Patents by Inventor Xiaoru Xu
Xiaoru Xu 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: 20150382418Abstract: In one embodiment, a light-emitting diode (LED) driver can include: (i) a reference voltage control circuit configured to provide a reference voltage signal in response to an enable signal; (ii) a current control circuit configured to control an output current of the LED driver in response to the reference voltage signal; and (iii) the LED driver being configured to drive an LED load when the enable signal is active.Type: ApplicationFiled: September 2, 2015Publication date: December 31, 2015Inventors: Xiaoru Xu, Lu Zhang
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Patent number: 9170588Abstract: Disclosed are compensation circuits for a switching power supply. In one embodiment, a compensation circuit can include: (i) a transconductance amplifier configured to receive a reference signal and a feedback signal, and to generate an amplifier output signal according to a difference between the reference signal and the feedback signal; (ii) a switching circuit configured to receive the amplifier output signal, where the switching circuit is controllable by a control signal from a switch control circuit; and (iii) a charging circuit coupled to the switching circuit, where the charging circuit is configured to be charged by the amplifier output signal in response to the control signal, and to generate a compensation signal therefrom.Type: GrantFiled: September 6, 2013Date of Patent: October 27, 2015Assignee: Silergy Semiconductor Technology (Hangzhou) LTDInventors: Xiaoru Xu, Guojia Liu
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Patent number: 9167643Abstract: In one embodiment, a light-emitting diode (LED) driver can include: (i) a reference voltage control circuit configured to provide a reference voltage signal in response to an enable signal; (ii) a current control circuit configured to control an output current of the LED driver in response to the reference voltage signal; and (iii) the LED driver being configured to drive an LED load when the enable signal is active.Type: GrantFiled: September 26, 2013Date of Patent: October 20, 2015Assignee: Silergy Semiconductor Technology (Hangzhou) LTDInventors: Xiaoru Xu, Lu Zhang
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Patent number: 9130468Abstract: The present invention relates to a constant voltage constant current (CVCC) controller, and associated control methods. In one embodiment, a CVCC controller for a flyback converter can include: (i) a current controller configured to generate an error signal by comparing an output current feedback signal against a reference current; (ii) a voltage controller configured to receive an output voltage feedback signal and a reference voltage, and to generate a control signal; (iii) a selector configured to control the flyback converter to operate in a first or a second operation mode based on the control signal, and to further generate a constant voltage or a constant current control signal based on the error signal; and (iv) a pulse-width modulation (PWM) controller configured to generate a PWM control signal to control a main switch, and to maintain the output voltage and/or current of the flyback converter as substantially constant.Type: GrantFiled: November 5, 2014Date of Patent: September 8, 2015Assignee: Silergy Semiconductor Technology (Hangzhou) LTDInventor: Xiaoru Xu
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Publication number: 20150245434Abstract: The present invention pertains to an inductor current detection circuit in a switching mode power supply, and a light-emitting diode (LED) driver thereof. In one embodiment, an inductor current detection circuit configured in a switching mode power supply under discontinuous conduction mode, can include: (i) a voltage detection circuit configured to generate a sampling voltage based on a drain-source voltage of a power switch in the switching mode power supply; (ii) a voltage holding circuit configured to receive the sampling voltage, and to generate a holding voltage through a sampling and holding operation; and (iii) a comparison circuit configured to compare the sampling voltage against the holding voltage, and to generate a zero-crossing signal when the sampling voltage is less than the holding voltage, where the zero-crossing signal is configured to represent an inductor current ending time of the switching mode power supply.Type: ApplicationFiled: May 12, 2015Publication date: August 27, 2015Inventor: Xiaoru Xu
