Patents by Inventor Kohji Yoshii
Kohji Yoshii 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: 8446215Abstract: A constant voltage circuit is disclosed that includes an output control transistor and an overcurrent protection circuit. The overcurrent protection circuit includes a proportional current generation circuit part, a current division circuit part, a division ratio control circuit part, a current-voltage conversion circuit part, and an output current control circuit part. When the output voltage of the current-voltage conversion circuit part reaches a predetermined voltage, the output current control circuit part prevents an increase in the output current of the output control transistor so as to reduce a voltage output from an output terminal. When the voltage output from the output terminal is reduced to a predetermined limit voltage, the division ratio control circuit part changes the division ratio of the current division circuit part so that a current supplied to the current-voltage conversion circuit part increases so as to reduce the output current of the output control transistor.Type: GrantFiled: January 17, 2007Date of Patent: May 21, 2013Assignee: Ricoh Company, Ltd.Inventors: Toshihisa Nagata, Hideki Agari, Kohji Yoshii
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Patent number: 8253404Abstract: A disclosed constant voltage circuit is configured to become active or inactive and convert an input voltage applied to an input terminal into a predetermined constant voltage for output from an output terminal. The circuit includes an output transistor for supplying, from the input terminal to the output terminal, an output current, an error amplifier circuit unit for controlling operations of the output transistor to make a first proportional voltage, which is proportional to the output voltage from the output terminal, equal to a predetermined reference voltage, a ramp voltage generating circuit unit for generating and outputting a ramp voltage whose voltage level increases at a predetermined speed from start-up, and an amplifier circuit unit for amplifying the voltage difference between the ramp voltage and a second proportional voltage, which is proportional to the output voltage, and outputting the amplified voltage difference to a control electrode of the output transistor.Type: GrantFiled: December 4, 2008Date of Patent: August 28, 2012Assignee: Ricoh Company, Ltd.Inventor: Kohji Yoshii
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Patent number: 7948223Abstract: A constant voltage circuit that is capable of realizing high speed response with respect to an abrupt change in an input voltage or a load current is disclosed. The constant voltage circuit includes a first error amplifier with a high direct current gain and a second error amplifier with high speed responsiveness with respect to a change in an output voltage. The constant voltage circuit uses the first and second error amplifiers to conduct operation control of an output voltage control transistor in response to a change in the output voltage.Type: GrantFiled: March 27, 2008Date of Patent: May 24, 2011Assignee: Ricoh Company, Ltd.Inventors: Toshihisa Nagata, Kohji Yoshii, Yusuke Minakuchi
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Publication number: 20100320993Abstract: A disclosed constant voltage circuit is configured to become active or inactive and convert an input voltage applied to an input terminal into a predetermined constant voltage for output from an output terminal. The circuit includes an output transistor for supplying, from the input terminal to the output terminal, an output current, an error amplifier circuit unit for controlling operations of the output transistor to make a first proportional voltage, which is proportional to the output voltage from the output terminal, equal to a predetermined reference voltage, a ramp voltage generating circuit unit for generating and outputting a ramp voltage whose voltage level increases at a predetermined speed from start-up, and an amplifier circuit unit for amplifying the voltage difference between the ramp voltage and a second proportional voltage, which is proportional to the output voltage, and outputting the amplified voltage difference to a control electrode of the output transistor.Type: ApplicationFiled: December 4, 2008Publication date: December 23, 2010Applicant: RICOH COMPANY, LTD.Inventor: Kohji Yoshii
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Patent number: 7856253Abstract: An integrated circuit for supplying power includes an IC chip having a rectangular shape and having a first edge and a second edge opposite the first edge, a switching regulator implemented on the IC chip and having a driver transistor whose ON time of switching is controlled to adjust an output voltage of the switching regulator, and a series regulator implemented on the IC chip, wherein the driver transistor of the switching regulator is positioned near the first edge, and the series regulator is positioned near the second edge.Type: GrantFiled: March 13, 2007Date of Patent: December 21, 2010Assignee: Ricoh Company, Ltd.Inventors: Hideki Agari, Kohji Yoshii
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Patent number: 7831851Abstract: A switching regulator is disclosed that includes a switching transistor controlling output of an input voltage by switching in accordance with an input control signal; a smoothing circuit part configured to smooth the output voltage of the switching transistor and output the smoothed voltage to an output terminal; a control circuit part configured to control the switching of the switching transistor in synchronization with an externally input clock signal so that a voltage at the output terminal is a predetermined constant voltage; and a clock signal detector circuit part configured to detect the presence or absence of inputting of the clock signal. Upon detecting stoppage of the inputting of the clock signal, the clock signal detector circuit part causes the control circuit part to stop operating and perform a standby operation for reducing power consumption and thereby to turn off the switching transistor.Type: GrantFiled: September 28, 2005Date of Patent: November 9, 2010Assignee: Ricoh Company, Ltd.Inventor: Kohji Yoshii
