What is the turn-off thyristor?
What is the turn-off thyristor?
The GTO is also a PNPN four-layer semiconductor device whose structure and equivalent circuit are the same as ordinary thyristors.Figure is the circuit symbol and pin arrangement diagram of the GTO.High power turn-off thyristors are mostly packaged in modular form.The GTO is the same as the ordinary thyristor,and also has three electrodes, the anode A,the cathode K and the gate G,respectively.The principle of GTO triggering is basically the same as that of ordinary thyristors,but there is a fundamental difference between the turn-off principle and the shutdown mode.The ordinary thyristor gate G plus the positive trigger signal can be turned on,even if the trigger signal is removed,it can be turned on.If it is to be turned off,the A and K power supply is cut off,so that the forward current is lower than the maintenance current,or the reverse voltage is forced to turn off.The application circuit is more complex,and the waveform distortion and noise are easy to be generated.The turn-off thyristor has the advantages of large current of ordinary thyristor,high voltage resistance,and also has the function of self-closing.The ordinary thyristor is in a state of deep saturation after conduction,and the GTO is in a critical saturation state after its conduction,so it can be turned off only by adding a negative trigger signal to the GTO gate G.
what parameters can be turned off thyristor?
(URGM) the reverse peak voltage of the gate.
Off state repetitive peak voltage UDRM indicates the maximum value of the off state voltage applied at both ends of GTO.
IATM is the maximum turn off current.
turn off gain beta off is a very important parameter,equivalent to the current amplification factor HPE of transistors.It is equal to the ratio of the maximum positive current IATM of the anode to the maximum negative current IGM of the gate,that is,the magnitude of the value of the beta Bof can represent the strength of the control ability of the gate current to the anode current.Generally,the beta ofr is a few speed to more than ten times.The larger the beta of,the stronger the control ability of the gate current to the anode current.