Patents by Inventor Takeshi Uematsu
Takeshi Uematsu 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: 7218059Abstract: A discharge-lamp control device for lighting a discharge-lamp includes two electrodes, first and second driving units to supply power to the discharge-lamp through the electrodes, respectively. Each driving unit includes a transformer having primary and secondary coils and a capacitor connected in parallel to the secondary coil. The first driving unit has impedance characteristics with a minimum impedance at a first frequency and a maximum impedance at a second frequency lower than the first frequency. The second driving unit has impedance characteristics having a minimum impedance at a third frequency and a maximum impedance at a fourth frequency lower than the third frequency. The first frequency is set to be higher than the third frequency. The second frequency is set to be lower than the fourth frequency. An operating frequency of the driving circuit is selected within a frequency bandwidth from the fourth frequency to the third frequency.Type: GrantFiled: October 20, 2005Date of Patent: May 15, 2007Assignee: TDK CorporationInventors: Ge Li, Koichiro Miura, Takeshi Uematsu
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Publication number: 20060193154Abstract: A power supply device includes two input ports, two output ports, a transformer having primary and secondary windings, switching means, and a controller. The switching means includes a switching element connected in series with the primary winding, and a capacitor. The controller switches the switching element to energize the transformer and charge the capacitor. When an AC power failure such as instantaneous interruption occurs, energy stored in the capacitor is discharged to flow through the primary winding. Accordingly, the transformer is energized to maintain generating an output power from the power supply device for a certain time period. The capacitor is provided on a primary side of the transformer, generally higher voltage side, in the power supply device, so that a smaller capacitance of the capacitor can be used.Type: ApplicationFiled: February 24, 2006Publication date: August 31, 2006Applicant: TDK CORPORATIONInventor: Takeshi Uematsu
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Publication number: 20060187685Abstract: A power supply device has first and second terminals, a transformer, a switching element, and auxiliary power supply means. The first and second terminals receive input power having an input voltage. The transformer has a primary winding and a secondary winding. The primary winding has a pair of winding terminals. One of the pair of winding terminals is connected to the first terminal. The switching element is connected between the second terminal and the other of the pair of winding terminals of the primary winding. The auxiliary power supply means feeds electric power to the transformer when the input voltage decreases to or less than a predetermined value. The auxiliary power supply means has a capacitor and a second switching mean for storing energy from the primary winding into the first capacitor during a normal operation of the power supply device.Type: ApplicationFiled: February 15, 2006Publication date: August 24, 2006Applicant: TDK CorporationInventor: Takeshi Uematsu
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Publication number: 20060164869Abstract: An inverter circuit has a switching element, an inductance, a transformer, a capacitor, and a controller. The switching element is connectable between a higher potential terminal and a lower potential terminal of a direct-current power supply. The inductance is connected between the higher potential terminal and the switching element. The transformer has a primary winding and a secondary winding. The secondary winding has two ends. The capacitor is connected to the primary winding in series. The series-connected capacitor and primary winding is connected in parallel to the switching element. The controller switches the switching element. Therefore, the inverter circuit converts a direct current supplied from the direct-current power supply to an alternating current. The number of switching element in the inverter circuit is only one so that the structure of the inverter circuit is simplified and the manufacturing cost thereof can be reduced.Type: ApplicationFiled: January 20, 2006Publication date: July 27, 2006Applicant: TDK CorporationInventor: Takeshi Uematsu
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Patent number: 7078884Abstract: A selector sets respective phases of pulse driving signals in reverse when a proportion signal or integration signal does not exceed a threshold. Shifting the respective phases of the pulse driving signals from each other lowers the ripple voltage. When the load current increases drastically, the output voltage Vo tends to decrease remarkably because of the shortage of capacity in the power supply. In this case, when the proportion signal or integration signal exceeds its corresponding threshold, a phase control unit causes the pulse driving signals to synchronize their phases, i.e., the selector supplies the same ramp wave to the comparators, so that respective output voltages supplied from the DC voltage converter circuits attain the same phase, thereby restraining the output voltage supplied to the load from decreasing remarkably.Type: GrantFiled: March 30, 2004Date of Patent: July 18, 2006Assignee: TDK CorporationInventors: Koichiro Miura, Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Ken Matsuura
