Patents by Inventor Yungtaek Jang
Yungtaek Jang 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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Publication number: 20070040644Abstract: A PFC circuit comprises a first converter and a second converter and a multi-port electromagnetic device. The first converter has a first inductive element and the second converter has a second inductive element. The multi-port electromagnetic device. comprises a first magnetic core having a first closed flux path and a second magnetic core having a second closed flux path, with the first closed flux path being independent of the second closed flux path. The first inductive element of the first boost circuit comprises a first winding that electromagnetically couples the first magnetic core to the second magnetic core and the second inductive element of the second boost circuit comprises a second winding that electromagnetically couples the first magnetic core to the second magnetic core independent of the electromagnetic coupling of the first winding such that current application in one windings does not induce a substantial voltage in the other.Type: ApplicationFiled: February 17, 2006Publication date: February 22, 2007Applicant: Delta Electronics, Inc.Inventors: Yungtaek Jang, Milan Jovanovic
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Patent number: 7161458Abstract: A multi-port electromagnetic device comprises a first magnetic core having a first closed flux path and a second magnetic core having a second closed flux path, with the first closed flux path being independent from the second closed flux path. At least one first winding electromagnetically couples the first magnetic core to the second magnetic core, and at least one second winding electromagnetically couples the first magnetic core to the second magnetic core independent of the electromagnetic coupling of the at least one first winding such that current application in one of the first or second windings does not induce a magnetic flux in the other one of the first or second windings.Type: GrantFiled: February 22, 2005Date of Patent: January 9, 2007Assignee: Delta Electronics, Inc.Inventors: Yungtaek Jang, Milan Jovanović
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Publication number: 20060186981Abstract: A multi-port electromagnetic device comprises a first magnetic core having a first closed flux path and a second magnetic core having a second closed flux path, with the first closed flux path being independent from the second closed flux path. At least one first winding electromagnetically couples the first magnetic core to the second magnetic core, and at least one second winding electromagnetically couples the first magnetic core to the second magnetic core independent of the electromagnetic coupling of the at least one first winding such that current application in one of the first or second windings does not induce a magnetic flux in the other one of the first or second windings.Type: ApplicationFiled: February 22, 2005Publication date: August 24, 2006Applicant: Delta Electronics, Inc.Inventors: Yungtaek Jang, Milan Jovanovic
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Publication number: 20060152954Abstract: The present invention relates to a current control circuit for controlling inrush current through an energy storage capacitor of a power supply having an input voltage. A semiconductor device is coupled in series to the energy storage capacitor; and a control circuit produces a constant current through the semiconductor device during an inrush current period when the energy storage capacitor is charged by the input voltage to reach an energy storage capacitor voltage that causes the semiconductor device to act as a short switch.Type: ApplicationFiled: January 7, 2005Publication date: July 13, 2006Applicant: Delta Electronics, Inc.Inventors: Milan Jovanovic, Yungtaek Jang, Chi-Hsing Huang
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Publication number: 20060087295Abstract: A non-isolated power conversion system has an input stage and an output stage. A plurality of cascaded switching power converter stages are coupled between the input stage and the output stage. Each of the plurality of switching power converter stages has at least one switch that is activated in accordance with a duty cycle associated with a switching cycle. At least one energy storage device temporarily stores energy that is proportional to the duty cycle during the switching cycle for delivery to the output stage.Type: ApplicationFiled: October 26, 2004Publication date: April 27, 2006Applicant: Delta Electronics, Inc.Inventors: Yungtaek Jang, Milan Jovanovic
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Patent number: 6992902Abstract: A soft-switched, full-bridge pulse-width-modulated converter and its variations provide zero-voltage-switching conditions for the turn-on of the bridge switches over a wide range of input voltage and output load. The FB PWM converters of this invention achieve ZVS with a substantially reduced duty cycle loss and circulating current. The ZVS of the primary switches is achieved by employing an auxiliary circuit having an inductor and transformer to store energy for ZVS turn-on of the bridge switches.Type: GrantFiled: August 21, 2003Date of Patent: January 31, 2006Assignee: DELTA Electronics, Inc.Inventors: Yungtaek Jang, Milan M. Jovanović
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Patent number: 6987675Abstract: A soft-switched boost converter includes an active snubber to provide soft switching of all semiconductor components. Specifically, the current (“turn-off current”) in the rectifier is switched off at a controlled rate, the main switch is closed under zero-voltage switching (ZVS) condition, and the auxiliary switch in the active snubber is opened under zero-current switching (ZCS) condition. As a result, switching losses are reduced with beneficial effects on conversion efficiency and EMC performance.Type: GrantFiled: May 23, 2003Date of Patent: January 17, 2006Assignee: Delta Electronics, Inc.Inventors: Milan M. Jovanovic, Yungtaek Jang, Yu-ming Chang, Kung-Hui Fang
