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LTC4090/LTC4090-5

4090fc

FEATURES

APPLICATIONS

DESCRIPTION

USB Power Manager with

2A High Voltage Bat-Track

Buck Regulator

The LTC

4090/LTC4090-5 are USB power managers plus

high voltage Li-Ion/Polymer battery chargers. The devices

control the total current used by the USB peripheral for

operation and battery charging. Battery charge current is

automatically reduced such that the sum of the load current

and the charge current does not exceed the programmed

input current limit. The LTC4090/LTC4090-5 also accom-

modate high voltage power supplies, such as 12V AC/DC

wall adapters, Firewire, or automotive power.

The LTC4090 provides a Bat-Track adaptive output that

tracks the battery voltage for high efﬁ ciency charging from

the high voltage input. The LTC4090-5 provides a ﬁ xed 5V

output from the high voltage input to charge single-cell

Li-Ion batteries. The charge current is programmable and an

end-of-charge status output (CHRG) indicates full charge.

Also featured are programmable total charge time, an NTC

thermistor input used to monitor battery temperature while

charging and automatic recharging of the battery.

Seamless Transition Between Power Sources:

Li-Ion Battery, USB, and 6V to 36V Supply (60V Max)

2A Output High Voltage Buck Regulator with

Bat-Track™ Adaptive Output Control (LTC4090)

Internal 215mΩ Ideal Diode Plus Optional External

Ideal Diode Controller Provides Low Loss Power

Path When External Supply/ USB Not Present

Load Dependent Charging from USB Input

Guarantees Current Compliance

Full Featured Li-Ion Battery Charger

1.5A Maximum Charge Current with Thermal Limiting

NTC Thermistor Input for Temperature Qualiﬁ ed

Charging

Tiny (3mm × 6mm × 0.75mm) 22-Pin DFN Package

HDD-Based Media Players

Personal Navigation Devices

Other USB-Based Handheld Products

Automotive Accessories

HVIN

BOOST

4.7μF

22μF

4.7μF

1μF

TIMER

CLPROG

LTC4090

GND PROG

HVOUT

HVPR

OUT

BAT

0.1μF

270pF

100k2k

5V WALL

ADAPTER

USB

HIGH (7.5V-36V)

VOLTAGE INPUT

59k

40.2k

Li-Ion BATTERY

LOAD

4090 TAO1

OUT

(TYP)

BAT

+ 0.3V

BAT

AVAILABLE INPUT

HV INPUT (LTC4090)

HV INPUT (LTC4090-5)

USB ONLY

BAT ONLY

6.8μH

0.47μF

LTC4090/LTC4090-5 High Voltage

Battery Charger Efﬁ ciency

BAT

(V)

2.0

EFFICIENCY (%)

4.0

4090 TA01b

2.5

3.0

3.5

4.5

FIGURE 12 SCHEMATIC

WITH R

PROG

= 52k

NO OUTPUT LOAD

HVIN = 8V

HVIN = 12V

HVIN = 24V

HVIN = 36V

LTC4090

LTC4090-5

TYPICAL APPLICATION

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Bat-Track is

a trademark of Linear Technology Corporation. All other trademarks are the property of their

respective owners.

Summary of content (28 pages)

