Abstract

Bidirectional buck-boost converters are used in applications such as electric vehicles DC-DC converters at high power and output current levels (>200A load). These multi-phase DC-DC converters are common in the 48V to 12V power systems found in mild hybrid automotive applications. These designs are typically multi-phase systems with the ability to enable and disable phases to optimize efficiency in different operating modes of the controller. These different operating modes pose unique operating conditions for the gate drivers that the designer needs to be aware of. The 100V half-bridge gate drivers are used in various high power, high power density applications with a 48V bus. These drivers are commonly used in the bidirectional DC-DC power systems and are the focus of this application note. This paper cover unique operational challenges with respect to driver bootstrap bias operation for gate drivers in the multi-phase buck-boost power systems used in automotive as well as grid power systems.