There are two types of bi-directional transistor:
The 650 and 850V devices are both normally-off monolithic gate-injection transistors with four operational modes via two separate gates and a substrate terminal, to deliver what the company calls ‘independent isolated control’.
“They utilize the same drift region to block voltages in both directions with outstanding performance under repetitive short-circuit conditions,” claimed the company. “The devices optimise performance in the replacement of back-to-back switches in single-phase H4 PFC and HERIC inverters, and three-phase Vienna rectifiers. Additional implementations include single-stage AC power conversion in ac-dc or dc-dc topologies.”
The 40V device, IGK080B041S, is a normally-off monolithic Schottky gate transistor that can block voltages in both directions.
It is optimised, according to the company, to replace back-to-back silicon mosfets in battery disconnection switches in consumer products.
The three terminal device has one gate and two drains and is symmetrical, with a typical on-resistance of 6mΩ (4mΩ and 9mΩ devices are in the pipeline).
It is rated for maximum pulses of 48V and 70A drain-to-drain (14A continuous), and up to +5.5V on the gate with respect to the least positive drain. With 20V across the drains and 10A through them, total gate charge is 5.5nC.
Current sensing GaN hemt
Announced at the same time as the bi-directional transistors was a current sensing GaN transistor.
Infineon is not saying much about this, except that it “can connect to controller current sense for peak current control and overcurrent protection. The current sense response time is ~200 ns, which is equal or less than common controller blanking time”.
The only other thing revealed for certain is 2kV electrostatic discharge withstand.
Samples of the current sensing GaN transistor are due in August 2024, while samples of the 40V 6mΩ bi-directional transistor are already available – find the IGK080B041S on this product page, which includes a data sheet link.
Samples of the 4 and 9mΩ 40V types are scheduled for Q3, followed by 650V samples in Q4 and 850V samples in “early 2025”, said Infineon. Some information on the higher-voltage parts is behind a data wall on Infineon’s website.
Chinese GaN transistor maker Innoscience already offers three-terminal (gate-drain-drain) bi-directional GaN power transistors for power rail switching at 100V and 40V (read here for operating techniques). Innoscience also played applications information close to its chest at launch, but datasheets can now be downloaded freely.