PAGE 1
LTC4090/LTC4090-5 USB Power Manager with 2A High Voltage Bat-Track Buck Regulator DESCRIPTION FEATURES n n n n n n n n The LTC®4090/LTC4090-5 are USB power managers plus high voltage Li-Ion/Polymer battery chargers. The devices control the total current used by the USB peripheral for operation and battery charging. Battery charge current is automatically reduced such that the sum of the load current and the charge current does not exceed the programmed input current limit.
PAGE 2
LTC4090/LTC4090-5 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Notes 1, 2, 3, 4) HVIN, HVEN (Note 9) ................................................60V BOOST ......................................................................56V BOOST above SW .....................................................30V PG, SYNC ..................................................................30V IN, OUT, HVOUT t < 1ms and Duty Cycle < 1% .................. –0.3V to 7V Steady State........................................
PAGE 3
LTC4090/LTC4090-5 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. HVIN = HVEN = 12V, BOOST = 17V, VIN = HPWR = 5V, VBAT = 3.7V, RPROG = 100k, RCLPROG = 2k and SUSP = 0V, unless otherwise noted.
PAGE 4
LTC4090/LTC4090-5 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. HVIN = HVEN = 12V, BOOST = 17V, VIN = HPWR = 5V, VBAT = 3.7V, RPROG = 100k, RCLPROG = 2k and SUSP = 0V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN tTIMER TIMER Accuracy VBAT = 4.3V –10 Recharge Time Percent of Total Charge Time 50 % Low Battery Trickle Charge Time Percent of Total Charge Time, VBAT <2.
PAGE 5
LTC4090/LTC4090-5 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. HVIN = HVEN = 12V, BOOST = 17V, VIN = HPWR = 5V, VBAT = 3.7V, RPROG = 100k, RCLPROG = 2k and SUSP = 0V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX 1.4 2.5 3.5 4.4 4.85 UNITS IVNTC VNTC Pin Current VNTC = 2.
PAGE 6
LTC4090/LTC4090-5 TYPICAL PERFORMANCE CHARACTERISTICS Charging from USB, IBAT vs VBAT 600 600 VIN = 5V VOUT = NO LOAD 500 RPROG = 100k RCLPROG = 2k HPWR = 5V VBAT = 3.7V 900 VIN = 0V 800 700 300 200 IOUT (mA) 400 IBAT (mA) IBAT (mA) 1000 500 400 300 200 0 0 0.5 1 1.5 2 2.5 VBAT (V) 3 3.5 4 4.5 100 2000 –50°C 0°C 50°C 100°C 60 40 VFWD (mV) 80 90 90 85 85 75 70 100 0 0.2 0.6 0.4 IOUT (A) MINIMUM IOUT (A) 2.0 1.8 5 10 15 20 25 HVIN (V) 30 35 4090 G10 0.
PAGE 7
LTC4090/LTC4090-5 TYPICAL PERFORMANCE CHARACTERISTICS High Voltage Regulator Switch Frequency High Voltage Regulator Frequency Foldback High Voltage Regulator Soft-Start 1000 1100 4.0 900 900 800 700 600 3.5 800 SWITCH CURRENT LIMIT (A) SWITCHING FREQUENCY (kHz) FREQUENCY (kHz) 1000 700 600 500 400 300 200 0 0 0 25 50 75 100 125 150 TEMPERATURE (°C) 1 2 3 HVOUT (V) High Voltage Regulator Switch Current Limit 2.5 2.0 1.5 1.0 DUTY CYCLE = 10 % 6.5 3.5 3.0 DUTY CYCLE = 90 % 2.5 2.
PAGE 8
LTC4090/LTC4090-5 TYPICAL PERFORMANCE CHARACTERISTICS LTC4090 Input Connect Waveforms LTC4090 Input Disconnect Waveforms LTC4090 Response to Suspend VIN 5V/DIV VIN 5V/DIV SUSP 5V/DIV VOUT 5V/DIV IIN 0.5A/DIV VOUT 5V/DIV IIN 0.5A/DIV VOUT 5V/DIV IIN 0.5A/DIV IBAT 0.5A/DIV IBAT 0.5A/DIV IBAT 0.5A/DIV 1ms/DIV VBAT = 3.
PAGE 9
LTC4090/LTC4090-5 PIN FUNCTIONS SYNC (Pin 1): External Clock Synchronization Input. See synchronizing section in the Applications Information section. Ground pin when not used. PG (Pin 2): Open Collector Output of an Internal Comparator. PG remains low until the HVOUT pin is above 2.8V. PG output is valid when HVIN is above 3.6V and HVEN is high. RT (Pin 3): Oscillator Resistor Input. Connecting a resistor to ground from this pin sets the switching frequency.
PAGE 10
