AS3020
800mA Linear Battery Charger
In SOT23-5LPackage DESCRIPTION
AS3020 is a complete constant - current and
constant-voltage linear charger for single cell
lithium-ion and Lithium-Polymer batteries. Its
SOT23-5L Package and low external component
count make AS3020 ideally suited for portable
applications. Furthermore the AS3020 is specifically
designed to work within USB power specification. At
the same time AS3020 can also be ud in the
standalone lithium-ion and Lithium-polymer battery
charger.
No external n 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 A3020 automatically terminates the
charge cycle when the charge current drops to
1/10th the programmed value after the final float
voltage is reached.
When the input supply (wall adapter or USB supply)
is removed the AS3020 automatically enters a low
current stage dropping the battery drain current to
less than 2μA. The AS3020 can be put into
shutdown mode reducing the supply current to 25μA.
Other features include charge current monitor,
undervoltage lockout, automatic recharge and a
status pin to indicate termination and the prence of
an input voltage.
ORDER INFORMATION
Part Number Operating Temperature
AS3020EGT
-40°C to 85°C
EVALUATION BOARD
Board Number Dimensions
EV3020EG-00A 50mm X x 50mm Y x 1.4mm Z
FEATURES
Programmable Charge Current Up to 800mA
brochureNo MOSFET, Sen Resistor or Blocking Diode
Required
Constant-Current/Constant-Voltage Operation
with Thermal Protection to Maximize Charge
Rate without Risk of Overheating
Charges Single Cell Li-Ion Batteries Directly
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ichatPress 4.2V Charge Voltage with ± 1% Accuracy
25μA. Supply Current in Shutdown
2.9V Trickle Charge Threshold
Available Without Trickle Charge
Soft-Start Limits Inrush Current
Available in SOT23-5L Package
APPLICATIONS
Cellular Telephones,
PDA’s, MP3 Players
Charging Docks and Cradles
Bluetooth Applications
“ANI” and “ANISEM” is Trademarks of ANISEM Semiconductor, Inc.
TYPICAL APPLICATION
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4.2V
Li-lon
Batery
VIN
Package
NOTEs:
1) Exceeding the ratings may damage the device.
2) The device is not guaranteed to function outside of its operating conditions.
3) Measure on approximately 1’’square of 1 oz copper. ABSOLUTE MAXIMUM RATINGS(1) VCC Supply Voltage………………..……………7V PROG Voltage ……………...………….VCC +0.3V PROG Current…………………………….…800uA CHRG Voltage ………………….………………..7V BAT Voltage ……………………..………………..7V BAT Current…………………………………800mA Junction Temperature ……………….……….. 125°C Lead Temperature (Soldering, 10c.) …..…+300°C Storage Temperature Range …….... -65℃ to 150°C Recommended Operating Conditions(2)
Supply Voltage V IN……………….………-0.3V to 7V Operating Temperature ……………. -40°C to 85°C
ELECTRICAL CHARACTERISTICS
V IN =5V, T A = 25°C, Unless otherwi noted.
PARAMETER CONDITIONS MIN
TYP
MAX UNITS Supply Voltage 4.25 6.5 V
Supply Current Charge Mode, R PROG9K
300
2000uA Standby Mode 200 500 uA
Shutdown Mode(R PROG unconnected,
V CC<V BAT or V CC<V UV
25
50
uA
Regulated Output Voltage I BAT40mA 4.158 4.2 4.242V
BAT Current R PROG=9K, Current Mode 93 100 107 mA
R PROG=1.8K, Current Mode 465 500 535 mA
Standby Mode, V BAT 4.2V 0
-2.5
-6
uA Shutdown Mode 1 2 uA
Sleep Mode, VCC=0V 1 2 uA
Trickle Charge Current V BAT<V TRIK1, R PROG 1.8K 20
45
70
mA
Trickle Charge Threshold R PROG=9K, V BAT Rising 2.8 2.9 3.0 V
Trickle Voltage Hysteresis R PROG9K 60
80
110
mV VCC UVLO Threshold From Vcc Low to High 3.7 3.8 3.93V
VCC UVLO Hysteresis 150 200 300 mV
Manual Shutdown Threshold PROG Pin Rising 1.15 1.21 1.30V PROG Pin Falling 0.9 1.0 1.1 V
V CC-V BAT Lockout Threshold VCC from Low to High 70 100 140 mV VCC from High to Low 5 30 50 mV
ELECTRICAL CHARACTERISTICS
V IN =5V, T A = 25°C, Unless otherwi noted.
PARAMETER CONDITIONS MIN TYP MAX UNITS
C/10 Termination Current Threshold R PROG =9K 0.085 0.10 0.115mA/mA R PROG =
1.8K 0.085 0.10 0.115mA/mA
PROG Pin Voltage R PROG =9K, Current Mode
0.93
c l
1.0
1.07
V
CHRG Pull-down Current V CHRG =
did you know
5V 8 20 35 uA
CHRG Output Low Voltage I CHRG =
5mA 0.35 0.6 V
Recharge Battery Threshold
V FLOAT -V RECHRG 100 200 mV
PIN FUNCTIONS
PIN NUMBER
PIN NAME FUNCTION
低能1 CHRG 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
Prent” condition.
2 GND Ground.
3 BAT
Charge Current Output. Provides charge current to the3 battery and regulates the final float voltage to 4.2V.
4 VCC
Input Supply Voltage. Provides power to the charger. VCC can range from 4.25 to 6.5 and should be bypasd with at least a 1uF capacitor.
5 PROG
Charge Current Program. Charge current Monitor and Shutdown Pin.
FUNCTION BLOCK DIAGRAM
OPERATION
The AS3020 is a single cell lithium-lon battery charger using a constant-current/constant-voltage algorithm. It can deliver up to 800mA of charger current(using a good thermal PCB layout) with a final float voltage accuracy of ±1%. The AS3020 includes an internal P-MOSFET and thermal regulation circuitry. No blocking diode or external current n resistor is required; thus, the basic charger circuit requires only two external components. Furthermore, the AS3020 is capable of operating from a USB power source.
NORMAL CHARGER CYCLE
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A charge cycle begins when the voltage at the VCC pin ris 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 constant-current is supplied to the battery. When the BAT pin approaches the final float voltage(4.2V), the AS3020 enters constant-voltage mode and the charge current begins to decrea. 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 1100 times the current out of the PROG pin. The program resistor and the charge current are calculated using the following equations:
R PROG=900V
I CHG
, I CHG=
900V
R PROG
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=
V PROG
R PROG
* 900
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 TERM(typically
1ms), charging is terminated. The charge current is
latched off and the AS3020 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 cau the PROG pin to fall
below 100mV for short periods to 1/10th the
programmed value. The 1ms filter time(t TERM) on the
termination comparator 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 AS3020
terminates the charge cycle and ceas to provide
any current through the BAT pin. In this state, all
loads on the BAT pin must be supplied by the battery.
The AS3020 constantly monitors the BAT pin voltage
in standby mode. If this voltage drops below the
4.05V recharge threshold, another charge cycle
begins and current is once again supplied to the冒名顶替农家女上学者被解聘
battery.
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