Patents by Inventor Masayuki Yasumura

Masayuki Yasumura 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).

  • Patent number: 6590787
    Abstract: A complex resonance-type converter provided with a voltage-resonance-type converter on the primary side and a resonant circuit on the secondary side for supplying a plurality of direct-current output voltages from the secondary side, and having an inductance connected in parallel with a primary winding of an isolating converter transformer. A switching output current is distributed to the primary winding of the isolating converter transformer and the inductance, and a current flowing to a switching device and a damper diode inserted in parallel with the switching device has a normal waveform regardless of the level of load current of the secondary-side direct-current output to ensure stable zero voltage switching (ZVS) operation.
    Type: Grant
    Filed: November 30, 2001
    Date of Patent: July 8, 2003
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Patent number: 6587358
    Abstract: A switching power supply circuit, which is small, lightweight, and highly efficient in power conversion, includes an insulating converter transformer, which is formed by a core with no gap and a primary and secondary winding wound on the core such that the mutual inductance between the windings exhibits an additive mode. A half-wave rectifier circuit is provided on the secondary side of the circuit and performs a rectification operation in the additive mode to obtain a secondary side DC output voltage. In a constant voltage control circuit system for stabilizing the secondary side output voltage, the switching frequency of a switching element is varied in response to the secondary side output voltage level to control the resonance impedance of a primary side parallel resonance circuit and the continuity angle of the switching element compositely.
    Type: Grant
    Filed: May 21, 2002
    Date of Patent: July 1, 2003
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Patent number: 6577510
    Abstract: A power supply uses a switching element of a desired voltage withstanding property to obtain a desired conversion output. The power supply includes a converter transformer having primary and secondary windings loosely coupled to one another, and an auxiliary winding with a predetermined number of turns wound contiguously from one end of the primary winding to an end portion of the converter transformer. An input voltage smoothing capacitor is connected on one side to an end of the primary winding of the converter transformer through a forwardly directed diode. A switching element is connected to the other end of the primary winding. A control circuit controls the switching element to perform switching so that an output voltage of the secondary winding has a predetermined voltage value (or is within a predetermined voltage range). A second capacitor is coupled across opposite ends of the auxiliary winding via the forwardly directed diode, to boost-up voltage applied to the converter transformer.
    Type: Grant
    Filed: May 21, 2002
    Date of Patent: June 10, 2003
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Publication number: 20030095419
    Abstract: A switching power supply circuit ready for worldwide use is disclosed which suppresses a variation of a pulse voltage to be fed back when the alternating-current input varies. The switching power supply circuit includes a composite resonance type converter of a switching frequency control scheme wherein a voltage resonance pulse voltage generated in a primary side voltage resonance converter is fed back to a rectification diode through a high speed diode and an inductance or a transformer. An active clamp circuit is provided on the primary side to clamp the voltage resonance pulse voltage.
    Type: Application
    Filed: November 15, 2002
    Publication date: May 22, 2003
    Applicant: Sony Corporation
    Inventor: Masayuki Yasumura
  • Patent number: 6515875
    Abstract: A power supply circuit has a so-called composite resonance type switching converter equipped with a primary resonance circuit for forming a voltage resonance type converter at a primary side, and a secondary resonance circuit comprising a secondary winding and a secondary parallel resonance capacitor at a secondary side. The secondary side is equipped with active clamp means for stabilizing a DC output low voltage taken out from an intermediate tap of the secondary winding to control the conduction angle of an auxiliary main switching element in accordance with the level of the DC output low voltage, whereby the power loss due to the cross-regulation of the DC output low voltage can be reduced, and the power conversion efficiency can be enhanced.
    Type: Grant
    Filed: November 19, 2001
    Date of Patent: February 4, 2003
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Patent number: 6496389
    Abstract: A switching power circuit having a power factor improving circuit for a composite resonance type converter, wherein a switching pulse is fed back from a tertiary winding, which is coiled around an insulating converter transformer, via a series resonance capacitor. And a rectified current is turned on and off by a fast recovery diode in accordance with the feedback output, hence achieving power factor improvement. In this structure, a smoothing capacitor is charged with the resonance current even during an off-period of the fast recovery diode due to the resonance of a series resonance circuit including the series resonance capacitor. This circuit configuration eliminates the necessity of selection of a higher withstand voltage relative to the primary-side smoothing capacitor by suppressing rise of the DC input voltage in a no-load state.
    Type: Grant
    Filed: September 19, 2000
    Date of Patent: December 17, 2002
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Patent number: 6456509
    Abstract: A direct-current output voltage obtained by rectifying an alternating voltage generated in a secondary winding of an isolating converter transformer PIT is made constant using an active clamp circuit including an auxiliary switching device, a clamp capacitor, and a clamp diode connected in parallel with a parallel resonant capacitor supplied with the alternating voltage to step down and-make constant the direct-current output voltage without using a three-terminal regulator and a chopper regulator. A control circuit effects PWM control of the auxiliary switching device of the active clamp circuit and changes a capacitance of the parallel resonant capacitor. The direct-current output voltage is made constant, and a resulting power loss is reduced.
