Suitable for EV, HEV 12V, 24V, 48V Batteries
Forward and Reverse Current Monitoring Capable
Analog Devices announced on the 18th the launch of new bidirectional buck-boost switching regulator controller products, the LT8708 and LT8708-1, featuring 98% efficiency and optimized for redundant battery applications in autonomous vehicles, operating between two batteries with identical voltage.

Both the LT8708 and LT8708-1 can operate when input voltage is equal to, higher than, or lower than output voltage, making them suitable for 12V, 24V, or 48V batteries commonly used in electric vehicles (EV) and hybrid vehicles (HEV). The new products operate between two batteries, and even if one of the batteries fails, they prevent the system from shutting down. Additionally, the LT8708/-1 can be used in 48V/12V combinations or 48V/24V dual battery systems.

The LT8708/-1 uses a single inductor in the 2.8V~80V input voltage range to generate output from 1.3V~80V, and can deliver several kilowatts (kW) of power depending on which external components are used or how many phases are employed. The new products simplify bidirectional power conversion for battery/capacitor backup systems requiring control of VOUT, VIN, IOUT, and IIN in both forward and reverse directions. Since this product supports six independent control methods, it can be used in various applications.

The LT8708/-1 is used together with the LT8708 for adding power and phases. The LT8708-1 operates as a slave to the master LT8708, operating with a clock having a set out-of-phase offset, capable of delivering power equivalent to the master device. One or more slaves can be connected to a single master, and the system's power and current capacity increase proportionally to the number of slaves connected.

Another application includes an input source for supplying power to a load. In this case, the same input voltage is used in the LT8708/-1 circuit charging a bank of batteries or supercapacitors. Even if input voltage is removed, power supply to the load is maintained through the LT8708's bidirectional capability regardless of battery or supercapacitor status.

Forward and reverse currents can be monitored and limited at the input and output stages of this converter. All four current limits (forward input, reverse input, forward output, reverse output) can be individually set using four resistors. When used with the DIR (direction setting) pin, this chip can be configured to supply power from VOUT to VIN or from VIN to VOUT, making it ideal for automotive, solar, telecom, and battery power systems.

The LT8708 is supplied in a 5mm x 8mm QFN-40 package. Three grades of products are offered by operating temperature range, with extended and industrial grade operating temperature ranges of –40~125°C, and high-temperature automotive grade of –40~150°C.