LTC4090/LTC4090-5 PIN FUNCTIONS CLPROG (Pin 14): Current Limit Program and Input Current Monitor. Connecting a resistor, RCLPROG, to ground programs the input to output current limit. The current limit is programmed as follows: ICL (A) = 1000V RCLPROG In USB applications, the resistor RCLPROG should be set to no less than 2.1k. The voltage on the CLPROG pin is always proportional to the current ﬂowing through the IN to OUT power path.
PAGE 11
LTC4090/LTC4090-5 BLOCK DIAGRAM C2 BOOST HVIN INTERNAL REFERENCE D1 + HVEN + IL – SOFT-START R S – 10 RT1 10 10 RC RT Q Q DRIVER OSCILLATOR 200kHz - 2.4MHz SYNC HVOUT – VC GM CF C1 VSET 3.6V (LTC4090) 5V (LTC4090-5) + + – VC CLAMP CC 10 + – PG 22 75mV (RISING) 25mV (FALLING) + + 2.8V IIN 1000 CLPROG HVPR 4.25V (RISING) 3.
PAGE 12
LTC4090/LTC4090-5 OPERATION Introduction the ideal diode instead of connecting the load directly to the battery allows a fully charged battery to remain fully charged until external power is removed. Once external power is removed the output drops until the ideal diode is forward biased. The forward biased ideal diode will then provide the output power to the load from the battery. The LTC4090/LTC4090-5 are complete PowerPath™ controllers for battery powered USB applications.
PAGE 13
LTC4090/LTC4090-5 OPERATION USB Input Current Limit The input current limit and charge control circuits of the LTC4090/LTC4090-5 are designed to limit input current as well as control battery charge current as a function of IOUT. OUT drives the external load and the battery charger. If the combined load at OUT does not exceed the programmed input current limit, OUT will be connected to IN through an internal 215mΩ P-channel MOSFET.
PAGE 14
LTC4090/LTC4090-5 OPERATION IIN 500 IIN 100 500 IIN 400 ILOAD 300 200 100 ILOAD 60 40 IBAT (CHARGING) (CHARGING) 4090 F02a 100 200 300 400 500 IBAT ILOAD(mA) (IDEAL DIODE) (a) High Power Mode/Full Charge RPROG = 100k and RCLPROG = 2k IBAT = ICHG 200 IBAT = ICL = IOUT IBAT (CHARGING) 0 0 0 ILOAD 300 100 20 IBAT 0 CURRENT (mA) 80 CURRENT (mA) CURRENT (mA) 400 0 20 40 4090 F02b 60 100 IBAT ILOAD(mA) (IDEAL DIODE) 0 80 4090 F02c (b) Low Power Mode/Full Charge RPROG = 10
PAGE 15
LTC4090/LTC4090-5 OPERATION Suspend Mode Battery Charger trickle charge mode to bring the cell voltage up to a safe level for charging. The charger goes into the fast charge constant-current mode once the voltage on the BAT pin rises above 2.9V. In constant-current mode, the charge current is set by RPROG. When the battery approaches the ﬁnal ﬂoat voltage, the charge current begins to decrease as the LTC4090/LTC4090-5 switch to constant-voltage mode.
PAGE 16
LTC4090/LTC4090-5 OPERATION 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 LTC4090/LTC4090-5 are powered from the IN pin, the programmed input current limit takes precedence over the charge current. In such a scenario, the charge current cannot exceed the programmed input current limit.
PAGE 17
LTC4090/LTC4090-5 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. Note: The end-of-charge (EOC) comparator that monitors the charge current latches its decision. Therefore, the ﬁrst time the charge current drops below 10% of the programmed full charge current while in constant-voltage mode, it will toggle CHRG to a high impedance state.
PAGE 18
LTC4090/LTC4090-5 APPLICATIONS INFORMATION USB and 5V Wall Adapter Power Although the LTC4090/LTC4090-5 are designed to draw power from a USB port, a higher power 5V wall adapter can also be used to power the application and charge the battery (higher voltage wall adapters can be connected directly to HVIN). Figure 4 shows an example of combining a 5V wall adapter and a USB power input.
PAGE 19
LTC4090/LTC4090-5 APPLICATIONS INFORMATION minimum switch-off time (~150ns). These equations show that duty cycle range increases when switching frequency is decreased. A good choice of switching frequency should allow adequate input voltage range (see next section) and keep the inductor and capacitor values small.
PAGE 20