    Type: Grant
    Filed: August 9, 2001
    Date of Patent: September 24, 2002
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Patent number: 6452817
    Abstract: In an insulating converter transformer of a composite resonance type switching power supply circuit having a secondary active clamp circuit, a primary winding and a secondary winding are wound in a so-called inverse winding style, and connected to each other with additive polarity. In this construction, a primary magnetic flux and a secondary magnetic flux act to offset each other, so that no saturation occurs without forming any gap in the core of the insulating converter transformer.
    Type: Grant
    Filed: October 25, 2001
    Date of Patent: September 17, 2002
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Publication number: 20020089863
    Abstract: In an insulating converter transformer of a composite resonance type switching power supply circuit having a secondary active clamp circuit, a primary winding and a secondary winding are wound in a so-called inverse winding style, and connected to each other with additive polarity. In this construction, a primary magnetic flux and a secondary magnetic flux act to offset each other, so that no saturation occurs without forming any gap in the core of the insulating converter transformer.
    Type: Application
    Filed: October 25, 2001
    Publication date: July 11, 2002
    Inventor: Masayuki Yasumura
  • Publication number: 20020080635
    Abstract: In a complex resonance type converter provided with a voltage resonance type converter on the primary side and a resonant circuit on the secondary side for supplying a plurality of direct-current output voltages from the secondary side, an inductance is connected in parallel with a primary winding of an isolating converter transformer. A switching output current is thereby distributed to the primary winding of the isolating converter transformer and the inductance, and a current flowing to a switching device and a damper diode inserted in parallel with the switching device has a normal waveform regardless of the level of load current of the secondary-side direct-current output. Therefore, stable ZVS operation can be ensured.
    Type: Application
    Filed: November 30, 2001
    Publication date: June 27, 2002
    Inventor: Masayuki Yasumura
  • Patent number: 6411528
    Abstract: The invention provides a switching power circuit and an insulating converter transformer. A tertiary winding to be formed on the secondary side of an insulating converter transformer is coiled in such a manner as to achieve a state of tight coupling with respect to a primary winding on the primary side of the insulating converter transformer and also to a secondary winding on the secondary side thereof, so that the peak value of a secondary current outputted from a second half-wave rectifying circuit can be reduced by the tertiary winding of the insulating converter transformer.
    Type: Grant
    Filed: September 28, 2000
    Date of Patent: June 25, 2002
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Publication number: 20020071294
    Abstract: A power supply circuit has a so-called composite resonance type switching converter equipped with a primary resonance circuit for forming a voltage resonance type converter at a primary side, and a secondary resonance circuit comprising a secondary winding and a secondary parallel resonance capacitor at a secondary side. The secondary side is equipped with active clamp means for stabilizing a DC output low voltage taken out from an intermediate tap of the secondary winding to control the conduction angle of an auxiliary main switching element in accordance with the level of the DC output low voltage, whereby the power loss due to the cross-regulation of the DC output low voltage can be reduced, and the power conversion efficiency can be enhanced.
    Type: Application
    Filed: November 19, 2001
    Publication date: June 13, 2002
    Inventor: Masayuki Yasumura
  • Patent number: 6396717
    Abstract: A switching power supply circuit formed by providing a complex resonance type converter with a power factor improving circuit feeds back a voltage resonance pulse voltage generated in a primary-side voltage resonance converter to fast recovery type diodes via a tertiary winding or the tertiary winding and a series resonant capacitor by magnetic coupling to thereby improve a power factor to 0.9, and achieves an improvement in AC/DC conversion efficiency and a reduction in a ripple component of a direct-current output voltage by voltage doubler rectifier operation. Also, a first rectifier circuit and a second rectifier circuit shunt the current to be stored in a smoothing capacitor, so that a range of zero volt switching operation is not narrowed even when the power factor is improved.
    Type: Grant
    Filed: July 9, 2001
    Date of Patent: May 28, 2002
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Patent number: 6388902
    Abstract: A switching power supply circuit is disclosed which allows selective use of a switching element having a comparatively low voltage withstanding property and a low current capacity and can be produced in a low lost and with a small size. Upon starting of power supply, the switching frequency of the switching element is raised by a soft starting circuit to increase a period of time until a secondary side DC output voltage reaches a steady level thereof As a result, the levels of a resonance voltage and a collector current obtained when the switching element starts its switching operation are suppressed.
