Static IV Characteristics of MOS Controller Thyristor (MCT)

Static (I-V) Characteristics of MOS Controller Thyristor (MCT)

In the static condition, the I-V characteristics of the MCT are similar to those of SCR and GTO.

Switching Characteristics of MOS Controller Thyristor (MCT)

MCT can change its state from ON to OFF or OFF to ON within 1 µsec. Figure (a) shows a switching circuit using an N-MCT and Figure (b) shows the switching waveforms of the device.
Figure (a)

Figure (b)

1. The turn on time

The total turn on time is equal to the sum of two different time durations :

(a) Turn on delay time (t_{d on})

(b) The current rise time (t_r)

(a) Turn on delay time (t_{d on})

It is equal to the time taken by the anode current to increase to 10% of its maximum value I_max. This delay time corresponds to the time required for the injection of excess carriers before the beginning of the regenerative action. Typically t_{d on} = 0.5 µS.

(b) Rise time

This is the time required for spreading of the plasma of excess carriers under the gate electrode. Typically t_r = 0.5 µS.
During the turn on process of MCT, we can connect a small series inductance as the turn on snubber as shown in Figure (a) in order to protect it against high di/dt rate.

2. The turn off time

(a) The delay time t_{d off}

(b) The fall time t_f

(a) The delay time t_{d off} :

This time corresponds to the time taken by anode to cathode voltage to reach its off state value. Typically t_{d off} ≤1 µsec.

(b) Fall time t_f :

It is the time required for the recombination to take place in the base regions. Typically t_f = 0.5 to 1 µS.

Ratings of MCT

Ratings : 1000 V / 100 A
Can be turned on and off by applying small negative and positive voltages respectively to the gate.