POWER LP78090 Programmable charge current up to 1000ma Datasheet

Preliminary Datasheet
LP78090
Smart Charger With Power Path
General Description
Features
The LP78090 is a monolithic linear battery charger
whit smart power path switch for single-cell Li-ion
batteries in a wide range of tablet and other portable
devices. It integrates a linear regulated voltage for
power the system and charging the battery at the
same time. This device supports both USB and high
power DC adapter input. Its charger is a complete
constant-current constant voltage linear charger with
adjustable charge current up to 1000mA. 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 ISET rammed
externally with a single resistor. The charger
automatically terminates the charge cycle when the
charge current drops to 1/10th the ISET rammed value
after the final float voltage is reached. When the input
supply (wall adapter or USB supply) is removed, the
LP78090 automatically enters a low current state,
dropping the battery drain current to less than 15µA.
When connecting a high power DC adapter, the smart
power path management allows LP78090 power the
system with VIN voltage or BAT voltage by switching
the voltage level on SC pin and charge the battery
simultaneously. This allows immediate system
operation even under moving away or deeply
discharged battery. When the input current limit is
reached, the voltage applied on the SYS pin would pull
down to the battery voltage making the charge current
decrease. If the current out of SYS pin is more than
charge current plus 1200mA, LP78090 with turn power
adapter and battery support the system load together.
The LP78090 provides an internal path from battery to
system in the event the input is removed.
Other features include charge current monitor, under
voltage lockout, automatic recharge and a status pin to
indicate charge termination and the presence of an
input voltage.
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Marking Information
Device
□ □ □
F: Pb-Free
Marking
LP78090QVF
Package
Shipping
QV:TDFN10
3K/REEL
Applications
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Order Information
LP78090
Programmable Charge Current Up to 1000mA
Smart Power Path Management
No MOSFET, Sense Resistor or Blocking Diode
Required
Constant-Current/Constant-Voltage Operation
with Thermal Regulation to Maximize Charge
Rate Without Risk of Overheating
Charges Single Cell Li-Ion Batteries Directly from
USB Port
15µA Leakage Current in Shutdown
Charging Operation and Charge Complete
Indicator
Thermal Limiting Regulation on Chip
Internal Soft Start Function
Built-in Short-Circuit Protection
Consumption Available in TDFN-10 Package
RoHS Compliant and 100% Lead (Pb)-Free
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MID/Pad
Automobile Data Recorder or Event Data
Recorder
Power Bank
Smart Phone
Bluetooth Applications
Package Type
QV:TDFN-10
LP78090 – 00 Version 1.0 Feb.-2014
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Page 1 of 10
Preliminary Datasheet
LP78090
Functional Pin Description
P acka ge Type
P i n Co n fi gur a ti ons
TDFN-10
Pin Description
PIN No.
PIN
DESCRIPTION
1,3
SYS
Output of power supply for system.
2,5
VIN
Power supply input for system and charge.
BAT is the connection to the battery. Typically a 10µF Tantalum capacitor is needed for stability
4,6
BAT
when there is no battery attached. When a battery is attached, only a 0.1µF ceramic capacitor is
required.
7
CHRG
8
STDBY
Open-Drain Charge Status Output. When the battery is charging, the STAT pin is pulled low by
an internal N-channel MOSFET. When the charge cycle is completed, the pin is pulled High.
Open-Drain Complete Status Output. When the battery is charging, the STAT pin is pulled high
by an internal N-channel MOSFET. When the charge cycle is completed, the pin is pulled Low.
Charge Current Program, Charge Current Monitor and Shutdown Pin. The charge current is
programmed by connecting a 1% resistor(R PROG)to ground. When charging in constant-current
9
ISET
mode, this pin servos to 2V. In all modes, the voltage on this pin can be used to measure the
charge current using the following formula.LP78090: Iset=1200/RPROG.
10
SC
11
GND
Smart controller.
Ground pin.
LP78090 – 00 Version 1.0 Feb.-2014
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Page 2 of 10
Preliminary Datasheet
LP78090
Application Circuit
VCC
C1
10uF
VIN
VIN
R1
1K
SY S
SY S
SY S
C2
10uF
D1-Red
CHRG
ZENER
BAT
BAT
BAT
D2-Green
C3
10uF
STDBY
SC
R2
2K
LP78090 – 00 Version 1.0 Feb.-2014
GND
4.3V
ISET
LP78090
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R3
2K
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Page 3 of 10
Preliminary Datasheet
LP78090
Function Block Diagram
LP78090 – 00 Version 1.0 Feb.-2014
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Preliminary Datasheet
LP78090
Absolute Maximum Ratings
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Input Voltage to GND (VIN) --------------------------------------------------------------------------------------- -0.3V to 6.5V
V SYS -------------------------------------------------------------------------------------------------------------------------- -0.3V to 6V
BAT, ISET, STAT ------------------------------------------------------------------------------------------- -0.3V to VIN+0.3V
BAT Short-Circuit Duration -------------------------------------------------------------------------------------------- Continuous
BAT Pin Current ------------------------------------------------------------------------------------------------------------ 1200mA
Maximum Junction Temperature -------------------------------------------------------------------------------------------- 125°C
Operating Junction Temperature Range (TJ) ------------------------------------------------------------------ -40℃ to 85°C
Maximum Soldering Temperature (at leads, 10 sec) ------------------------------------------------------------------- 260°C
Thermal Information
 Maximum Power Dissipation (PD,TA<40°C) ------------------------------------------------------------------------------ 1.5W
 Thermal Resistance (JA) ---------------------------------------------------------------------------------------------------- 68℃/W
LP78090 – 00 Version 1.0 Feb.-2014
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Page 5 of 10
Preliminary Datasheet
LP78090
Electrical Characteristics
(The specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN1/2=BVIN =
5V, unless otherwise noted.)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP.
