9kW GaN Half-Bridge Eval Board without Paralleling

August 01, 2018 by Paul Shepard

VisIC Technologies has announced a new water-cooled V22N65A-HBEVB half-bridge evaluation board to demonstrate the high-power performance achievable using its GaN All-Switches™ (Advanced Low Loss Switches).

This evaluation platform can be operated in any half-bridge topology and was tested in Buck and Boost topologies up to 9kW, using only single V22N65A transistors. This is the first GaN based solution on the market that can deliver up to 9kW of power, without the need for paralleling, making it suited for high-density on-board-chargers (OBCs) in hybrid and electric vehicles.

The V22N65A All-Switch™ SMD discrete top cooled devices feature ultra-low conduction and switching losses coupled with an advanced isolated package design, allowing maximum performance and power out of each GaN device.

A low parasitic inductance power and gate loop design, combined with a high threshold voltage (5V) allows designers to safely employ VisIC GaN switches in high power applications in multi-kW range.

V22N65A-HBEVB - 22mOhm GaN Transistors in a Half-Bridge Evaluation Board (Air cooled version) (credit: VisIC Technologies)

The V22N65A-HBEVB evaluation platform consists of:

  • Half Bridge power stage using 22mOhm GaN All-Switches;
  • Isolated half bridge driver from Silicon Labs (Si82394);
  • Two isolated auxiliary power supplies from Murata (NXE251212MC);
  • Dead Time control from 75ns to 200ns;
  • High current (85A) connectors from Wurth Electronics (74655095R)

The all-In-one water cooled V22N65A-HBEVB is available at a cost of $600. An air-cooled version is available at a cost of $500.

V22N65A Efficiency and Junction Temperature in function of Power (click on graph to enlarge, credit: (VisIC Technologies)

The ALL-Switch

The ALL-Switch is a System In Package (SIP) switch.  A Normally-Off safe function is integrated within the package, designed according to SmartGaN topology, an innovation by VisIC Technologies. ALL-Switch V22N65A combines a patented, high-density, lateral-layout GaN power transistor, into a product with extremely lowRDS(ON), exceptionally fast switching performance and a conveniently small footprint.  It is very effective in applications requiring high efficiency, high power density and low cost.

An Enable Circuit is responsible for operation sequence of the All Switch device during a system start up and shutdown. It verifies the proper status of the gate driver and supply voltage. At normal switching operation mode, it has no impact on the switching performances of the GaN transistor.

Key features include:

  • Ultra-fast switching
  • Kelvin connection
  • Normally-Off
  • High power density
  • Fully-isolated package-(2.5KV)