Datasheet SE9017 Datasheet (Seaward)

Description

SE9017 is a complete constant-current & constant voltage linear charger for single cell lithium-ion and Lithium-Polymer batteries. Its SOT-23 package and low external component count make SE9017 ideally suited for portable applications. Furthermore, the SE9017 is specifically designed to work within USB power specification. At the same time, SE9017 can also be used in the standalone lithium-ion and Lithium-polymer battery chargers.

No external sense resistor is needed, and no blocking diode is required due to the internal MOSFET architecture. Thermal feedback regulates the charge current to limit the die temperature during high power operation or high ambient temperature. The charge voltage is fixed at 4.2V, and the charge current can be programmed externally with a single resistor. The SE9017 automatically terminates the charge cycle when the charge current drops to 1/10 value after the final float voltage is reached.

When the input supply (wall adapter or USB supply) is removed, the SE9017 automatically enters a low current stage, dropping the battery drain current to less than 2uA. The SE9017 can be put into shutdown mode, reducing the supply current to 20uA.

Other features include charge current monitor, undervoltage lockout, automatic recharge and a status pin to indicate charge termination and the presence of an input voltage. SE9017 is intentionally designed to have slightly negative Tempco. This provides extra protection to Lithium battery during charging.

th

the programmed

Features

¾ Programmable Charge Current Up to 800mA.

¾ No MOSFET, Sense Resistor or Blocking Diode

Required.

¾ Constant-Current/Constant-Voltage Operation

with Thermal Protection to Maximize Charge

Rate without Risk of Overheating.

¾ Charges Single Cell Li-Ion Batteries Directly

from USB Port.

¾ Preset 4.2V Charge Voltage with ±1% Accuracy.

¾ 20uA Supply Current in Shutdown.

¾ 2.9V Trickle Charge Threshold

¾ Soft-Start Limits Inrush Current.

¾ Available in 6-Lead SOT-23 and PSOP-8

(Exposed Pad) Packages.

¾ RoHS Compliant and 100% Lead (Pb)-Free

Application

¾ Cellular Telephones, PDA’s, MP3 Players.

¾ Charging Docks and Cradles

¾ Bluetooth Applications

Application Diagram

Pin Configuration

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Preliminary and all contents are subject to change without prior notice

Absolute Maximum Rating

Parameter Symbol Value Units

Input Supply Voltage VCC 7 V

PROG Voltage V

BAT Voltage V

CHRG Voltage V

BAT Short-Circuit Duration Continuous

Thermal Resistance, Junction-to-Ambient ΘJA

Maximum Junction Temperature TJ 125 °C

BAT Pin Current I

PROG Pin Current I

Storage Temperature TS -65 to +125 °C

(1)

VCC+0.3 V

PROG

7 V

BAT

7 V

CHRG

250 (SOT-23-6)

75(PSOP8)

800 mA

BAT

800

PROG

°C/W

μA

Lead Temperature (Soldering, 10 sec) 300 °C

Operating Rating

(2)

Parameter Symbol Value Units

Supply Input Voltage VIN -0.3 to +7 V

Junction Temperature TJ -40 to +85 °C

Electrical Characteristics

VIN = 5V; TJ = 25°C; unless otherwise specified.

Symbol Parameter Conditions Min Typ Max Unit

VCC Input Supply Voltage 4.25 6 V

ICC

V

FLOAT

I

BAT

Input Supply Current

Regulated Output (Float) Voltage I

BAT Pin Current

Charge Mode

Standby Mode (Charge Terminated) 70 µA

Shutdown Mode(R

< V

V

CC

= 30mA, I

BAT

R

= 10k, Current Mode 90 106 130 mA

PROG

R

= 2k, Current Mode 530 mA

PROG

Standby Mode, VBAT = 4.2V

Shutdown Mode (R

Sleep Mode, V

(3)

PROG

, or VCC < VUV)

BAT

CHRG

CC

, R

= 10k 110 500 µA

PROG

Not Connected,

20 40 µA

= 5mA 4.158 4.2 4.242 V

0 +/-1 +/-5

Not Connected)

PROG

= 0V

+/-0.5 +/-5

+/-1 +/-5

µA

I

Trickle Charge Current V

TRIKL

V

Trickle Charge Threshold Voltage R

TRIKL

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BAT

PROG

< V

, R

TRIKL

= 10k, V

= 10k 10 mA

PROG

Rising 2.8 2.9 3.0 V

BAT

Electrical Characteristics (Continued)

