Designers of modern electric vehicles try to reduce the size of the low-voltage (LV) batteries or remove them completely to save weight and cost. Power converters like the 3.6kW HV to LV DCDC converter are needed for buffering and charging the LV batteries. For states where the car is not required to be fully operational, such as sentry mode, smaller converters, so called mini- and µDCDCs, can do the job while being more efficient as smaller power levels are required. There are a several topologies to select from for the different power ranges, but at this time there are not too many suitable automotive qualified control ICs on the market for the 300W range. This presentation will look at the potential candidates and highlight their advantages and disadvantages (including AEC qualification). A second important point is output voltage regulation and accuracy in isolated, automotive power converters. Opto-couplers are typically avoided due to reliability concerns, and the other two options until now are either inaccurate or not very cost-effective for a 300W converter. The presentation introduces the opto-emulator device and demonstrates how it can be paired with a low-standby power controller. The presentation concludes with test results from a reference design.