    Type: Grant
    Filed: March 29, 2001
    Date of Patent: May 14, 2002
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Publication number: 20020044469
    Abstract: In making constant a direct-current output voltage obtained by rectifying an alternating voltage generated in a secondary winding of an isolating converter transformer PIT, an active clamp circuit formed with an auxiliary switching device, a clamp capacitor, and a clamp diode is connected in parallel with a parallel resonant capacitor to be supplied with the alternating voltage, instead of using a three-terminal regulator and a chopper regulator, which step down and make constant the direct-current output voltage. A control circuit effects PWM control of the auxiliary switching device of the active clamp circuit and thereby equivalently changes capacitance of the parallel resonant capacitor. Thus, the direct-current output voltage is made constant, and power loss caused in making the direct-current output voltage constant is reduced.
    Type: Application
    Filed: August 9, 2001
    Publication date: April 18, 2002
    Inventor: Masayuki Yasumura
  • Patent number: 6370043
    Abstract: A switching power supply circuit of the resonance type which can handle high load power and has high power conversion efficiency, small size and light weight is provided. The switching power supply circuit may be formed as a composite resonance converter wherein a voltage resonance converter is provided on a primary side and a parallel resonance circuit is provided on a secondary side. The switching power supply circuit may include an insulating converter transformer having a pair of E-shaped cores each with outer and center legs in which a gap is formed between the middle legs thereof so that a loose coupling condition having a coupling coefficient higher than a predetermined level may be obtained. A half-wave rectifier circuit of an additive mode may be provided on the secondary side. A switching frequency of a switching element for switching a dc input voltage to the insulating converter transformer on and off may be varied to effect constant voltage control.
    Type: Grant
    Filed: January 10, 2001
    Date of Patent: April 9, 2002
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Patent number: 6370041
    Abstract: Instead of inputting a horizontal deflection output pulse, a resonance voltage outputted from the secondary side of an isolation converter transformer forming a switching power supply circuit of the complex resonance type is inputted to the primary side of a flyback transformer via a series resonant capacitor. Then, a resonance voltage having a substantially sinusoidal waveform generated in the primary winding of the flyback transformer is stepped up thereby providing a high direct-current voltage having a specified high voltage level. Thus, it is possible to improve power conversion efficiency and reduce power loss. Also, by inducing a resonance voltage having a substantially sinusoidal waveform on the secondary side of the flyback transformer, the conduction angle of a rectifier diode is widened, and variation in the high direct-current voltage can be surpressed even when the load is varied.
    Type: Grant
    Filed: July 9, 2001
    Date of Patent: April 9, 2002
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Patent number: 6366476
    Abstract: An active clamp circuit is provided on the primary side of a complex resonance type switching converter having a voltage resonance type converter on the primary side and a parallel resonant circuit on the secondary side. The active clamp circuit clamps a parallel resonance voltage pulse generated across a primary-side parallel resonant capacitor to thereby suppress the level of the parallel resonance voltage pulse. Thus, products having low withstand voltage may be selected for components such as switching devices and the primary-side parallel resonant capacitor provided in the power supply circuit. An auxiliary switching device Q2 of the active clamp circuit is driven by a self-oscillation circuit formed by winding a wire of the primary winding of an insulating converter transformer by one turn. Thus, the circuit system for driving the active clamp circuit is simplified, thereby improving power conversion efficiency and miniaturizing the power supply circuit.
    Type: Grant
    Filed: May 15, 2001
    Date of Patent: April 2, 2002
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Patent number: 6356465
    Abstract: An active clamp circuit is provided on the primary side of a complex resonance type switching converter having a parallel resonant circuit on the primary side and a parallel resonant circuit or a series resonant circuit on the secondary side. The active clamp circuit clamps a parallel resonance voltage pulse generated across a primary-side parallel resonant capacitor to thereby lower the level of the parallel resonance voltage pulse. Thus, withstand voltage of components such as switching devices and the primary-side parallel resonant capacitor can be lowered.
    Type: Grant
    Filed: April 26, 2001
    Date of Patent: March 12, 2002
    Assignee: Sony Corporation
    Inventor: Masayuki Yasumura
  • Publication number: 20020021575
    Abstract: An active clamp circuit is provided on the primary side of a complex resonance type switching converter having a voltage resonance type converter on the primary side and a parallel resonant circuit on the secondary side. The active clamp circuit clamps a parallel resonance voltage pulse generated across a primary-side parallel resonant capacitor to thereby suppress the level of the parallel resonance voltage pulse. Thus, products having low withstand voltage may be selected for components such as switching devices and the primary-side parallel resonant capacitor provided in the power supply circuit. An auxiliary switching device Q2 of the active clamp circuit is driven by a self-oscillation circuit formed by winding a wire of the primary winding of an insulating converter transformer by 1T. Thus, the circuit system for driving the active clamp circuit is simplified, thereby improving power conversion efficiency and miniaturizing the power supply circuit.
    Type: Application
    Filed: May 15, 2001
    Publication date: February 21, 2002
    Inventor: Masayuki Yasumura