Tuesday, June 26, 2018 - Thursday, June 28, 2018
Location: Shanghai, China

A Synchronous FET Class E Rectifier for >30 W Highly Resonant Wireless Power Receivers Speaker: Michael de Rooij, Ph.D., VP of Applications, Efficient Power Conversion

6.78 MHz highly resonant wireless power receivers based on the AirFuel standard experience high rectifier losses when using Schottky diodes and fail to meet the thermal limit requirements for many products such as laptops. This proposal uses a synchronous switch GaN FET in a class E topology as an alternative for a 30 W or higher receiver. Initial results show that a full bridge Schottky diode solution reaches a temperature of 70°C with 83.4% system end to end efficiency when delivering 30 W, while the GaN FET used in a class E rectifier reaches only 53°C and 86.1% efficiency

Kilowatt Laser Driver with 120 A, sub-10 nanosecond pulses in < 3 cm2 using an GaN FET Speaker: John Glaser, Ph.D., Director of Applications, Efficient Power Conversion

Lidar time-of-flight distance measurement has become the primary means of high-speed, accurate mapping of 3-D space. A primary application for lidar is for navigation and obstacle avoidance in real-time Advanced Driver Assistance System (ADAS) and autonomous vehicle navigation. The lidar pulsed laser transmitter is a key lidar subsystem. The transmitter must generate high power optical pulses of short duration of less than 10 ns. For a 10 s vehicle sense and response time, a range of 300 m is required, which in turn requires high peak laser power. This work describes a laser driver using a single commercial GaN FET to achieve current pulses into a laser diode of >120 A peak for a peak laser input power of > 4 kW, with a duration < 10 ns. The area occupied by the driver and laser is < 3 cm2.

Webinar: Power Technology Roadmap Forum (10:00 am Central Time)

Thursday, June 28, 2018 10:00 AM
Webinar: Power Technology Roadmap Forum (10:00 am Central Time)
Location: Online

Getting from 48 Volts in Emerging Server and Automotive Applications Speaker: Alex Lidow, Ph.D., CEO and Co-Founder, Efficient Power Conversion

Cloud servers, advanced gaming systems, artificial intelligence, cryptocurrency mining, and automotive electronics are all converging rapidly on 48 Volts as the new standard bus voltage. 48 V has the advantage of not requiring isolation and is therefore simpler, smaller, more efficient, and lower cost than other power conversion architectures. In every case, the relatively new GaN transistors and integrated circuits have demonstrated the ability to convert to-and-from 48 Volts with higher efficiency, and smaller size. GaN is also able to significantly reduce costs. In this seminar we will show the various applications and topologies used in these markets and show the steps taken to convince conservative design engineers that the best solution involves GaN.

If you would like to participate, please register online.


Tuesday, September 25, 2018
Location: Portland, OR

GaN based Switched Capacitor Three Level Buck Converter with Cascaded Synchronous Bootstrap Gate-Drive Scheme Speaker: Suvankar Biswas, Ph.D., Senior Applications Engineer

With the power architecture transition from a 12 V to 48 V rack in modern data centers there is an increased interest in improving 48 V power conversion efficiency and power density. A three-level GaN based converter provides a high density and efficiency solution. In this paper, we will introduce a high performance GaN based switched capacitor three level buck converter for 48 V applications. To fully utilize GaN technology in multilevel topologies, an improved cascaded synchronous bootstrapping technique is also proposed. The proposed gate driving technique is smaller and simpler than the previous gate driving techniques employed in GaN based multilevel topologies and offers very good gate voltage regulation. For experimental verification, a three level switched capacitor buck converter with the improved gate drive scheme and closed loop flying capacitor balancing is compared against a traditional buck converter, with the three level converter providing a 50% reduction in inductor volume and a 25% reduction in converter power loss. In order to demonstrate a possible further application of the gate-drive scheme, a high voltage (400 V) prototype is built, with improved experimental results over a regular half-bridge prototype. A simple startup protection scheme using Zener diodes is also verified, which removes the need for full voltage rated switches altogether.