DAVID CHALMERS SCHIE
Pilots at Ricardo Rd, Cupertino, CA

6781351, Aug 24, 2004

Oct 28, 2002

10/283395

Alexander Mednik - Campbell CA
David Chalmers Schie - Cupertino CA
Wei Gu - San Jose CA

Supertex Inc. - San Jose CA

G05F 110

323222

AC/DC cascaded power converters having high DC conversion ratio and improved AC line harmonics provide low input harmonic currents, high power factor and efficient operation for low voltage DC outputs when coupled directly to a source of unfiltered rectified AC voltage. The power converter incorporates an intermediate storage element that provides most or all of the energy storage capacitance within the power converter and a blocking device that enables continuous energy transfer from AC line to output to achieve unity power factor and regulated output while maintaining low AC input current ripple.

6525515, Feb 25, 2003

Sep 24, 2001

09/960832

Sang Ton Ngo - Cupertino CA
James Hung Nguyen - San Jose CA
David Chalmera Schie - Cupertino CA
Ladislas G. Kerenyi - White Plains NY
Khai Minh Le - Saratoga CA

Supertex, Inc. - Sunnyvale CA

G05F 1573

323277, 323274, 323275

A feedback apparatus and method for adaptively controlling power supplied to a hot-pluggable subsystem controls the inrush current of the hot-pluggable subsystem upon application of power. The apparatus and method adaptively control a pass device by detecting the current through the pass device during initial charging of a load capacitance and scaling back the turn-on rate at the pass device control terminal input in conformity with the detected current and a predetermined rate set by a ramp generator. A ramp capacitor is coupled to the control terminal of the pass device through a diode to permit use of the capacitor for timing purposes as well as preventing transient turn-on of the pass device during initial application of power.

6771679, Aug 3, 2004

May 16, 2001

09/859570

David Chalmers Schie - Cupertino CA 95014

H01S 300

372 381, 372 3801, 372 3802

An apparatus and method for programmable control of laser diode modulation and operating point provides control for laser diodes having widely varying characteristics, such as laser diodes from a variety of manufacturers. Operating a wide variety of lasers is useful for implementation of a device independent integrated circuit for control of a laser diode. Laser diode maximum AC drive levels, AC input circuit response and DC operating point are programmed via a programmable storage coupled via control circuits to a drive amplifier and a bias circuit. The laser diode modulation control may be combined with laser diode bias control in a single integrated circuit, providing a single-chip solution for laser diode transceiver module manufacturers. The programmable storage may be one-time programmable for factory customization of laser diode transceiver module diodes, or may be an electrically alterable storage.

6958920, Oct 25, 2005

May 4, 2004

10/838820

Alexander Mednik - Campbell CA, US
David Chalmers Schie - Cupertino CA, US
James Hung Nguyen - San Jose CA, US
Wei Gu - San Jose CA, US

Supertex, Inc. - Sunnyvale CA

H02M003/335

363 19, 363 2101, 363 2118, 323285

A switching power converter and method of controlling an output voltage thereof using predictive sensing of magnetic flux provides a low-cost switching power converter via primary-side control using a primary-side winding. An integrator generates a voltage that represents flux within a magnetic element by integrating a primary-side winding voltage. A detection circuit detects the end of a half-cycle of post-conduction resonance that occurs in the power magnetic element subsequent to zero energy level in the power magnetic element. The integrator voltage is stored at the end of the half-cycle and is used to determine a sampling point prior to or equal to the start of post-conduction resonance in a subsequent switching cycle of the power converter. The primary-side winding voltage is then sampled at the sampling point, providing an indication of the output voltage of the power converter by which the output voltage of the converter can be controlled.

7622820, Nov 24, 2009

Apr 23, 2008

12/107832

Aleksandar Prodic - Toronto, Ontario, CA
Zhenyu Zhao - Toronto, Ontario, CA
David Chalmers Schie - Cupertino CA, US

H02M 3/337

307 31, 307 38, 361689, 323282

A switch-mode power supply (SMPS) with auto-tuning using limit-cycle oscillation response evaluation provides optimized performance with reduced capacitance and inductance requirements for a given design. During operation of the SMPS, parameters of the converter are extracted, and the feedback and/or feed-forward compensation is adjusted to either hold the loop bandwidth of the converter near the critical bandwidth of the output capacitors, or maintain output voltage transients within a specified limit. The compensator response is either periodically updated, or is updated in response to an event, such as detection of a transient voltage spike having a characteristic that exceeds one or more predetermined thresholds.

