GTO thyristor with sensitive gate

[pns2050]

Hello i have been trying to find a GTO thyristor with a sensitive gate but i couldnt find any..

The lowest(that i found) latching current that the gate needs to operate as a GTO thyristor was 0.75A, otherwise below latching level
the device behaves like a transistor with a gain dependent on current..

Do GTO thyristors with more sensitive gates exist ? if yes could i get some examples?

Thanks in advance

 

[FvM]

In my view, the higher gate trigger current of a GTO is a necessary companion of the turn-off capability, which involves reduced intrinsic current gain.

Practically, the high turn-off current implies a low impedance gate circuit. It doesn't seem to fit to a sensitive, high impedance turn-on circuit, even if the device operation would allow it.

 

[pns2050]

After experimenting a bit(I am a University student) with BT157 fast gate turn off thyristor i found out that i could turn the thyristor on
with around 45mA at the gate. But after the pulse is removed the thyristor will turn off instanteniously..

I read about Latching current and i understand that to be able to keep the thyristor on i should have high current flowing from anode to cathode..around 0.75A.

 

[FvM]

Yes, latching current hasn't to do with gate current. Minimum trigger current of BT157 is specified with 200 mA, of course the actual trigger current may be lower.

As far as I'm aware of, small GTOs like BT157 aren't available any more these days, because respective applications have changed compeletely to IGBTs. The main domain of GTO is kV and kA high power switching, e.g. in HV power transmission.

 

[pns2050]

So trying to make a dc to ac three phase inverter using GTO's was a bad choice for my final year project .. I already spent so much time to learn how thyristors work and i will end up using IGBT's :¬.

Having so high currents and also be able to produce negative and positive pulses is a bit tricky for my current knowledge