Having Voltage Protection Patents (Class 363/56.08)
  • Patent number: 12176825
    Abstract: Disclosed herein are systems and methods for operation of a switched capacitor converter (SCC). In some variations, the SCC includes a resonant circuit including an inductor. Aspects of the disclosure include methods for controlling the SCC switches to decrease switching losses associated with operating the converter and to increase efficiency of the SCC. According to some aspects, a control method is used to switch converter switches under zero-voltage conditions. According to some aspects, a control method is used to switch converter switches under zero-current conditions.
    Type: Grant
    Filed: January 19, 2024
    Date of Patent: December 24, 2024
    Assignee: Solaredge Technologies Ltd.
    Inventors: Milan Ilic, Ramesh Govindarajan, Sang Dong Lee
  • Patent number: 12165999
    Abstract: A semiconductor device includes: a semiconductor layer; first and second transistors; one or more first source pads and a first gate pad of the first transistor in a first region of the upper surface of the semiconductor layer; and one or more second source pads and a second gate pad of the second transistor in a second region of the upper surface adjacent to the first region in a plan view of the semiconductor layer. In a plan view of the semiconductor layer, a virtual straight line connecting the centers of the first and second gate pads passes through the center of the semiconductor layer and forms a 45 degree angle with each side of the semiconductor layer. An upper surface boundary line between the first and second regions monotonically changes in the directions of extension of the longer and shorter sides of the semiconductor layer.
    Type: Grant
    Filed: February 10, 2022
    Date of Patent: December 10, 2024
    Assignee: NUVOTON TECHNOLOGY CORPORATION JAPAN
    Inventors: Kouki Yamamoto, Shinichi Akiyoshi, Ryouichi Ajimoto
  • Patent number: 12057767
    Abstract: A method for operating a switching power converter to reduce ripple current magnitude includes controlling duty cycle of a plurality power stages of the switching power converter to regulate at least one parameter of the switching power converter. Each power stage includes a respective power transfer winding that is magnetically coupled to the respective power transfer winding of each other power stage. The method further includes controlling an injection stage of the switching power converter to reduce voltage across a respective leakage inductance of each power transfer winding. The injection stage includes an injection winding that is magnetically coupled to each power transfer winding.
    Type: Grant
    Filed: April 6, 2022
    Date of Patent: August 6, 2024
    Assignee: Maxim Integrated Products, Inc.
    Inventors: Alexandr Ikriannikov, Alberto Giovanni Viviani
  • Patent number: 12027845
    Abstract: A shoot-through protection circuit includes a current sensor providing a sensor signal connected to a comparator input via at least a burden resistor. A switch protection circuit including a protection input connected to an output of the comparator and a plurality of outputs. Each of the outputs is connected to a corresponding switch in a plurality of stacked switches. Wherein the switch protection circuit is configured to drive each switch of the plurality of stacked switches open in response to a positive output signal from the comparator.
    Type: Grant
    Filed: February 19, 2020
    Date of Patent: July 2, 2024
    Assignee: AEROJET ROCKETDYNE, INC.
    Inventor: Carl R. Haynie
  • Patent number: 11923786
    Abstract: Disclosed herein are systems and methods for operation of a switched capacitor converter (SCC). In some variations, the SCC includes a resonant circuit including an inductor. Aspects of the disclosure include methods for controlling the SCC switches to decrease switching losses associated with operating the converter and to increase efficiency of the SCC. According to some aspects, a control method is used to switch converter switches under zero-voltage conditions. According to some aspects, a control method is used to switch converter switches under zero-current conditions.
    Type: Grant
    Filed: July 15, 2022
    Date of Patent: March 5, 2024
    Assignee: Solaredge Technologies Ltd.