VIN = 5V; TJ = 25°C; unless otherwise specified

Symbol Parameter Conditions Min Typ Max Unit

VUV V

Undervoltage Lockout Threshold From VCC Low to High 3.4 V

CC

V

VCC Undervoltage Lockout Hysteresis 100 mV

UVHYS

MSD

Manual Shutdown Threshold Voltage

PROG Pin Rising 1.25 V V

PROG Pin Falling 1.2 V

ASD

VCC – V

Lockout Threshold Voltage

BAT

TERM

V

PROG Pin Voltage R

PROG

I

CHRG Pin Weak Pull-Down Current V

CHRG

V

CHRG Pin Output Low Voltage I

CHRG

ΔV

RECHRG

T

Thermal Protection Temperature 120 °C

LIM

tSS Soft-Start Time I

t

RECHARGE

t

Termination Comparator Filter Time I

TERM

I

PROG Pin Pull-Up Current 1 µA

PROG

C/10 Termination Current Threshold

Recharge Battery Threshold Voltage V

Recharge Comparator Filter Time V

VCC from Low to High 100 mV V

from High to Low 30 mV

V

CC

R

PROG

R

PROG

CHRG

= 5mA 0.6 V

CHRG

FLOAT

= 0 to 1000V/R

BAT

High to Low 1 ms

BAT

Falling Below I

BAT

(4)

= 10k

0.1 mA/mAI

= 2k 0.1 mA/mA

= 10k, Current Mode 0.9 1.03 1.1 V

= 3V 15 µA

- V

100 mV

RECHRG

100 µs

PROG

/10 1000 µs

CHG

Note 1: Exceeding the absolute maximum rating may damage the device. Note 2: The device is not guaranteed to function outside its operating rating. Note 3: Supply current includes PROG pin current (approximately 100µA) but does not include any current delivered to the battery

through the BAT pin (approximately 100mA). Note 4: I

is expressed as a fraction of measured full charge current with indicated PROG resistor.

TERM

Pin Functions

Pin Pin Function Description Pin Pin Function Description

VCC

GND

BA T

Positive Input Supply Voltage. Provides

power to the charger. VCC can range

from 4.25V to 6.5V and should be

bypassed with at least a 1μF capacitor.

Ground.

Charge Current Output. Provides

charge current to the battery and

regulates the final float voltage to 4.2V.

CHRG

PROG

CHRGT

Open-Drain Charge Status Output. When the battery is charging, the

CHRG pin is pulled low by an internal N-channel MOSFET. When the

charge cycle is completed, a weak pull-down of approximately 20uA is

connected to the CHRG pin, indicating an “AC present” condition.

Charge Current Program, Charge Current Monitor and Shutdown Pin.

Open-Drain Charge Termination Status Output. When the battery is

charging, the CHRGT pin is pulled high by an external compenent

such as an LED. After the charging is completed, this pin is pulled low

by internal N-channel MOSFET and it can be used as a charging

termination indicator.

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BLOCK DIAGRAM

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4.230

4.225

4.220

4.215

4.210

(V)

4.205

BAT

V

4.200

4.195

4.190

4.185

Float Voltage vs Supply Voltage

R

=10k

PROG

=25

T

℃

A

4.0 4.5 5.0 5.5 6.0 6.5 (V)

V

CC

600

500

400

300

(m A )

BAT

I

200

100

0

4.04.55.05.56.06.57.0

Charge Current vs Supply Voltage

R

=2k

PROG

V

=4V

BAT

=25

T

℃

A

=10k

R

PROG

V

(V)

CC

ONSET OF THE RMAL REGULATION

70

60

50

40

30

(mA )

TRIKL

I

20

10

Trickle Charge Current vs Supply Voltage

R

=2k

PROG

V

=2.5V

BAT

T

=25

℃

A

=10k

R

PROG

4.215

4.210

4.205

(V)

4.200

FLOAT

V

4.195

4.190

Float Voltage vs Temperature

0

4.04.55.05.56.06.57.0 (V)

V

CC

4.185

20 40 60 80 100 120

Temperature (℃)

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O

peration

The SE9017 is a single cell lithium-ion battery

charger using a constant-current/constant-voltage

algorithm. It can deliver up to 800mA of charge

current (using a good thermal PCB layout) with a

final float voltage accuracy of ±1%. The SE9017

includes an internal P-channel power MOSFET and

thermal regulation circuitry. No blocking diode or

external current sense resistor is required; thus, the

basic charger circuit requires only two external

components. Furthermore, the SE9017 is capable

of operating from a USB power source.

