Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsPMICsPMIC - battery management Charge management, Power management Li-Ion, Li-Po DFN 14 (4

LTC4085-3/LTC4085-4

408534fb

USB Power Manager with

Ideal Diode Controller and

3.95V Li-Ion Charger

The LTC

4085-3/LTC4085-4 is a USB power manager

and Li-Ion/Polymer battery charger designed for portable

battery-powered applications. The part controls the total

current used by the USB peripheral for operation and

battery charging. The total input current can be limited to

20% or 100% of a programmed value up to 1.5A (typically

100mA or 500mA). Battery charge current is automati-

cally reduced such that the sum of the load current and

charge current does not exceed the programmed input

current limit.

The LTC4085-3/LTC4085-4 includes a complete constant-

current/constant-voltage linear charger for single cell Li-Ion

batteries. These 3.95V versions of the standard LTC4085

are intended for applications which have extended battery

lifetime requirements or those that require high temperature

(approximately >60°C) operation or storage. Under these

conditions, a reduced ﬂ oat voltage will trade-off initial cell

capacity for the beneﬁ t of increased capacity retention

over the life of the battery. A reduced ﬂ oat voltage also

minimizes swelling in prismatic and polymer cells, and

avoids open CID (pressure fuse) in cylindrical cells.

The LTC4085-3/LTC4085-4 also includes a programmable

termination timer, automatic recharging, an end-of-charge

status output and an NTC thermistor.

■

Portable USB Devices

■

Seamless Transition Between Input Power Sources:

Li-Ion/Polymer Battery, USB and 5V Wall Adapter

■

215mΩ Internal Ideal Diode Plus Optional External

Ideal Diode Controller Provide Low Loss PowerPath

™

When Wall Adapter/USB Input Not Present

■

Load Dependent Charging Guarantees Accurate

USB Input Current Compliance

■

3.95V Float Voltage Improves Battery Life Span and

High Temperature Safety Margin

■

Constant-Current/Constant-Voltage Operation with

Thermal Feedback to Maximize Charging Rate without

Risk of Overheating*

■

Selectable 100% or 20% Input Current Limit

(e.g., 500mA/100mA)

■

Battery Charge Current Independently Programmable

Up to 1.2A

■

Automatic Output Undervoltage Charge Current

Reduction (LTC4085-3)

■

Tiny (4mm × 3mm × 0.75mm) 14-Lead DFN Package

Input and Battery Current vs Load Current

PROG

= 100k, R

CLPROG

= 2k

FEATURES DESCRIPTION

APPLICATIONS

TYPICAL APPLICATION

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

Bat-Track, PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other

trademarks are the property of their respective owners. Protected by U.S. Patents, including

6522118, 6700364. Other patents pending.

LOAD

(mA)

600

500

400

300

200

100

–100

300 500

408534 TA01b

100 200

400 600

CURRENT (mA)

LOAD

BAT

(CHARGING)

BAT

(DISCHARGING)

WALL = 0V

SUSP

HPWR

PROG

CLPROG

NTC

WALL

ACPR

OUT

GATE

BAT

CHRG

TIMER

LTC4085-3/

LTC4085-4

GND

0.1µF

4.7µF

TO LDOs,

REGs, ETC

10k

10k2k100k

5V WALL

ADAPTER

INPUT

5V (NOM)

FROM USB

CABLE V

BUS

4.7µF

SUSPEND USB POWER

100mA 500mA SELECT

510

408534 TA01

OPTIONAL - TO LOWER

IDEAL DIODE IMPEDANCE

LOAD

BAT

Summary of content (24 pages)

