James Hoan Nguyen

Address:

10421 Blake St, Garden Grove, CA 92843

Phone:

7146033988

VIN:

5TDKK3DC7BS136389

Make:

TOYOTA

Model:

SIENNA

Year:

2011

US Patent:

6525515, Feb 25, 2003

Filed:

Sep 24, 2001

Appl. No.:

09/960832

Inventors:

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

Assignee:

Supertex, Inc. - Sunnyvale CA

International Classification:

G05F 1573

US Classification:

323277, 323274, 323275

Abstract:

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.

US Patent:

6917504, Jul 12, 2005

Filed:

May 2, 2001

Appl. No.:

09/846478

Inventors:

James Hung Nguyen - San Jose CA, US
Sang Ton Ngo - Cupertino CA, US
David Chalmers Schia - Cupertino CA, US
Ladislas G. Kerenyi - White Plains NY, US
Khai Minh Le - Saratoga CA, US

Assignee:

Supertex, Inc. - Sunnyvale CA

International Classification:

H02H003/00

US Classification:

361100, 361 18, 361 58

Abstract:

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.

US Patent:

6940733, Sep 6, 2005

Filed:

Aug 22, 2003

Appl. No.:

10/646450

Inventors:

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

Assignee:

Supertex, Inc. - Sunnyvale CA

International Classification:

H02M003/335

US Classification:

363 2112, 363 71

Abstract:

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.

US Patent:

6958920, Oct 25, 2005

Filed:

May 4, 2004

Appl. No.:

10/838820

Inventors:

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

Assignee:

Supertex, Inc. - Sunnyvale CA

International Classification:

H02M003/335

US Classification:

363 19, 363 2101, 363 2118, 323285

Abstract:

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.

US Patent:

7116089, Oct 3, 2006

Filed:

Oct 28, 2005

Appl. No.:

11/261874

Inventors:

James H. Nguyen - San Jose CA, US
Thomas T. Chiang - San Jose CA, US
Christopher T. Falvey - Fremont CA, US

Assignee:

Monolithic Power Systems, Inc. - Los Gatos CA

International Classification:

G05F 1/613

US Classification:

323284, 323285

Abstract:

Methods and apparatus are disclosed for controlling switching regulators to automatically switch from a traditional pulse-width modulation (PWM) mode, when the load current is higher than a predetermined value, to a pulse-frequency modulation (PFM) mode, when the load current drops to a point lower than the predetermine value. Switching modes increases the efficiency of the regulator when the load current is low without provoking a large output voltage transient. In some embodiments, a single switching cycle regulates the output in the PFM mode, which reduces the switching losses and enhances the efficiency of the regulator.

US Patent:

7208927, Apr 24, 2007

Filed:

Dec 9, 2005

Appl. No.:

11/299171

Inventors:

James H. Nguyen - San Jose CA, US

Assignee:

Monolithic Power Systems, Inc. - San Jose CA

International Classification:

G05F 1/40

US Classification:

323282, 323901

Abstract:

The present invention introduces methods and circuits to provide a soft start for a switching regulator. A feedback voltage from output terminal is monitored and used to regulate the bias current of the regulator's error amplifier. The present invention also enables a smooth transition from the soft start to normal operation.

US Patent:

7439720, Oct 21, 2008

Filed:

Aug 25, 2006

Appl. No.:

11/509908

Inventors:

James H. Nguyen - San Jose CA, US
Thomas T. Chiang - San Jose CA, US
Christopher T. Falvey - Fremont CA, US

Assignee:

Monolithic Power Systems - San Jose CA

International Classification:

G05F 1/575
G05F 1/62

US Classification:

323284, 323222

Abstract:

Methods and apparatus are disclosed for controlling switching regulators to automatically switch from a traditional pulse-width modulation (PWM) mode, when the load current is higher than a predetermined value, to a pulse-frequency modulation (PFM) mode, when the load current drops to a point lower than the predetermine value. Switching modes increases the efficiency of the regulator when the load current is low without provoking a large output voltage transient. In some embodiments, a single switching cycle regulates the output in the PFM mode, which reduces the switching losses and enhances the efficiency of the regulator.

US Patent:

7893677, Feb 22, 2011

Filed:

Mar 28, 2008

Appl. No.:

12/057717

Inventors:

James H. Nguyen - San Jose CA, US

Assignee:

Monolithic Power Systems, Inc. - San Jose CA

International Classification:

G05F 1/575

US Classification:

323284, 323223

Abstract:

A switch-mode synchronous boost voltage regulator is disclosed that includes a boost voltage regulator and an active current modulator. The active current modulator detects a negative current flowing through the high-side switch during a light load condition. When the negative current is detected, the active current modulator is operable to maintain the high-side switch “on” in a linear mode and to limit the negative current to a predetermined current level.