Other Parts Discussed in Thread: TINA-TI, , LMG1205, LM5113
Tool/software: TINA-TI or Spice Models
Dear community,
I am willing to use the LMG5200 half bridge IC with integrated GaN-FET drivers in a buck converter setup. Therefore, I have simulated the circuit in PSpice with the available simulation model of the LMG5200 and I came across a circuit behavior I did not expect. When the HS-FET turns on after the adjusted dead time (10 ns), an unintended turn-on of the LS-FET occurs, which leads to a shoot trough from V_IN to GND. The attached picture shows the voltage of the switch node voltage V(U1:SW) in the upper graph, and the two currents I(U1:VIN) and I(U1:PGND) in the lower graph present the current flowing through the HS-FET and LS-FET, respectively. Note that I(U1:PGND) is the current flowing from source to drain of the LS-FET and that the current spikes are clipped in the picture (the current peaks up to 35 A in the HS-FET).
Is this just a problem with the simulation model or is there no internal circuitry in the device that prevents the LS-FET from turning on during the rising transition of the switch node voltage? I assumed that the internal driver behaves like the LMG1205 GaN-FET driver (or similar) which is explicitly capable of preventing unintended turn-on.
Best regards,
Maximilian Grams