I'm attempting to design an ideal diode capable of operating with an input from 16V to 40V, and driving up to 25A of current. The design utilizes Infineon's IAUT300N08S5N012, which should be overkill for the voltage and current requirements. I attempted to simulate the LTC4357 with this model from digikey. It works as expected when the input voltage is positive - 40V at the input yields 76mV across the FET with a 25A load. However, when the input voltage is a negative polarity, I see a negative current across the load.
I know that this controller is intended to function by turning the FET off when the virtual anode is at a lower voltage than the virtual cathode, and as a result, I'm beginning to trust the integrity of the model. A test bench was included with the model, and altering this test bench for a negative polarity input voltage yielded the same negative current. Has anyone tried to use the model in this way? Is there something I've overlooked, perhaps in the way I've set up the circuit?
Thanks for any assistance,
Hello Josh, By itself, the LTC4357 is not designed to work with negative (or reverse) inputs. See "-48V Reverse Input Protection" circuit on datasheet page 10 or check out the LTC4359.
Thanks for the assistance! I actually discovered that and the model is working correctly, it was my mistake. Thanks!