Abstract: A family of emitter controlled thyristors employ plurality of control schemes for turning the thyristor an and off. In a first embodiment of the present invention a family of thyristors are disclosed all of which comprise a pair of MOS transistors, the first of which is connected in series with the thyristor and a second which provides a negative feedback to the thyristor gate. A negative voltage applied to the gate of the first MOS transistor causes the thyristor to turn on to conduct high currents. A zero to positive voltage applied to the first MOS gate causes the thyristor to turn off. The negative feedback insures that the thyristor only operates at its breakover boundaries of the latching condition with the NPN transistor portion of the thyristor operating in the active region. Under this condition, the anode voltage VA continues to increase without significant anode current increase.

Abstract: A buck regulator having a voltage sensor for sensing a voltage reversal caused by freewheeling current from an output inductor in the regulator. Upon sensing a reversed voltage, the voltage sensor triggers a gate controller to turn on a switch in the regulator, and thereby terminate a dead time. The voltage sensor and gate controller are high speed circuits, and therefore can reduce the duration of the dead time. Reducing the dead time duration improves efficiency by reducing the duration of body diode conduction. The dead time can be reduced to less than a turn-on time of the body diode, thereby preventing charge buildup in the body diode, and, consequently, preventing reverse recovery loss in the body diode. The present invention improves electrical conversion efficiency, and allows for increased operating frequency in buck regulators.

Abstract: A buck regulator having a voltage sensor for sensing a voltage reversal caused by freewheeling current from an output inductor in the regulator. Upon sensing a reversed voltage, the voltage sensor triggers a gate controller to turn on a switch in the regulator, and thereby terminate a dead time. The voltage sensor and gate controller are high speed circuits, and therefore can reduce the duration of the dead time. Reducing the dead time duration improves efficiency by reducing the duration of body diode conduction. The dead time can be reduced to less than a turn-on time of the body diode, thereby preventing charge buildup in the body diode, and, consequently, preventing reverse recovery loss in the body diode. The present invention improves electrical conversion efficiency, and allows for increased operating frequency in buck regulators.

Abstract: A gate-controlled switch includes a gate turn-off thyristor in series with a diode. By using the diode in series with the GTO, the switch significantly increases the turn-off voltage that can be used for the current commutation. The unity turn-off gain and the snubberless turn-off capability are demonstrated.