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Publication number: 20050243579Abstract: The present invention includes multiple power converters for driving one or more loads via an input power source, AC or DC. A first switching power converter has first one or more windings coupled to an input power source, and a second switching power converter having second one or more windings coupled to one or more loads. A magnetic device comprising a single integrated magnetic core couples the first one or more windings to the second one or more windings for reducing switching loss.Type: ApplicationFiled: April 29, 2004Publication date: November 3, 2005Applicant: Delta Electronics, Inc.Inventors: Yungtaek Jang, Milan Jovanovic
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Publication number: 20050226012Abstract: A soft-switched boost converter includes an active snubber to provide soft switching of all semiconductor components. Specifically, the current (“turn-off current”) in the rectifier is switched off at a controlled rate, the main switch is closed under zero-voltage switching (ZVS) condition, and the auxiliary switch in the active snubber is opened under zero-current switching (ZCS) condition. As a result, switching losses are reduced with beneficial effects on conversion efficiency and EMC performance.Type: ApplicationFiled: May 23, 2003Publication date: October 13, 2005Inventors: Milan Jovanovic, Yungtaek Jang, Yu-Ming Chang, Kung-Hui Fang
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Patent number: 6934167Abstract: A contactless electrical energy transmission system includes a transformer having a primary winding that is coupled to a power source through a primary resonant circuit and a secondary winding that is coupled to a load through a secondary resonant circuit. The primary and secondary resonant circuits are inductively coupled to each other. A primary control circuit detects current changes through the primary resonant circuit to control the switching frequency of a controllable switching device for maintaining a substantially constant energy transfer between the primary winding and secondary winding in response to at least one of a power source voltage change and a load change. As a result, excessive circulating energy of the CEET system is minimized providing a tight regulation of the output voltage over the entire load and input voltage ranges without any feedback connection between the primary side and the secondary side.Type: GrantFiled: May 1, 2003Date of Patent: August 23, 2005Assignee: Delta Electronics, Inc.Inventors: Yungtaek Jang, Milan M. Jovanovic
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Patent number: 6906930Abstract: An isolated boost converter includes first and second switches that are switched simultaneously, a transformer and an energy storage capacitor on the primary side of the transformer for storing energy received from input power source. In one embodiment, when the first and second switches are closed, the energy in the capacitor is transferred to the output load while a boost inductor is charged, and when the first and second switches are open, the boost inductor provides energy from the input voltage source to supply the load and to charge the capacitor, In one embodiment, a third switch is provided to relieve the voltage stress on the secondary side.Type: GrantFiled: June 26, 2003Date of Patent: June 14, 2005Assignee: Delta Electronics, Inc.Inventors: Yungtaek Jang, Milan M. Jovanovic
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Publication number: 20050041439Abstract: A soft-switched, full-bridge pulse-width-modulated (FB PWM) converter and its variations provide zero-voltage-switching (ZVS) conditions for the turn-on of the bridge switches over a wide range of input voltage and output load. The FB PWM converters of this invention achieve ZVS with a substantially reduced duty cycle loss and circulating current, which optimizes the conversion efficiency. The ZVS of the primary switches is achieved by employing an auxiliary circuit comprising an inductor and transformer to store energy for ZVS turn-on of the bridge switches.Type: ApplicationFiled: August 21, 2003Publication date: February 24, 2005Applicant: DELTA Electronics, Inc.Inventors: Yungtaek Jang, Milan Jovanovic
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Publication number: 20040264224Abstract: An isolated boost converter includes first and second switches that are switched simultaneously, a transformer and an energy storage capacitor on the primary side of the transformer for storing energy received from input power source. In one embodiment, when the first and second switches are closed, the energy in the capacitor is transferred to the output load while a boost inductor is charged, and when the first and second switches are open, the boost inductor provides energy from the input voltage source to supply the load and to charge the capacitor, In one embodiment, a third switch is provided to relieve the voltage stress on the secondary side.Type: ApplicationFiled: June 26, 2003Publication date: December 30, 2004Inventors: Yungtaek Jang, Milan M. Jovanovic
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Publication number: 20040218406Abstract: A contactless electrical energy transmission system includes a transformer having a primary winding that is coupled to a power source through a primary resonant circuit and a secondary winding that is coupled to a load through a secondary resonant circuit. The primary and secondary resonant circuits are inductively coupled to each other. A primary control circuit detects current changes through the primary resonant circuit to control the switching frequency of a controllable switching device for maintaining a substantially constant energy transfer between the primary winding and secondary winding in response to at least one of a power source voltage change and a load change. As a result, excessive circulating energy of the CEET system is minimized providing a tight regulation of the output voltage over the entire load and input voltage ranges without any feedback connection between the primary side and the secondary side.Type: ApplicationFiled: May 1, 2003Publication date: November 4, 2004Inventors: Yungtaek Jang, Milan M. Jovanovic