    Inventors: Milan Ilic, Ramesh Govindarajan, Sang Dong Lee
  • Patent number: 11863136
    Abstract: The electronic circuits and semiconductor device having the same are provided. The electronic circuit includes: a first transistor including a first electrode coupled with an input voltage; a second transistor including a first electrode coupled with a second electrode of the first transistor; a first capacitor coupled between the first transistor and the second transistor; a first diode including a first terminal coupled with the first electrode of the first transistor; a second diode including a first terminal coupled with a second terminal of the first diode and a second terminal coupled with a second electrode of the second transistor; a second capacitor coupled between the first transistor and the first diode; and a third capacitor coupled between the first diode and the second transistor.
    Type: Grant
    Filed: July 15, 2020
    Date of Patent: January 2, 2024
    Assignee: INNOSCIENCE (ZHUHAI) TECHNOLOGY CO., LTD.
    Inventors: Tao Zhang, Yulin Chen, Jihua Li, Wenjie Lin
  • Patent number: 11611283
    Abstract: A switching power supply unit includes: a transformer; an inverter circuit including first to fourth switching devices, first to third capacitors, first and second rectifying devices, a resonant inductor, and a resonant capacitor; and a driver. The first to fourth switching devices are coupled in series. The first and second capacitors are coupled in series. The first rectifying device is disposed between a first connection point between the first and second capacitors and a second connection point between the first and second switching devices. The second rectifying device is disposed between the first connection point and a third connection point between the third and fourth switching devices. The third capacitor is disposed between the second and third connection points. The resonant capacitor, the resonant inductor, and a primary winding are coupled in series between a fourth connection point between the second and third switching devices and the first connection point.
    Type: Grant
    Filed: May 11, 2021
    Date of Patent: March 21, 2023
    Assignee: TDK CORPORATION
    Inventors: Masahiko Hirokawa, Xiaofeng Wu, Naoyuki Ishibashi
  • Patent number: 11539299
    Abstract: A switching power supply unit includes a pair of input terminals, a pair of output terminals, a transformer, an inverter circuit, a rectifying and smoothing circuit, and a driver. The inverter circuit includes first to fourth switching devices, a first capacitor, a resonant inductor, and a resonant capacitor. The rectifying and smoothing circuit includes a rectifying circuit including rectifying devices, and a smoothing circuit. The first to fourth switching devices are coupled in series in this order between two input terminals constituting the pair of input terminals. The first capacitor is disposed between a connection point between the first and second switching devices and a connection point between the third and fourth switching devices. The resonant inductor, the resonant capacitor, and a primary winding are coupled in series in no particular order between a connection point between the second and third switching devices and one of the two input terminals.
    Type: Grant
    Filed: April 7, 2021
    Date of Patent: December 27, 2022
    Assignee: TDK CORPORATION
    Inventors: Masahiko Hirokawa, Naoyuki Ishibashi, Xiaofeng Wu
  • Patent number: 11233415
    Abstract: In an example embodiment, a battery unit comprises a battery unit housing; and a battery unit circuit. In this example embodiment, the battery unit housing contains at least a portion of the battery unit circuit, and the battery unit circuit further comprises: a battery cell, an inverter to control the charging and discharging of the battery cell, a processor to provide control signals to the inverter for controlling the charging and discharging of the battery cell, and one of: a power plug for coupling to and uncoupling from a power outlet assembly, and a luminaire base for coupling to and uncoupling from a luminaire socket in a light fixture. In this example embodiment, the battery unit is rated at less than or equal to 2400 Volt-Amperes. The battery unit may further comprise a transceiver.
    Type: Grant
    Filed: October 18, 2019
    Date of Patent: January 25, 2022
    Inventor: Eric Hafner
  • Patent number: 10554063
    Abstract: In an example embodiment, a battery unit comprises a battery unit housing; and a battery unit circuit. In this example embodiment, the battery unit housing contains at least a portion of the battery unit circuit, and the battery unit circuit further comprises: a battery cell, an inverter to control the charging and discharging of the battery cell, a processor to provide control signals to the inverter for controlling the charging and discharging of the battery cell, and one of: a power plug for coupling to and uncoupling from a power outlet assembly, and a luminaire base for coupling to and uncoupling from a luminaire socket in a light fixture. In this example embodiment, the battery unit is rated at less than or equal to 2400 Volt-Amperes. The battery unit may further comprise a transceiver.