Normal Charge Cycle

A charge cycle begins when the voltage at the VCC

pin rises above the UVLO threshold level and a 1%

program resistor is connected from the PROG pin to

ground or when a battery is connected to the

charger output. If the BAT pin is less than 2.8V, the

charger enters trickle charge mode. In this mode,

the SE9017 supplies approximately 1/10 the

programmed charge current to bring the battery

voltage up to a safe level for full current charging.

When the BAT pin voltage rises above 2.8V, the

charger enters constant-current mode, where the

programmed charge current is supplied to the

battery. When the BAT pin approaches the final

float voltage (4.2V), the SE9017 enters

constant-voltage mode and the charge current

begins to decrease. When the charge current drops

to 1/10 of the programmed value, the charge cycle

ends.

Programming Charge Current

The charge current is programmed using a single

resistor from the PROG pin to ground. The battery

charge current is 1060 times the current out of the

PROG pin. The program resistor and the charge

current are calculated using the following equations:

1060 1060

VV

RI

==

PROG CHG

The charge current out of the BAT pin can be

determined at any time by monitoring the PROG pin

voltage using the following equation:

I

BAT

This actual current will vary from IC to IC. The typical

variation is within +/-20%.

,

IR

CHG PROG

V

PROG

=•

R

1060

PROG

,

Charge Termination

A charge cycle is terminated when the charge current

falls to 1/10th the programmed value after the final

float voltage is reached. This condition is detected by

using an internal, filtered comparator to monitor the

PROG pin. When the PROG pin voltage falls below

100mV for longer than t

is terminated. The charge current is latched off and

the SE9017 enters standby mode, where the input

supply current drops to 200mA. (Note: C/10

termination is disabled in trickle charging and thermal

limiting modes).

When charging, transient loads on the BAT pin can

cause the PROG pin to fall below 100mV for short

periods of time before the DC charge current has

dropped to 1/10th the programmed value. The 1ms

filter time (t

ensures that transient loads of this nature do not

result in premature charge cycle termination. Once

the average charge current drops below 1/10th the

programmed value, the SE9017 terminates the

charge cycle and ceases to provide any current

through the BAT pin. In this state, all loads on the

BAT pin must be supplied by the battery.

The SE9017 constantly monitors the BAT pin voltage

) on the termination comparator

TERM

(typically 1ms), charging

TERM

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in standby mode. If this voltage drops below the4.05V

recharge threshold (V

begins and current is once again supplied to the

battery. To manually restart a charge cycle when in

standby mode, the input voltage must be removed

and reapplied, or the charger must be shut down and

restarted using the PROG pin. Figure 1 shows the

state diagram of a typical charge cycle.

Charge Status Indicator (CHRG)

The charge status output has three different states:

strong pull-down (~10mA), weak pull-down (~20μA)

and high impedance. The strong pull-down state

indicates that the SE9017 is in a charge cycle. Once

the charge cycle has terminated, the pin state is

determined by undervoltage lockout conditions. A

weak pull-down indicates that V

conditions and the SE9017 is ready to charge. High

impedance indicates that the SE9017 is in

undervoltage lockout mode: either V

100mV above the BAT pin voltage or insufficient

voltage is applied to the V

Thermal Limiting

An internal thermal feedback loop reduces the

programmed charge current if the die temperature

attempts to rise above a preset value of

approximately 120℃. This feature protects the

SE9017 from excessive temperature and allows the

user to push the limits of the power handling

capability of a given circuit board without risk of

damaging the SE9017. The charge current can be set

according to typical (not worst-case) ambient

temperature with the assurance that the charger will

automatically reduce the current in worst-case

conditions.

), another charge cycle

RECHRG

meets the UVLO

CC

is less than

CC

pin.

CC

Undervoltage Lockout (UVLO)

An internal undervoltage lockout circuit monitors the

input voltage and keeps the charger in shutdown

mode until VCC rises above the undervoltage lockout

threshold. The UVLO circuit has a built-in hysteresis

of 200mV. Furthermore, to protect against reverse

current in the power MOSFET, the UVLO circuit

keeps the charger in shutdown mode if VCC falls to

within 30mV of the battery voltage. If the UVLO

comparator is tripped, the charger will not come out of

shutdown mode until VCC rises 100mV above the

battery voltage.

