Figure 2-7 DC/DC Converter Block Diagram

The DC/DC converter is in charge of stepping down or up the voltage in a high voltage system. Most commonly, the converter takes the 400V or 800V from the battery and steps the converter down to 48V for low-voltage uses. Applications include the HVDC/HVDC or HVDC/LVDC converter in automotive and solar optimizer and maximum power point tracking (MPPT) in grid. There are three isolated current sensing locations. The first location, indicated by the blue box Figure 2-7, is the DC link. The best choice is to use a no gate driver present design. Accuracy in this location is not always a priority since the power coming out of the battery is measured accurately. If this is the case, it is common to have an isolated comparator such as the AMC23C12 for industrial applications and the AMC23C12-Q1 for automotive applications to sense if power is present. The second location, indicated by the red box in Figure 2-7, is the DC tank. The best choice is to use a no gate driver present design. Isolated current sensing done in this location is most commonly for over-current protection or zero cross detection. Again, TI recommends using the AMC23C12 for industrial applications and the AMC23C12-Q1 for automotive applications. The third location, indicated by the gray box in Figure 2-7, is the HV/LV DC/DC. The best choice is to use a no gate driver present design. One great resource is the AMC-AMP-50A-EVM, which is a simple design to evaluate isolated shunt current sensing for 50A applications.