using 1EDN8550B Gate Driver to IRL7486MTRPbF MOSFET

[tejesh]

I would like to use the mentioned Gate-Driver and MOSFET for the Double Pulse Test using a Function generator. As I am designing it for the first time, I have a lot of questions.

1. How to design the First pulse and second pulse for the 300A pulsed for appx. in Pico seconds drain current?

2. Where will I get the component design formulas for MOSFET to choose the right components, for eg. Source Gate Resistor, Sink Gate Resistor, Bootstrap: Diode, Resistor, and Capacitor, etc?

[Shivam_P · Accepted solution]

Hello @tejesh ,

1. The pulse timings in Pico seconds may be too short to turn ON/OFF the MOSFET. Hence suggest you to apply the pulses in us (microseconds) range. Also, sometimes the load inductor limits the di/dt, Hence, the key considerations for the selection of this inductor include:
• It should not saturate at the peak test currents.
• It should limit the di/dt so that the switching times (pulses) should be applied ensuring the devices have fully
turned on or off. 
• The di/dt should not be so low that the switching times are longer than 200 µS so as not to cause the DC bus voltage to dip by more than ≈5 percent, and so change the switching performance. In addition, if the current pulse is long, then the chip temperature can increase by more than a few °C, again affecting the switching performance.
• The inductor should be mounted well away from the test setup to prevent EMI interference or magnetic field coupling into any gate drive circuits or instrumentation.

While selection of pulse duration, remember that the current will linearly rise via the inductor when the DUT (Device under test) is turned ON and it will be discharged (freewheel) through the diode/body diode (depending upon the topology), during the inductor charging and discharging period, based on the test conditions of Vds, Id and the inductance value you can select the pulse durations considering the equation: V= L*(di/dt) ensuring the MOSFET is fully turned ON (Gate pulse should be pulled low only after fully turning ON the MOSFET). Before applying the next pulse make sure that the MOSFET is fully turned OFF.

Ref- (https://www.infineon.com/dgdl/Infineon-Double_pulse_testing-Bodos_power_systems-Article-v01_00-EN.pd... )

2. For the guidelines related to bootstrap circuit design, you can refer the below mentioned documents-

• https://www.infineon.com/dgdl/Infineon-Bootstrap_Network_Analysis-ApplicationNotes-v01_00-EN.pdf?fil...
• https://www.infineon.com/dgdl/Infineon-HV_Floating_MOS_Gate_Drivers-ApplicationNotes-v01_00-EN.pdf?f... (pg-6)

BR

Shivam