Power On

V

<2.8V

BAT

PROG Reconnected Or UVLO Connection Stops

Shutdown Mode

Drops to < 20μA

I

CC

Chrg: Hi-Z In UVLO WeakPull-Dn Otherwise

PROG Floate d Or UVLO Connection

Figure1. State Diagram of a Typical Charge Cycle

Trickle Charge Mode

TH

1/10

of Full Current

Chrg LED: Strong Pull-Dn

V

>2.8V

BAT

CC/CV Charge Mode Full Current

Chrg LED: Strong Pull-Dn

V

<100mV

PROG

Standby Mode No Charge Current

Chrg LED: Weak Pull-Dn

4.05V>V

BAT

V

BAT

>2.8V

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Applicati

Stability Considerations

The constant-voltage mode feedback loop is stable

without an output capacitor provided a battery is

connected to the charger output. With no battery

present, an output capacitor is recommended to

reduce ripple voltage. When using high value, low

ESR ceramic capacitors, it is recommended to add

a 1Ω resistor in series with the capacitor. No series

resistor is needed if tantalum capacitors are used.

on Hints

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

feedback loop, not the battery. The constant-current

mode stability is affected by the impedance at the

PROG pin. With no additional capacitance on the

PROG pin, the charger is stable with program

resistor values as high as 20k. However, additional

capacitance on this node reduces the maximum

allowed program resistor. The pole frequency at the

PROG pin should be kept above 100kHz.

VCC Bypass Capacitor

Many types of capacitors can be used for input

bypassing, however, caution must be exercised

when using multilayer ceramic capacitors. Because

of the self-resonant and high Q characteristics of

some types of ceramic capacitors, high voltage

transients can be generated under some start-up

conditions, such as connecting the charger input to

a live power source. Adding a 1.5Ω resistor in series

with a ceramic capacitor will minimize start-up

voltage transients.

Power Dissipation

The conditions that cause the SE9017 to reduce

charge current through thermal feedback can be

approximated by considering the power dissipated

in the IC. Nearly all of this power dissipation is

generated by the internal MOSFET—this is

calculated to be approximately:

P

= (VCC – V

D

The approximate ambient temperature at which the

thermal feedback begins to protect the IC is:

= 120°C – PDθJA

T

A

T

= 120°C – (VCC – V

A

BAT

) • I

BAT

• θJA

Thermal Considerations

Because of the small size of the thin SOT23

package, it is very important to use a good thermal

PC board layout to maximize the available charge

current. The thermal path for the heat generated by

the IC is from the die to the copper lead frame,

through the package leads, (especially the ground

lead) to the PC board copper. The PC board copper

is the heat sink. The footprint copper pads should

be as wide as possible and expand out to larger

copper areas to spread and dissipate the heat to

the surrounding ambient. Other heat sources on the

board, not related to the charger, must also be

considered when designing a PC board layout

because they will affect overall temperature rise and

the maximum charge current.

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Preliminary and all contents are subject to change without prior notice

Applications

No-load indications

Put a 1uF capacitor between BAT and GND . This

makes up of a No-load indications circuit as

shown below. If there is not a battery connected

to BAT and GND of SE9017 then we can see that

LED-R will be flashing at 2.5 Hz/S. If there is a

battery connected to BAT and GND Pin of

SE9017. Than SE9017 enters normal chargeing

cycle.

4.5V to 6. 5V

330 ohm

104

LE D-RLE D-G

CHRG

CHRGT

Vcc

SE901 7

PROG

GN D

BAT

105

10K

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OUTLINE DRAWING SOT-23-6L

OUTLINE DRAWING PSOP-8

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Preliminary and all contents are subject to change without prior notice

Customer Support

Seaward Electronics Incorporated – China

Section B, 2nd Floor, ShangDi Scientific Office Complex, #22 XinXi Road

Haidian District, Beijing 100085, China

Tel: 86-10-8289-5700/01/05

Fax: 86-10-8289-5706

Seaward Electronics Corporation – Taiwan

2F, #181, Sec. 3, Minquan East Rd,

Tai p e i , Ta i w a n R . O .C

Tel: 886-2-2712-0307

Fax: 886-2-2712-0191

Seaward Electronics Incorporated – North America

1512 Centre Pointe Dr.

Milpitas, CA95035, USA

Tel: 1-408-821-6600

Last Updated - 4/16/2009

Revision 4/16/2009

Preliminary and all contents are subject to change without prior notice