PAGE 1
LTC4085-3/LTC4085-4 USB Power Manager with Ideal Diode Controller and 3.95V Li-Ion Charger DESCRIPTION FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ The LTC®4085-3/LTC4085-4 is a USB power manager and Li-Ion/Polymer battery charger designed for portable battery-powered applications. The part controls the total current used by the USB peripheral for operation and battery charging. The total input current can be limited to 20% or 100% of a programmed value up to 1.5A (typically 100mA or 500mA).
PAGE 2
LTC4085-3/LTC4085-4 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Notes 1, 2, 3, 4, 5) Terminal Voltage IN, OUT t < 1ms and Duty Cycle < 1%................... –0.3V to 7V Steady State ............................................. –0.3V to 6V BAT, CHRG, HPWR, SUSP, WALL, ACPR....... –0.3V to 6V NTC, TIMER, PROG, CLPROG .......–0.3V to (VCC + 0.3V) Pin Current (Steady State) IN, OUT, BAT (Note 6)...............................................2.5A Operating Temperature Range..................
PAGE 3
LTC4085-3/LTC4085-4 ELECTRICAL CHARACTERISTICS The ● indicates speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C (Note 5). VIN = 5V, VBAT = 3.7V, HPWR = 5V, WALL = 0V, RPROG = 100k, RCLPROG = 2k, unless otherwise noted.
PAGE 4
LTC4085-3/LTC4085-4 ELECTRICAL CHARACTERISTICS The ● indicates speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C (Note 5). VIN = 5V, VBAT = 3.7V, HPWR = 5V, WALL = 0V, RPROG = 100k, RCLPROG = 2k, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN External Ideal Diode Forward Voltage VGATE = 1.
PAGE 5
LTC4085-3/LTC4085-4 TYPICAL PERFORMANCE CHARACTERISTICS Input Supply Current vs Temperature 800 700 70 100 VIN = 5V VBAT = 3.95V 60 R PROG = 100k RCLPROG = 2k 50 SUSP = 5V VIN = 5V VBAT = 3.95V RPROG = 100k RCLPROG = 2k IIN (μA) 600 IIN (μA) Battery Drain Current vs Temperature (BAT Powers OUT, No Load) Input Supply Current vs Temperature (Suspend Mode) 500 400 300 VIN = 0V 90 VBAT = 3.95V 80 70 40 IBAT (μA) 900 TA = 25°C unless otherwise noted.
PAGE 6
LTC4085-3/LTC4085-4 TYPICAL PERFORMANCE CHARACTERISTICS Battery Current and Voltage vs Time 600 ILOAD = 400mA 250 IBAT (mA) RON (mΩ) 300 3 75 2 C/10 100 400 100 TIME (min) 100 VIN = 5V VBAT = 3.5V VJA = 50°C/W 0 50 25 75 –50 –25 0 TEMPERATURE (°C) 0 200 150 300 200 TERMINATION 1 600 408534 G12 1000 120 VIN = 5V VOUT = NO LOAD 100 RPROG = 100k RCLPROG = 2k HPWR = 0V 80 VBAT = 3.
PAGE 7
LTC4085-3/LTC4085-4 TYPICAL PERFORMANCE CHARACTERISTICS Input Connect Waveforms Input Disconnect Waveforms VIN 5V/DIV VOUT 5V/DIV VIN 5V/DIV VOUT 5V/DIV IIN 0.5A/DIV IBAT 0.5A/DIV IIN 0.5A/DIV IBAT 0.5A/DIV 1ms/DIV VBAT = 3.85V IOUT = 100mA TA = 25°C unless otherwise noted. 1ms/DIV 408534 G19 VBAT = 3.85V IOUT = 100mA Wall Connect Waveforms, VIN = 0V 408534 G20 Wall Disconnect Waveforms, VIN = 0V HPWR 5V/DIV WALL 5V/DIV VOUT 5V/DIV IIN 0.5A/DIV IWALL 0.5A/DIV IBAT 0.5A/DIV IBAT 0.
PAGE 8
LTC4085-3/LTC4085-4 PIN FUNCTIONS IN (Pin 1): Input Supply. Connect to USB supply, VBUS. Input current to this pin is limited to either 20% or 100% of the current programmed by the CLPROG pin as determined by the state of the HPWR pin. Charge current (to BAT pin) supplied through the input is set to the current programmed by the PROG pin but will be limited by the input current limit if charge current is set greater than the input current limit. HPWR (Pin 4): High Power Select.
