IXYS intros new generation of overvoltage protection devices that increase high power system reliability

BIEL, SWITZERLAND: IXYS Corp. has launched its latest generation of overvoltage protection devices for greater power electronic system safety and reliability.

IXYS’ Break-Over Diodes (BOD) are traditionally embedded in the control/gate drive units in order to detect high voltage transients that can destroy a vast range of high cost, power semiconductor switches. BODs are designed to self trigger when a preset voltage level is reached thus allowing protection against voltage spikes or line faults which can destroy many different system components. These devices are also self resetting unlike a fuse or mechanical isolators which must be reset or manually replaced prior to system restart.

It is the most efficient and lowest cost solution for protecting high power systems that can be up to megawatts in power rating. The applications include Smart Grid Systems, High Voltage Direct Current (HVDC) power transmission systems, windmill generators, UPS’s, Motor Drives and power generators in hydroelectric dams.

“It is not often in high power applications that such a low cost component can be utilised to protect semiconductors with a value of thousands of dollars and a system of over hundreds of thousands of dollars,” said Bradley Green, VP of International Sales for IXYS.

“But the IXYS’ solid state semiconductor BOD range with its improved reaction speeds and higher voltage capability give our customers a self resetting, overvoltage protection system which reduces down time and improves system ruggedness at low comparative cost which in today’s environment are pre-requisites in any design.”

With this new development, IXYS has improved two important characteristics of the BOD. The temperature coefficient has been reduced by a factor of 3 improving the tolerance of the break-over voltage limit over the complete temperature range. This gives designers the benefit for a more precise and controllable design due to smaller tolerances.

Additionally, the latest generation dramatically reduces switch-on-time of the BOD in reaction to an overvoltage event down to a few nanoseconds. This not only improves the safety of the system but also increases the relevant application space for this technology and gives designers a solid state alternative to older, more complicated and expensive protection solutions.

The extremely high rate of change of the voltage (dv/dt) makes the new generation attractive for ignition applications of high voltage impulse technology such as High Intensity Discharge (HID) lighting.

The latest generation is called the IXBOD2TM range and features extended voltage operating range over previous solutions thereby giving the designer options in single element ratings from 100V to 1400V. Series connection of the IXBOD2TM is also possible to extend the system voltage protected to over 10kV.