL

HYS

CLK

Low Level Input Voltage SDA & SCL 0.4 0.3 V

High Level Input Voltage SDA & SCL 0.7 V

Low Level Output Voltage SDA & SCL 0 0.2 V

Schmitt Trigger Input Hysteresis SDA & SCL 0.1 V

Clock Frequency 400 kHz

Hold Time Repeated START
Condition

t

CLK-LP

t

CLK-HP

t

SU

CLK Low Period (Note 7) 1.3 µs

CLK High Period (Note 7) 0.6 µs

Set-up Time Repeated START
Condition

t

DATA-HOLD

t

DATA-SU

t

SU

Data Hold Time (Note 7) 300 ns

Data Set-up Time (Note 7) 100 ns

Set-up Time for STOP Condition (Note 7) 0.6 µs

CHG-IN

= 5V, V

= 4V. Typical values and limits appearing in normal type apply for TJ= 25˚C.

BATT

(Note 7)

(Note 7)

= −40˚C to +85˚C. (Notes

J

Limit

Min Max

DDVDD

DD

+0.5 V

Units

DD

DD

0.6 µs

0.6 µs

www.national.com5

V

V

V