    Type: Grant
    Filed: November 9, 2017
    Date of Patent: February 4, 2020
    Inventor: Eric Hafner
  • Patent number: 9615440
    Abstract: A current-limiting reactor that regulates a short-circuit current, a controller that controls an action of an inverter, and a detection unit that detects a short circuit. The controller causes the inverter to stop when a short circuit has occurred.
    Type: Grant
    Filed: October 4, 2013
    Date of Patent: April 4, 2017
    Assignee: Toshiba Mitsubishi-Electric Industrial Systems Corporation
    Inventors: Yoichiro Tabata, Yujiro Okihara, Noriyuki Nakamura, Shinichi Nishimura
  • Patent number: 9584013
    Abstract: The present disclosure relates to methods, systems and a module for operating a power converter module, the power converter module comprises a voltage source, a remote control terminal configured to be connected to a voltage potential for remote control of the power converter module. A voltage converter is configured to send an alarm signal, determine the voltage potential of the remote control terminal, and control an output voltage of the voltage converter at an output terminal of the power converter module based on the determined voltage potential of the remote control terminal. An alarm branch is configured to change the voltage potential of the remote control terminal by a voltage source in response to an alarm signal from the voltage converter when the remote control terminal is connected to a voltage potential, thereby causing the voltage converter to control the output voltage at the output terminal.
    Type: Grant
    Filed: March 1, 2012
    Date of Patent: February 28, 2017
    Assignee: Telefonaktiebolaget L M Ericsson (publ)
    Inventors: Magnus Karlsson, Oscar Persson
  • Publication number: 20140376286
    Abstract: When a snubber capacitor is charged to a level greater than or equal to a predetermined voltage, a protection circuit renders a clamp diode conductive to complete charging of the snubber capacitor.
    Type: Application
    Filed: March 2, 2012
    Publication date: December 25, 2014
    Applicants: TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATION, OSAKA UNIVERSITY
    Inventors: Yasuhiko Hosokawa, Toshifumi Ise, Shinsuke Kadoi
  • Patent number: 8633512
    Abstract: A circuit is proposed for limiting maximum switching FET drain-source voltage (VDS) of a transformer-coupled push pull power converter with maximum DC supply voltage VIN—MAX. Maximum VDS is accentuated by leakage inductances of the push pull transformer and the power converter circuit traces. The limiting circuit bridges the drains of the switching FETs and it includes two serially connected opposing Zener diodes each having a Zener voltage Vzx. The invention is applicable to both N-channel and P-channel FETs. In a specific embodiment, Vzx is selected to be slightly ?2*VIN—MAX with the maximum VDS clamped to about VIN—MAX+½Vzx. In another embodiment, a proposed power switching device with integrated VDS-clamping includes a switching FET; and a Zener diode having a first terminal and a second terminal, the second terminal of the Zener diode is connected to the drain terminal of the switching FET.
    Type: Grant
    Filed: April 24, 2012
    Date of Patent: January 21, 2014
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventor: Sanjay Havanur
  • Patent number: 8575885
    Abstract: To make it possible to avoid an unstable state with a simple configuration even one of the phases of the motor fails. A motor drive system in accordance with the present invention includes a motor to which a plurality of phase coils of five phases or more are connected in a star connection, an inverter connected to one end of each of the phase coils, the inverter being configured to convert a DC power into an AC power and supply the AC power to each phase of the motor, a power relay disposed at another end of each of the phase coils, the power relay being configured so as to be able to cut off a supply power to at least one phase coil among the plurality of phase coils of the motor by using a plurality of contact points interposed between the star-connected coils, and a control unit that generates a control signal for the inverter and thereby controls driving of the motor.
