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公开(公告)号：US20170179834A1
公开(公告)日：2017-06-22
申请号：US15170897
申请日：2016-06-01
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor： Tzu-Chen Lin
CPC classification number: H02M3/33507 , H02M1/08 , H02M2001/0009 , Y02B70/1483
Abstract: A power converter includes: a transformer having a primary side winding to receive a rectified voltage, and a secondary side winding to generate an output DC voltage; a gallium nitride (GaN) M0SFET, coupled to the primary side winding for controlling a primary side current flowing through the primary side winding; a sensing resistor coupled to the GaN transistor switch, for sensing the primary side current to generate a current sensing signal; and a switch control unit, for controlling the GaN transistor switch according to the current sensing signal. The sensing resistor and the GaN transistor switch are connected at a ground node having a voltage level which is the ground of the primary side.
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公开(公告)号：US09680369B2
公开(公告)日：2017-06-13
申请号：US14547870
申请日：2014-11-19
Applicant: Richtek Technology Corporation
Inventor： Chang-Yu Wu , Tzu-Chen Lin
IPC: H02M1/42
CPC classification number: H02M3/33507 , H02M1/083 , H02M1/12 , H02M1/42 , H02M1/4225 , H02M1/4258 , H02M2001/0009 , Y02B70/126 , Y02P80/112
Abstract: A power factor correction (PFC) circuit of a power converter is disclosed. The power converter includes a primary side coil, a secondary side coil, an inductive coil, and a power switch. The PFC circuit includes a zero current detection circuit for detecting an inductive signal of the inductive coil to generate a detection signal; an error detection circuit for generating an error signal corresponding to an output voltage signal or an output current signal according to a reference signal; a ramp signal generating circuit for generating a ramp signal; a comparison circuit for comparing the ramp signal with the error signal to generate a comparison signal; and a trigger circuit for generating a control signal to control the power switch and for controlling the ramp signal generating circuit to adjust a slope of the ramp signal according to the detection signal and the comparison signal.
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公开(公告)号：US11496055B2
公开(公告)日：2022-11-08
申请号：US16241964
申请日：2019-01-07
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor： Kuang-Fu Chang , Tzu-Chen Lin
Abstract: The present invention discloses a power converter, a switch control circuit, and a short circuit detection method for current sensing resistor of the power converter. The power converter includes: a transformer, a power switch, a current sensing resistor and a switch control unit. The current sensing resistor has one end coupled to the power switch and another end coupled to ground. The switch control unit generates the operation signal to control the power switch. The switch control unit generates a first sample-and-hold voltage at a first time point and a second sample-and-hold voltage at a second time point according to a voltage across the current sensing resistor. When a voltage difference between the first sample-and-hold voltage and the second sample-and-hold voltage is smaller than a reference voltage, it is determined that a short circuit occurs in the current sensing resistor.
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公开(公告)号：US10560012B1
公开(公告)日：2020-02-11
申请号：US16247520
申请日：2019-01-14
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor： Ta-Yung Yang , Tzu-Chen Lin , Chien-Fu Tang
Abstract: A ZVS (zero voltage switching) control circuit for use in a flyback power converter includes a primary side controller and a secondary side controller. The primary side controller generates a switching signal to control a power transformer through a power transistor to generate an output voltage. The secondary side controller generates an SR (synchronous rectifier) signal to control an SR transistor at a secondary side of the power transformer. The SR signal includes an SR-control pulse and a ZVS pulse. The SR-control pulse controls the SR transistor according to a demagnetizing period of the power transformer. The ZVS pulse determines the starting timing of the switching signal to achieve zero voltage switching for the power transistor. The secondary side controller generates the ZVS pulse after a delay time from when the power transformer is demagnetized. The delay time is determined according to an output load of the output voltage.
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公开(公告)号：US20190149032A1
公开(公告)日：2019-05-16
申请号：US16134906
申请日：2018-09-18
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor： Ta-Yung Yang , Tzu-Chen Lin , Li-Di Luo , Pei-Sheng Tsu
Abstract: A ZVS (zero voltage switching) control circuit for use in a flyback power converter includes a primary side controller circuit, a secondary side controller circuit, and a pulse transformer. In one switching cycle, a synchronous rectifier transistor is turned ON twice to generate a circulation current at the primary side winding, and after the synchronous rectifier transistor is turned OFF, the power transistor is turned ON for zero voltage switching. A synchronous signal coupled between the primary side and the secondary side is employed to synchronize the power transistor and the synchronous transistor. The synchronous signal also triggers an SR-ZVS pulse to turn ON the synchronous rectifier transistor for achieving the zero voltage switching when the power transistor is turned ON.
