Gate Drivers Engineered for New Era in Power Electronics

Change never comes easy in the world of power electronics.

To achieve higher power densities, the latest 3.3 kW switched-mode power supplies (SMPS) are adopting silicon-carbide (SiC) power MOSFETs in the totem-pole PFC stage and gallium-nitride (GaN) power switches in high-voltage DC-DC converter stages. While silicon MOSFETs and IGBTs are always improving, these new semiconductor materials are upping the ante. That’s largely thanks to their ability to manipulate more power at higher voltages and currents than silicon while losing less to heat.

These new switching technologies bring to the table fast switching speeds and other unique properties that lend themselves to use in EV traction inverters and DC-DC converters, uninterruptible power supplies (UPS) in data centers, industrial motor drives, and solar and other types of inverters for renewable-powered grids.

To bring the best out of SiC and GaN power devices, you need to carefully control and drive them. Digital control of both the power-factor-correction (PFC) and DC-DC stages is critical to improving power efficiency and robustness, as is the use of optimal gate-driver ICs.

To that end, semiconductor firms are rolling out more optimized isolated gate-driver ICs that can better manage the pros and cons of SiC and GaN power switches and even the latest silicon or superjunction (SJ) MOSFETs and IGBTs.

Choosing the right gate driver is critical because of the role it plays in power electronics. They act as the (usually isolated) interface between the microcontroller (MCU) or analog controllers—which pump out the pulse-width-modulation (PWM) signals to control a power supply’s duty cycle, frequency, dead time, and phase-shift—and the power MOSFET. It’s standard practice to put the MCU on the low-voltage side of a power supply so that it stays away from the noise and transient voltages that the FETs experience.

The gate driver must supply sufficient current to turn the FET on and off as fast as possible. Doing so shortens the dead time between the on and off phases and reduces power losses that can add up in the interim.

As the demands for gate drivers change rapidly in the era of SiC and GaN, semiconductor firms are rising to the challenge. They’re developing gate-driver ICs with higher sink and source currents, faster propagation delay, and more robust galvanic isolation that can fit into smaller form factors. In this product roundup, we review some of the latest gate driver ICs to hit the market.