SLUP412 February 2022 LMG3522R030-Q1
The first generations of onboard chargers (OBCs) leveraged insulated gate bipolar transistors (IGBTs) and were huge and bulky. Figure 1-1 illustrates the improvement in solution size with better technologies and thermal concepts.
GaN’s ultra-fast switching slew rates and liquid-cooled thermal interface yield a 22% reduction in size (area: 38,171 mm2)  compared to the convection-cooled SiC-based DC/DC and power factor correction (PFC) reference designs on the left  and right  inside the light-blue frame in Figure 1-1, respectively. Texas Instruments (TI) had designed these latter two reference designs (area: 27,886 mm2 + 20,915 mm2) three years earlier than the reference design in the green frame. This topic explains the design process behind the GaN-based reference design in the green frame.