In the power electronics field, wide bandgap (WBG) semiconductors such as SiC (silicon carbide) and GaN (gallium nitride) are emerging as mainstream. These devices capable of high voltage and high-speed switching are rapidly spreading to electric vehicles (EVs), renewable energy inverters, and high-performance server power supplies. However, in order to operate these high-performance devices safely and efficiently, precise control different from traditional methods is required, and this is where the importance of the 'gate driver' is highlighted.

WBG semiconductors can maximize system efficiency because they can withstand high voltage and have fast switching speeds, but they are sensitive to noise and require precise operating conditions. “High-voltage devices such as GaN or SiC cannot be accurately turned on and off with only low-voltage and low-current signals from the controller,” said Noh Geun-dong, director of Novosense. “The gate driver is a key analog circuit that amplifies and converts this signal into voltage and current to suit the power device.”

The core roles of a gate driver can be summarized into three main points: First, the function of voltage-shifting the low-voltage level PWM signal output from a digital controller such as an MCU or DSP to match the threshold voltage of the device. Second, the driving function that helps to quickly turn the device on and off by providing sufficient current during switching. Third, the built-in various protection functions for system reliability.

“Recently, ‘smart gate drivers’ with various protection functions such as isolation, undervoltage lockout (UVLO), short-circuit protection, and mirror clamping are in the spotlight,” said Director Noh. “The selection is very important because the specifications of the driver vary depending on the stress hold voltage or on/off speed of the power component.” He added, citing an example of a real system design, “For SiC devices, a gate voltage of 0 V to 15 V is standard, but in some cases a negative voltage of -5 V must be applied to account for noise sensitivity, which increases the design difficulty.”

In particular, GaN devices offer faster switching characteristics and high-frequency response than SiC, but they are vulnerable to noise and difficult to secure circuit stability. Accordingly, the distance between the driver and the device, the wiring structure, and even the operating parameters must be carefully designed. Director Noh said, “Recently, products that provide GaN devices and drivers as a single chip have been released,” and “These integrated products can be expected to reduce design difficulty, clarify responsibilities between vendors, and even reduce EMI.”

The adoption of gate drivers depends on the system power capacity and protection function requirements. In small systems, a simple driving circuit can be configured using discrete TRs, resistors, diodes, etc., but in systems exceeding several hundred watts or environments requiring protection functions, the use of specialized gate driver ICs is virtually essential.

NovoSense will present its diverse range of gate drivers, including half-bridge, single-channel, isolated, and protection-enabled, in a technical webinar. In particular, he said, “We plan to focus on explaining technical points that should be taken into consideration when applying the device in a half-bridge structure that requires high-side and low-side switching, such as driver selection, setting sink/source current specifications, and package considerations.”

Finally, Director Noh emphasized, “Gate drivers are not simply switch control circuits, but technologies that determine the reliability and efficiency of the entire power system,” and “With increasing power density and protection design requirements, driver selection is not simply an option, but an essential design element.”

This webinar is expected to provide practical design insights to practitioners at a time when the transition from silicon-based power devices to high-speed, high-efficiency WBG semiconductors such as SiC and GaN is accelerating.