Power electronics news

Wise-integration makes use of the newly qualified 650V GaN/Si available technology from Taiwan Semiconductor Manufacturing Co. (TSMC) and is able to manage all the industrialization flow, starting from the device specification up to the system assembly.

As silicon-based MOSFETs and power devices approach their physical limits, power engineers have begun to turn to gallium nitride (GaN) to boost performance and reduce the overall solution size. In order to achieve a small form factor and a higher efficiency, more and more power supply designers are using GaN-based transistors rather than silicon-based devices. Being a wide bandgap material, gallium nitride offers superior properties than silicon: it can operate at higher frequencies, dissipates less power, conducts heat more efficiently, and provides a better thermal management.

SiC and GaN devices have a much higher critical breakdown voltage than Si, allowing for a thinner drift layer and higher doping concentration. This leads to lower on-resistance for a given die area and voltage rating, providing for greater efficiency through reduced power loss. Additionally, SiC has a thermal conductivity more than three times better than Si, enabling the use of smaller die for the same temperature rise. SiC and GaN also provide efficiency improvements over Si by having higher maximum operating temperatures, limiting stress.

In SMPS power supplies, a high switching frequency is a major benefit, since it allows reducing the size of magnetics and other components, achieving a higher miniaturization and cost savings. Switching losses, however, are linearly dependent on frequency. This is the reason why Si-MOSFETs, switching at a frequency of several hundred hertz, generate a non-negligible loss of energy. Gallium nitride, on the other hand, features a higher electron saturation velocity and lower capacitances, providing higher switching rates and lower power losses.

By adopting GaN-based switching power transistors, next-generation power applications can operate at higher voltages and switching frequencies, significantly improving performance and reducing losses, footprint and weight than traditional silicon-based solutions. These intrinsic characteristics of robustness make GaN an ideal material for large-scale adoption in evolving applications such as those in the automotive, industrial, telecommunications and other specific applications of the consumer electronics market, both in 100 V clusters and in those at 650 V.

Wise-integration GaN solutions
Any electronic equipment, from home appliances to laptops to data centers, relies on power conversion systems. However, most of today’s electricity systems are based on a technology that dates back several decades, lacking efficiency and occupying a not negligible space.

Wise-integration makes use of the newly qualified 650V GaN/Si available technology from Taiwan Semiconductor Manufacturing Co. (TSMC) and is able to manage all the industrialization flow, starting from the device specification up to the system assembly.

“Our GaN-based product, named WiseGan, integrates power switches with smart functions on the same die. The power transistors are 650V e-mode, while smart functions include gate control and protection circuits, designer-friendly functions and application security features”, said Dominique Bergogne, CTO at Wise-integration.

The WiseGan IC (shown in Figure 1) is suitable for medium power applications with power ranging from 30W to 3KW, including:

Consumer battery chargers
In wall USB-C Charger
e-mobility (e-bike chargers)
Industrial (data center power supply)
Figure 1: the WiseGan
WiseGan features an optimized architecture allowing a 30% volume reduction on standard GaN-based chargers. GaN technology enables extreme performance, while Wise-Integration proprietary architecture allows to boost even further the cost performance by reducing component count in AC-DC power converters and enabling high-efficiency solutions without compromising performance.

According to the speakers, the main benefits arising from the WiseGan technology adoption are the following:

Smarter uses of resources with boosted performance owing to ultra-fast switching at high frequency with reduced active area
Smaller size components for higher output power and reduced power losses
Higher power densities with integrated GaN devices able to operate at above 1MHz frequency
Higher energy efficiency (98% vs. 94% as in traditional converters)
“Our vision is to maximize the customer product benefits and attractivity reducing energy consumption, size and cost”, said Thierry Bouchet, CEO at Wise-Integration.

To better address the power supply market, the French-based company has combined its WiseGan technology with the WiseWare patented AC-DC system architecture running by digital control. WiseWare is a software application which can be run on a microcontroller. This twofold platform is able to reduce by 6x the charger’s size, weight, and power consumption.

Wise-Integration research team has recently raised 2.7 million euro as one of the winners of the national i-Lab 2019 Competition financed by the Ministry of Higher Education, Research and Innovation and supported by the Innovation and Industry Fund. According to the company, the funds will be used to support the industrialization and commercialization by 2022 of its first-generation WiseGan IC, and to further develop its WiseWare power conversion platform.

WiseGan ZVS evaluation board
Wise-Integration has also developed an evaluation board which allows to evaluate its WI62100, half-bridge 100mΩ (or WI62175 half-bridge 175mΩ), enhancement mode-high electron mobility transistors (EHEMTs) with the Si8274GB4D-IS1 gate driver in a half-bridge configuration (see Figure 2).

The board features a ZVS (zero voltage switching) feature, allowing for a soft switching of the component which reduces switching losses while enabling high-frequency switching. The test board includes also a LTC6907 to generate the control signal, headers for power connections, and probe points for waveform measurements.

The WI62100 IC is an half-bridge circuit integrating two GaN power transistors with RDS(on)=100mΩ in a 6x8mm PQFN package. The LTC6907 oscillator is configured to provide a 1MHz PWM signal to Si8274GB4D-IS1 isolated gate driver, both powered by the 5VDC voltage through the micro-USB power supply connector. The DT pin of the isolated gate driver, corresponding to the programmable dead time control, provides an overlap protection preventing the two driver outputs from both going high at the same time. It is thus used for setting the amount of time between one output going low and the other output going high. The two driver outputs are directly connected to the gate terminals of the GaN power transistors.

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