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Patent number: 7075278Abstract: A controller 7A for generating a drive signal (PWM signal) PS for controlling a switching power supply, comprises control signal setting means 10, 11 for setting a control signal CS on the basis of an output voltage Vo and a target voltage Vr; current estimating means 12 for estimating an inductor current on the basis of the drive signal PS and for generating an estimated current signal PC; DC component removing means 14, 15 for extracting a DC component DC included in the estimated current signal PC and for removing the DC component DC from the estimated current signal PC; DC component resetting means 13, 14 for resetting the extracted DC component DC every predetermined time; and comparing means 16 for comparing the control signal CS with the estimated current signal PC? after the removal of the DC component DC.Type: GrantFiled: March 11, 2004Date of Patent: July 11, 2006Assignee: TDK CorporationInventors: Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Koichiro Miura, Ken Matsuura
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Patent number: 7071666Abstract: An output voltage of a switching power supply is regulated to a target value. When the target value of the output voltage is altered, the reference value is changed monotonously and linearly a plurality of times at a plurality of gradients to the altered target value. An input voltage of the power supply is switched in response to a switching pulse with the duty ratio calculated according to a difference between the reference value and the output voltage.Type: GrantFiled: March 16, 2004Date of Patent: July 4, 2006Assignee: TDK CorporationInventors: Takakazu Imai, Takeshi Uematsu, Hiroshi Kawasaki, Koichiro Miura, Ken Matsuura
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Publication number: 20060091821Abstract: A discharge-lamp control device for lighting a discharge-lamp includes two electrodes, first and second driving units to supply power to the discharge-lamp through the electrodes, respectively. Each driving unit includes a transformer having primary and secondary coils and a capacitor connected in parallel to the secondary coil. The first driving unit has impedance characteristics with a minimum impedance at a first frequency and a maximum impedance at a second frequency lower than the first frequency. The second driving unit has impedance characteristics having a minimum impedance at a third frequency and a maximum impedance at a fourth frequency lower than the third frequency. The first frequency is set to be higher than the third frequency. The second frequency is set to be lower than the fourth frequency. An operating frequency of the driving circuit is selected within a frequency bandwidth from the fourth frequency to the third frequency.Type: ApplicationFiled: October 20, 2005Publication date: May 4, 2006Applicant: TDK CORPORATIONInventors: Ge Li, Koichiro Miura, Takeshi Uematsu
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Patent number: 7002324Abstract: This invention provides a switching power supply control circuit based on the parallel operation scheme that suppresses ripples in the output voltage. The control circuit comprises switching circuit blocks 10 and 20 connected in parallel, output reactors 31 and 32 connected in parallel corresponding to the switching circuit blocks 10 and 20, and a control circuit 40 that controls the operation of the switching circuit blocks 10 and 20.Type: GrantFiled: March 7, 2003Date of Patent: February 21, 2006Assignee: TDK CorporationInventors: Takeshi Uematsu, Takakazu Imai, Hiroshi Kawasaki
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Patent number: 6960904Abstract: An adder 11 outputs a signal VS indicating a value of (Vr?Vo), and a multiplier 12 outputs a control signal GS indicating a value of G(Vr?Vo) on the basis of the signal VS. An adder 13 outputs a signal HS on the basis of the control signal GS and a signal FS outputted from an operation circuit 30, and a PWM signal generating circuit 20 generates a PWM signal KS on the basis of the signal HS and a ramp signal RS outputted from a ramp signal circuit 15, and outputs this signal KS to a switching power supply. A counter 14 counts an on time of the PWM signal KS and retains a count value at a time of receiving a sample signal SMP. The operation circuit 30 has a high-pass filter 31 and an integrator 32, performs an operation based on a signal DS indicating the count value outputted from the counter 14, and outputs the signal FS after the operation.Type: GrantFiled: March 17, 2004Date of Patent: November 1, 2005Assignee: TDK CorporationInventors: Ken Matsuura, Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Koichiro Miura