    Type: Grant
    Filed: January 25, 2010
    Date of Patent: November 5, 2013
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Yoshihiro Okumatsu
  • Patent number: 8335093
    Abstract: According to the invention, a blocking oscillator type converter circuit functions with a transformator that only comprises a primary winding and a secondary winding. Said transformator does not comprise a return coupling winding for the blocking oscillator. The control voltage of the oscillator is derived from the primary voltage of the transformator during the free-wheeling phase. The invention also relates to a voltage monitoring circuit that works independently from the oscillator, the output voltage of the oscillator being repressed when the voltage on the output of the blocking oscillator is too high. A flow monitoring circuit functions independently from the oscillator and the voltage monitoring circuit and suppresses the impulses for the power transistor when the power on the output side exceeds a predetermined measurement.
    Type: Grant
    Filed: November 14, 2008
    Date of Patent: December 18, 2012
    Assignee: Stahl Schaltergate GmbH
    Inventor: Fritz Frey
  • Patent number: 8264861
    Abstract: A circuit is proposed for limiting maximum switching FET drain-source voltage (VDS) of a transformer-coupled push pull power converter with maximum DC supply voltage VIN—MAX. Maximum VDS is accentuated by leakage inductances of the push pull transformer and the power converter circuit traces. The limiting circuit bridges the drains of the switching FETs and it includes two serially connected opposing Zener diodes each having a Zener voltage Vzx. The invention is applicable to both N-channel and P-channel FETs. In a specific embodiment, Vzx is selected to be slightly ?2*VIN—MAX with the maximum VDS clamped to about VIN—MAX+½Vzx. In another embodiment, a proposed power switching device with integrated VDS clamping includes: In another embodiment, a proposed power switching device with integrated VDS-clamping includes a switching FET; and a Zener diode having a first terminal and a second terminal, the second terminal of the Zener diode is connected to the drain terminal of the switching FET.
    Type: Grant
    Filed: February 25, 2011
    Date of Patent: September 11, 2012
    Assignee: Alpha & Omega Semiconductor, Inc.
    Inventor: Sanjay Havanur
  • Patent number: 8107265
    Abstract: This inverter circuit includes two switching elements which are turned alternately ON and OFF, and a first primary winding connected in series between these switching elements, and also includes an output transformer having a secondary winding for obtaining an output voltage. This inverter circuit also includes a first voltage source and a second voltage source. The first voltage source applies a voltage to the first switching element via the first primary winding. And the second voltage source applies a voltage to the second switching element via the second primary winding. This inverter circuit also includes a regeneration snubber circuit for regenerating charge accumulated in a snubber capacitor. The regeneration snubber circuit includes a regeneration circuit including a voltage boost section which converts the primary side voltage of the output transformer to a predetermined voltage, which it outputs.
    Type: Grant
    Filed: January 30, 2009
    Date of Patent: January 31, 2012
    Assignee: Sansha Electric Manufacturing Co., Ltd.
    Inventors: Toshikazu Fujiyoshi, Hajime Katsushima, Kenji Morimoto, Satoshi Yamamura
  • Patent number: 8094470
    Abstract: This current balanced push-pull type inverter circuit includes first and second switching elements, and an output transformer which includes a first primary winding and a second primary winding connected in series between said first and second switching elements, and also includes a secondary winding for obtaining an output voltage. This inverter circuit also includes a first voltage supply capacitor, a second voltage supply capacitor, and a control unit. A first snubber circuit, in which a first free wheel diode and first and second snubber capacitors are connected in series, is connected in inverse parallel to the first switching element. A first discharge resistor is connected between the first snubber capacitor and a first power supply capacitor, and a second discharge resistor is connected between the second snubber capacitor and a third power supply capacitor. And a second snubber circuit and discharge resistors are connected to the second switching element as well, in a similar manner.