MAX
UNITS
3.9
5
5.5
V
Charge Mode, RISET = 10k
330
2000
Standby Mode (Charge Terminated)
230
500
40
60
Charge
VIN
IQ
Adapter/USB Voltage Range
Input Supply Current
Shutdown Mode (RISET Not Connected, VIN <
VBAT, or VIN < VUV and SC=0V)
VFLOAT
IBAT
Regulated Output (Float) Voltage
Current Input to Battery
0°C ≤ TA ≤ 85°C, IBAT = 40mA
4.158
4.2
4.242
RISET = 1.2k, Current Mode
800
1000
1200
RISET = 2k, Current Mode
500
600
700
Standby Mode, VBAT = 4.2V Shutdown Mode
V
mA
-2.5
-6
±1
±2
±1
±2
1100
1250
1400
mA
100
120
mA
2.9
3.0
(RISET Not Connected)
0
Sleep Mode, VIN = 0V
uA
ISYS
Current Limit
ITRIKL
Trickle Charge Current
VBAT < V TRIKL, R ISET = 1.2k
80
VTRIKL
Trickle Charge Threshold Voltage
RISET = 10k, VBAT Rising
2.8
VTRHYS
Trickle Charge Hysteresis Voltage
RISET = 10k
120
mV
VIN From Low to High
3.9
V
VUV
VUVHYS
VMSD
VASD
form BAT or VIN to SYS
uA
VIN Under voltage Lockout Threshold for
Charge
VIN Under voltage Lockout Hysteresis for
150
200
VIN from Low to High
70
300
mV
100
140
mV
VIN from High to Low
5
30
50
mV
RISET = 10k, ITERM / ICharge
0.085
0.10
0.115
mA/mA
RISET = 2k, ITERM / ICharge
0.085
0.10
0.115
mA/mA
Charge
Manual Shutdown Charge Threshold Voltage ISET Pin Falling
VIN – VBAT Lockout Threshold Voltage
ITERM
C/10 Charge Termination Current Threshold
VSET
ISET Pin Voltage
RISET = 10k, Current Mode
V STAT
CHRG、STDBY Pin Output Low Voltage
ISTAT = 5mA
VRESTAT
Recharge Battery Voltage
ΔVRESTAT
RON
R DS(ON)
VFLOAT - VRESTAT
100
Path Switch NMOS R DS(ON)
Logic-Low Voltage
VSCH
Logic-High Voltage
V
150
200
mV
300
mΩ
V
mΩ
0.4
1
4.3V<VIN
Voltage on SYS pin
V
0.6
130
VIN=VSC=5V
ISC
V
2
0.35
Power FET “ON” Resistance (Between VIN and BAT)
VSCL
VSYS
2.2
4.05
Recharge Battery Threshold Voltage
V
V
V
-1
1
uA
VIN
VIN=FLOAT
VBAT
VIN < 4.3V
VBAT
V
TLT
Thermal Limit Temperature
120
℃
TSD
Thermal Shutdown
150
℃
Charge Characteristics
LP78090 – 00 Version 1.0 Feb.-2014
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Preliminary Datasheet
LP78090 – 00 Version 1.0 Feb.-2014
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LP78090
Page 7 of 10
Preliminary Datasheet
LP78090
Application Information
The LP78090 is a linear switching charger IC with smart power
Normal Charge Cycle
path management integrated for powering the system and
A charge cycle begins when the voltage at the VIN pin rises
charging a single cell lithium-ion battery simultaneously. It can
above the UVLO threshold level and a 1% ISET ram resistor is
deliver up to 1000mA of charge current (using a good thermal
connected from the ISET pin to ground or when a battery is
PCB layout) with a final float voltage accuracy of ±1%. The
connected to the charger output. If the BAT pin is less than 2.9V,
LP78090 includes an internal P-channel power MOSFET and
the charger enters trickle charge mode. In this mode, the
thermal regulation circuitry. No blocking diode or external
LP78090 supplies approximately 1/10 the ISET rammed charge
current sense resistor is required; thus, the basic application
current to bring the battery voltage up to a safe level for full
circuit requires only four external components. Furthermore, the
current charging.
