JAMES T. NGUYEN, MD
Physical Therapy at International Cir, San Jose, CA

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.

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.

6917504, Jul 12, 2005

May 2, 2001

09/846478

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

Supertex, Inc. - Sunnyvale CA

H02H003/00

361100, 361 18, 361 58

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.

7928713, Apr 19, 2011

Mar 28, 2008

12/057747

James H. Nguyen - San Jose CA, US

Monolithic Power Systems, Inc. - San Jose CA

G05F 1/40

323282, 323285

A circuit is disclosed that includes a buck voltage regulator electrically coupled to an active current modulator. The active current modulator is operable to detect a negative current in the low-side switch of the buck voltage regulator circuit during a light mode operation. Whenever the negative current is detected, the active negative current modulator causes the low-side switch to stay ON in a linear mode and limits the negative current to a predetermined current level.

7893677, Feb 22, 2011

Mar 28, 2008

12/057717

James H. Nguyen - San Jose CA, US

Monolithic Power Systems, Inc. - San Jose CA

G05F 1/575

323284, 323223

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.