Ladislas G Kerenyi

US Patent:

6667583, Dec 23, 2003

Filed:

May 7, 2002

Appl. No.:

10/141051

Inventors:

Ladislas G. Kerenyi - White Plains NY

Assignee:

Supertex, Inc. - Sunnyvale CA

International Classification:

H05B 3702

US Classification:

315219, 315225, 315224, 315243, 315272, 315307

Abstract:

A method an apparatus for efficiently driving a low-voltage device from a wide-range input supply uses and inductor and a diode coupled in parallel to provide a high-efficiency energy storage circuit. The parallel diode/inductor circuit is coupled to a switch for intermittently supplying a current to maintain a level of energy storage in the circuit. The switch is coupled to a control circuit for controlling the switch. The external device be a relay and the inductor may be a coil of the relay. The external device may be one or more LEDs connected in series and the diode may be the series LED circuit. The control circuit may include a fault-tolerant synchronization input for connection to multiple driver circuits, whereby audible noise produced by beat frequencies between the relays is eliminated.

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:

20040105283, Jun 3, 2004

Filed:

Aug 22, 2003

Appl. No.:

10/646450

Inventors:

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

International Classification:

H02M003/335

US Classification:

363/021120

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:

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.