LTC4091

1

4091fa

For more information www.linear.com/LTC4091

FEATURES

APPLICATIONS

DESCRIPTION

36V Battery Charger and

Power Backup Manager

The LTC®4091 is a 36V Li-Ion battery charger and power

backup manager. The integrated step-down switching

regulator charges a battery from a primary power source

while providing power to the load. If primary power is lost,

the load is seamlessly transitioned to the backup Li-ion/

polymer battery. To protect sensitive downstream loads,

the maximum output voltage is 4.45V.

The LTC4091 provides an adaptive output that tracks the

battery voltage for high efficiency charging. The charge

current is programmable and an end-of-charge status

output (CHRG) indicates full charge. Also featured is a

termination timer and an NTC thermistor input used to

monitor battery temperature while charging.

During backup, an internal 75mΩ ideal diode connects the

battery to the load. An optional external ideal diode FET

driver is available to reduce the voltage drop even further.

4.1V or 4.2V battery charge voltages can be selected.

TYPICAL APPLICATION

L

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

and PowerPath and Bat-Track are trademarks of Analog Devices, Inc. All other trademarks are

the property of their respective owners.

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Fleet and Asset Tracking

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Automotive GPS Data Loggers

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Automotive Telematics Systems

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Battery Backup Systems

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Seamless Transition Between Primary Power

Source and Li-Ion Battery

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2A High Voltage Step-Down Regulator with

Adaptive Output Control

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Internal 75mΩ Ideal Diode Plus Optional External

Ideal Diode Controller Provides Low Loss

PowerPath™ When Primary Supply Not Present

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Wide Input Voltage Range: 6V to 36V (60V Abs Max)

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4.45V Max Output Voltage

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Full Featured Li-Ion Battery Charger

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Pin Selectable 4.1V and 4.2V Charge Voltage Options

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Thermally Enhanced Low Profile (0.75mm)

6mm × 3mm 22-Lead DFN Package

BOOST

SW

68µF

3.3µF

2A

MAX

4.99k

4.7µF

TIMER

LTC4091

GND

PROG

HVOUT

HVPR

OUT

BAT

0.1µF

220pF

AUTOMOTIVE

INPUT

6V TO 36V

15k

RT

40.2k

52.3k

Li-Ion BATTERY

+

LOAD

4.45V MAX

4091 TAO1a

6.8µH

0.47µF

0

0.6

1.2

1.8

2.4

3

3.6

4.2

BATTERY VOLTAGE (V)

0

0.6

1.2

1.8

2.4

3.0

3.6

4.2

4.8

4091 TA01b

OUT

I

= 1A

BAT

V

OUT

V

BAT

I

1.0

1.5

2.0

0

0.5