8378658, Feb 19, 2013

Jun 25, 2010

12/823829

David Schie - Cupertino CA, US

Micrel, Inc. - San Jose CA

H01F 29/14, G05F 3/02

323313, 327538, 327542

A semiconductor device, circuit, and AC and DC load switch for maintaining a small input-output differential voltage and providing a defined response. The load switch can include a pass element coupled to an input terminal and an output terminal. The pass element can include a control terminal, with the control terminal controlling a response of the pass element. The load switch can include a first loop coupled to the control terminal configured to control a voltage drop between the input terminal and the output terminal while maintaining high impedance with the pass element. The load switch can include a second loop coupled to the control terminal configured to provide a defined filter response from the input terminal. The defined response can be a low pass response, high pass response, or a band pass response. The passband and/or stopband of the response can be programmed.

2002016, Nov 7, 2002

May 2, 2001

09/846478

James Nguyen - San Jose CA, US
Sang Ngo - Cupertino CA, US
David Schie - Cupertino CA, US
Ladislas Kerenyi - White Plains NY, US
Khai Le - Saratoga CA, US

G06F001/26, G06F001/28, G06F001/30

713/300000

An apparatus and method for adaptively controlling power supplied to a hot-pluggable subsystem controls the inrush current of the hot-pluggable subsystem when the subsystem is coupled to another system that supplies power, and optionally other signal connections. The apparatus and method adaptively control a pass device by detecting the voltage at the gate of the pass device during initial charging of the gate. The gate voltage may be sampled and used subsequently to control the operation of the pass device, and short-circuit conditions may be detected by determining that the miller effect does not change the charging of the gate capacitance. Automatic restart circuitry can be included to generate multiple startup attempts, and under-voltage lockout circuitry and power-on-reset timers can be used to provide a robust solution. The apparatus and method can be adapted to provide a three terminal device that does not require a feedback connection from a power supply output. The three terminal device may include the pass device, or may control an external pass device.

2004026, Dec 30, 2004

Oct 2, 2003

10/677439

Alexander Mednik - Campbell CA, US
David Schie - Cupertino CA, US
James Nguyen - San Jose CA, US
Wei Gu - San Jose CA, US

H02M003/335

363/018000

A switching power converter and method of controlling an output voltage thereof using predictive sensing of magnetic flux provides a low-cost switching power converter via primary-side control using a primary-side winding. An integrator generates a voltage representing magnetic flux within a power magnetic element by integrating a voltage on a primary-side winding of the power magnetic element. A detection circuit detects the end of a half-cycle of post-conduction resonance in the power magnetic element after the energy level in the power magnetic element reaches zero. The voltage of the integrator is stored at the end of the post-conduction resonance half-cycle and is used to determine a sampling point prior to or equal to the start of post-conduction resonance in a subsequent switching cycle of the power converter. The primary-side winding voltage is then sampled at the sampling point, providing an indication of the output voltage of the power converter.

6940733, Sep 6, 2005

Aug 22, 2003

10/646450

David Chalmers Schie - Cupertino CA, US
Alexander Mednik - Campbell CA, US
James Hung Nguyen - San Jose CA, US
Sang Ton Ngo - Cupertino CA, US
Khai Minh Le - Saratoga CA, US
Wei Gu - San Jose CA, US
Larry Kerenyi - White Plains NY, US

Supertex, Inc. - Sunnyvale CA

H02M003/335

363 2112, 363 71

A switch state controller generating a pulse train is used in a power converter utilizing a plurality of converter stages all simultaneously controlled by a single switch controlled by said pulse train. On time of the pulse train is controlled according to an input or interim node characteristic of the supply and period is controlled by a characteristic of the output of the converter. This allows development of AC-to-DC converters, including power-factor-correction converters, and DC to DC converters with high conversion ratio with minimal parts count & high reliability.