A Capacitively Coupled OOK Transmitter with 4.43 dB Simulated Carrier Spectrum Peak Reduction and Enhanced CMTI for Wide-Bandgap FET Gate Driver.

This paper addresses the trade-off between electromagnetic interference (EMI) and common-mode transient immunity (CMTI) performance in capacitively isolated gate drivers for high-frequency silicon carbide (SiC) applications. Starting from the fundamental architecture of on-off keying (OOK) modulation, a novel transmitter (TX) modulator architecture is proposed. The proposed architecture employs a dynamic high-frequency carrier regulation circuit to suppress electromagnetic interference caused by the fixed carrier at the spectral source, while simultaneously utilizing a dynamic substrate regulation circuit to mitigate the impact of common-mode transient interference on the TX side, thereby enhancing the overall CMTI performance. The chip is fabricated in a 0.18-μm BCD process. Simulated carrier spectrum peak attenuation across different process-temperature corners demonstrates that the attenuation ranges from 4.43 dB to 19.621 dB across the fundamental through the third harmonic components. Under the same typical process-temperature corner, the simulated CMTI reaches 220 V/ns, which fully validates the effectiveness of the proposed architecture in both spectral peak reduction for EMI suppression and CMTI enhancement. Post-fabrication chip testing primarily focuses on output performance, with both the simulated carrier spectrum results for EMI and the CMTI being simulation-verified indicators. The measured output voltage range is 15-24 V; at a supply voltage of 15 V, the charging and discharging currents are 5 A and 4.5 A, respectively, and at 24 V, they are 5.7 A and 5.3 A, respectively.