Analog Devices has announced the LT8708/-1, a 98% efficient bidirectional buck-boost switching regulator slave controller for the LT8708 that operates between two batteries or chemistries that have the same voltage; this is ideal for redundancy, especially in self-driving cars.
A 4-phase 48V to 12V Bi-directional dual battery system using Forward Hybrid Conduction Mode (FHCM) and Reverse Hybrid Conduction Mode (RHCM) (Source: Analog Devices)
This regulator operates from an input voltage that can be above, below or equal to the output voltage, making it perfect for two-each 12V, 24V or 48V batteries commonly found in electric and hybrid vehicles. It operates between two batteries and prevents system shut-down should one of the batteries fail. The regulator can also be used in 48V/12V and 48V/24V dual battery systems.
This power IC operates with just a single inductor over a 2.8V to 80V input voltage range and can produce an output voltage from 1.3V to 80V, delivering up to several kilowatts of power depending on the choice of external components and number of phases. This device greatly simplifies bidirectional power conversion in battery/supercapacitor backup systems that need regulation of VOUT , VIN , and/or IOUT , IIN, both in the forward or reverse direction.
This device’s six independent forms of regulation allow it to be used in many different applications as well.
The LT8708/-1 can be placed in parallel with the LT8708 to add power and phases. The device always operates as a slave to the master LT8708, can be clocked out-of-phase and has the capability to deliver as much power as the master. One or more slaves can be connected to a single master, proportionally increasing power and current capability of the system.
An additional application is for an input voltage to power a load, where this same input voltage is used to power a LT8708/-1 circuit that charges a battery or bank of supercapacitors. When the input voltage goes away, the load maintains power without disruption from the battery or supercaps by way of the LT8708’s bidirectional capability.
>> Read the full article on our sister site, EDN: “Redundancy design solution for battery systems in autonomous vehicles.”