Hi Henk

The volt-second product indicates how long a voltage can be applied to a transformer primary before the core starts to saturate. The rating you need will depend on the voltage you are going to apply to the primary (usually 12V) and the switching frequency of the converter (typically 100kHz so 5us if operating at Dmax). This is a ET product of 60Vus.

Of course, with a bipolar drive the transformer flux is centred on zero for equal positive and negative swings so a transformer with a ET of 60Vus will use 30Vus to get from -Bmax to 0 and and 30Vus to get from 0 to +Bmax.

The 56PR3362 has a ET product of 45Vus for example so it will be able to withstand 90Vus with a two ended drive. I tested this once (by accident) and it did saturate after about 90Vus !

Hope this helps.

Regards

Colin

Hello Henk

I hesitate to recommend either because there are a lot of things I don't know about your application. If the controller is referenced to the secondary then the gate drive transformer must cross the safety isolation barrier. You will need to choose a gate drive transformer which meets the isolation barrier specifications that are relevant to your application -

Given that you are working at 100kHz with a 12V rail then the Vs product of either is ok. You should also look for the lowest leakage inductance you can get because leakage inductance will generate spikes that can be large enough to damage circuits on either the primary or secondary of the GDT. On the other hand you need to watch that the primary/secondary capacitance through the transformer is not too high because the high dv/dt rates seen as the MOSFETs turn on and off will drive common mode currents from secondary to the primary. These can be large enough to cause erratic operation of the driver on the primary of the GDT. So - it's a trade off and you won't really know if you have a problem until you start working with hardware.

Pulse is one of several reputable manufacturers so you may be able to discuss your requirements with them - things like isolation voltage, leakage inductance both of which are specified in the part data sheets and primary/secondary parasitic capacitance which is not. Anyhow, I'm sure that either of these parts will function ok in your circuit in a lab environment BUT do check the isolation ratings before making a final choice.

Regards

Colin