Patents by Inventor William C. Alexander

William C. Alexander 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: 20190088645
    Abstract: The present application discloses new approaches to providing “passive-off” protection for a B-TRAN-like device. Even if the control circuitry is inactive, AC coupling uses transient voltage on the external terminals to prevent forward biasing an emitter junction. Preferably the same switches which implement diode-mode and pre-turnoff operation are used as part of the passive-off circuit operation.
    Type: Application
    Filed: July 23, 2018
    Publication date: March 21, 2019
    Applicant: Ideal Power, Inc.
    Inventor: William C. Alexander
  • Patent number: 10211283
    Abstract: Methods and systems for operating a double-base bidirectional power bipolar transistor. Two timing phases are used to transition into turn-off: one where each base is shorted to its nearest emitter/collector region, and a second one where negative drive is applied to the emitter-side base to reduce the minority carrier population in the bulk substrate. A diode prevents reverse turn-on while negative base drive is being applied.
    Type: Grant
    Filed: January 11, 2018
    Date of Patent: February 19, 2019
    Assignee: Ideal Power Inc.
    Inventors: William C. Alexander, Richard A. Blanchard
  • Patent number: 10056372
    Abstract: The present application discloses new approaches to providing “passive-off” protection for a B-TRAN-like device. Even if the control circuitry is inactive, AC coupling uses transient voltage on the external terminals to prevent forward biasing an emitter junction. Preferably the same switches which implement diode-mode and pre-turnoff operation are used as part of the passive-off circuit operation.
    Type: Grant
    Filed: December 30, 2016
    Date of Patent: August 21, 2018
    Assignee: Ideal Power Inc.
    Inventor: William C. Alexander
  • Publication number: 20180226254
    Abstract: Methods and systems for double-sided semiconductor device fabrication. Devices having multiple leads on each surface can be fabricated using a high-temperature-resistant handle wafer and a medium-temperature-resistant handle wafer. Dopants can be introduced on both sides shortly before a single long high-temperature diffusion step diffuses all dopants to approximately equal depths on both sides. All high-temperature processing occurs with no handle wafer or with a high-temperature handle wafer attached. Once a medium-temperature handle wafer is attached, no high-temperature processing steps occur. High temperatures can be considered to be those which can result in damage to the device in the presence of aluminum-based metallizations.
    Type: Application
    Filed: October 26, 2017
    Publication date: August 9, 2018
    Applicant: Ideal Power Inc.
    Inventors: Richard A. Blanchard, William C. Alexander
  • Publication number: 20180219061
    Abstract: Methods and systems for operating a double-base bidirectional power bipolar transistor. Two timing phases are used to transition into turn-off: one where each base is shorted to its nearest emitter/collector region, and a second one where negative drive is applied to the emitter-side base to reduce the minority carrier population in the bulk substrate. A diode prevents reverse turn-on while negative base drive is being applied.
    Type: Application
    Filed: January 11, 2018
    Publication date: August 2, 2018
    Applicant: Ideal Power Inc.
    Inventors: William C. Alexander, Richard A. Blanchard
  • Publication number: 20180130898
    Abstract: The present application teaches, among other innovations, power semiconductor devices in which breakdown initiation regions, on BOTH sides of a die, are located inside the emitter/collector regions, but laterally spaced away from insulated trenches which surround the emitter/collector regions. Preferably this is part of a symmetrically-bidirectional power device of the “B-TRAN” type. In one advantageous group of embodiments (but not all), the breakdown initiation regions are defined by dopant introduction through the bottom of trench portions which lie within the emitter/collector region. In one group of embodiments (but not all), these can advantageously be separated trench portions which are not continuous with the trench(es) surrounding the emitter/collector region(s).
    Type: Application
    Filed: May 25, 2017
    Publication date: May 10, 2018
    Applicant: Ideal Power, Inc.
    Inventors: Richard A. Blanchard, William C. Alexander
  • Publication number: 20180109101
    Abstract: A new approach to Ground Fault Detection and Interruption. The entire DC port is driven with a small-amplitude oscillation or modulation, and the power converter's controller tests for the presence of some version of that signal. If the detected oscillations are too small, either as a result of the GFDI fuse being blown, OR as a result of the DC port having too low of an impedance to ground (ground fault), the circuit detects that and causes the power converter to shut down.
    Type: Application
    Filed: April 28, 2017
    Publication date: April 19, 2018
    Applicant: Ideal Power, Inc.
