EPC development boards offer the opportunity to evaluate eGaN^® FETs and ICs in common applications. For example, the EPC9094 half-bridge development board can be configured as a buck or boost converter. The EPC9094 features the newly released EPC2054 200 V 43 mOhm max eGaN FET in a 1.3 x 1.3 mm 2 x 2 pin WLCSP package. The very low R_DS(on) value of this very small FET permits it to support high current loads from a high voltage supply. To demonstrate this ability, we will modify the EPC9094 development board to a buck converter. Using a 140 V supply, Spice simulation suggest 28 V output at 2.5 A will offer a high 90% efficiency. A Vishay IHLP-4040DZET330M11, 33 uH, 4.4 A, 95 mOhm Max, 10.2 x 10.8 x 4 mm inductor is selected which will provide 40% ripple at 500 Khz. Output capacitors consisted of four 10 uF Y5V 50V 1210 ceramic capacitors. The simulation showed a tradeoff between ripple current and overall efficiency when switching frequency was changed between 500 kHz down to 375 kHz. The simulation also showed that adjusting the dead time to permit full ZVS transition from high to low maximized the light load efficiency performance in the buck converter.

Until recently, to achieve high-quality sound from an audio amplifier cost thousands of dollars and relied on a large, heavy, power-hungry class-A amplifier. Now, the advent of gallium nitride FETs and ICs is ushering the age of high quality, lower cost class-D audio amplifiers. 

Distortion Performance Issues Lowered with GaN

Historically, meeting the required distortion performance targets (THD+N, TIM and IM) for high-quality audio, class-D amplifiers had to resort to incorporating large amounts of feedback circuitry to compensate for poor open-loop performance. The source of this distortion was the silicon power MOSFET.

Guest GaN Talk Blog by: Pavel Gurev, Sinftech Rus LLC

This article originally appeared in Bodo’s Power Systems April 2021

In the past few years, gallium-nitride (GaN) FETs have become more widespread in power electronics. Due to their outstanding characteristics, GaN FETs play an increasingly important role in miniaturization of the switching converters with very high-power densities exceeding 100 W / cm³ and more. The efficiency of converters based on GaN transistors can reach 99.5%. Due to the extension of the conversion frequency towards the MHz range, the magnetic components (chokes, transformers) also decrease in size significantly. However, designers face numerous challenges in implementing practical GaN transistor designs. The best family members are presented in wafer-level chip-scale package; the drivers are also quite miniature.

Pulsed lidar systems typically use either 905 nm or 1550 nm lasers for optical emission.  Above 1400 nm, various elements of the eye absorb the light, impeding it from reaching and damaging the retina.  As laser power is increased, not all of it is absorbed, and at some point, retinal damage may occur.  Since 905 nm light does not get absorbed, it does reach the retina, so care must be used to limit the energy density to prevent damage.

If the decision is to use 1550 nm light, efficiency differences in the semiconductor laser make it necessary to use higher current for the same optical power emitted compared with 905 nm light.  Additionally, the same characteristics that allow the light to be absorbed by the eye before getting to the retina cause it to be absorbed by the atmosphere.  This phenomenon is amplified as humidity increases to fog, rain, or snow.  The drive power required for a 1550 nm laser may be up to 10 times higher than for a 905 nm laser based system.  Fortunately, there is a solution to deliver the power necessary to drive 1550 nm lasers while maintaining the edge speed and pulse required for high resolution in pulsed lidar applications.

GaN-based solutions coupled with digital control and high-performance magnetics can increase efficiency, shrink the size, and reduce system costs for high density computing applications like ultra-thin laptops and high-end gaming systems.

As computers, displays, smart phones and other consumer electronics systems have become thinner and more powerful over the past decade, there is increasing demand for addressing the challenge of thinner solutions while extracting more power out of limited space.

The multilevel converter is an exceptional candidate to shrink the size of the magnetic components and achieve high efficiency in a compact solution. Leveraging the advantages of eGaN^® FETs, such as small size and low loss, further enhances the performance of a multilevel solution. This blog will evaluate the EPC9148, a 48 V to 20 V, 250 W three-level converter using eGaN FETs and digital control which achieves a peak total system efficiency of 97.8% and only 4.1 mm component height.

Co-written by Steve Colino

Laser drivers for light distancing and ranging (lidar) are used in a pulsed-power mode. What are the basic requirements for these laser drivers?

A new family of integrated laser driver ICs meets all these requirements.  The first release, the EPC21601 laser driver IC, integrates a 40 V, 10 A FET with integrated gate driver and 3.3 V logic level input in a single chip for time-of-flight (ToF) lidar systems used in robotics, surveillance systems, drones, autonomous cars, and vacuum cleaners. This chip offers frequency capability up to 200 MHz in a low inductance, economical, 1 mm x 1.5 mm BGA package.

Power electronics engineers are constantly working towards designs with higher efficiency and higher power density while maintaining high reliability and minimizing cost. Advances in design techniques and improved component technologies enable engineers to consistently achieve these goals. Power semiconductors are at the heart of these designs and their improvements are vital to better performance. In this EPC space blog, we will demonstrate how GaN power semiconductors allow for innovation in the harsh radiation environments of space applications.

GaN power semiconductors offer designers in the high reliability market a sudden and significant improvement in electrical performance over their silicon power MOSFET predecessors. Table 1 compares radiation hardened GaN and Si power semiconductor device characteristics important for circuit designers to increase efficiency and power density in their converter.

Rethinking the Ordinary and Overcoming Mental Biases

Motor drive applications span several markets: industrial, appliance, and automotive. A commonality that occurs regardless of market is that when a new technology is proposed, it faces resistance to its adoption; after all, it is human nature to stick with what is known and resist change.

Brushless DC (BLDC) motors are popular and finding increasing application in robotics, e-mobility, and drones. Such applications have special requirements such as lightweight, small size, low torque ripple, low audible noise, and extreme precision control.  To address these needs, the inverters powering the motors need to operate at higher frequency but require advanced techniques to reduce the resultant higher power loss. Enhancement-mode gallium nitride (eGaN ^®) transistors and integrated circuits offer the ability to operate at much higher frequencies without incurring significant losses. 

Brick DC-DC converters are widely used in data center, telecommunication and automotive applications, converting a nominal 48 V bus to (or from) a nominal 12 V bus. Advances in GaN integrated circuit (IC) technology have enabled the integration of the half bridge and gate drivers, resulting in a single chip solution that simplifies layout, minimizes area, and reduces cost.

This application note discusses the design of a digitally controlled bi-directional 1/16th brick converter using the integrated GaN power stage for 48 V-to-12 V application, with up to 300 W output power, and peak efficiency of 95%.

The standard dimension of the 1/16th brick converter is 33 x 22.9 mm (1.3 x 0.9 inch). The height limit for this design is set to 10 mm (0.4 inch).