Thyristor with a self-protection function for breakover turn-on failure
AssigneeTokyo Shibaura Denki Kabushiki Kaisha
InventorTsuneo Ogura
Life of this patent
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Abstract
A thyristor is comprised of a main thyristor region, a gate region for causing the main thyristor region to be turned on in response to a gate signal, and an amplifying gate region which is turned on to permit the main thyristor region to be turned on when an overvoltage is supplied to the thyristor in the absence of gate signal at the gate portion. The amplifying gate region is provided in a region except an intermediate region between the gate portion and the end of the main thyristor region facing the gate portion. A minority carrier lifetime in the amplifying gate region is longer than that of the main thyristor region and the gate portion.
Claims19
A thyristor with a self-protection function for a breakover turn-on failure comprising:
- a main thyristor region;
- gate means for causing said main thyristor region to be turned on in response to an annular shaped gate signal;
- and
- a first amplifying gate region serving as an auxiliary thyristor and provided in a region except an intermediate region between said gate means and the end of said main thyristor region facing said gate means, a minority carrier lifetime of said first amplifying gate region being longer than that of a region under said main thyristor region and said gate means so that when an overvoltage is applied to said thyristor in the absence of a gate signal at the gate portion, said first amplifying gate region is first turned on to permit said main thyristor region to be turned on.
A thyristor with a self-protection function for a breakover turn-on failure comprising:
- a P type emitter layer;
- an N type base layer forming a junction together with said P type emitter layer;
- a P type base layer forming a junction together with said N type base layer;
- an N type emitter layer provided on the surface of said P type base layer;
- an anode electrode provided on said P type emitter layer;
- a cathode electrode connected to said N type emitter layer;
- said P type emitter layer, said N type base layer, said P type base layer and said N type emitter layer, which are sandwiched between said anode and cathode electrodes, cooperatively forming a main thyristor region;
- gate means provided on the surface of said P type base layer for causing said main thyristor region to be turned on;
- an N type auxiliary emitter layer provided at a predetermined portion on said P type base layer surface except the P type base layer between said gate means and the end of said N type emitter layer facing said gate means;
- an auxiliary electrode connected to said N type auxiliary emitter layer and said P type base layer;
- a lifetime of minority carriers in an annular portion of the N type base layer under said N type auxiliary emitter layer being longer than that of minority carriers in other portion of N type base layers;
- and
- said P type emitter layer, said N type base layer with longer minority carrier lifetime, said P type base layer, and said N type auxiliary emitter layer, which are sandwiched between said anode electrode and said auxiliary electrode, cooperatively forming a first amplifying gate region which serves as an auxiliary thyristor, whereby when an overvoltage is applied between said anode and cathode electrodes in the absence of a gate signal at said gate means, said first amplifying gate region including said auxiliary emitter layer and said auxiliary electrode is first turned on to permit said main thyristor region to be turned on.
Dependencies are inferred from the claim text.