Efficient Power Conversion Corp (EPC) of El Segundo, CA, USA, which makes enhancement-mode gallium nitride on silicon (eGaN) power field-effect transistors (FETs) for power management applications, has launched the EPC2107 (100V) and EPC2108 (60V) eGaN monolithic half-bridge power integrated circuits with an integrated bootstrap FET, eliminating gate-driver-induced reverse recovery loses as well as the need for a high-side clamp. EPC says that this is the first time that a bootstrap FET has been integrated in an eGaN power circuit.
Designed specifically for resonant wireless power transfer applications, the new products enable rapid design of highly efficient end-user systems, setting the stage for mass adoption of wireless power transfer, it is reckoned. In addition, the GaN power integrated circuits come in small chip-scale packages, reducing the size of the overall system. Also, the new line of chips is lower in cost due to reduced overall component count (one GaN device versus three FETs).
Rezence wireless power standard
Although there are several standards for wireless power transfer, the Rezence standard of the Alliance For Wireless Power (A4WP) offers superior features and capabilities to consumer end-users, says EPC. For example, Rezence allows for spatial freedom when charging, eliminating the need for exact positioning of devices when charging. It also has an exceptional charging range, providing true 'drop and go' charging. Additionally, the A4WP standard allows charging of multiple devices with different power requirements simultaneously. Another key feature is that Rezence-compliant wireless power systems will charge devices in the presence of metallic objects such as keys, coins and utensils, making it suitable for automotive, retail, and household applications.
In short, says EPC, Rezence provides the flexibility and capabilities to bring wireless charging to the masses, a rapidly emerging market that is expected to be a $15.6bn industry by 2020.
EPC says that, having introduced the first eGaN FET for wireless power transfer in 2012, its gallium nitride devices play a major role in this market. In addition to designing Rezence-compliant power products, EPC has published a 'Wireless Power Handbook' dedicated to addressing wireless power system design issues such as multi-mode operation and EMI compliance.
EPC's new products and benefits
By integrating two eGaN power FETs into an integrated power circuit, the interconnect inductances and the interstitial space needed on the PCB are eliminated. Having this single integrated power component increases both efficiency (especially at higher frequencies) and power density, while reducing assembly costs to the wireless power system designer's end-product, says EPC.
The new devices come in 1.35mm x 1.35mm chip-scale package for reduced size, improved switching speed and thermal performance, leading to increased power density.
Wireless power demonstration systems
In support of the EPC2107 and EPC2108 integrated circuits (which cost $0.89 and $0.85 each, respectively, in 1000-unit quantities), EPC also offers complete demonstration wireless power transfer systems, as well as development boards for the evaluation of the two new eGaN power integrated circuits.
The A4WP Class 3 (EPC9113) or A4WP Class 2 (EPC9114) wireless power demonstration systems have three components:
ZVS Class-D Source (or amplifier) board (Rezence Class 2: EPC9510 (costing $418.95) – included in EPC9114 kit and featuring the 100V EPC2107; Rezence Class 3: EPC9509 (costing $418.95) – included in EPC9113 kit and featuring the 60V EPC2108); Class 2 or 3 Rezence-compliant source (or transmit) coil; and Category 3 Rezence-compliant device (or receiving) board including coil.
The EPC9113 wireless power demonstration kit is A4WP Class 3-compliant, capable of delivering up to 16W into a DC load while operating at 6.78MHz (which can be modified to operate at 13.56MHz). The EPC9114 wireless power demonstration kit is A4WP Class 2-compliant at 10W. The purpose of the demonstration kits (which both cost $895 each) is to simplify the evaluation process of using eGaN FETs for highly efficient wireless power transfer. Both kits utilize the high-frequency switching capability of EPC's GaN transistors to facilitate high-efficiency wireless power systems.
For customers with their own coil design, the source (or amplifier) boards are also sold separately as EPC9509 (featuring the 60V EPC2108) and EPC9510 (featuring the 100V EPC2107).