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Patent number: 6956360Abstract: A controller 7A for generating a drive signal PS for switching control of a switching element in a switching power supply, includes a duty ratio generator 10, 11 for detecting a duty ratio D of the drive signal PS for controlling the switching element of the switching power supply, and generating a signal corresponding to the duty ratio; a control signal generator 13, 14 for generating a control signal CS on the basis of a difference between a target voltage VREF in the switching power supply and an output voltage Vo detected in the switching power supply; an operation unit 15 for generating a signal corresponding to a product of the signal corresponding to the duty ratio, and the control signal CS; and a drive signal generator 16, 17 for generating the drive signal PS on the basis of the signal generated by the operation unit 15.Type: GrantFiled: March 17, 2004Date of Patent: October 18, 2005Assignee: TDK CorporationInventors: Ken Matsuura, Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Koichiro Miura
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Publication number: 20050180180Abstract: The present invention is directed to a power supply unit that provides large power supply to the load. The voltage detector 51 generates a voltage detection signal by detecting the voltage generated at the output terminals 21, 22. The current detector 52 generates a current detection signal by detecting the current that runs through the transformer 3. The control circuit 9 uses the voltage detection signal and the current detection signal and thereby controls, in at least one of the first and second switching elements SW1, SW2, the timing with which the switching element is turned ON and the length of time that the switching element remains ON, such that the transformer current flows in a continuous mode.Type: ApplicationFiled: February 11, 2005Publication date: August 18, 2005Applicant: TDK CorporationInventor: Takeshi Uematsu
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Patent number: 6838784Abstract: The present invention relates to a control circuit for a switching power supply device that is adapted to drive two or more loads and can quickly eliminate a voltage difference occurring between the two or more loads. The control circuit for a switching power supply device has an output terminal that is to be connected to a power supply terminal of a first load by a first wiring and a power supply terminal of a second load by a second wiring. The control circuit comprises a first control loop for stabilizing an output voltage appearing at the output terminal and a second control loop for eliminating a difference between a first voltage appearing at the first wiring in a vicinity of the power supply terminal of the first load and a second voltage appearing at the second wiring in a vicinity of the power supply terminal of the second load.Type: GrantFiled: March 25, 2003Date of Patent: January 4, 2005Assignee: TDK CorporationInventor: Takeshi Uematsu
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Publication number: 20040189266Abstract: A selector sets respective phases of pulse driving signals in reverse when a proportion signal or integration signal does not exceed a threshold. Shifting the respective phases of the pulse driving signals from each other lowers the ripple voltage. When the load current increases drastically, the output voltage Vo tends to decrease remarkably because of the shortage of capacity in the power supply. In this case, when the proportion signal or integration signal exceeds its corresponding threshold, a phase control unit causes the pulse driving signals to synchronize their phases, i.e., the selector supplies the same ramp wave to the comparators, so that respective output voltages supplied from the DC voltage converter circuits attain the same phase, thereby restraining the output voltage supplied to the load from decreasing remarkably.Type: ApplicationFiled: March 30, 2004Publication date: September 30, 2004Applicant: TDK CORPORATIONInventors: Koichiro Miura, Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Ken Matsuura
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Publication number: 20040189273Abstract: An output voltage of a switching power supply is regulated to a target value. When the target value of the output voltage is altered, the reference value is changed monotonously and linearly a plurality of times at a plurality of gradients to the altered target value. An input voltage of the power supply is switched in response to a switching pulse with the duty ratio calculated according to a difference between the reference value and the output voltage.Type: ApplicationFiled: March 16, 2004Publication date: September 30, 2004Applicant: TDK CORPORATIONInventors: Takakazu Imai, Takeshi Uematsu, Hiroshi Kawasaki, Koichiro Miura, Ken Matsuura
