Fred E Sawyer

US Patent:

20190074826, Mar 7, 2019

Filed:

Sep 6, 2017

Appl. No.:

15/697381

Inventors:

- Grand Cayman, KY
Fred Sawyer - Foxboro MA, US

International Classification:

H03K 17/082
H03K 17/0814
H02M 3/158
H02H 3/12
H02H 3/20
H02H 9/04

Abstract:

Aspects of the present disclosure disclose a power semiconductor device coupled to a load operable to draw a load current comprising a power switch having a first terminal coupled to the load and a controller coupled to a control terminal of the power switch. The controller comprises a gate driving circuit configured to provide control of the control terminal of the power switch during normal switching operations; an overvoltage detection circuit configured to detect an overvoltage event occurring at the first terminal of the power switch; and an overvoltage protection circuit configured to provide control of the control terminal of the power switch during detection of the overvoltage event.

US Patent:

20170222561, Aug 3, 2017

Filed:

Feb 3, 2016

Appl. No.:

15/014974

Inventors:

- Villach, AT
Gong Xiao Wu - Singapore, SG
Fred Sawyer - Foxboro MA, US

International Classification:

H02M 3/335

Abstract:

In some embodiments, a power system includes an integrated circuit (IC). The IC includes a first switching transistor having a load path coupled between a sensing terminal of the IC and a first terminal of the IC. The first terminal of the IC is configured to be coupled to a first load path terminal of a second switching transistor. The IC also includes a first diode coupled between the first terminal of the IC and a second terminal of the IC. The second terminal is configured to be coupled to an auxiliary winding of the power system. The IC further includes a first driver circuit having an output coupled to a third terminal of the IC. The third terminal is configured to be coupled to a control node of the second switching transistor.

US Patent:

20170222643, Aug 3, 2017

Filed:

Jan 28, 2016

Appl. No.:

15/009438

Inventors:

- Villach, AT
Fred Sawyer - Foxboro MA, US

International Classification:

H03K 17/567
H03K 17/22
H03K 7/08
H03K 17/74
H03K 17/691

Abstract:

In accordance with an embodiment, a circuit includes a first and a second switching transistors configured to be coupled in series between a first reference voltage terminal and a transformer. The circuit also includes a first diode coupled between a first drain of the first switching transistor and a first input terminal. The first diode is configured to clamp a voltage of the first drain to a voltage of the first input terminal. The circuit further includes a switching circuit coupled between the second switching transistor and the first input terminal. The switching circuit is configured to connect a second source of the second switching transistor to a second gate of the second switching transistor when a voltage of the second source exceeds the voltage of the first input terminal.

US Patent:

20160197556, Jul 7, 2016

Filed:

Jan 6, 2015

Appl. No.:

14/590778

Inventors:

- Durham NC, US
Fred Sawyer - Foxboro MA, US

International Classification:

H02M 3/335

Abstract:

An embodiment method for designing a power converter system includes receiving, by a processor, power converter design parameters. The design parameters include a minimum DC input voltage Vand a maximum DC input voltage V, a minimum switching frequency fand a maximum switching frequency fof a switching bridge of the power converter, and a target output voltage and a target output power. The method also includes calculating, by the processor, a first power converter configuration. The first power converter configuration includes a calculated magnetizing inductance Lequal to Rtan(φ)(2πf), where φ is a load angle complement equal to a sin(VV), and Ris an equivalent reflected load resistance of the power converter. The first power converter configuration also includes a calculated resonant inductance Lequal to Lcos(φ)(ff−1)and a calculated resonant capacitance Cequal to L(2πf).

US Patent:

20140167634, Jun 19, 2014

Filed:

Dec 17, 2012

Appl. No.:

13/716677

Inventors:

- Milpitas CA, US
Fred Sawyer - Foxboro MA, US

Assignee:

INFINEON TECHNOLOGIES NORTH AMERICA CORP. - Milpitas CA

International Classification:

H05B 37/02

US Classification:

315210

Abstract:

An LED driver includes a transformer, current control loop and current adjustment circuit. The primary side of the transformer transfers energy to the secondary side of the transformer responsive to an input signal. The secondary side delivers output current to one or more LEDs at a magnitude corresponding to the amount of energy transferred to the secondary side. The current control loop controls current in the primary side so that the output current equals a reference current signal. The current adjustment circuit injects a current adjustment signal into the current control loop responsive to a phase-cut signal which removes a portion of the input signal. The current control loop also decreases the current in the primary side responsive to the current adjustment signal so that a brightness of each LED connected to the secondary side is decreased by an amount corresponding to the magnitude of the current adjustment signal.

US Patent:

20140153295, Jun 5, 2014

Filed:

Nov 30, 2012

Appl. No.:

13/690388

Inventors:

- Milpitas CA, US
Fred Sawyer - Foxboro MA, US

Assignee:

Infineon Technologies North America Corp. - Milpitas CA

International Classification:

H02M 3/335

US Classification:

363 2112

Abstract:

A two-transistor flyback converter includes a transformer having a primary side and a secondary side, a first transistor connected between an input voltage source and a first terminal of the primary side, a second transistor connected between ground and a second terminal of the primary side, and a diode directly connected between the first terminal of the primary side and ground. The first and second transistors are operable to switch on and off simultaneously and with no current return from the primary side to the input voltage source when the input voltage source is less than a reflected voltage from the secondary side.