1.7 A simple, robust, and low-EMI solution for inverter gate-driver bias supplies
Isolated gate-driver bias supplies are widely used in the traction inverter, on board charger, UPS, and solar inverters. A simple, robust design is required since it is a supporting component of the overall system. The use of wide bandgap devices such as SiC or GaN MOSFET in the inverters, demands higher switching speed. Therefore, it is critical to minimize the EMI noise coupling through the gate-driver bias supply transformers.
In this video, a simple 8-pin open loop LLC transformer driver UCC25800-Q1 is introduced. With the use of LLC resonant topology, the UCC25800-Q1 allows the designer to use an isolation transformer with larger leakage inductance but minimum primary side to secondary side parasitic capacitor. This small parasitic capacitance reduces the common mode noise coupling from the inverter switch node. Besides, due to the soft switching and sinusoidal current, the LLC converter inherently provides less EMI noise. Together with the open loop control, UCC25800-Q1 provides a simple, robust, and low-EMI solution for the inverter gate driver bias supplies.
The training session covers the basic inverter gate driver bias architectures, different gate driver bias supply topology comparisons, introduction of the open loop LLC converter and its variations, the UCC25800-Q1 introduction, as well as the EMI performance analysis.