Patents by Inventor Gilbert S. Z. Lee

Gilbert S. Z. Lee 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).

  • Publication number: 20230353049
    Abstract: A controller for a switching regulator incorporates a protection circuit to limit the negative current to a negative current threshold while operating the switching regulator to sink current from the load without damage to the power switches. In some embodiments, in response to the negative current reaching the negative current threshold, the protection circuit turns off the low-side power switch and turns on the high-side power switch for a maximum time period. In the event the negative current has not recovered, the high-side power switch and the low-side power switch are both turned off while the high-side power switch conducts the negative current through the high-side power switch body diode. When the negative current recovers to a recovery level, the low-side power switch can then be turned on. The protection circuit repeats the process each time the negative current is detected to have reached the negative current threshold.
    Type: Application
    Filed: May 2, 2022
    Publication date: November 2, 2023
    Inventors: Zhiye Zhang, Gilbert S. Z. Lee
  • Patent number: 10830799
    Abstract: A power MOSFET Rdson compensation device comprising analog circuitry receives an input signal proportional to a voltage drop across a power MOSFET, one or more base reference voltages, a voltage-dependent reference voltage, and a temperature-dependent reference voltage. The analog circuitry is configured to produce an output current corresponding to the input signal with compensation for voltage and temperature variation of a drain-source on resistance of the power MOSFET.
    Type: Grant
    Filed: July 12, 2019
    Date of Patent: November 10, 2020
    Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.
    Inventor: Gilbert S. Z. Lee
  • Patent number: 10063146
    Abstract: Aspects of the present disclosure describe a SMPS system, comprising a SMPS and an inductor current sensing device. The SMPS comprise a high-side (HS) switch and a low-side (LS) switch coupled in series and an output filter including an inductor and a capacitor coupled to a switch node formed by the HS and LS switches. An inductor current is supplied by the inductor to a load. The inductor current sensing device coupled across the LS switch has a first input configured to receive a node signal indicating a voltage level at the switch node, a second input configured to receive an input voltage of the system and a third input configured to receive an output voltage of the system.
    Type: Grant
    Filed: March 31, 2017
    Date of Patent: August 28, 2018
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN) LTD.
    Inventor: Gilbert S. Z. Lee
  • Patent number: 9697450
    Abstract: A magnetic stripe data transmission (MST) driver and a method for driving the MST are disclosed. The MST driver is configured to transmit magnetic strip data comprising of streams of pulses. The MST driver comprises a pair of high side switches and a pair of low side switches. The pair of high side switches comprises a first switch and a second switch. The pair of low side switches comprises a third switch and a fourth switch. The first, second, third and fourth switches are arranged in a full bridge type configuration connected across a voltage source and a ground. An inductive coil is connected across outputs of the full bridge type configuration of the switches. The MST driver includes a switch driver configured to drive the pair of low side switches and the pair of high side switches under current slope control using pulse width modulation.
    Type: Grant
    Filed: July 29, 2016
    Date of Patent: July 4, 2017
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventor: Gilbert S. Z. Lee
  • Patent number: 9491014
    Abstract: Switching logic receives an input signal and a frequency divided signal and generates switching signals. A delay modulator receives the switching signals and generates a high output when a first node voltage is greater than a second node voltage and low output otherwise. An XOR gate receives the delay modulator's output and the frequency divided signal and produces a final output that is high when one of them is low and the other high and low otherwise. A duty ratio of the final output depends on a ratio of a slope of the first node voltage to a slope of the second node voltage.
    Type: Grant
    Filed: September 23, 2015
    Date of Patent: November 8, 2016
    Assignee: ALPHA AND OMEGA SEMICONDUCTOR INCORPORATED
    Inventor: Gilbert S. Z. Lee