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Patent number: 7755395Abstract: An inverter circuit for generating an output signal at an output node obtained by inverting an input signal level at an input node includes a common-source MOS transistor having a gate node connected to the input node, a source connected to a predetermined voltage and a substrate gate, a load resistor connected in series with the MOS transistor, and a resistor connected between the gate node and the substrate gate of the MOS transistor.Type: GrantFiled: June 26, 2009Date of Patent: July 13, 2010Assignee: Ricoh Company, Ltd.Inventors: Kohji Yoshii, Yasutaka Shimizu
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Patent number: 7709899Abstract: A semiconductor apparatus is disclosed. The semiconductor apparatus comprises a substrate with a pad, an internal circuitry region, and a protection resistance formed on the substrate. The pad is connected to a first electrode of the protection resistance by wiring, the internal circuitry region is connected to a second electrode of the protection resistance by wiring, and the protection resistance protects the internal circuitry region from electrostatic discharging. The semiconductor apparatus is characterized in that the pad is placed between the protection resistance and the internal circuitry region.Type: GrantFiled: March 29, 2005Date of Patent: May 4, 2010Assignee: Ricoh Company, Ltd.Inventors: Hideki Agari, Kohji Yoshii, Tsugunori Okuda
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Publication number: 20100013519Abstract: An inverter circuit for generating an output signal at an output node obtained by inverting an input signal level at an input node includes a common-source MOS transistor having a gate node connected to the input node, a source connected to a predetermined voltage-and a substrate gate, a load resistor connected in series with the MOS transistor, and a resistor connected between the gate node and the substrate gate of the MOS transistor.Type: ApplicationFiled: June 26, 2009Publication date: January 21, 2010Applicant: RICOH COMPANY, LTD.Inventors: Kohji YOSHII, Yasutaka SHIMIZU
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Patent number: 7541787Abstract: A transistor drive circuit, a constant voltage circuit, and a method thereof provided with a reference voltage generator, a power voltage detector, and a plurality of error amplifying circuits. The plurality of error amplifying circuits have different operational characteristics. One of the error amplifying circuits is selectively activated in response to a control signal in accordance with an operational mode selected. A reference voltage produced by the reference voltage generator or a divided voltage produced by the power voltage detector is also changed in response to the control signal suitably for each one of the plurality of error amplifying circuits which is selectively activated so as to control the power voltage generated by a power transistor to output a constant power voltage.Type: GrantFiled: September 20, 2006Date of Patent: June 2, 2009Assignee: Ricoh Company, Ltd.Inventors: Katsuhiro Hayashi, Kohji Yoshii
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Publication number: 20080238385Abstract: A constant voltage circuit that is capable of realizing high speed response with respect to an abrupt change in an input voltage or a load current is disclosed. The constant voltage circuit includes a first error amplifier with a high direct current gain and a second error amplifier with high speed responsiveness with respect to a change in an output voltage. The constant voltage circuit uses the first and second error amplifiers to conduct operation control of an output voltage control transistor in response to a change in the output voltage.Type: ApplicationFiled: March 27, 2008Publication date: October 2, 2008Inventors: Toshihisa Nagata, Kohji Yoshii, Yusuke Minakuchi
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Publication number: 20080197829Abstract: A semiconductor device provided with a monitor transistor for detecting electric current flowing in a driver transistor mounted on a semiconductor chip is disclosed. The semiconductor device includes plural transistors provided in the monitor transistor and connected in parallel. The plural transistors are disposed at a periphery of an area of the semiconductor chip on which the driver transistor is mounted.Type: ApplicationFiled: September 21, 2005Publication date: August 21, 2008Inventors: Toshihisa Nagata, kohji Yoshii
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Patent number: 7368896Abstract: A constant voltage circuit that is capable of realizing high speed response with respect to an abrupt change in an input voltage or a load current is disclosed. The constant voltage circuit includes a first error amplifier with a high direct current gain and a second error amplifier with high speed responsiveness with respect to a change in an output voltage. The constant voltage circuit uses the first and second error amplifiers to conduct operation control of an output voltage control transistor in response to a change in the output voltage.Type: GrantFiled: March 28, 2005Date of Patent: May 6, 2008Assignee: Ricoh Company, Ltd.Inventors: Toshihisa Nagata, Kohji Yoshii, Yusuke Minakuchi
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Publication number: 20070187763Abstract: A semiconductor apparatus is disclosed. The semiconductor apparatus comprises a substrate with a pad, an internal circuitry region, and a protection resistance formed on the substrate. The pad is connected to a first electrode of the protection resistance by wiring, the internal circuitry region is connected to a second electrode of the protection resistance by wiring, and the protection resistance protects the internal circuitry region from electrostatic discharging. The semiconductor apparatus is characterized in that the pad is placed between the protection resistance and the internal circuitry region.Type: ApplicationFiled: March 29, 2005Publication date: August 16, 2007Inventors: Hideki Agari, Kohji Yoshii, Tsugunori Okuda
