Driver ICs Focus On High-voltage, High-integration, and More—a Roundup

Driver ICs rank high as a critical part of many power-related designs—in electric vehicles (EVs) for example. An optimized design requires a closer look at the requirements, like efficiency, density and cost. Depending on particulars of the application, there are always trade offs.

In this article, we examine the gaps that each of these devices address in the industry, and we examine their key features and attributes.

 

Gate Driver IC for 1200 V Power Designs

Despite their popularity in commercial technologies, the industry lacks power gate driver ICs that can handle high voltage levels (greater than 600 V) in applications such as electric vehicles (EVs) while still maintaining high isolation.

Along those lines, Renesas Electronics recently unveiled a new gate driver IC, the RAJ2930004AGM, that supports 1200 V power devices featuring 3.75 kVrms in isolation voltage. It is designed to drive IGBTs and silicon carbide (SiC) MOSFETs for EV inverters.

 

The RAJ2930004AGM provides isolation between its MCU side and its IGBT side, with CMTI to avoid problems from high-voltage spikes. Image used courtesy of Renesas. (Click image to enlarge)

 

Gate drivers receive control signals from the microcontroller (MCU) in the low-voltage domain. They transfer these signals to switch power devices in the high-voltage domain, creating a need for electrical isolation between input and output.

High isolation at high voltages is, however, particularly challenging. Isolation still demands connection in some way to allow control over power switches. It shouldn't allow a significant amount of current to flow between the two sides, which is difficult at high voltages.

The higher the voltages, the greater the stress on the isolation material, making it harder to maintain a high level of isolation. In addition, high voltage spikes can also stress this insulation.

According to Renesas, its RAJ2930004AGM device overcomes these challenges and features a 3.75 kVrms isolator while withstanding up to 1200 V. To reduce the high voltage spike, the driver adds CMTI (common mode transient immunity) at 150 V/ns.

In addition, it integrates an active miller clamp, soft turn-off, overcurrent protection circuit, under-voltage lockout (UVLO), and fault feedback. Its small SOIC16 package makes it suitable for inverters, onboard chargers and DC-DC converters. More details can be found in the RAJ2930004AGM datasheet.

 

High Integration for Space-constrained Designs

A major gap in the gate driver industry is integration. Most gate driver ICs on the market may not be suitable for space-constrained applications. There is a need for driver ICs that can integrate multiple functions, such as gate driving, voltage regulation and protection, into a single small form factor package to reduce external components and save board space.

With all that in mind, Infineon Technologies recently introduced its 160 V MOTIX 6ED2742SOIQ 3-phase gate driver IC. The device targets space-constrained applications like cordless power tools, robotics, drones, and light electric vehicles (EVs). It integrates a power management unit (PMU), a current sense amplifier (CSA), and overcurrent protection, making it well suited for battery-powered BLDC (brushless DC) motor control isolations in those applications.

 

The 6ED2742SOIQ integrates a power management unit (PMU), a current sense amplifier (CSA), and overcurrent protection. Image used courtesy of Infineon

 

The new Infineon MOTIX 6ED2742SOIQ is a 160 V silicon-on-Insulator (SOI) gate driver featuring an integrated power management unit, current sense amplifier with selectable gain between the supply voltage and ground, and overcurrent protection. It also has integrated bootstrap diodes powering three external capacitors.

The IC can support 100% duty cycle operation through trickle charge. It also includes protection features like undervoltage-lockout (UVLO), overcurrent protection with adjustable threshold, fault communication and automatic fault recovery. The output driver is designed for minimal cross-conduction. The device offers a propagation delay of 100 ns and a minimum dead time of 100 ns with built-in delay matching.

For battery-powered industrial motor-driver applications, thermal reliability is critical. The MOTIX driver is available in the QFN-32 package with a thermally efficient exposed power pad. More information is available in the 6ED2742SOIQ datasheet.

 

Laser Driver IC for High-density Lidar Systems

Another application-specific gate driver IC recently released was from Efficient Power Conversion (EPC). Dubbed EPC21701, the chip is targeted for time-of-flight (ToF) applications, including robotics, 3D sensing, security, and vacuum cleaners. It is a low-cost laser driver IC integrating 80 V, 40 A controlled with a 3.3 V logic level.

 

With its small BGA form factor and high level of integration, EPC claims its EPC21701 takes up 36% less space on PCBs than an equivalent multi-chip discrete implementation. Image used courtesy of EPC

 

High switching speeds are necessary for laser drivers. However, it is challenging due to voltage stress on the driver and transistors. To prevent damage, the gate driver must limit its switching time. EPC's solution boasts switching times of less than 1 ns, essential for laser systems.

According to EPC, the EPC21701 is capable of operating at greater than 50 MHz and has a short pulse of 2 nA to drive currents up to 15 A. It boasts a propagation delay time of less than 3.6 ns. With its small BGA form factor and high level of integration, EPC claims its solution takes up 36% less space on PCBs than an equivalent multi-chip discrete implementation. More information can be found in the EPC21701 datasheet.