PAGE 9
LTC4085-3/LTC4085-4 PIN FUNCTIONS WALL (Pin 7): Wall Adapter Present Input. Pulling this pin above 4.25V will disconnect the power path from IN to OUT. The ACPR pin will also be pulled low to indicate that a wall adapter has been detected. NTC (Pin 8): Input to the NTC Thermistor Monitoring Circuits. The NTC pin connects to a negative temperature coefﬁcient thermistor which is typically co-packaged with the battery pack to determine if the battery is too hot or too cold to charge.
PAGE 10
LTC4085-3/LTC4085-4 BLOCK DIAGRAM VBUS 1 IN CURRENT LIMIT OUT ILIM_CNTL 3 2k 4 SOFT-START + CL – CLPROG HPWR CURRENT CONTROL – + ILIM CC/CV REGULATOR CHARGER IN 500mA/100mA 25mV 2 25mV + –EDA GATE 13 IDEAL_DIODE ENABLE 105°C DIE TEMP 2μA OUT BAT + – IIN 1000 1V ENABLE + – BAT TA 14 SOFT-START2 CHARGE CONTROL + – ICHRG + – 1V CHG PROG 12 100k – + 7 10 +– 25mV WALL ACPR VOLTAGE DETECT 4.25V + – 0.25V + – 2.9V BATTERY UVLO + – 3.
PAGE 11
LTC4085-3/LTC4085-4 OPERATION The LTC4085 is a complete PowerPath controller for battery powered USB applications. The LTC4085 is designed to receive power from a USB source, a wall adapter, or a battery. It can then deliver power to an application connected to the OUT pin and a battery connected to the BAT pin (assuming that an external supply other than the battery is present).
PAGE 12
LTC4085-3/LTC4085-4 OPERATION WALL ADAPTER 10 4.25V (RISING) 3.
PAGE 13
LTC4085-3/LTC4085-4 OPERATION Table 1. Operating Modes—PowerPath States Current Limited Input Power (IN to OUT) WALL PRESENT SUSPEND VIN > 3.8V VIN > (VOUT + 100mV) VIN > (VBAT + 100mV) CURRENT LIMIT ENABLED Y X X X X N X Y X X X N X X N X X N X X X N X N X X X X N N N N Y Y Y Y Battery Charger (OUT to BAT) WALL PRESENT SUSPEND VOUT > 4.
PAGE 14
LTC4085-3/LTC4085-4 OPERATION USB Current Limit and Charge Current Control The current limit and charger control circuits of the LTC4085 are designed to limit input current as well as control battery charge current as a function of IOUT.
PAGE 15
LTC4085-3/LTC4085-4 OPERATION Programming Current Limit The formula for input current limit is: ⎛ 1000 ⎞ 1000V ICL = ⎜ • VCLPROG ⎟ = ⎝ RCLPROG ⎠ RCLPROG where VCLPROG is the CLPROG pin voltage and RCLPROG is the total resistance from the CLPROG pin to ground. For example, if typical 500mA current limit is required, calculate: RCLPROG = 1V • 1000 = 2k 500mA In USB applications, the minimum value for RCLPROG should be 2.1k.
PAGE 16
LTC4085-3/LTC4085-4 OPERATION Battery Charger The battery charger circuits of the LTC4085 are designed 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 programmable current and a programmable timer for charge termination. Charge current can be programmed up to 1.5A. The ﬁnal ﬂoat voltage accuracy is ±0.8% typical. No blocking diode or sense resistor is required when powering the IN pin.
PAGE 17