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Publication number: 20070155444Abstract: An integrated circuit for supplying power includes an IC chip having a rectangular shape and having a first edge and a second edge opposite the first edge, a switching regulator implemented on the IC chip and having a driver transistor whose ON time of switching is controlled to adjust an output voltage of the switching regulator, and a series regulator implemented on the IC chip, wherein the driver transistor of the switching regulator is positioned near the first edge, and the series regulator is positioned near the second edge.Type: ApplicationFiled: March 13, 2007Publication date: July 5, 2007Inventors: Hideki Agari, Kohji Yoshii
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Publication number: 20070114986Abstract: A switching regulator is disclosed that includes a switching transistor controlling output of an input voltage by switching in accordance with an input control signal; a smoothing circuit part configured to smooth the output voltage of the switching transistor and output the smoothed voltage to an output terminal; a control circuit part configured to control the switching of the switching transistor in synchronization with an externally input clock signal so that a voltage at the output terminal is a predetermined constant voltage; and a clock signal detector circuit part configured to detect the presence or absence of inputting of the clock signal. Upon detecting stoppage of the inputting of the clock signal, the clock signal detector circuit part causes the control circuit part to stop operating and perform a standby operation for reducing power consumption and thereby to turn off the switching transistor.Type: ApplicationFiled: September 28, 2005Publication date: May 24, 2007Inventor: Kohji Yoshii
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Publication number: 20070115045Abstract: A constant voltage circuit is disclosed that includes an output control transistor and an overcurrent protection circuit. The overcurrent protection circuit includes a proportional current generation circuit part, a current division circuit part, a division ratio control circuit part, a current-voltage conversion circuit part, and an output current control circuit part. When the output voltage of the current-voltage conversion circuit part reaches a predetermined voltage, the output current control circuit part prevents an increase in the output current of the output control transistor so as to reduce a voltage output from an output terminal. When the voltage output from the output terminal is reduced to a predetermined limit voltage, the division ratio control circuit part changes the division ratio of the current division circuit part so that a current supplied to the current-voltage conversion circuit part increases so as to reduce the output current of the output control transistor.Type: ApplicationFiled: January 17, 2007Publication date: May 24, 2007Inventors: Toshihisa Nagata, Hideki Agari, Kohji Yoshii
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Patent number: 7215180Abstract: A constant voltage circuit is disclosed that includes an output control transistor and an overcurrent protection circuit. The overcurrent protection circuit includes a proportional current generation circuit part, a current division circuit part, a division ratio control circuit part, a current-voltage conversion circuit part, and an output current control circuit part. When the output voltage of the current-voltage conversion circuit part reaches a predetermined voltage, the output current control circuit part prevents an increase in the output current of the output control transistor so as to reduce a voltage output from an output terminal. When the voltage output from the output terminal is reduced to a predetermined limit voltage, the division ratio control circuit part changes the division ratio of the current division circuit part so that a current supplied to the current-voltage conversion circuit part increases so as to reduce the output current of the output control transistor.Type: GrantFiled: August 2, 2004Date of Patent: May 8, 2007Assignee: Ricoh Company, Ltd.Inventors: Toshihisa Nagata, Hideki Agari, Kohji Yoshii
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Patent number: 7209770Abstract: An integrated circuit for supplying power includes an IC chip having a rectangular shape and having a first edge and a second edge opposite the first edge, a switching regulator implemented on the IC chip and having a driver transistor whose ON time of switching is controlled to adjust an output voltage of the switching regulator, and a series regulator implemented on the IC chip, wherein the driver transistor of the switching regulator is positioned near the first edge, and the series regulator is positioned near the second edge.Type: GrantFiled: December 4, 2003Date of Patent: April 24, 2007Assignee: Ricoh Company, Ltd.Inventors: Hideki Agari, Kohji Yoshii
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Publication number: 20070069819Abstract: A transistor drive circuit, a constant voltage circuit, and a method thereof provided with a reference voltage generator, a power voltage detector, and a plurality of error amplifying circuits. The plurality of error amplifying circuits have different operational characteristics. One of the error amplifying circuits is selectively activated in response to a control signal in accordance with an operational mode selected. A reference voltage produced by the reference voltage generator or a divided voltage produced by the power voltage detector is also changed in response to the control signal suitably for each one of the plurality of error amplifying circuits which is selectively activated so as to control the power voltage generated by a power transistor to output a constant power voltage.Type: ApplicationFiled: September 20, 2006Publication date: March 29, 2007Inventors: Katsuhiro Hayashi, Kohji Yoshii