On the final day of Electronica 2010, International Rectifier (IR) presented a roadmap for the commercialization of GaN power switches that included both low-voltage (20-40V) and high-voltage (600V) devices. The first 20-40V devices are being targeted at low-voltage dc-dc converter applications while the initial 600V devices are expected to find use in power factor correction and inverter designs.
IR currently plans to be in production with a 600V cascaded GaN switch in 2011. The normally-off device will offer up to 10X better Figure-of-Merit than Si-based equivalents. It is expected to have a 20X lower Qrr compared to IGBT Copak devices and more than 200X less than Super Junction body diodes.
The switching losses for the 600V GaN device are expected to be 72% lower than for a Si IGBT. Compared with Si solutions, the high-voltage GaN switch will feature lower reverse recovery losses, lower Rds(on), lower Qg, lower EMI and will be in a smaller package.
In addition to the new 600V devices, IR presented a roadmap for improvement in the already-available 20-40V switches. Using one possible Figure-of-Merit R X Qg (mΩ-nC), IR’s roadmap projects improvement from 15 mΩ-nC for today’s devices down to about 2.5 mOhm-nC by 2014.
The company also demonstrated a point-of-load (PoL) converter prototype delivering 12A and switching at 5 MHz. The GaN PoL delivered an efficiency of 85% when converting from 12 to 1.2Vdc. The prototype was 65% smaller (7 x 9mm) compared with a Si solution (15 x 15mm) operating at 1MHz and delivering 10A of current.
Finally, the company shared the results of its on-going reliability testing for the low-voltage GaN devices. Running at 150°C and Vgs of 50V, the devices have demonstrated highly-stable operation for over 9,000 hours per device and over 7 million cumulative device-hours. Similar positive reliability results have been achieved for HTRB testing with a -7.5V Vgss.
