Gary D Eastman

54615321, Oct 24, 1995

Jun 14, 1994

8/261025

Gary B. Eastman - Plano TX

Texas Instruments Incorporated - Dallas TX

H02M 3337

361 56

A pulse transformer circuit which comprises a transformer core having a plurality of individual primary windings and a secondary winding, a plurality of preferably single turn primary circuits, each primary circuit coupled to a different one of the primary windings. Each primary circuit comprises a switch in series with the primary winding, a capacitor coupled across the primary winding and the switch and a voltage source coupled across the capacitor. A load circuit is coupled across said secondary winding. The switch is a semiconductor device having a control electrode and a current carrying path coupled to the primary winding and controlled by the control electrode. A clamp circuit can be coupled to the load circuit to minimize voltage overshoot in the secondary winding. The clamp circuit includes a voltage source of opposite polarity to the direction of voltage overshoot coupled through a unidirectional current conducting device between the load circuit and a source of reference potential and an RC circuit connected in parallel with the voltage source of opposite polarity to the direction of the voltage overshoot and the unidirectional current conducting device. A second embodiment of the clamp circuit includes an RC circuit coupled through a unidirectional current conducting device between the load circuit and a source of reference potential, the RC circuit including a capacitor and a variable resistance circuit in parallel with the capacitor.

53654218, Nov 15, 1994

Jan 11, 1994

8/182538

Gary B. Eastman - Plano TX

Texas Instruments Incorporated - Dallas TX

H02M 742

363 71

A pulse transformer circuit which comprises a transformer core having a plurality of individual primary windings and a secondary winding, a plurality of preferably single turn primary circuits, each primary circuit coupled to a different one of the primary windings. Each primary circuit comprises a switch in series with the primary winding, a capacitor coupled across the primary winding and the switch and a voltage source coupled across the capacitor. A load circuit is coupled across said secondary winding. The switch is a semiconductor device having a control electrode and a current carrying path coupled to the primary winding and controlled by the control electrode. A clamp circuit can be coupled to the load circuit to minimize voltage overshoot in the secondary winding. The clamp circuit includes a voltage source of opposite polarity to the direction of voltage overshoot coupled through a unidirectional current conducting device between the load circuit and a source of reference potential and an RC circuit connected in parallel with the voltage source of opposite polarity to the direction of the voltage overshoot and the unidirectional current conducting device. A second embodiment of the clamp circuit includes an RC circuit coupled through a unidirectional current conducting device between the load circuit and a source of reference potential, the RC circuit including a capacitor and a variable resistance circuit in parallel with the capacitor.