LTC4090/LTC4090-5 APPLICATIONS INFORMATION Catch Diode The catch diode conducts current only during switch-off time. Average forward current in normal operation can be calculated from: ID(AVG) =IHVOUT • ( VHVIN – VHVOUT ) VHVIN where IHVOUT is the output load current. The only reason to consider a diode with a larger current rating than necessary for nominal operation is for the worst-case condition of shorted output. The diode current will then increase to the typical peak switch current.
PAGE 21
LTC4090/LTC4090-5 APPLICATIONS INFORMATION High Voltage Regulator Frequency Compensation The LTC4090/LTC4090-5 high voltage regulator uses current mode control to regulate the output. This simpliﬁes loop compensation. In particular, the high voltage regulator does not require the ESR of the output capacitor for stability, so you are free to use ceramic capacitors to achieve low output ripple and small circuit size.
PAGE 22
LTC4090/LTC4090-5 APPLICATIONS INFORMATION If low quiescent current is not required, the LTC4090/ LTC4090-5 can operate in pulse-skipping mode. The beneﬁt of this mode is that the LTC4090/LTC4090-5 will enter full frequency standard PWM operation at a lower output load current than when in Burst Mode operation. The front page application circuit will switch at full frequency at output loads higher than about 60mA.
PAGE 23
LTC4090/LTC4090-5 APPLICATIONS INFORMATION designed to work with thermistors whose resistance-temperature characteristics follow Vishay Dale’s R-T curve 2. The Vishay NTHS0603N02N1002J is an example of such a thermistor. However, Vishay Dale has many thermistor products that follow the R-T curve 2 characteristic in a variety of sizes. Furthermore, any thermistor whose ratio of rCOLD to rHOT is about 7.0 will also work (Vishay Dale R-T curve 2 shows a ratio of 2.815/0.409 = 6.89).
PAGE 24
LTC4090/LTC4090-5 APPLICATIONS INFORMATION equations can be used to easily calculate a new value for the bias resistor: rHOT •R 0.409 25C r RNOM = COLD • R25C 2.815 RNOM = where rHOT and rCOLD are the resistance ratios at the desired hot and cold trip points. Note that these equations are linked. Therefore, only one of the two trip points can be chosen, the other is determined by the default ratios designed in the IC. Consider an example where a 40°C hot trip point is desired.
PAGE 25
LTC4090/LTC4090-5 APPLICATIONS INFORMATION be estimated by calculating the regulator power loss from an efﬁciency measurement, and subtracting the catch diode loss. ⎛ 5V ⎞ PD = (1– η) • 5V • (IBAT +IOUT ) – VD • ⎜ 1– • ⎝ VHVIN ⎟⎠ ( ) (IBAT +IOUT ) + (5V – VBAT ) •IBAT The difference between this equation and that for the LTC4090 is the last term, which represents the power dissipation in the battery charger. For a typical application, an example of this calculation would be: 5V ⎞ ⎛ • PD = (1– 0.
PAGE 26
LTC4090/LTC4090-5 APPLICATIONS INFORMATION IN and HVIN Bypass Capacitor Battery Charger Stability Considerations 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 from connecting the charger input to a hot power source.
PAGE 27
LTC4090/LTC4090-5 PACKAGE DESCRIPTION DJC Package 22-Lead Plastic DFN (6mm × 3mm) (Reference LTC DWG # 05-08-1714) 0.889 0.70 ±0.05 R = 0.10 0.889 3.60 ±0.05 1.65 ±0.05 2.20 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 5.35 ± 0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 3. DRAWING IS NOT TO SCALE 6.00 ±0.10 (2 SIDES) 0.889 R = 0.10 TYP 3.00 ±0.10 (2 SIDES) R = 0.115 TYP 0.40 ± 0.
PAGE 28
LTC4090/LTC4090-5 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1733 Monolithic Lithium-Ion Linear Battery Charger Standalone Charger with Programmable Timer, Up to 1.5A Charge Current LTC1734 Lithium-Ion Linear Battery Charger in ThinSOT™ Simple ThinSOT Charger, No Blocking Diode, No Sense Resistor Needed LTC4002 Switch Mode Lithium-Ion Battery Charger Standalone, 4.