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Patent number: 6504497Abstract: The stored energy in the energy-storage capacitors of a power supply during the hold-up time is improved by providing two groups of energy storage capacitors, and by connecting one group of capacitors to the input of a hold-up-time extension circuit that has its output connected to the other group of energy-storage capacitors. Each group of energy-storage capacitors may consist of a single capacitor, or a number of capacitors connected in parallel. The hold-up-time extension circuit is designed so that its output is regulated at a voltage that is lower than the minimum regulation voltage of the output-stage dc/dc converter. As a result, the hold-up-time extension circuit is inactive during the normal operation mode. i.e., when the input voltage is present. In fact, during the normal operation mode both groups of capacitors are effectively connected in parallel so that their voltages are equal.Type: GrantFiled: May 16, 2001Date of Patent: January 7, 2003Assignee: Delta Electronics, Inc.Inventors: Yungtaek Jang, Milan M. Jovanovic
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Publication number: 20020071300Abstract: The stored energy in the energy-storage capacitors of a power supply during the hold-up time is improved by providing two groups of energy storage capacitors, and by connecting one group of capacitors to the input of a hold-up-time extension circuit that has its output connected to the other group of energy-storage capacitors. Each group of energy-storage capacitors may consist of a single capacitor, or a number of capacitors connected in parallel. The hold-up-time extension circuit is designed so that its output is regulated at a voltage that is lower than the minimum regulation voltage of the output-stage dc/dc converter. As a result, the hold-up-time extension circuit is inactive during the normal operation mode. i.e., when the input voltage is present. In fact, during the normal operation mode both groups of capacitors are effectively connected in parallel so that their voltages are equal.Type: ApplicationFiled: May 16, 2001Publication date: June 13, 2002Inventors: Yungtaek Jang, Milan M. Jovanovic
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Patent number: 6392902Abstract: A soft-switched full-bridge pulse-width modulated (“FB PWM”) converter includes a coupled inductor provides ZVS conditions over a wide range of input voltages and output loads. Further, the FB PWM converter of the present invention requires neither a large leakage inductance in the transformer, nor an external inductor, to achieve ZVS.Type: GrantFiled: August 31, 2000Date of Patent: May 21, 2002Assignee: Delta Electronics, Inc.Inventors: Yungtaek Jang, Milan M. Jovanovic
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Publication number: 20020044461Abstract: A family of soft-switched, full-bridge pulse-width-modulated (FB PWM) converters provides zero-voltage-switching (ZVS) conditions for the turn-on of the bridge switches over a wide range of input voltage and output load. The FB PWM converters of this family achieve ZVS with the minimum duty cycle loss and circulating current, which optimizes the conversion efficiency. The ZVS of the primary switches is achieved by employing two magnetic components whose volt-second products change in the opposite directions with a change in phase shift between the two bridge legs. One magnetic component always operates as a transformer, where the other magnetic component can either be a coupled inductor, or uncoupled (single-winding) inductor. The transformer is used to provide isolated output(s), whereas the inductor is used to store the energy for ZVS.Type: ApplicationFiled: February 5, 2001Publication date: April 18, 2002Inventors: Yungtaek Jang, Milan M. Jovanovic
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Patent number: 6356462Abstract: A family of soft-switched, full-bridge pulse-width-modulated (FB PWM) converters provides zero-voltage-switching (ZVS) conditions for the turn-on of the bridge switches over a wide range of input voltage and output load. The FB PWM converters of this family achieve ZVS with the minimum duty cycle loss and circulating current, which optimizes the conversion efficiency. The ZVS of the primary switches is achieved by employing two magnetic components whose volt-second products change in the opposite directions with a change in phase shift between the two bridge legs. One magnetic component always operates as a transformer, where the other magnetic component can either be a coupled inductor, or uncoupled (single-winding) inductor. The transformer is used to provide isolated output(s), whereas the inductor is used to store the energy for ZVS.Type: GrantFiled: February 5, 2001Date of Patent: March 12, 2002Assignee: Delta Electronics, Inc.Inventors: Yungtaek Jang, Milan M. Jovanovic
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Patent number: 6353547Abstract: Three-level, constant-frequency, soft-switched isolated converters provide zero-voltage-switching (ZVS) conditions for the turn-on of all primary switches over a wide range of input voltage and output load. These converters achieve ZVS with the minimum duty cycle loss and circulating current, which optimizes the conversion efficiency. The ZVS of the primary switches is achieved by the energy stored in an inductor on the primary side of the isolation transformer. The inductor and transformer are arranged so that a change in the phase shift between the outer and inner pair of switches of the series connection of four switches changes the volt-second product on the windings of the transformer and the windings of the inductor in opposite directions. In some embodiments the primary-side inductor is coupled inductor with two windings, whereas in the other embodiments the inductor has only one winding.Type: GrantFiled: March 29, 2001Date of Patent: March 5, 2002Assignee: Delta Electronics, Inc.Inventors: Yungtaek Jang, Milan M. Jovanovic