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Publication number: 20040189272Abstract: A controller 7A for generating a drive signal PS for switching control of a switching element in a switching power supply, includes a duty ratio generator 10, 11 for detecting a duty ratio D of the drive signal PS for controlling the switching element of the switching power supply, and generating a signal corresponding to the duty ratio; a control signal generator 13, 14 for generating a control signal CS on the basis of a difference between a target voltage VREF in the switching power supply and an output voltage Vo detected in the switching power supply; an operation unit 15 for generating a signal corresponding to a product of the signal corresponding to the duty ratio, and the control signal CS; and a drive signal generator 16, 17 for generating the drive signal PS on the basis of the signal generated by the operation unit 15.Type: ApplicationFiled: March 17, 2004Publication date: September 30, 2004Applicant: TDK CORPORATIONInventors: Ken Matsuura, Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Koichiro Miura
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Publication number: 20040189264Abstract: An adder 11 outputs a signal VS indicating a value of (Vr−Vo), and a multiplier 12 outputs a control signal GS indicating a value of G(Vr−Vo) on the basis of the signal VS. An adder 13 outputs a signal HS on the basis of the control signal GS and a signal FS outputted from an operation circuit 30, and a PWM signal generating circuit 20 generates a PWM signal KS on the basis of the signal HS and a ramp signal RS outputted from a ramp signal circuit 15, and outputs this signal KS to a switching power supply. A counter 14 counts an on time of the PWM signal KS and retains a count value at a time of receiving a sample signal SMP. The operation circuit 30 has a high-pass filter 31 and an integrator 32, performs an operation based on a signal DS indicating the count value outputted from the counter 14, and outputs the signal FS after the operation.Type: ApplicationFiled: March 17, 2004Publication date: September 30, 2004Applicant: TDK CORPORATIONInventors: Ken Matsuura, Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Koichiro Miura
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Publication number: 20040178783Abstract: A controller 7A for generating a drive signal (PWM signal) PS for controlling a switching power supply, comprises control signal setting means 10, 11 for setting a control signal CS on the basis of an output voltage Vo and a target voltage Vr; current estimating means 12 for estimating an inductor current on the basis of the drive signal PS and for generating an estimated current signal PC; DC component removing means 14, 15 for extracting a DC component DC included in the estimated current signal PC and for removing the DC component DC from the estimated current signal PC; DC component resetting means 13, 14 for resetting the extracted DC component DC every predetermined time; and comparing means 16 for comparing the control signal CS with the estimated current signal PC′ after the removal of the DC component DC.Type: ApplicationFiled: March 11, 2004Publication date: September 16, 2004Applicant: TDK CORPORATIONInventors: Takeshi Uematsu, Hiroshi Kawasaki, Takakazu Imai, Koichiro Miura, Ken Matsuura
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Patent number: 6791305Abstract: This invention provides a switching power supply control circuit that can switch the output voltage with high precision and at high speed. The control circuit comprises an A/D converter 31 that generates a output voltage digital value D1 indicating the actual output Vo in response to clock signal CLK1, a reference voltage generating circuit 32 that generates a reference voltage digital value D2 that indicated the target value of the output voltage in response to clock signal CLK2, a subtracter 33 that compares the output voltage digital value D1 and reference voltage digital value D2 and generates an error voltage digital value D3 based thereupon, a latch circuit 34 that reads the error voltage digital value D3 in response to clock signal CLK3 and controls the operation of the switching circuit block 10 based thereupon and an arithmetic circuit 35.Type: GrantFiled: February 24, 2003Date of Patent: September 14, 2004Assignee: TDK CorporationInventors: Takakazu Imai, Takeshi Uematsu
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Publication number: 20030185030Abstract: The present invention relates to a control circuit for a switching power supply device that is adapted to drive two or more loads and can quickly eliminate a voltage difference occurring between the two or more loads. The control circuit for a switching power supply device has an output terminal that is to be connected to a power supply terminal of a first load by a first wiring and a power supply terminal of a second load by a second wiring. The control circuit comprises a first control loop for stabilizing an output voltage appearing at the output terminal and a second control loop for eliminating a difference between a first voltage appearing at the first wiring in a vicinity of the power supply terminal of the first load and a second voltage appearing at the second wiring in a vicinity of the power supply terminal of the second load.Type: ApplicationFiled: March 25, 2003Publication date: October 2, 2003Applicant: TDK CorporationInventor: Takeshi Uematsu