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Publication number: 20150214829Abstract: In one embodiment, a zero-crossing detection circuit can include: (i) a first detection circuit configured to detect a current through a main transistor of a main circuit of a switching power supply, and to generate a voltage sense signal that represents the current through the main transistor; (ii) a second detection circuit configured to detect if quasi-resonance occurs in the main circuit, the second detection circuit being configured to generate at least one pulse signal when the quasi-resonance is detected; and (iii) a control circuit configured to receive the at least one pulse signal and the voltage sense signal, to turn the main transistor off when the current through the main transistor reaches a predetermined value, and to turn the main transistor on when the at least one pulse signal is active.Type: ApplicationFiled: January 23, 2015Publication date: July 30, 2015Inventors: Xiaoru Xu, Guojia Liu, Jian Deng
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Publication number: 20150207417Abstract: In one embodiment, a method of controlling a switching power supply, can include: (i) generating a driving current signal that follows a waveform of a sense voltage signal, where the sense voltage signal is related to a current through a collector of a transistor that is configured as a power switch of the switching power supply, where the collector is coupled to an inductive element of the switching power supply; (ii) providing the driving current signal to a base of the transistor, where the transistor is in a saturated conduction state when a pulse-width modulation (PWM) signal is active; and (iii) releasing charge accumulated on the base when the PWM signal is inactive to turn off the transistor.Type: ApplicationFiled: January 16, 2015Publication date: July 23, 2015Inventors: Huiqiang Chen, Yunlong Han, Xiaoru Xu, Wei Chen
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Patent number: 9065331Abstract: The present invention pertains to an inductor current detection circuit in a switching mode power supply, and a light-emitting diode (LED) driver thereof. In one embodiment, an inductor current detection circuit configured in a switching mode power supply under discontinuous conduction mode, can include: (i) a voltage detection circuit configured to generate a sampling voltage based on a drain-source voltage of a power switch in the switching mode power supply; (ii) a voltage holding circuit configured to receive the sampling voltage, and to generate a holding voltage through a sampling and holding operation; and (iii) a comparison circuit configured to compare the sampling voltage against the holding voltage, and to generate a zero-crossing signal when the sampling voltage is less than the holding voltage, where the zero-crossing signal is configured to represent an inductor current ending time of the switching mode power supply.Type: GrantFiled: May 24, 2013Date of Patent: June 23, 2015Assignee: Silergy Semiconductor Technology (Hangzhou) LTDInventor: Xiaoru Xu
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Publication number: 20150171742Abstract: In one embodiment, an active power factor correction (APFC) control circuit, configured to generate a pulse-width modulation (PWM) control signal to control the operation of a power converter, can include: (i) an inductor current zero crossing detection circuit coupled to a common node between a power switch of the power converter and a first switch that are coupled in series, where the inductor current zero crossing detection circuit is configured to generate a comparison signal based on a voltage signal at the common node; (ii) the comparison signal being activated when an inductor current of the power converter decreases to zero; and (iii) the APFC control circuit being configured as a source driver, wherein a control terminal of the power switch is coupled to a constant voltage supply.Type: ApplicationFiled: December 11, 2014Publication date: June 18, 2015Inventor: Xiaoru Xu
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Patent number: 9055629Abstract: The present invention relates to an SCR dimming circuit and method for regulating the luminance of an LED load. In one embodiment, an SCR dimming circuit can include: an SCR element that generates a lack-phase AC voltage based on a sinusoidal AC supply; a rectifier bridge that generates a lack-phase DC voltage based on the lack-phase AC voltage; a conduction angle generator that receives the lack-phase DC voltage, and generates a controlling signal representative of a conduction angle of the SCR element; and a dimming signal generator that generates a dimming signal to regulate luminance of the LED load, where the dimming signal generator receives the controlling signal, an adjustable signal, and a clamping voltage, an amplitude of a dimming phase angle range is selected by a fixed signal determined by the clamping voltage, and the dimming phase angle range may be shifted by regulating the adjustable signal.Type: GrantFiled: May 8, 2014Date of Patent: June 9, 2015Assignee: Silergy Semiconductor Technology (Hangzhou) LTDInventors: Shenglun Chen, Wei Chen, Xiaoru Xu
