Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
133 words
A method for turn-on driving a thyristor (10, 50, 100) having a voltage-controlled switching transistor (Q), which has a first emitter layer (12), a first base layer (14), a second base layer (16), a second emitter layer (18), a first gate electrode (G1) insulatively provided above said first base layer for functioning as the gate of said transistor (Q), and a second gate electrode (G2) formed on said second base layer, characterized in that said method comprises the steps of: applying a first voltage for conducting said transistor to said first gate electrode (G1); while substantially simultaneously applying to said second gate electrode (G2) a second voltage for forwardly biasing between said second base layer (16) and said second emitter layer (18) to expedite the turn-on operation of said thyristor (10, 50, 100).
Claim 2
Independent Claim
133 words
A method for turn-on driving a thyristor (10, 50, 100) having a voltage-controlled switching transistor (Q), which has a first emitter layer (12), a first base layer (14), a second base layer (16), a second emitter layer (18), a first gate electrode (G1) insulatively provided above said first base layer for functioning as the gate of said transistor (Q), and a second gate electrode (G2) formed on said second base layer, characterized in that said method comprises the steps of: applying a first voltage for conducting said transistor to said first gate electrode (G1); while substantially simultaneously applying to said second gate electrode (G2) a second voltage for forwardly biasing between said second base layer (16) and said second emitter layer (18) to expedite the turn-on operation of said thyristor (10, 50, 100).
Claim 3
Dependent Claim
36 words
The method according to claim 1, characterized in that the application of said first voltage to said first gate electrode (G1) is conducted simultaneously upon application of said second voltage to said second gate electrode (G2).
Claim 4
Dependent Claim
36 words
The method according to claim 1, characterized in that the application of said first voltage to said first gate electrode (G1) is conducted before the application of said second voltage to said second gate electrode (G2).
Claim 5
Dependent Claim
36 words
The method according to claim 1, characterized in that the application of said first voltage to said first gate electrode (G1) is conducted after the application of said second voltage to said second gate electrode (G2).
Claim 6
Independent Claim
146 words
A method for turn-off driving a thyristor (10, 50, 100) having a voltage-controlled switching transistor (Q), said thyristor having a first emitter layer (12), a first base layer (14), a second base layer (16), a second emitter layer (18), a first gate electrode (G1) insulatively provided above said first base layer for functioning as the gate of said transistor (Q), and a second gate electrode (G2) formed on said second base layer, characterized in that said method comprises the steps of: applying to said second gate electrode (G2) a first voltage for reversely biasing said second emitter layer (18) and said second base layer (16) to stop the operation of said thyristor, said transistor (Q) being kept conductive at this time; and rendering said transistor (Q) nonconductive after a predetermined time is elapsed from the application of said first voltage to said second gate electrode (G2).
Claim 7
Independent Claim
146 words
A method for turn-off driving a thyristor (10, 50, 100) having a voltage-controlled switching transistor (Q), said thyristor having a first emitter layer (12), a first base layer (14), a second base layer (16), a second emitter layer (18), a first gate electrode (G1) insulatively provided above said first base layer for functioning as the gate of said transistor (Q), and a second gate electrode (G2) formed on said second base layer, characterized in that said method comprises the steps of: applying to said second gate electrode (G2) a first voltage for reversely biasing said second emitter layer (18) and said second base layer (16) to stop the operation of said thyristor, said transistor (Q) being kept conductive at this time; and rendering said transistor (Q) nonconductive after a predetermined time is elapsed from the application of said first voltage to said second gate electrode (G2).
Claim 8
Dependent Claim
73 words
The method according to claim 5, characterized in that said thyristor (10, 50, 100) starts turning-off in response to the application of said first voltage to said second gate electrode (G2), charge carriers exhausted from said second emitter layer (18) at this time are allowed to flow into said first base layer (14) through said transistor (Q) which is rendered conductive, thereby suppressing a local concentration of the turn-off current in said thyristor.
Claim 9
Dependent Claim
39 words
The method according to claim 6, characterized in that said thyristor (10, 50, 100) is completed to be turned-off when said transistor (Q) is rendered nonconductive by the application of said second voltage to said first gate electrode (Gl).
Claim 10
Dependent Claim
26 words
The method according to claim 7, characterized in that said transistor (Q) is rendered nonconductive by applying a second voltage to said first gate electrode (G1).
Claim 11
Dependent Claim
67 words
The method according to claim 7, characterized in that said transistor (Q) is rendered nonconductive by substantially increasing the absolute value of a potential at said second gate electrode (G2) than that at said first gate electrode (G1) after the injection of charge carriers from said second emitter layer (18) to said second base layer (16) is stopped by applying a third voltage to said second electrode.
Claim 12
Dependent Claim
123 words
An insulated gate thyristor (10, 50, 100) comprising a first emitter layer (12), a first base layer (14), a second base layer (16), a second emitter layer (18), a first gate electrode (G1) insulatively provided above said first base layer to form a voltage-controlled switching transistor (Q) together with said second emitter layer (18) and said first base layer (14), characterized in that said thyristor further comprises a second gate electrode (G2) formed on said second base layer (16), and a heavily doped semiconductor layer (52, 60b, 62b) formed in said second base layer (16) so as to electrically directly contact with said second gate electrode (G2), said semiconductor layer having the same conductivity type as that of said second base layer (16).
Claim 13
Dependent Claim
123 words
An insulated gate thyristor (10, 50, 100) comprising a first emitter layer (12), a first base layer (14), a second base layer (16), a second emitter layer (18), a first gate electrode (G1) insulatively provided above said first base layer to form a voltage-controlled switching transistor (Q) together with said second emitter layer (18) and said first base layer (14), characterized in that said thyristor further comprises a second gate electrode (G2) formed on said second base layer (16), and a heavily doped semiconductor layer (52, 60b, 62b) formed in said second base layer (16) so as to electrically directly contact with said second gate electrode (G2), said semiconductor layer having the same conductivity type as that of said second base layer (16).
Claim 14
Dependent Claim
32 words
The thyristor according to claim 10, characterized in that said second base layer (16) comprises a lightly doped semiconductor region (60a, 60aʹ) for surrounding at least partially said second emitter layer (18).
Claim 15
Dependent Claim
45 words
The thyristor according to claim 11, characterized by further comprising a heavily doped semiconductive buffer layer (30) provided between said first emitter layer (12) and said first base layer (14) and which has the same conductivity type as that of said first base layer (14).
Claim 16
Dependent Claim
25 words
The thyristor according to claim 12, characterized in that said buffer layer (30ʹ) comprises a layer portion partly exposed through said first emitter layer (12).
Claim 17
Dependent Claim
27 words
The thyristor according to claim 13, characterized by further comprising a third gate electrode (G3) formed directly on a layer portion exposed from said buffer layer (30ʹ).
Claim 18
Dependent Claim
61 words
The thyristor according to claim 14, characterized by further comprising a first conductive layer (20) formed on said first emitter layer (12) for functioning as a first main electrode of said thyristor (10, 50, 100), and a second conductive layer (22) formed on said second emitter layer (18) for functioning as a second main electrode of said thyristor (10, 50, 100).
Claim 19
Dependent Claim
20 words
The thyristor according to claim 15, characterized in that said transistor comprises a metal oxide semiconductor field effect transistor (Q).
Claim 20
Dependent Claim
28 words
The thyristor according to claim 16, characterized in that said first main electrode is an anode electrode (A), and said second main electrode is a cathode electrode (K).