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US 3,940,633 AGranted
GTO turn-off circuit providing turn-off gate current pulse proportional to anode current
AssigneeGeneral Electric Company
InventorRobert L. Steigerwald
Life of this patent
Estimating the term…
Abstract
A turn-off circuit for a gate turn-off thyristor (GTO) generates a ramped turn-off gate current pulse which, because of the increase in device storage time with anode current, has a peak magnitude approximately proportional to the anode current. The direct-coupled or transformer-coupled turn-off circuit employs a transformer controlled by a solid state switch with the secondary winding connected to return excess energy to a supply.
Claims5
A solid state circuit including a semiconductor device with a gate turn-off circuit comprising
- a gate turn-off thyristor semiconductor device having an anode and a cathode and a gate terminal for controlling switching of said device between a conducting state in which anode current flows and a nonconducting state, said gate turn-off thyristor being coupled to a pair of unidirectional input voltage supply lines between which is applied an energizing voltage, and
- turn-off circuit means for selectively generating a ramped turn-off gate current pulse with a peak magnitude which increases and decreases as said anode current increases and decreases,
- said turn-off circuit means being comprised by a transformer having a primary winding connected in series with a controlled solid state switch device between said gate terminal and a negative unidirectional gate voltage supply line, and means for rendering conductive said controlled solid state switch for a selected interval to initiate generation of said gate turn-off current pulse, said transformer having a secondary winding connected in series with a diode and comprising means for returning excess energy stored in said primary winding to a selected voltage supply.
A solid state circuit including a semiconductor device with a turn-off circuit comprising
- a gate turn-off thyristor semiconductor device having an anode and a cathode and a gate terminal for controlling switching of said device between a conducting state in which anode current flows and a nonconducting state, said gate turn-off thyristor being coupled between a pair of input voltage supply lines between which is applied an energizing voltage, and
- turn-off circuit means for selectively generating a ramped turn-off gate current pulse with a peak magnitude which increases and decreases as said anode current increases and decreases,
- said turn-off circuit means being energized by a pair of constant unidirectional gate voltage supply lines and including a first transformer having a primary winding connected in series with a controlled solid state switch and the primary winding of a second transformer between said gate voltage supply lines, and means for rendering conductive said controlled solid state switch for a preselected interval to initiate generation of said turn-off current pulse, said second transformer having a secondary winding connected between said gate terminal and cathode to couple said turn-off current pulse to said gate terminal, said first transformer having a secondary winding connected in series with a diode and comprising means for returning excess energy stored in said first transformer primary winding to a selected voltage supply.
Dependencies are inferred from the claim text.