Many modern electronic applications require power supplies that are both small and thin due to the trend of miniaturization of electronic devices. Historically, power supplies tended to be larger in size due to the use of bulky transformers. Still, with the advent of new technologies like GaN (gallium nitride) integrated circuits and advances in power management, it is possible to design smaller power supplies without sacrificing efficiency or performance.
This article focuses on the latest achievements obtained in this area by Wise Integration, which specializes in developing innovative electronics solutions for power management. They have developed a range of power management products based on their patented GaN integrated circuits technology and digital controller, which enables greater energy efficiency and miniaturization of power supply units.
Their solution combines WiseGan GaN Power devices with WiseWare® the digital controller, resulting in highly integrated power management solutions offering improved efficiency and power density. This technology is used in various applications such as AC/DC power supplies, smart charging stations, and electric vehicles.
The ‘new era’ of digital control
Combining the unique properties of GaN, like high voltage breakdown and operation at the high current and switching frequency, with the high performance of digital control, Wise Integration has developed a technology offering ultra-miniaturized power supplies.
Wide bandgap gallium nitride (GaN), a next-generation semiconductor technology, has become essential for creating cutting-edge power electronics. Compared to silicon, it can function up to 20 times faster and deliver up to three times as much power or charge while being half the size and weight.
The company recently announced an agreement with Powernet, a primary South Korean power supply manufacturer, for delivering digitally controlled, compact, and energy-efficient GaN-based power supplies. Through this memorandum of understanding (MOU), Wise Integration will replace the analog controls currently used in GaN power supplies with its WiseWare® digital controller.
Digitally controlled power-supply systems will satisfy OEM’s needs for compact, digitally controlled systems for faster, smaller, and more energy-efficient electronic equipment in products ranging from USB PD fast chargers to monitors, TVs, and electric vehicles. To meet Powernet’s demand for efficient switched mode power supplies (SMPS) applications from 30W to 3kW, the digital controller will be integrated with WiseGan® 650V e-mode GaN-on-Si IC (Figure 1). WiseGan power ICs also include protection and safety circuits.
“We started developing the reference design for a 65W power supply a few months ago, but soon we will provide an SMPS with output power above 300W. Our next product will address devices like displays, monitors, and TV sets. Those applications are very challenging, as the power supplies need to be thin and compact to be embedded into the final product,” said Thierry Bouchet, CEO of Wise Integration.
According to Bouchet, standard topologies used in GaN switched mode power supplies don’t allow making very thin devices. For instance, the PFC stage often uses a large and cumbersome inductance. A digitally controlled solution increases the switching frequency (even above 1 MHz) maximizing the benefit of GaN. That means smaller and thinner capacitors and inductances can be used.
WiseWare (figure 2) includes a standard MCU 32-bit-based controller and runs the proprietary firmware developed by Wise Integration. This manages the WiseGan devices and controls the power supply. The power capability offered by a 32 bits microcontroller is needed to manage in real-time the required calculations.
The new power-electronic architecture lowers production costs by reducing the weight and volume of typical solutions by 30% while using 30% fewer components than analog controllers.
“Our patented solution removes the need for a PFC circuit because inside the MCU we run some algorithms that digitalize the PFC. Since we no longer need a large inductance, we can make a very thin power supply that fit with the requirements of very thin displays for monitors and TVs,” said Bouchet.
Moreover, the number of active components is also reduced, as WiseGan only needs four GaN power switches in place of the six switches normally used in traditional power supply topologies. By removing some other passive components and specific drivers, a 10% cost reduction of the total bill of material (BOM) can be achieved.
Wise-integration is the first company to provide digital control to the power-supply sector, where only analog controls were previously available. Original equipment manufacturers (OEM) who need an ever smaller and ultra-efficient power supply for future product lines are raising their demands, while original design manufacturers (ODM) like Powernet are attempting to match these needs. GaN is seen as a major semiconductor for these capabilities, but power supply manufacturers find it exceedingly challenging to use analog devices at switching frequencies higher than 300 kHz. The innovative power-electronic architecture developed by Wise Integration lowers production costs and reduces the weight and space of typical solutions by 30% in analog controllers.
As Bouchet points out, another advantage of WiseGan technology is reduced development time. Power supplies with analog control are usually structured on three power levels that require a long time to fine-tune the PFC and the LLC stages. Additionally, the PFC and LLC stages usually have different analog control comparators whose fine-tuning is difficult and time-consuming.
“With digital control, you can reduce the development time, achieving a target compatible with a silicon-based solution. It’s also interesting to use digital control because it performs very well in real time” said Bouquet.
An interesting aspect of the WiseWare technology is that its architecture, comprising the digitization of the PFC stage plus the digital control of the power switches, can also support silicon carbide (SiC) devices. It could also be used for silicon carbide, another wide bandgap semiconductor that performs well at high operating voltage providing excellent efficiency.
The main applications of Wise Integration’s technology include:
- AC-DC converters
- High-density power conversion
- High-efficiency power conversion
- VS phase shifted full bridge
- Synchronous buck or boost
- Bridgeless totem pole PFC.
The 650 V e-mode WiseGan power switches are available in a low inductance PQFN package (with a 6×8 or 8x8mm PCB footprint), have a bottom-side cooling configuration and require a standard gate drive (0 V to 6 V).