    Inventor: William C. Alexander
  • Patent number: 9899932
    Abstract: Methods and systems for transforming electric power between two or more portals. Any or all portals can be DC, single phase AC, or multi-phase AC. Conversion is accomplished by a plurality of bi-directional conducting and blocking semiconductor switches which alternately connect an inductor and parallel capacitor between said portals, such that energy is transferred into the inductor from one or more input portals and/or phases, then the energy is transferred out of the inductor to one or more output portals and/or phases, with said parallel capacitor facilitating “soft” turn-off, and with any excess inductor energy being returned back to the input. Soft turn-on and reverse recovery is also facilitated. Said bi-directional switches allow for two power transfers per inductor/capacitor cycle, thereby maximizing inductor/capacitor utilization as well as providing for optimum converter operation with high input/output voltage ratios. Control means coordinate the switches to accomplish the desired power transfers.
    Type: Grant
    Filed: August 17, 2015
    Date of Patent: February 20, 2018
    Assignee: Ideal Power, Inc.
    Inventor: William C. Alexander
  • Patent number: 9900002
    Abstract: Methods, systems, circuits, and devices for power-packet-switching power converters using bidirectional bipolar transistors (B-TRANs) for switching. Four-terminal three-layer B-TRANs provide substantially identical operation in either direction with forward voltages of less than a diode drop. B-TRANs are fully symmetric merged double-base bidirectional bipolar opposite-faced devices which operate under conditions of high non-equilibrium carrier concentration, and which can have surprising synergies when used as bidirectional switches for power-packet-switching power converters. B-TRANs are driven into a state of high carrier concentration, making the on-state voltage drop very low.
    Type: Grant
    Filed: November 10, 2015
    Date of Patent: February 20, 2018
    Assignee: Ideal Power, Inc.
    Inventors: William C. Alexander, Richard A. Blanchard
  • Patent number: 9899868
    Abstract: Methods and systems for smart transfer switch circuits and operation, and for operation of transfer and/or cutoff switches in combination with a power-packet-switching-architecture (PPSA) power converter. The transistors of the transfer and cutoff switches, and the transistors of the phase legs of the PPSA power converter if present, preferably all use double-base bipolar transistors which have low on-state series resistance as the switching elements.
    Type: Grant
    Filed: November 2, 2015
    Date of Patent: February 20, 2018
    Assignee: Ideal Power, Inc.
    Inventors: Paul A. Bundschuh, John W. Merritt, William C. Alexander
  • Publication number: 20180026122
    Abstract: Three optimizations are provided for B-TRAN devices which include field plate trenches: 1) the trench dielectric thickness is large enough to withstand the base-to-emitter voltage, but thin enough to provide good electrical coupling between the poly field plate and the adjacent p-type silicon; 2) the base contact width is small enough to provide an acceptably low reverse base contact region pinch-off voltage, but large enough to avoid degradation of both base resistance; and 3) the emitter width is small enough to keep an acceptably high current density at the emitter's center.
    Type: Application
    Filed: October 9, 2015
    Publication date: January 25, 2018
    Applicant: Ideal Power Inc.
    Inventors: Richard A. Blanchard, William C. Alexander
  • Patent number: 9818615
    Abstract: Methods and systems for double-sided semiconductor device fabrication. Devices having multiple leads on each surface can be fabricated using a high-temperature-resistant handle wafer and a medium-temperature-resistant handle wafer. Dopants can be introduced on both sides shortly before a single long high-temperature diffusion step diffuses all dopants to approximately equal depths on both sides. All high-temperature processing occurs with no handle wafer or with a high-temperature handle wafer attached. Once a medium-temperature handle wafer is attached, no high-temperature processing steps occur. High temperatures can be considered to be those which can result in damage to the device in the presence of aluminum-based metallizations.
    Type: Grant
    Filed: May 25, 2016
    Date of Patent: November 14, 2017
    Assignee: Ideal Power, Inc.
    Inventors: Richard A. Blanchard, William C. Alexander
  • Publication number: 20170317575
    Abstract: Power-packet-switching circuits (and methods and systems) in which at least one port uses series-connected combinations of bidirectional switches to connect a link inductor (or transformer), with selectable polarity, to an outside line. Optionally, series-connected combinations of bidirectional switches are used for phase legs in some ports, while single bidirectional switches are used for the phase legs in other ports. This can be particularly advantageous where the converter interfaces between lines at significantly different operating voltages. By using B-TRANs as the series-combined elements of the combinations of switches, voltage-dividing circuitry is not needed to equalize the voltages seen by the individual devices in each combination.