LTC4085-3/LTC4085-4 OPERATION Programming Charge Current The formula for the battery charge current is: ICHG = (IPROG ) • 50,000 = VPROG • 50,000 RPROG where VPROG is the PROG pin voltage and RPROG is the total resistance from the PROG pin to ground. Keep in mind that when the LTC4085 is powered from the IN pin, the programmed input current limit takes precedent over the charge current. In such a scenario, the charge current cannot exceed the programmed input current limit.
PAGE 18
LTC4085-3/LTC4085-4 OPERATION For example, if the full charge current is programmed to 500mA with a 100k PROG resistor the CHRG pin will change state at a battery charge current of 50mA. when VOUT falls to approximately 4.2V. The LTC4085-4 does not include this Undervoltage Current Limit feature. Note: The end-of-charge (EOC) comparator that monitors the charge current latches its decision.
PAGE 19
LTC4085-3/LTC4085-4 APPLICATIONS INFORMATION VNTC LTC4085-3/ LTC4085-4 9 RNOM 10k NTC t 7NTC – TOO_COLD VNTC LTC4085-3/ LTC4085-4 9 t 7NTC RNOM 124k NTC – TOO_COLD 8 + 8 + RNTC 10k – R1 24.3k – TOO_HOT t 7NTC TOO_HOT t 7NTC + RNTC 100k + + + NTC_ENABLE 0.1V NTC_ENABLE – 0.1V – 408534 F04a 408534 F04b (4a) (4b) Figure 4.
PAGE 20
LTC4085-3/LTC4085-4 APPLICATIONS INFORMATION The nearest 1% value for RNOM is 115k. This is the value used to bias the NTC thermistor to get cold and hot trip points of approximately 0°C and 39°C, respectively. To extend the delta between the cold and hot trip points, a resistor (R1) can be added in series with RNTC (see Figure 4). The values of the resistors are calculated as follows: RNOM = RCOLD – RHOT 2.816 – 0.484 0.484 ⎡ ⎤ R1= ⎢ ⎥ • [RCOLD – RHOT ] – RHOT ⎣ 2.816 – 0.
PAGE 21
LTC4085-3/LTC4085-4 APPLICATIONS INFORMATION Where, PD is the power dissipated, VOUT is the supply voltage, VBAT is the battery voltage, and IBAT is the battery charge current. It is not necessary to perform any worstcase power dissipation scenarios because the LTC4085 will automatically reduce the charge current to maintain the die temperature at approximately 105°C.
PAGE 22
LTC4085-3/LTC4085-4 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. DE Package 14-Lead Plastic DFN (4mm × 3mm) (Reference LTC DWG # 05-08-1708 Rev B) 0.70 0.05 3.30 0.05 3.60 0.05 2.20 0.05 1.70 0.05 PACKAGE OUTLINE 0.25 0.05 0.50 BSC 3.00 REF RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED R = 0.115 TYP 4.00 0.10 (2 SIDES) R = 0.05 TYP 3.00 0.10 (2 SIDES) 8 0.40 0.10 14 3.30 0.
PAGE 23
LTC4085-3/LTC4085-4 REVISION HISTORY REV DATE A 4/10 B 5/12 DESCRIPTION PAGE NUMBER Updated Block Diagram Added new part number LTC4085-4 10 throughout Added feature bullet for LTC4085-3 version 1 Added table of product options 2 Enhanced Note 5 to add testing conditions 4 Enhanced Charger Undervoltage Lockout section for LTC4085-3 version 18 408534fb Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
PAGE 24
LTC4085-3/LTC4085-4 TYPICAL APPLICATION USB Power Control Application with Wall Adapter Input 5V WALL ADAPTER INPUT 4.7μF 1k 510Ω TO LDOs REGs, ETC 4.7μF 510Ω 1Ω* OUT 5V (NOM) FROM USB CABLE VBUS IN 4.7μF CHRG GATE ACPR 1Ω* WALL BAT VNTC LTC4085-3/ LTC4085-4 RNTCBIAS 10k + Li-Ion CELL NTC SUSPEND USB POWER SUSP 500mA/100mA SELECT HPWR PROG *SERIES 1Ω RESISTOR ONLY NEEDED FOR INDUCTIVE INPUT SUPPLIES RNTC 10k CLPROG RPROG 71.5k TIMER GND 0.15μF RCLPROG 2.