Patents by Inventor Masato Kashima
Masato Kashima has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7936157Abstract: A switching power supply system, in which a DC voltage obtained by full-wave rectification of an AC voltage is turned on and off by a switching device, converted to a desired DC voltage and outputted, includes a slope compensating circuit and an overcurrent protecting circuit, and a full-wave rectified voltage inputted to a terminal Tm is subtracted from a reference voltage Vref inputted to a terminal Tr to produce a reference voltage waveform signal (OCP correction value) Vocp to eliminate the influence of slope compensation. The reference signal of the overcurrent protection circuit is varied by a signal having a reverse phased waveform relative to the phase of the full-wave rectified waveform. This enables highly accurate overcurrent protection with a net overcurrent protection level unaffected by the slope compensation varied by the input voltage when the system is operated in a current mode.Type: GrantFiled: May 29, 2008Date of Patent: May 3, 2011Assignee: Fuji Electric Device Technology Co., Ltd.Inventor: Masato Kashima
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Patent number: 7515441Abstract: A switching power supply, in which a switching element turns on and off electric current flowing on the primary side of an output transformer so as to rectify and output a pulsating flow generated on the secondary side of the output transformer, includes a voltage detecting section that detects an output voltage, a current detecting section that detects electric current flowing through a power transistor as the switching element, a controller that compares a voltage detection signal from the voltage detecting section and a current detection signal from the current detecting section to control the duty of the power transistor during an ON time, and a slope compensation circuit that compensates the rate of change of the voltage detection signal using a slope compensation signal. The slope compensation circuit subtracts the slope compensation signal from the voltage detection signal and outputs the resulting signal to a PWM comparator.Type: GrantFiled: June 15, 2007Date of Patent: April 7, 2009Assignee: Fuji Electric Device Technology Co., Ltd.Inventor: Masato Kashima
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Publication number: 20080298105Abstract: A switching power supply system, in which a DC voltage obtained by full-wave rectification of an AC voltage is turned on and off by a switching device, converted to a desired DC voltage and outputted, includes a slope compensating circuit and an overcurrent protecting circuit, and a full-wave rectified voltage inputted to a terminal Tm is subtracted from a reference voltage Vref inputted to a terminal Tr to produce a reference voltage waveform signal (OCP correction value) Vocp to eliminate the influence of slope compensation. The reference signal of the overcurrent protection circuit is varied by a signal having a reverse phased waveform relative to the phase of the full-wave rectified waveform. This enables highly accurate overcurrent protection with a net overcurrent protection level unaffected by the slope compensation varied by the input voltage when the system is operated in a current mode.Type: ApplicationFiled: May 29, 2008Publication date: December 4, 2008Applicant: Fuji Electric Device Technology Co., LtdInventor: Masato Kashima
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Publication number: 20080007975Abstract: A switching power supply, in which a switching element turns on and off electric current flowing on the primary side of an output transformer so as to rectify and output a pulsating flow generated on the secondary side of the output transformer, includes a voltage detecting section that detects an output voltage, a current detecting section that detects electric current flowing through a power transistor as the switching element, a controller that compares a voltage detection signal from the voltage detecting section and a current detection signal from the current detecting section to control the duty of the power transistor during an ON time, and a slope compensation circuit that compensates the rate of change of the voltage detection signal using a slope compensation signal. The slope compensation circuit subtracts the slope compensation signal from the voltage detection signal and outputs the resulting signal to a PWM comparator.Type: ApplicationFiled: June 15, 2007Publication date: January 10, 2008Applicant: Fuji Electric Device Technology Co., LtdInventor: Masato Kashima
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Patent number: 6657877Abstract: A power supply circuit improves the power factor when the load is light, and incorporates a starting circuit for reacting quickly to the changes in the output from the power supply circuit and a short-circuit detecting means for detecting the short-circuit of the feedback signal. The apparatus includes: an error amplifier; a comparator that monitors the output from the error amplifier and generates an offset regulating current ISO; a multiplier; a sensing current comparator that compares the output signal from the multiplier and the AC line current and generates a reset signal; a timer that directly monitors the inputted zero-cross signal; and a comparator for short-circuit detection, that facilitates reducing the exterior parts and components.Type: GrantFiled: September 28, 2001Date of Patent: December 2, 2003Assignee: Fuji Electric Co., Ltd.Inventors: Masato Kashima, Mitsuru Sato, Eiji Kuroda, Hironobu Shiroyama
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Publication number: 20020089860Abstract: A power supply circuit improves the power factor when the load is light, and incorporates a starting circuit for reacting quickly to the changes in the output from the power supply circuit and a short-circuit detecting means for detecting the short-circuit of the feedback signal. The apparatus includes: an error amplifier; a comparator that monitors the output from the error amplifier and generates an offset regulating current ISO; a multiplier; a sensing current comparator that compares the output signal from the multiplier and the AC line current and generates a reset signal; a timer that directly monitors the inputted zero-cross signal; and a comparator for short-circuit detection, that facilitates reducing the exterior parts and components.Type: ApplicationFiled: September 28, 2001Publication date: July 11, 2002Inventors: Masato Kashima, Mitsuru Sato, Eiji Kuroda, Hironobu Shiroyama