    Type: Grant
    Filed: March 10, 2009
    Date of Patent: January 10, 2012
    Assignee: Sansha Electric Manufacturing Co., Ltd.
    Inventors: Toshikazu Fujiyoshi, Hajime Katsushima, Kenji Morimoto, Satoshi Yamamura
  • Publication number: 20110149620
    Abstract: A circuit is proposed for limiting maximum switching FET drain-source voltage (VDS) of a transformer-coupled push pull power converter with maximum DC supply voltage VIN—MAX. Maximum VDS is accentuated by leakage inductances of the push pull transformer and the power converter circuit traces. The limiting circuit bridges the drains of the switching FETs and it includes two serially connected opposing Zener diodes each having a Zener voltage Vzx. The invention is applicable to both N-channel and P-channel FETs. In a specific embodiment, Vzx is selected to be slightly ?2*VIN—MAX with the maximum VDS clamped to about VIN—MAX+½Vzx, In another embodiment, a proposed power switching device with integrated VDS-clamping includes: a) A switching FET. b) A Zener diode having a first terminal and a second terminal, the second terminal of the Zener diode is connected to the drain terminal of the switching FET.
    Type: Application
    Filed: February 25, 2011
    Publication date: June 23, 2011
    Inventor: Sanjay Havanur
  • Patent number: 7898831
    Abstract: A circuit is proposed for limiting maximum switching FET drain-source voltage (VDS) of a transformer-coupled push pull power converter with maximum DC supply voltage VIN—MAX. Maximum VDS is accentuated by leakage inductances of the push pull transformer and the power converter circuit traces. The limiting circuit bridges the drains of the switching FETs and it includes two serially connected opposing Zener diodes each having a Zener voltage Vzx. The invention is applicable to both N-channel and P-channel FETs. In a specific embodiment, Vzx is selected to be slightly ?2*VIN—MAX with the maximum VDS clamped to about VIN—MAX+½ Vzx. In another embodiment, a proposed power switching device with integrated VDS-clamping includes: a) A switching FET. b) A Zener diode having a first terminal and a second terminal, the second terminal of the Zener diode is connected to the drain terminal of the switching FET.
    Type: Grant
    Filed: May 9, 2008
    Date of Patent: March 1, 2011
    Assignee: Alpha and Omega Semiconductor Inc.
    Inventor: Sanjay Havanur
  • Publication number: 20090279330
    Abstract: A circuit is proposed for limiting maximum switching FET drain-source voltage (VDS) of a transformer-coupled push pull power converter with maximum DC supply voltage VIN—MAX. Maximum VDS is accentuated by leakage inductances of the push pull transformer and the power converter circuit traces. The limiting circuit bridges the drains of the switching FETs and it includes two serially connected opposing Zener diodes each having a Zener voltage Vzx. The invention is applicable to both N-channel and P-channel FETs. In a specific embodiment, Vzx is selected to be slightly ?2*VIN—MAX with the maximum VDS clamped to about VIN—MAX+½ Vzx. In another embodiment, a proposed power switching device with integrated VDS-clamping includes: a) A switching FET. b) A Zener diode having a first terminal and a second terminal, the second terminal of the Zener diode is connected to the drain terminal of the switching FET.
    Type: Application
    Filed: May 9, 2008
    Publication date: November 12, 2009
    Inventor: Sanjay Havanur
  • Patent number: 7554820
    Abstract: A series resonant Dc-DC converter powers an audio amplifier as a load. The series resonant DC-DC converter may include a power input stage, a switching stage, a series resonant stage, a transformer stage and a power output stage. The series resonant DC-DC converter further may include a clamping stage and a leakage inductance canceling stage. The clamping stage may operate to clamp an excess voltage generated at least by a leakage inductance and a parasitic capacitance. The leakage inductance canceling stage may operate to generate a voltage drop corresponding to a voltage drop generated by the leakage inductance. The generated voltage drop may be subject to clamping. The clamping stage may operate under all load conditions without any influence of the leakage inductance. As a result, the series resonant converter may achieve improved load regulation.
