VisIC Technologies Ltd of Nes Ziona, Israel, a fabless developer of power conversion devices based on gallium nitride (GaN) metal-insulator-semiconductor high-electron-mobility transistors (MISHEMTs) founded in 2010, has introduced a half-bridge evaluation board using its VT15R65A GaN Power ALL Switch (Advanced Low Loss Switch) in a 'work horse' half-bridge power conversion circuit.
The VT15R65A-EVBHB demonstrates 98.5% power conversion efficiency operating at a switching frequency of 200kHz. Silicon MOSFET-based systems demonstrating similar efficiencies in this power range are limited to operation at 60kHz or less, and competitive GaN devices have only shown similar efficiency at 100kHz, the firm claims.
The evaluation board can be easily configured into any half bridge-based topology such as synchronous boost or buck conversion. It can also operate in a pulsed switching configuration for evaluating transistor waveforms. VisIC's GaN ALL Switch is driven by industry-standard high-frequency drivers.
Providing power conversion system designers with a complete, working power stage, the evaluation board includes high-frequency drivers for two VT15R65A power switches in a half-bridge configuration, the gate driver power supply, and a heat-sink. With what is claimed to be the lowest Rdson among 650V GaN transistors or switches, the VT15R65A achieves extremely efficient power conversion with switching transitions exceeding 100V/nS, the firm adds.
Configured as shipped with VIN up to 400VDC, the VT15R65A-EVBHB supports 2kW loads. The half-bridge evaluation board has a built-in planar inductor but also provides connections for external power inductors and capacitors to allow users to operate the board in higher power modes.
The user needs to provide an external 15VDC AUX voltage at a two-pin input. On-board voltage regulators create the required voltages for the logic circuits and gate drives. The high-voltage DC BUS input is connected using screw connections and the output bus is also connected via screw-type connection.