ADAPTIVE VOLTAGE AND CURRENT SLEW RATE CONTROL
An adaptive SiC MOSFET current source gate driver
This paper presents a novel current source gate driver for SiC MOSFETs with adaptive functionalities that aims to improve controllability of turn-on/off delays, di/dt and dv/dt compared to conventional totem-pole voltage source gate drivers.
A gate driver which can regulate di/dt, dv/dt and turn-on/off delay times can be highly beneficial, and even adapt the system characteristics to changing applications or environment without doing changes to the hardware.
The current source driver works by injecting/extracting charge to/from the gate in two intervals by charging three different inductors. The first interval controls the turn-on/off delay as well as the di/dt, while the second interval controls the dv/dt. By charging the inductors to predefined values, accurate values of gate current can be injected/extracted from the gate at time intervals with approximately 5ns resolution. The driver can further be adopted into a closed loop scheme. The di/dt and dv/dt are measured, compared to a variable set point value, and the current values calculated and adjusted to accommodate the set point values. This whitepaper explains:
- The advantages of Silicon Carbide MOSFETs and the challenges imposed by the high achievable di/dt and dv/dt,
- A way to deal with the challenges by deploying an adaptive current source gate driver, and
- A compressed description of how the proposed gate driver works.
First publication of the paper at PCIM Europe Digital Days 2021.
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