    Type: Grant
    Filed: September 20, 2005
    Date of Patent: June 30, 2009
    Assignee: Harman International Industries, Incorporated
    Inventor: Gerald R. Stanley
  • Patent number: 7529109
    Abstract: A driving circuit for switching DC power includes a DC power generator, a bridge circuit, a control signal generator, and a clamping module. The bridge circuit includes a plurality of legs each including an up-bridge switch and a down-bridge switch. The clamping circuit is coupled to each up-bridge switch of the bridge circuit for clamping voltage of an input end of the up-bridge switch.
    Type: Grant
    Filed: September 21, 2006
    Date of Patent: May 5, 2009
    Assignee: Anpec Electronics Corporation
    Inventors: Kun-Min Chen, Ching-Sheng Li, Shiue-Shr Jiang, Shen-Min Lo, Ming-Jung Tsai
  • Patent number: 7492618
    Abstract: An inverter device includes an inverter circuit, an inverter driving unit, and a clamp diode. The inverter circuit includes an upper arm unit and a lower arm unit connected in series. The upper arm unit and the lower arm unit include switching elements that drive a load. The inverter driving unit includes a high-withstand-voltage IC that drives the switching elements of the upper arm unit and the lower arm unit. The high-withstand-voltage IC has a first terminal for supplying a reference voltage to the lower arm unit and a second terminal for supplying a high-voltage to the upper arm unit. The clamp diode clamps a potential difference between the first terminal and the second terminal.
    Type: Grant
    Filed: January 14, 2005
    Date of Patent: February 17, 2009
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Kensaku Matsuda, Shinzou Tomonaga
  • Patent number: 7180759
    Abstract: A power inverter comprises a push-pull inverter circuit that includes a transformer having a primary winding coupled to a DC bus and a secondary winding coupled to an AC bus, main power switches coupling each end of the primary winding to a DC return, and one or more supplemental power switches coupling at least one end of the primary winding to a snubber bus. The supplemental switch at a given end of the primary winding forms a buck-mode converter in combination with the primary winding and the associated free-wheeling diode at that end of the primary winding, and can be controlled by a switching controller to effect energy transfer between the snubber bus and DC bus. The switching controller can be configured to control power flow between the DC, AC, and snubber buses by controlling the common-mode and differential-mode voltages of the primary winding via main/supplemental power switch control.
    Type: Grant
    Filed: November 3, 2004
    Date of Patent: February 20, 2007
    Assignee: Square D Company
    Inventors: Julius Michael Liptak, Mark John Kocher, John Kenneth MacKenzie, IV
  • Patent number: 7116565
    Abstract: An over-power protection apparatus for self-excited power converter comprises a soft-start unit, an adjusting unit and a timing unit. A PWM unit of the self-excited power converter generates a switching signal in response to a compensating signal of the soft-start unit to control the output power of the self-excited power converter. The soft-start unit couples to the adjusting unit. The adjusting unit drives the soft-start unit and the PWM unit for modulating the switching signal to reduce the pulse width of the switching signal and the output power of the self-excited power converter once the short-circuit and over-load are happened at the output of the self-excited power converter. In the meantime, a timing unit starts to count. The timing unit drives the self-excited power converter to stop supplying the power source after the counting and the over-power lasting for a period of time.
    Type: Grant
    Filed: August 24, 2005
    Date of Patent: October 3, 2006
    Assignee: System General Corp.
    Inventor: Ta-Yung Yang
  • Patent number: 6954364
    Abstract: A backlight inverter for an LCD panel which is capable of detecting a fault in a transformer device or an open-lamp condition and performing a control operation to stop its operation upon detecting the fault in the transformer device or the open-lamp condition. The inverter supplies a PWM signal through a switch in normal operation. The inverter also detects a voltage corresponding to current flowing through each lamp in a lamp device and determines from the detected voltage whether the open-lamp condition has occurred. The inverter further detects a voltage at a midpoint of secondary windings of the transformer device and determines from the detected voltage whether the fault exists in the transformer device. In the event of the open-lamp condition or the fault in the transformer device, the inverter turns off the switch.