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Patent Agency Ranking
公开(公告)号：US10291137B2
公开(公告)日：2019-05-14
申请号：US16040501
申请日：2018-07-19
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor： Chien-Fu Tang , Isaac Y. Chen , Tzu-Chen Lin , Kun-Yu Lin , Li-Yang Hsiao , Yung-Chih Lai
Abstract: A flyback power converter includes a transformer having an auxiliary winding for generating an auxiliary voltage and providing a supply voltage on a supply node; a primary side controller circuit which is powered by the supply voltage from the supply node; and a high voltage (HV) start-up circuit. The HV start-up circuit is coupled to an high voltage signal through a HV input terminal and generates the supply voltage through a supply output terminal, wherein when the supply voltage does not exceed a start-up voltage threshold, a HV start-up switch conducts the HV input terminal and the supply output terminal to provide the supply voltage, and when the supply voltage exceeds a start-up voltage threshold, the HV start-up switch is OFF. The HV start-up circuit and the primary side controller circuit are packaged in two separate integrated circuit packages respectively.
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17.发明申请公开(公告)号：US20190140547A1
公开(公告)日：2019-05-09
申请号：US16241964
申请日：2019-01-07
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor： Kuang-Fu Chang , Tzu-Chen Lin
Abstract: The present invention discloses a power converter, a switch control circuit, and a short circuit detection method for current sensing resistor of the power converter. The power converter includes: a transformer, a power switch, a current sensing resistor and a switch control unit. The current sensing resistor has one end coupled to the power switch and another end coupled to ground. The switch control unit generates the operation signal to control the power switch. The switch control unit generates a first sample-and-hold voltage at a first time point and a second sample-and-hold voltage at a second time point according to a voltage across the current sensing resistor. When a voltage difference between the first sample-and-hold voltage and the second sample-and-hold voltage is smaller than a reference voltage, it is determined that a short circuit occurs in the current sensing resistor.
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公开(公告)号：US20190028033A1
公开(公告)日：2019-01-24
申请号：US16040501
申请日：2018-07-19
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor： Chien-Fu Tang , Isaac Y. Chen , Tzu-Chen Lin , Kun-Yu Lin , Li-Yang Hsiao , Yung-Chih Lai
Abstract: A flyback power converter includes a transformer having an auxiliary winding for generating an auxiliary voltage and providing a supply voltage on a supply node; a primary side controller circuit which is powered by the supply voltage from the supply node; and a high voltage (HV) start-up circuit. The HV start-up circuit is coupled to an high voltage signal through a HV input terminal and generates the supply voltage through a supply output terminal, wherein when the supply voltage does not exceed a start-up voltage threshold, a HV start-up switch conducts the HV input terminal and the supply output terminal to provide the supply voltage, and when the supply voltage exceeds a start-up voltage threshold, the HV start-up switch is OFF. The HV start-up circuit and the primary side controller circuit are packaged in two separate integrated circuit packages respectively.
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公开(公告)号：US09755529B2
公开(公告)日：2017-09-05
申请号：US15147182
申请日：2016-05-05
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor： Yu-Chang Chen , Li-Di Luo , Tzu-Chen Lin
CPC classification number: H02M3/33515 , H02M1/08 , H02M3/33592 , H02M2001/0006 , H02M2001/0009 , Y02B70/1475
Abstract: The present invention provides a flyback power converter and a control circuit thereof. The flyback power converter includes a transformer, a power switch, a driver, a synchronous rectification (SR) switch, a controller, and a signal coupler circuit. The transformer has a primary winding and a secondary winding. The power switch controls the conduction time of the primary winding; and the SR switch controls the conduction time of the secondary winding. The controller controls the SR switch and generates an ON pulse signal and an OFF pulse signal in a normal operation mode. When an output voltage reaches a lower limit voltage, the flyback power converter operates in the normal operation mode. The driver generates a switching signal according to the ON pulse signal and the OFF pulse signal in the normal operation mode, to determine a start conduction time point and an end conduction time point of the primary winding.
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公开(公告)号：US09755525B2
公开(公告)日：2017-09-05
申请号：US14947233
申请日：2015-11-20
Applicant: RICHTEK TECHNOLOGY CORPORATION
Inventor： Tzu-Chen Lin
CPC classification number: H02M3/33507 , H02M1/15 , H02M7/06 , H02M2001/007
Abstract: A power converter circuit includes a transformer for converting a primary side voltage to a secondary side voltage and generating an output current. A power limit control unit senses the secondary side voltage to obtain a waveform feature of the primary side voltage, and decides a target of the output current according to the waveform feature of the primary side voltage. When the primary side voltage drops to a threshold, the output current is reduced.
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