Last revised: November 1, 2024

Reviewed by: Scott Orlosky, consulting engineer

Gate drivers are electronic circuits that apply correct power levels to metal-oxide field-effect transistors (MOSFETs) and insulated gate bipolar transistors (IGBTs). With power-MOSFETs, gate drivers can be implemented as transformers, discrete transistors, or dedicated integrated circuits (IC).

They can also be integrated within controller ICs. Partitioning the gate-drive function of controllers that use pulse width modulation (PWM) improves controller stability by eliminating the high peak currents and heat dissipation needed to drive power-MOSFETs at very high frequencies.

With IGBTs, gate drivers serve as isolation amplifiers and often provide short-circuit protection. Because of their insulated gates, IGBTs require a continuous gate circuit in order to sustain gate current.    

Types of Gate Drivers

There are four basic types of gate drivers.

• High-side gate drivers are used to drive power-MOSFETs or IGBTs that are connected to a positive supply and not ground referenced (floating).
• Conversely, low-side gate drivers are used to drive power-MOSFETs and IGBTs that are connected to a negative supply.
• Dual gate or half-bridge gate drivers have both low-side and high-side gates.
• Three-phase drivers derive their name from the fact that they are used in three-phase applications. These drivers have three independent low-side and high-side referenced output channels.

Typically, gate drivers have 1, 2, or 4 output channels. Their output voltage can be either inverted or non-inverted.   

Performance Specifications

• Output voltage
• Peak output current
• Supply voltage
• Rise time
• Fall time
• Propagation delay
• Power dissipation
• Switching frequency
• Operating temperature

Rise time is the time needed for the output voltage to increase from 10% to 90% of maximum. Conversely, fall time is the time needed for the output voltage to decrease from 90% to 10% of the maximum.

Features

• Input threshold

Consists of transistor-transistor logic (TTL), complementary metal-oxide semiconductor (CMOS), pulse width modulation, and combinations such as TTL/CMOS and TTL/PWM

• Integrated protection

Includes over-voltage protection (OVP), over-voltage protection current (OVPC), undervoltage lockout (UVLO), thermal shutdown (TSD), and over-current protection (OCP).

• Dead time control

Dead time control eliminates shoot-through currents

• Internal regulation

Controls the level of the output voltage. 

Packaging Options

• Ball-grid array (BGA)
• Chip scale package (CSP)
• Quad flat package (QFP)
• Small outline package (SOP)
• Single in-line package (SIP)
• Dual in-line package (DIP).

Fine-pitch land grid array (FLGA) and SC-70, one of the smallest IC packages, are also available. Packing methods for gate drivers include tape reels, tubes, bulk packs, and trays or rails. Screening levels such as commercial, industrial, and military indicate the supported temperature range as well as mechanical and electrical specifications. Some listed gate drivers are still in development. Others are in full production. Devices that are discontinued are no longer available from the manufacturer, but may still be found in the supply chain.  

Related Standards 

SMD 5962-99511 — Microcircuit, digital-linear, radiation hardened dual inverting MOSFET driver, monolithic silicon.

SMD 5962-01521 — Microcircuit, digital-linear, radiation hardened, 9 amp non-inverting MOSFET driver, monolithic silicon.

MIL-PRF-28776/7 — Relays, hybrid, established reliability, DPDT, low level to 1.0 ampere (sensitive coil operate power at 25 deg. c), terminal MOSFET driver with Zener diode gate protection (electromechanical output) diode coil suppression and terminals with 0.100 grid lea.

Gate Drivers FAQs

What is the role of a gate driver in power electronic systems?

Gate drivers serve as an interface between the control circuitry and the power semiconductor devices (such as MOSFETs, IGBTs, and SiC transistors) in power electronic systems. They ensure efficient and reliable operation by providing the necessary voltage and current to switch these devices on and off.

What are isolated gate drivers and why are they important?

Isolated gate drivers provide input-to-output isolation, protecting the controller and personnel from high voltages and voltage transients. They also help maintain noise-immune operation for better efficiency and can safely switch high-power devices like silicon or superjunction MOSFETs, IGBTs, and wide-bandgap switches like GaN and SiC.

What are some common applications of gate drivers?

Gate drivers are used in various applications including traction inverters, onboard chargers, solar inverters, motor drives, consumer electronics, battery chargers, computer power supplies, automobile industries, and more.

How do gate drivers contribute to the performance of electric vehicle designs?

Gate drivers are critical in electric vehicle designs for achieving high-voltage, high-current, and high-temperature performance. They help in turning on and off the transistors used in these applications, ensuring adherence to strict safety standards.

What are some design considerations for gate drivers in high-voltage systems?

For high-voltage systems, designers need to consider factors such as noise immunity, operating temperature range, and the ability to handle high common-mode transient immunity (CMTI). For instance, the UCC23513 gate driver offers a wide junction temperature range and high CMTI, making it suitable for such applications.

What are the advantages of using GaN and SiC transistors with gate drivers?

GaN and SiC transistors offer better performance in terms of high-voltage, high-current, and high-temperature capabilities compared to traditional silicon IGBTs. They also enable reduced-size, high-speed switching performance, which is beneficial for many applications.

How do integrated sensing features in gate drivers improve system reliability?

Integrated sensing features enable fast detection of overcurrent events. This rapid response protects power semiconductor devices like IGBTs and SiC MOSFETs from damage due to excessive current. By ensuring a swift system shutdown in the event of an overcurrent, these features help prevent catastrophic failures and enhance overall system reliability. 

The integration of sensing components within the gate driver simplifies the overall design of the power electronic system. This reduction in complexity not only makes the design process more straightforward but also minimizes the potential points of failure, thereby improving the reliability of the system.

Integrated sensing features contribute to maintaining noise-immune operation. High-voltage transients can disrupt the operation of power electronic systems, leading to efficiency losses and potential malfunctions. By ensuring robust noise immunity, integrated sensing features help maintain stable and efficient operation, which is critical for system reliability.

These features provide input-to-output isolation, which protects the controller and personnel from high voltages and voltage transients. This isolation is essential for the safe operation of high-power devices and contributes to the overall reliability of the system by preventing damage from electrical surges.

They also ensure that the gate driver can safely switch high-power devices, such as silicon or superjunction MOSFETs, IGBTs, and wide-bandgap switches like GaN and SiC. This capability is vital for maintaining the safety and reliability of systems that operate at high voltages and currents.

In summary, integrated sensing features in gate drivers enhance system reliability by providing fast protection against overcurrent events, simplifying design, improving noise immunity, protecting against high-voltage transients, and ensuring safe operation of high-power devices.

Gate Drivers Media Gallery

References

GlobalSpec—Power Electronics Handbook: Devices, Circuits and Applications, Second Edition

Electronics360—Watch: TI makes strong showing at APEC 2019

Image Credits:

ROHM Semiconductor, USA LLC | 1-Source Electronic Components | Mornsun Power (Mfg.)