    Type: Grant
    Filed: August 1, 2003
    Date of Patent: October 11, 2005
    Assignee: Samsung Electro-Mechanics Co., Ltd.
    Inventor: Byoung Own Min
  • Patent number: 6469915
    Abstract: A resonant reset dual switch forward converter is disclosed. The resonant reset dual switch forward converter includes an input for accepting a DC voltage; a transformer having a primary winding and a secondary winding; a first and a second switch connected in series with the primary winding of the transformer for periodically connecting the input to the primary winding; a resonant capacitor for resetting the transformer during the OFF time of the first and second switches; and an auxiliary switch remaining OFF during the ON time of the first and second switches, and connecting the primary winding to the resonant capacitor during the OFF time of the first and second switches. The resonant reset dual switch forward converter provides a switching duty cycle greater than 50%, obtains a zero-voltage-switching condition for the first and second switches, and maintains the voltage stress of the f first and second switches around the input voltage.
    Type: Grant
    Filed: April 30, 2001
    Date of Patent: October 22, 2002
    Assignee: Delta Electronics Inc.
    Inventors: Guisong Huang, Yilei Gu, Zhizheng Liu, Alpha J. Zhang
  • Publication number: 20020122323
    Abstract: There is intended to provide an overvoltage-protective device capable of protecting a power system from overvoltage not destructively without using a fuse. An alarm signal from an MOS transistor Tr3, a structural element of a DC/DC converter 21, is inputted to a switching circuit 55, a structural element of the AC/DC converter 11. In case an alarm signal keeps high-level potential without indicating overvoltage-state, the switching circuit 55 connects a output current detecting circuit 53 having the smaller gain G1 to an output voltage detecting circuit 50 as well as a feedback circuit 51A, thereby to set large output-power-supply capability. In case an alarm signal inverses to low-level potential indicating overvoltage-state, the switching circuit 55 connects a output current detecting circuit 54 having the larger gain G2 to the output voltage detecting circuit 50 as well as the feedback circuit 51A, thereby to set small output-power-supply capability.
    Type: Application
    Filed: January 10, 2002
    Publication date: September 5, 2002
    Applicant: Fujitsu Limited
    Inventors: Yoshihiro Nagaya, Kyuichi Takimoto, Toshiyuki Matsuyama
  • Patent number: 6407937
    Abstract: The present invention relates to an active overvoltage protection apparatus for a bidirectional power switch which has two back-to-back in series connected semiconductor switches in the “common collector mode” topology. The overvoltage protection apparatus has a diode network which is linked to gate and emitter connections of the bidirectional power switch in the in such a manner as to provide a voltage clamping circuit for each of the semiconductor switches in the bidirectional power switch.
    Type: Grant
    Filed: March 23, 2001
    Date of Patent: June 18, 2002
    Assignee: Siemens Aktiengesellschaft
    Inventors: Manfred Bruckmann, Walter Springmann
  • Patent number: 6349044
    Abstract: A three-level DC-to-DC converter is provided having zero-voltage and zero-current switching (ZVZCS). A flying capacitor is provided on the primary side of the converter to achieve zero voltage switching (ZVS). In addition, during freewheeling (i.e., when no power is being transferred from the primary side to the secondary side), an auxiliary power source is provided to eliminate the circulating energy and to achieve zero current switching (ZCS) for the commutation switches.
    Type: Grant
    Filed: September 8, 2000
    Date of Patent: February 19, 2002
    Assignee: Virginia Tech Intellectual Properties, Inc.
    Inventors: Francisco Canales-Abarca, Peter M. Barbosa, Fred C. Lee