Earl M Estes

US Patent:

51967847, Mar 23, 1993

Filed:

Mar 18, 1991

Appl. No.:

7/670664

Inventors:

Earl M. Estes - Tucson AZ

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

G01R 3300
G01R 122

US Classification:

324117R

Abstract:

A method and circuit for measuring direct and high duty factor current in a conductor (1) with minimal interference with the operation of a monitored circuit. Current flow in the conductor is magnetically sensed with a transformer T1 having a primary winding connected electrically in series with the conductor (1). The transformer T1 is driven into saturation during a first time interval and brought out of saturation during a second time interval. After the transformer T1 is brought out of saturation, an output signal is provided which is proportional to the flow of current in the conductor (1).

US Patent:

49223798, May 1, 1990

Filed:

Jul 18, 1989

Appl. No.:

7/381559

Inventors:

Earl M. Estes - Tucson AZ

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

H01L 2336
H05K 720

US Classification:

361388

Abstract:

A hermetically sealed power semiconductor package includes a body 11 and a thick metal back 24. The metal back serves as a mounting device as well as a thermal channel for the package eliminating the need for intermediate heatsinks. For example, fasteners 47 extending into the back 24 can be used to mount the package to a printed wiring board 38 and directly to a heatsink 44.

US Patent:

51483580, Sep 15, 1992

Filed:

Apr 3, 1991

Appl. No.:

7/679965

Inventors:

Earl M. Estes - Tucson AZ

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

H02M 706
H02M 3155

US Classification:

363 24

Abstract:

A circuit for reducing the commutation transient in a switch-driven (12) free-wheeling rectifier (20) applied to a load (10) via a continuously conducting energy conducting inductor (28), in which a further inductor (34) and diodes (32, 38) are interconnected with the switch-driven rectifier (20) to free-wheel recovered commutation energy from rectifier (20) when the switch is non-conducting. In other circuit variations temporary energy storage is aided by one or more capacitors (72) and additional diodes (52, 54, 80, 107, 122) during turn-on of rectifier (20), which energy recycled back into the circuit to minimize power dissipation and reduce circuit component heating.

US Patent:

50139312, May 7, 1991

Filed:

Nov 15, 1988

Appl. No.:

7/271475

Inventors:

Earl M. Estes - Tucson AZ

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

H03K 500

US Classification:

307261

Abstract:

A triangle wave generator (10) which is programmable, and which provides variable amplitude, frequency independent, triangle waves over a wide frequency bandwidth while employing a low voltage power source. The triangle wave generator (10) comprises a square wave input signal source (12) and a reference voltage signal source (14). A first amplifier (16) amplifies the square wave input signals and couples them by way of a transformer (34) to an integrator (36,40) which generates triangle wave output signals in response thereto. A second amplifier (18) connected to the triangle wave signal and to the transformer coupled square wave current source for the purpose of providing a bootstrap. A third amplifier (20) samples and compares the triangle wave output signals to the reference voltage signals and generates output error signals in response thereto. A driver circuit (22) responds to the output error signals and provides bias voltage signals to the first amplifier (16) that controls the amplitude of the square wave output signals in proportion to the amplitude of the reference voltage signals.

US Patent:

48496510, Jul 18, 1989

Filed:

Feb 24, 1988

Appl. No.:

7/160219

Inventors:

Earl M. Estes - Tucson AZ

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

H02M 3335

US Classification:

307125

Abstract:

Two-state, bilateral, single-pole, double-throw, half-bridge power-switching apparatus capable of high speed, high current switching over a duty factor range of zero percent to 100% includes a single-wire connector to a source of switching signals, a first FET whose gate is connected to the single-wire connector, and a second FET having its gate connected to the drain of the first FET and its source connected to the drain of the first FET through a device for preventing, in part, cross-current from the first FET to the second FET and for permitting the gate voltage on the second FET to be raised sufficiently high to turn on the second FET. The apparatus also includes a system for delivering on/off signals to the second FET and for holding the second FET on or off in response to switching signals having a duty factor in the range of zero percent to 100%.

US Patent:

52931218, Mar 8, 1994

Filed:

Oct 8, 1992

Appl. No.:

7/957964

Inventors:

Earl M. Estes - Tucson AZ

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

G01R 3300
G01R 120

US Classification:

324117R

Abstract:

A method and circuit for measuring direct and high duty factor current in a conductor (1) with minimal interference with the operation of a monitored circuit. Current flow in the conductor is magnetically sensed with a transformer T1 having a primary winding connected electrically in series with the conductor (1). The transformer T1 is driven into saturation during a first time interval and brought out of saturation during a second time interval. After the transformer T1 is brought out of saturation, an output signal is provided which is proportional to the flow of current in the conductor (1).