Patents by Inventor Kazutoshi Sako
Kazutoshi Sako 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: 9746870Abstract: A semiconductor device includes: a voltage generation unit that generates a first voltage having a first temperature characteristic; a constant voltage generation unit that generates a constant voltage; and an adjustment unit that generates a second voltage having a second temperature characteristic and a third voltage having a third temperature characteristic using the first voltage and the constant voltage. The constant voltage generation unit generates the constant voltage independently of the adjustment unit. One of the second and third temperature characteristics is an opposite characteristic to the first temperature characteristic. The device can also include a control unit that selects one of the second and third voltages in response to a predetermined setting value.Type: GrantFiled: April 22, 2015Date of Patent: August 29, 2017Assignee: RENESAS ELECTRONICS CORPORATIONInventors: Kazutoshi Sako, Tomokazu Matsuzaki
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Publication number: 20150227158Abstract: A semiconductor device includes: a voltage generation unit that generates a first voltage having a first temperature characteristic; a constant voltage generation unit that generates a constant voltage; and an adjustment unit that generates a second voltage having a second temperature characteristic and a third voltage having a third temperature characteristic using the first voltage and the constant voltage. The constant voltage generation unit generates the constant voltage independently of the adjustment unit. One of the second and third temperature characteristics is an opposite characteristic to the first temperature characteristic. The device can also include a control unit that selects one of the second and third voltages in response to a predetermined setting value.Type: ApplicationFiled: April 22, 2015Publication date: August 13, 2015Inventors: Kazutoshi SAKO, Tomokazu MATSUZAKI
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Patent number: 9046910Abstract: A constant current generation circuit of the invention includes: a temperature variable voltage generation unit that generates a first variation voltage whose voltage value fluctuates with temperature; a variation gradient adjustment unit that generates a second variation voltage based on a reference voltage smaller in the amount of variation with temperature than the first variation voltage and the first variation voltage; and a current generation unit that includes a current setting resistor whose resistance value fluctuates with temperature and generates an output current based on the second variation voltage and the current setting resistor. The variation gradient adjustment unit sets the coefficient of variation with temperature of the second variation voltage so that the difference between it and the coefficient of variation with temperature of the resistance value of the current setting resistor is within a preset first stipulated range.Type: GrantFiled: March 22, 2012Date of Patent: June 2, 2015Assignee: Renesas Electronics CorporationInventors: Kazutoshi Sako, Tomokazu Matsuzaki
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Patent number: 8878621Abstract: A semiconductor device includes: a resistance R whose resistance value varies in response to a substrate temperature variation; a resistance corrector that is coupled in series with the resistance R and switches its resistance value by a preset resistance step width to suppress a resistance value variation of the resistance R; a first voltage generator for generating a first voltage that varies in response to the substrate temperature; a second voltage generator for generating second voltages Vf1 to Vfn?1 for specifying the first voltage at a point when a switching operation of the resistance value of the resistance corrector is performed; and a resistance switch unit for switching the resistance value of the resistance corrector by comparing the first voltage and the second voltages Vf1 to Vfn?1.Type: GrantFiled: February 19, 2013Date of Patent: November 4, 2014Assignee: Renesas Electronics CorporationInventors: Tomokazu Matsuzaki, Kazutoshi Sako
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Patent number: 8816789Abstract: A semiconductor device according to an exemplary aspect of the invention is capable of being selectively switched between an oscillation circuit and a signal input-output circuit, and includes first and second external connecting terminals that are connectable to an oscillation device; an inverting amplifier an input side of which is electrically connected to the first external connecting terminal through a coupling capacitor and an output side of which is electrically connected to the second external connecting terminal; a feedback resistor connected to the input side and the output side of the inverting amplifier; a bias stabilization circuit that stabilizes a bias applied to the coupling capacitor; a first signal input-output portion connected to the first external connecting terminal; and a second signal input-output portion connected to the second external connecting terminal.Type: GrantFiled: June 18, 2012Date of Patent: August 26, 2014Assignee: Renesas Electronics CorporationInventors: Kazutoshi Sako, Tomokazu Matsuzaki, Kouji Yokosawa
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Patent number: 8542073Abstract: A variable-capacitance device includes a first capacitance element coupled between a first power supply terminal and an output terminal, a capacitance selection switch that is turned on and off in accordance with a capacitance switching signal, a second capacitance element coupled in parallel to the first capacitance element and in series to the capacitance selection switch, and an error correction circuit configured to operate such that in a state in which the capacitance selection switch is in an OFF state, in response to a charge reset signal that causes a voltage at the output terminal to be reset to a reset voltage, the error correction circuit substantially eliminates a difference between the voltage at the output terminal and a voltage at a capacitance switching node at which the second capacitance element is coupled to the capacitance selection switch.Type: GrantFiled: May 25, 2011Date of Patent: September 24, 2013Assignee: Renesas Electronics CorportionInventors: Tomokazu Matsuzaki, Kazutoshi Sako
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Patent number: 8378752Abstract: An oscillator circuit in accordance with an aspect of the present invention includes a filter capacitor that generates an oscillating frequency control voltage according to a charge amount accumulated based on an oscillating frequency setting current, an oscillator that changes a frequency of an oscillation signal to be output according to the oscillating frequency control voltage, a control circuit that generates a timing control signal, a frequency detection circuit that generates a frequency detection voltage based on the timing control signal, a voltage level of the frequency detection voltage being changed according to a length of the period of the oscillation signal, and a differential amplifier that continuously changes the oscillating frequency setting current according to a voltage difference between the frequency detection voltage and a reference voltage, and outputs the resultant oscillating frequency setting current to the filter capacitor.Type: GrantFiled: April 1, 2011Date of Patent: February 19, 2013Assignee: Renesas Electronics CorporationInventors: Kazutoshi Sako, Tomokazu Matsuzaki