LP78090 is capable of operating from a USB power source,
When the BAT pin voltage rises above 2.9V, the charger enters
500mA for USB 2.0 and 850mA for USB3.0 with resistor change
constant-current mode, where the ISET rammed charge current
on ISET pin.
is supplied to the battery. When the BAT pin approaches the
It has precious average input current limit and average current
final float voltage (4.2V), the LP78090 enters constant-voltage
limit form battery to system, to make maximum use of the
mode and the charge current begins to decrease. When the
allowable input power. And LP78090 would give priority to
charge current drops to 1/10 of the ISET rammed value, the
ensuring the system load approximately up to 2.4A, which
charge cycle ends.
contains 1.2A form VIN and 1.2A form battery. LP78090 will
reduce charging current or even power from battery to satisfy
the system load when its demand is over the input current limit.
In low system load situation, the remaining current is supply for
charger programmed by an external resistor connected from
ISET pin to GND. The device would reduce the charge current
when the die temperature exceeds 120℃.
ISET ramming Charge Current
The charge current is ISET rammed using a single resistor from
the ISET pin to ground. The battery charge current is 500 times
the current out of the ISET pin. The ISET ram resistor and the
charge current are calculated using the following equations:
LP78090:
RSET=1200V/ICHG,ICHG= 1200V/RSET
Two 130mΩ MOSFET integrated work as an ideal diode to
connecting the battery and VIN to the system load, and one of
this two MOSFET will turn on allowing the battery to power up
the system when the input is removed with circuit in page 3.
The charge current out of the BAT pin can be determined at any
time by monitoring the ISET pin voltage using the following
equation:
SYS Pin Voltage Switch
IBAT= VSET x 600/RSET
The voltage on the SYS pin is set by the SC voltage, VIN
Note: Vset is 2Volts.
voltage and battery voltage. VIN<4.3V condition, voltage power
for system always keeps with battery voltage. 4.3V < VIN
condition, voltage power for system always keeps with VIN
voltage
Charge Termination
When charging, transient loads on the BAT pin can cause the
ISET pin to fall below 200mV for short periods of time before the
DC charge current has dropped to 1/10th the ISET rammed
Current Limit
value. The 1ms filter time (tTERM) on the termination comparator
The current limit regulate in two directions: from VIN to system
ensures that transient loads of this nature do not result in
and from battery to system, each one is limited to 1.2A. When
premature charge cycle termination. Once the average charge
the system load needs the current above 1.2A, LP78090 would
current drops below 1/10th the ISET rammed value, the
divert part of charge current to system. And the device would
LP78090 terminates the charge cycle and ceases to provide
power system from VIN and battery when the system current is
any current through the BAT pin. In this state, all loads on the
more than charge current plus 1.2A.
BAT pin must be supplied by the battery.
LP78090 – 00 Version 1.0 Feb.-2014
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Page 8 of 10
Preliminary Datasheet
LP78090
The LP78090 constantly monitors the BAT pin voltage in
Thermal Limiting
standby mode. If this voltage drops below the 4.05V recharge
An internal thermal feedback loop reduces the ISET rammed
threshold (VRESTAT), another charge cycle begins and current is
charge current if the die temperature attempts to rise above a
once again supplied to the battery. To manually restart a charge
preset value of approximately 120°C. This feature protects the
cycle when in standby mode, the input voltage must be
LP78090 from excessive temperature and allows the user to
removed and reapplied, or the charger must be shut down and
push the limits of the power handling capability of a given circuit
restarted using the ISET pin. Figure 2 shows the state diagram
board without risk of damaging the LP78090. The charge
of a typical charge cycle.
current can be set according to typical (not worst-case) ambient
temperature with
Charge Status Indicator
the assurance
that the
charger will
automatically reduce the current in worst-case conditions.
The charge status output has two different states: strong
pull-down (~10mA) and high impedance. The strong pull-down
state indicates that the LP78090 is in a charge cycle. Once the
TDFN power considerations are discussed further in the
Applications Information section.
charge cycle has terminated, the pin state is determined by
Automatic Recharge
under voltage lockout conditions. High impedance indicates that
Once the charge cycle is terminated, the LP78090 continuously
the LP78090 is in under voltage lockout mode: either VIN is less
monitors the voltage on the BAT pin using a comparator with a
than 100mV above the BAT pin voltage or insufficient voltage is
2ms filter time (tRECHARGE). A charge cycle restarts when the
applied to the VIN pin.
battery voltage falls below 4.05V (which corresponds to
A microprocessor can be used to distinguish between these two
states—this method is discussed in the Applications Information
section.
approximately 80% to 90% battery capacity). This ensures that
the battery is kept at or near a fully charged condition and
eliminates the need for periodic charge cycle initiations. STAT
Function
CHRG(pin8)
STDBY(pin7)
Charging
Low
High
charge completed
High
Low
LP78090 – 00 Version 1.0 Feb.-2014
output enters a strong pull-down state during recharge cycles.
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Page 9 of 10
Preliminary Datasheet
LP78090
Packaging Information
TDFN-10
LP78090 – 00 Version 1.0 Feb.-2014
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Page 10 of 10
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