William W Hwang

US Patent:

57085730, Jan 13, 1998

Filed:

Feb 1, 1996

Appl. No.:

8/593164

Inventors:

David M. Lusher - Torrance CA
Wilbur E. Hong - Torrance CA
William B. Hwang - Los Angeles CA

Assignee:

Hughes Electronics - Los Angeles CA

International Classification:

H02M 322
G05F 146

US Classification:

363 47

Abstract:

A DC to DC converter including a resonant switching circuit (13, 51 , 115, 151, 125, 153); an impedance matching circuit (53) responsive to the resonant switching circuit; a rectifier circuit (55) responsive to the impedance matching circuit; an output filter circuit (57) responsive to rectifier circuit for providing a filtered DC to DC converter voltage output; and a varactor diode circuit (27, 29, 31, 61) responsive to the filtered DC to DC converter voltage output for controlling the impedance matching circuit such that the filtered DC to DC converter output voltage is substantially constant.

US Patent:

56731884, Sep 30, 1997

Filed:

Mar 25, 1996

Appl. No.:

8/622511

Inventors:

David M. Lusher - Torrance CA
Wilbur E. Hong - Torrance CA
William B. Hwang - Los Angeles CA

Assignee:

Hughes Electronic - Los Angeles CA

International Classification:

H02H 7122

US Classification:

363132

Abstract:

A DC to AC inverter that includes a first capacitor (11) and a first inductor (13) connected in series between a positive voltage supply node and a central node; a first active switch switching (15) connected across the first capacitor and driven with a first periodic drive signal of a predetermined frequency; a second capacitor (21) and a second inductor (23) connected in series between a negative voltage supply node and the central node; a second active switch (25) connected across the second capacitor and being driven with a second periodic signal of said predetermined frequency and being out of phase by 180 degrees relative to the first periodic drive signal; a bandpass filter (31, 33) connected between the central node and an output node; and a load (47) connected between the output node and ground.

US Patent:

54102766, Apr 25, 1995

Filed:

Dec 28, 1993

Appl. No.:

8/174541

Inventors:

William B. Hwang - Los Angeles CA
Michael Brand - Los Angeles CA
Ronnie B. Chan - Gardena CA
Robert S. Boiles - Torrance CA

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

H03K 704

US Classification:

330297

Abstract:

Circuits for modulating an RF input signal applied to an RF high power amplifier to produce a modulated RF output signal. The present invention employs a VHF power supply or converter with a modulation control circuit that enables the power supply to be pulsed at frequencies commensurate with a radar in which it is employed, for example. Modulation of the high power amplifier is accomplished by applying a pulsed voltage output signal to a DC bias input of the high power amplifier. More particularly, the modulation control circuit receives a logic control signal, generates a pulse control signal in response thereto, and modulates a DC input signal processed by the converter. The VHF converter receives and modulates the DC input signal in response to the pulse control signal to cause the pulsed voltage output signal from the converter to pulse at a rate and duty cycle determined by the logic control signal. The output signal modulates the RF input signal amplified by the RF high power amplifier. The modulation control circuit comprises a digital input buffer for receiving the logic control signal, a driver circuit for generating the pulse control signal, and a modulation switch coupled to the converter for modulating the DC input signal in response to the logic control signal.

US Patent:

57037710, Dec 30, 1997

Filed:

Jul 19, 1996

Appl. No.:

8/690247

Inventors:

Wilbur E. Wong - Torrance CA
David M. Lusher - Torrance CA
William B. Hwang - Los Angeles CA

Assignee:

Hughes Electronics - Los Angeles CA

International Classification:

H02M 7538

US Classification:

363134

Abstract:

A VHF inverter including an inverter circuit (100) for providing an inverter output; a constant magnitude, variable phase impedance transforming circuit (54, 154) responsive the inverter; and a load circuit (55, 155) responsive to the impedance transforming circuit.

US Patent:

56687150, Sep 16, 1997

Filed:

Jun 27, 1996

Appl. No.:

8/671035

Inventors:

Wilbur E. Hong - Torrance CA
David M. Lusher - Torrance CA
William B. Hwang - Los Angeles CA

Assignee:

Hughes Electronics - Los Angeles CA

International Classification:

H02M 7537
H04B 118

US Classification:

363131

Abstract:

VHF DC to AC inverters which include switching circuitry (13, 115, 125) and multiple resonant waveshaping networks (C11, L11, C12; C21, L21, C22; C111, L111; C221, L221; C331, L331; C441, L441) connected between the switching circuitry and respective load circuits (33, 43, 133, 143).

US Patent:

56105690, Mar 11, 1997

Filed:

Jan 31, 1996

Appl. No.:

8/599524

Inventors:

William B. Hwang - Los Angeles CA
David M. Lusher - Torrance CA

Assignee:

Hughes Electronics - Los Angeles CA

International Classification:

H01F 2728

US Classification:

336200

Abstract:

A co-fired inductor structure that includes a plurality of planar co-fired ceramic dielectric insulating layers (13); a plurality of elongated conductive strips (11-1-11-4, 12-1-12-4, 21-1-21-3, 22-1-22-3) arranged in four groups of parallel elongated conductive strips each group disposed on a respective dielectric insulating layer; and a plurality of via columns (101, 102, 103, 104) for interconnecting the ends of the elongated conductive strips such that the elongated conductive strips and the via columns form a winding.

US Patent:

47092157, Nov 24, 1987

Filed:

Dec 30, 1985

Appl. No.:

6/814546

Inventors:

Robert F. McClanahan - Valencia CA
Robert Washburn - Malibu CA
William Hwang - Los Angeles CA

Assignee:

Hughes Aircraft Company - Los Angeles CA

International Classification:

H03F 358

US Classification:

330 43

Abstract:

A method and apparatus are disclosed for regulating the operation of a TWT. The TWT regulation is achieved by detecting the operating condition of the TWT, e. g. , by measuring dynamic gain, and regulating feedback of the TWT output in response to the TWT operating condition. The invention is preferably implemented so as to augment the TWT input drive from an exciter source to induce the TWT to drive itself into saturation. The inventive technique comprises determining whether the TWT is operating in a desired operating condition, e. g. , saturation, feeding back to the TWT input a portion of the TWT output power to the TWT input, and regulating the feedback signal to keep the TWT operating in the desired condition. Determination of whether the TWT is operating in a saturation condition may be affected through measurement of the TWT dynamic gain. The invention permits dynamic management of the feedback to accommodate variations in gain of the TWT, e. g.