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Publication number: 20120256691Abstract: A semiconductor device according to an exemplary aspect of the invention is capable of being selectively switched between an oscillation circuit and a signal input-output circuit, and includes first and second external connecting terminals that are connectable to an oscillation device; an inverting amplifier an input side of which is electrically connected to the first external connecting terminal through a coupling capacitor and an output side of which is electrically connected to the second external connecting terminal; a feedback resistor connected to the input side and the output side of the inverting amplifier; a bias stabilization circuit that stabilizes a bias applied to the coupling capacitor; a first signal input-output portion connected to the first external connecting terminal; and a second signal input-output portion connected to the second external connecting terminal.Type: ApplicationFiled: June 18, 2012Publication date: October 11, 2012Inventors: Kazutoshi Sako, Tomokazu Matsuzaki, Kouji Yokosawa
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Publication number: 20120249114Abstract: A constant current generation circuit of the invention includes: a temperature variable voltage generation unit that generates a first variation voltage whose voltage value fluctuates with temperature; a variation gradient adjustment unit that generates a second variation voltage based on a reference voltage smaller in the amount of variation with temperature than the first variation voltage and the first variation voltage; and a current generation unit that includes a current setting resistor whose resistance value fluctuates with temperature and generates an output current based on the second variation voltage and the current setting resistor. The variation gradient adjustment unit sets the coefficient of variation with temperature of the second variation voltage so that the difference between it and the coefficient of variation with temperature of the resistance value of the current setting resistor is within a preset first stipulated range.Type: ApplicationFiled: March 22, 2012Publication date: October 4, 2012Applicant: RENESAS ELECTRONICS CORPORATIONInventors: Kazutoshi SAKO, Tomokazu MATSUZAKI
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Patent number: 8217726Abstract: A semiconductor device according to an exemplary aspect of the invention is capable of being selectively switched between an oscillation circuit and a signal input-output circuit, and includes first and second external connecting terminals that are connectable to an oscillation device; an inverting amplifier an input side of which is electrically connected to the first external connecting terminal through a coupling capacitor and an output side of which is electrically connected to the second external connecting terminal; a feedback resistor connected to the input side and the output side of the inverting amplifier; a bias stabilization circuit that stabilizes a bias applied to the coupling capacitor; a first signal input-output portion connected to the first external connecting terminal; and a second signal input-output portion connected to the second external connecting terminal.Type: GrantFiled: September 27, 2010Date of Patent: July 10, 2012Assignee: Renesas Electronics CorporationInventors: Kazutoshi Sako, Tomokazu Matsuzaki, Kouji Yokosawa
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Publication number: 20110309889Abstract: A variable-capacitance device includes a first capacitance element coupled between a first power supply terminal and an output terminal, a capacitance selection switch that is turned on and off in accordance with a capacitance switching signal, a second capacitance element coupled in parallel to the first capacitance element and in series to the capacitance selection switch, and an error correction circuit configured to operate such that in a state in which the capacitance selection switch is in an OFF state, in response to a charge reset signal that causes a voltage at the output terminal to be reset to a reset voltage, the error correction circuit substantially eliminates a difference between the voltage at the output terminal and a voltage at a capacitance switching node at which the second capacitance element is coupled to the capacitance selection switch.Type: ApplicationFiled: May 25, 2011Publication date: December 22, 2011Applicant: Renesas Electronics CorporationInventors: Tomokazu Matsuzaki, Kazutoshi Sako
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Publication number: 20110248786Abstract: An oscillator circuit in accordance with an aspect of the present invention includes a filter capacitor that generates an oscillating frequency control voltage according to a charge amount accumulated based on an oscillating frequency setting current, an oscillator that changes a frequency of an oscillation signal to be output according to the oscillating frequency control voltage, a control circuit that generates a timing control signal, a frequency detection circuit that generates a frequency detection voltage based on the timing control signal, a voltage level of the frequency detection voltage being changed according to a length of the period of the oscillation signal, and a differential amplifier that continuously changes the oscillating frequency setting current according to a voltage difference between the frequency detection voltage and a reference voltage, and outputs the resultant oscillating frequency setting current to the filter capacitor.Type: ApplicationFiled: April 1, 2011Publication date: October 13, 2011Inventors: Kazutoshi Sako, Tomokazu Matsuzaki
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Publication number: 20110074499Abstract: A semiconductor device according to an exemplary aspect of the invention is capable of being selectively switched between an oscillation circuit and a signal input-output circuit, and includes first and second external connecting terminals that are connectable to an oscillation device; an inverting amplifier an input side of which is electrically connected to the first external connecting terminal through a coupling capacitor and an output side of which is electrically connected to the second external connecting terminal; a feedback resistor connected to the input side and the output side of the inverting amplifier; a bias stabilization circuit that stabilizes a bias applied to the coupling capacitor; a first signal input-output portion connected to the first external connecting terminal; and a second signal input-output portion connected to the second external connecting terminal.Type: ApplicationFiled: September 27, 2010Publication date: March 31, 2011Inventors: Kazutoshi SAKO, Tomokazu Matsuzaki, Kouji Yokosawa