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Publication number: 20150109835Abstract: In one embodiment, an output overvoltage protection method for a switching power supply, can include: (i) charging a first capacitor by a first current during a first time interval of a switching period of the switching power supply; (ii) charging a second capacitor by a second current during a second time interval of the switching period of the switching power supply; and (iii) generating an overvoltage protection signal by comparing a first voltage across the first capacitor against a second voltage across the second capacitor at the end of the second time interval, where the overvoltage protection signal is active when the first voltage is at least as high as the second voltage.Type: ApplicationFiled: October 8, 2014Publication date: April 23, 2015Inventor: Xiaoru Xu
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Publication number: 20150062979Abstract: The present invention discloses CVCC circuits and methods with improved load regulation for an SMPS. In one embodiment, the CVCC can include: a voltage feedback circuit to generate an output voltage feedback signal; a current feedback circuit to generate an output current feedback signal; a control signal generating circuit that receives the output voltage feedback signal and the output current feedback signal, and generates a constant voltage/constant current control signal; a first enable signal generating circuit that compares a first reference voltage and the constant voltage/constant current control signal to generate a first enable signal; and a PWM controller that generates a PWM control signal based on the constant voltage/constant current control signal to control a main switch of the flyback SMPS.Type: ApplicationFiled: October 20, 2014Publication date: March 5, 2015Inventor: Xiaoru Xu
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Publication number: 20150055383Abstract: The present invention relates to a constant voltage constant current (CVCC) controller, and associated control methods. In one embodiment, a CVCC controller for a flyback converter can include: (i) a current controller configured to generate an error signal by comparing an output current feedback signal against a reference current; (ii) a voltage controller configured to receive an output voltage feedback signal and a reference voltage, and to generate a control signal; (iii) a selector configured to control the flyback converter to operate in a first or a second operation mode based on the control signal, and to further generate a constant voltage or a constant current control signal based on the error signal; and (iv) a pulse-width modulation (PWM) controller configured to generate a PWM control signal to control a main switch, and to maintain the output voltage and/or current of the flyback converter as substantially constant.Type: ApplicationFiled: November 5, 2014Publication date: February 26, 2015Inventor: Xiaoru Xu
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Patent number: 8922174Abstract: The present invention relates to a power factor correction circuit, that can include: an inductor current detector that generates a sampling voltage signal, and sinusoidal half-wave current and voltage signals based on the sampling voltage signal; a mediate signal generator generating slope voltage and clock signals in response to the sinusoidal half-wave voltage signal, where a frequency of each varies with the sinusoidal half-wave voltage signal; a current modulation circuit receiving the sinusoidal half-wave current signal and a voltage feedback signal representative of a power stage output voltage to generate a regulation signal that is compared against the slope voltage signal to generate a modulation signal; and a logic/driving circuit receiving the modulation and clock signals, and generating a controlling signal that controls a power switch with variable frequency to maintain the inductor current in phase with the sinusoidal half-wave voltage signal and the power stage output voltage constant.Type: GrantFiled: April 16, 2012Date of Patent: December 30, 2014Assignee: Silergy Semiconductor Technology (Hangzhou) LtdInventor: Xiaoru Xu
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Patent number: 8917528Abstract: The present invention relates to a constant voltage constant current (CVCC) controller, and associated control methods. In one embodiment, a CVCC controller for a flyback converter can include: (i) a current controller configured to generate an error signal by comparing an output current feedback signal against a reference current; (ii) a voltage controller configured to receive an output voltage feedback signal and a reference voltage, and to generate a control signal; (iii) a selector configured to control the flyback converter to operate in a first or a second operation mode based on the control signal, and to further generate a constant voltage or a constant current control signal based on the error signal; and (iv) a pulse-width modulation (PWM) controller configured to generate a PWM control signal to control a main switch, and to maintain the output voltage and/or current of the flyback converter as substantially constant.Type: GrantFiled: January 25, 2013Date of Patent: December 23, 2014Assignee: Silergy Semiconductor Technology (Hangzhou) LtdInventor: Xiaoru Xu