    Type: Application
    Filed: December 30, 2016
    Publication date: November 2, 2017
    Applicant: Ideal Power Inc.
    Inventor: William C. Alexander
  • Patent number: 9799731
    Abstract: Power is inverted using double-base-contact bidirectional bipolar transistors in a three-level-inverter topology. The transistors not only switch to synthesize a PWM approximation of the desired AC waveform, but also have transient phases of diode conduction before each full turn-on or turn-off.
    Type: Grant
    Filed: January 22, 2016
    Date of Patent: October 24, 2017
    Assignee: Ideal Power, Inc.
    Inventor: William C. Alexander
  • Patent number: 9796258
    Abstract: Plug-in hybrid electric vehicles where a multiport power-packet-switching converter provides fully bidirectional power transfer among any of an engine motor, a drive motor, a vehicle battery and/or supercapacitor, and a connection to grid.
    Type: Grant
    Filed: March 12, 2014
    Date of Patent: October 24, 2017
    Inventors: Paul Bundschuh, William C. Alexander
  • Patent number: 9787298
    Abstract: Methods and systems for operating a double-base bidirectional power bipolar transistor. Two timing phases are used to transition into turn-off: one where each base is shorted to its nearest emitter/collector region, and a second one where negative drive is applied to the emitter-side base to reduce the minority carrier population in the bulk substrate. A diode prevents reverse turn-on while negative base drive is being applied.
    Type: Grant
    Filed: September 15, 2016
    Date of Patent: October 10, 2017
    Assignee: Ideal Power, Inc.
    Inventors: William C. Alexander, Richard A. Blanchard
  • Patent number: 9787304
    Abstract: Methods and systems for active charge control diodes with improved reverse recovery characteristics. An extra control terminal is added on the side of a diode nearest to its p-n junction. The control terminal connects to a control region which extends from the drift region to the cathode surface and which is most preferably separated from the cathode region by an insulated trench. During turn-off, the control terminal is most preferably driven negative relative to the cathode just before reversing the polarity of the applied external voltage.
    Type: Grant
    Filed: November 18, 2015
    Date of Patent: October 10, 2017
    Assignee: Ideal Power, Inc.
    Inventors: William C. Alexander, Richard A. Blanchard
  • Patent number: 9786773
    Abstract: B-TRAN bipolar power transistor devices and methods, using a drift region which is much thinner than previously proposed double-base bipolar transistors of comparable voltage. This is implemented in a high-bandgap semiconductor material (preferably silicon carbide). Very high breakdown voltage, and fast turn-off, are achieved with very small on-resistance.
    Type: Grant
    Filed: January 11, 2016
    Date of Patent: October 10, 2017
    Assignee: Ideal Power, Inc.
    Inventor: William C. Alexander
  • Publication number: 20170271328
    Abstract: The present application discloses new approaches to providing “passive-off” protection for a B-TRAN-like device. Even if the control circuitry is inactive, AC coupling uses transient voltage on the external terminals to prevent forward biasing an emitter junction. Preferably the same switches which implement diode-mode and pre-turnoff operation are used as part of the passive-off circuit operation.
    Type: Application
    Filed: December 30, 2016
    Publication date: September 21, 2017
    Applicant: Ideal Power Inc.
    Inventor: William C. Alexander
  • Patent number: 9742395
    Abstract: The present application teaches, inter alia, methods and circuits for operating a B-TRAN (double-base bidirectional bipolar junction transistor). Exemplary base drive circuits provide high-impedance drive to the base contact region on the side of the device instantaneously operating as the collector. (The B TRAN is controlled by applied voltage rather than applied current.) Current signals operate preferred implementations of drive circuits to provide diode-mode turn-on and pre-turnoff operation, as well as a hard ON state with low voltage drop (the “transistor-ON” state). In some preferred embodiments, self-synchronizing rectifier circuits provide adjustable low voltage for gate drive circuits. In some preferred embodiments, the base drive voltage used to drive the c-base region (on the collector side) is varied while base current at that terminal is monitored, so no more base current than necessary is applied. This solves the difficult challenge of optimizing base drive in a B-TRAN.
    Type: Grant
    Filed: August 10, 2016
    Date of Patent: August 22, 2017
    Assignee: Ideal Power Inc.
    Inventors: William C. Alexander, Richard A. Blanchard