Highly integrated 36V step-down battery charger with seamless backup power

Linear Technology Corporation, a subsidiary of Analog Devices, Inc. (ADI), introduced a complete lithium-ion battery backup management system, the LTC4091, for power rails from 3.45V to 4.45V. Must remain active when the main power supply fails for a long time. When external power is available, the device delivers up to 2.5A of total output current and delivers up to 1.5A of charge current to a single 4.1V or 4.2V Li-Ion battery. If the main input supply fails and does not power the load, the LTC4091 provides up to 4A from the backup lithium battery to the system output load through an internal ideal diode, providing unrestricted current if an external ideal diode transistor is used. To protect sensitive downstream loads, the maximum output load voltage is 4.45V. In the event of a power failure, the device's PowerPathTM control provides seamless switching between input and backup supplies and reverse isolation in the event of an input short.

The LTC4091 includes 60V absolute maximum input overvoltage protection, which allows the IC to withstand high input voltage transients.

The LTC4091 is available in a low profile (0.75mm) 22-pin 3mm x 6mm DFN package with a back metal pad for superior thermal performance. The E and I versions of the device operate over the –40°C to 125°C temperature range.

Performance Summary: LTC4091

Seamless conversion between main power and lithium-ion batteries

75mΩ internal ideal diode and optional external ideal diode controller provide low loss PowerPathTM when not connected to mains

Wide input voltage range: 6V to 36V (60V absolute maximum)

4.45V maximum output voltage

Full-featured lithium-ion battery charger

Pin selectable 4.1V and 4.2V charging voltage options

Thermally Enhanced, Flat (0.75mm) 3mm x 6mm 22-Pin DFN Package

Relevant LTC409 series products

Author：Brittany Antonia （The author of article owns the copyright.）