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Patent number: 8913404Abstract: The present invention discloses CVCC circuits and methods with improved load regulation for an SMPS. In one embodiment, the CVCC can include: a voltage feedback circuit to generate an output voltage feedback signal; a current feedback circuit to generate an output current feedback signal; a control signal generating circuit that receives the output voltage feedback signal and the output current feedback signal, and generates a constant voltage/constant current control signal; a first enable signal generating circuit that compares a first reference voltage and the constant voltage/constant current control signal to generate a first enable signal; and a PWM controller that generates a PWM control signal based on the constant voltage/constant current control signal to control a main switch of the flyback SMPS.Type: GrantFiled: February 28, 2013Date of Patent: December 16, 2014Assignee: Silergy Semiconductor Technology (Hangzhou) LtdInventor: Xiaoru Xu
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Publication number: 20140340946Abstract: In one embodiment, a power switch driving circuit can include: (i) an upper switch having a first power terminal coupled to a voltage source, and a second power terminal coupled to a driving signal; (ii) a lower switch having a first power terminal coupled to the driving signal, and a second power terminal coupled to a first voltage level, where the first voltage level is higher than a first ground potential; (iii) an upper switch driving sub circuit configured to receive a control signal, and to drive the upper switch in response thereto; and (iii) a lower switch driving sub circuit configured to receive the control signal, and to drive the lower switch in response thereto, where the upper and lower switch driving sub circuits are coupled to a second ground potential.Type: ApplicationFiled: August 6, 2014Publication date: November 20, 2014Inventors: Wei Chen, Xiaoru Xu
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Publication number: 20140313786Abstract: In one embodiment, a controlling circuit configured for an AC/DC converter that receives an AC voltage supply, can include: (i) a compensation signal generator configured to generate a compensation signal that follows an error between an output signal from the AC/DC converter and an expected converter output signal during a first time interval of a half period of the AC voltage supply, the compensation signal being substantially constant during a remaining time interval of the half period; and (ii) a controlling signal generator configured to generate a controlling signal based on the compensation signal to maintain the output signal as substantially consistent with the expected converter output signal.Type: ApplicationFiled: April 9, 2014Publication date: October 23, 2014Applicant: Silergy Semiconductor Technology (Hangzhou) LTDInventors: Wei Chen, Xiaoru Xu, Qiukai Huang
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Publication number: 20140307485Abstract: In one embodiment, a method of compensating for transmission voltage loss from a switching power supply, can include: (i) receiving a sampling signal that represents an output current of the switching power supply; (ii) delaying the sampling signal to generate a delayed sampling signal; (iii) converting the delayed sampling signal to generate a compensation signal; and (iv) regulating an output voltage of the switching power supply based on the compensation signal to compensate for the transmission voltage loss from the output voltage transmission to a load such that a voltage at the load is maintained as substantially consistent with an expected voltage at the load.Type: ApplicationFiled: April 5, 2014Publication date: October 16, 2014Applicant: Silergy Semiconductor Technology (Hangzhou) LTDInventors: Xiaoru Xu, Yunlong Han
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Publication number: 20140307486Abstract: In one embodiment, a method of controlling a capacitor discharge for a switching power supply, can include: (i) generating a first voltage signal from a voltage at an X capacitor that is coupled between input terminals of the switching power supply; (ii) activating a detection signal in response to the first voltage signal being inactive for a duration of a predetermined time interval, where the detection signal being activated indicates a cut-off of the input terminals; and (iii) at least partially discharging the X capacitor after the cut-off and in response to activation of the detection signal.Type: ApplicationFiled: April 2, 2014Publication date: October 16, 2014Applicant: Silergy Semiconductor Technology (Hangzhou) LTDInventors: Qiukai Huang, Yunlong Han, Xiaoru Xu