1
David M Stumfall, Kazutoyo Sekine: Apparatus and method for providing power to circuitry implementing two different power sources. Sony Corporation, Sony Trans Com, Blakely Sokoloff Taylor & Zafman, January 4, 2000: US06011322 (69 worldwide citation)

An apparatus and method for providing power control in an in-flight entertainment system is disclosed. The power control circuit comprises a first power supply that supplies a first voltage and a second power supply that supplies a second voltage. The circuit further comprises a detector circuit hav ...


2
David M Stumfall: Electronic apparatus having low radio frequency interference from system clock signal. Printronix, Fraser and Bogucki, March 26, 1985: US04507796 (26 worldwide citation)

A printer having greatly reduced radio frequency interference from the system clock signal therein is provided by angle modulating the system clock signal in accordance with a desired modulation signal. The modulation signal is chosen so as to spread and thereby reduce the energy level of the system ...


3
David M Stumfall, Kazutoyo Sekine: Apparatus and method for extending the supply of reserved power during a line power interruption. Sony Corporation, Sony Trans Com, Blakely Sokoloff Taylor & Zafman, August 24, 1999: US05942811 (24 worldwide citation)

An apparatus and method for extending the supply of reserved power during an interruption to power supplied by a primary power supply in an in-flight entertainment system is disclosed. The apparatus has a power supply that provides a first supply voltage and a capacitor coupled to the power supply t ...


4
David M Stumfall, Bruce R Ferguson: Apparatus and method of providing EMI filtering. Sony Corporation, Sony Trans Com, Blakely Sokoloff Taylor & Zafman, February 29, 2000: US06031299 (13 worldwide citation)

The present invention is a method and apparatus of providing EMI filtering through the implementation of a voltage sense circuit that is used in conjunction with a power correction circuit in an electromagnetic (EMI) filter system. The apparatus comprises a filter that receives an alternating curren ...


5
David M Stumfall, Kazutoyo Sekine: Apparatus and method of providing switching frequency synchronization. Sony Corporation, Sony Trans Com, Blakely Sokoloff Taylor & Zafman, December 12, 2000: US06160591 (8 worldwide citation)

An apparatus and method for reducing interference on a display screen in an in-flight entertainment system, where the interference results from power conversion by a power regulator that supplies voltage to the display screen, is disclosed. The apparatus comprises a clock generator that provides a v ...


6
David C Condon, David M Stumfall: Magnetic print hammer actuator protection circuit. Printronix, Scherlacher Mok & Roth, October 24, 1989: US04875409 (3 worldwide citation)

In a printer in which drive transistors coupled to hammer drive coils control energization of the coils within each of a plurality of magnetic print hammer actuators to provide firing of hammer springs associated with the print hammer actuators, leakage of one or more of the drive transistors when t ...