Scott V Lynch

US Patent:

7330364, Feb 12, 2008

Filed:

Oct 20, 2004

Appl. No.:

10/969665

Inventors:

Scott Lynch - Half Moon Bay CA, US

Assignee:

Supertex, Inc. - Sunnyvale CA

International Classification:

H02M 5/42
H02M 7/00
G05F 1/40

US Classification:

363 84, 363125

Abstract:

A method and circuit for converting high voltage AC to low voltage DC using a switched power supply and rising edge conduction has an alternating current (AC) power source. A rectifier is coupled to the AC power source. A switching device is coupled to the rectifier. The switching device is opened and closed only during rising edge conduction. Control circuitry is coupled to the switching device for opening and closing of the switching device only during rising edge conduction. A storage capacitive element is coupled to the switching device.

US Patent:

7813048, Oct 12, 2010

Filed:

Oct 28, 2008

Appl. No.:

12/260026

Inventors:

Scott Lynch - Half Moon Bay CA, US
Jimes Lei - Milpitas CA, US

Assignee:

Supertex, Inc. - Sunnyvale CA

International Classification:

G02B 1/06
G02B 3/12
G03B 3/10

US Classification:

359665, 396133

Abstract:

An electroactive lens driver comprises a voltage generator generating a high alternating current voltage signal for application to an electroactive lens in response to a low direct current voltage signal. The voltage generator does not include an inductor or a transformer.

US Patent:

7986178, Jul 26, 2011

Filed:

Dec 9, 2008

Appl. No.:

12/331353

Inventors:

Scott Lynch - Half Moon Bay CA, US

Assignee:

Supertex, Inc. - Sunnyvale CA

International Classification:

H03K 3/017

US Classification:

327172, 327175

Abstract:

An electroactive lens driver generates a variable root-mean-square drive voltage for controlling an electroactive lens by controlling the duty cycle of a modified square wave.

US Patent:

20030052615, Mar 20, 2003

Filed:

Sep 19, 2001

Appl. No.:

09/955255

Inventors:

Scott Lynch - Half Moon Bay CA, US
Jimes Lei - Milpitas CA, US
Roshanak Aflatouni - Los Gatos CA, US

International Classification:

G09G003/10

US Classification:

315/169300

Abstract:

A low noise method and apparatus for driving electroluminescent (EL) panels provides reduction in EL panel noise, and in the preferred embodiment, voltage compensation as the EL panel ages. The output of a high voltage power supply is applied to the EL panel through a circuit having an optimized time-constant, producing a waveform that reduces EL panel vibration. Additionally, if the time constant is derived in part from the capacitance of the EL panel, the time constant may be chosen such that aging of the EL panel maintains the time constant in the proper range to maintain noise reduction over the life of the panel and compensate for brightness reduction due to aging of the EL panel.

US Patent:

20120262075, Oct 18, 2012

Filed:

Aug 15, 2011

Appl. No.:

13/210155

Inventors:

Scott Lynch - Half Moon Bay CA, US
Benedict C.K. Choy - Sunnyvale CA, US

Assignee:

Supertex, Inc. - Sunnyvale CA

International Classification:

H05B 37/02
G05B 24/02

US Classification:

315192, 323318

Abstract:

An LED driver circuit operating from the AC power line providing high efficiency, good line and load regulation, high power factor, low line current harmonics, low conducted EMI, high LED utilization, and lamp dimming compatibility, while consisting of a minimal number of components. No inductors, nor capacitors (including electrolytics), nor high current switching transistors are employed. The top of a string of series connected LED segments is connected to the output of a rectifier, which in turn is connected to an AC sine wave power source. The string is tapped at various locations, including the bottom of the string. Each segment can consists of any number of serial or parallel connected LEDs. Current control elements or regulators sink current at each tap and are sequentially turned on and off one at a time, tracking the rectified sine wave voltage. Voltage across each regulator and current when conducting is individually controllable. Power loss in the regulators is minimized by keeping regulator voltage to a minimum. The regulators may control current in a multitude of ways, including a constant current, or a current dependent on voltage across the regulators including a resistor, or a combination. The driver is self-commutating, with the sequencing of the current control elements an inherent feature closely integrated with the current control elements and providing optimal performance over variable operating conditions. Given the large number of design variables, the driver circuit can be optimized for various performance criteria including input voltage range, line/load regulation, output power/current, efficiency, power factor, line current harmonics, dimmer compatibility, and LED utilization.

US Patent:

20170164437, Jun 8, 2017

Filed:

Feb 20, 2017

Appl. No.:

15/437081

Inventors:

- Chandler AZ, US
Scott Lynch - Half Moon Bay CA, US

International Classification:

H05B 33/08

Abstract:

Employed within an LED driver operating from the AC power line, the invention controls both input current and output power. With this regulation circuit, input current appears purely resistive, precisely tracking the input voltage waveshape. At the same time, it provides good line regulation and inherent phase dimmer compatibility, requiring no special circuitry to detect and handle a dimmer.

US Patent:

20170099708, Apr 6, 2017

Filed:

Sep 27, 2016

Appl. No.:

15/277566

Inventors:

- Chandler AZ, US
Scott Lynch - Half Moon Bay CA, US

Assignee:

Microchip Technology Incorporated - Chandler AZ

International Classification:

H05B 33/08
H02M 1/14

Abstract:

A ripple reduction circuit is provided. The ripple reduction circuit may include a ripple capacitor configured to drive at least a first segment of a string of light emitting diodes (LEDs), a first diode having an anode coupled to the ripple capacitor, and a cathode configured to be coupled to an input end of the first LED segment, a second diode having a cathode coupled to the ripple capacitor and the anode of the first diode, and an anode configured to be coupled between the first LED segment and a second LED segment of the string of LEDs, a third diode having an anode coupled to the ripple capacitor, and a cathode configured to be coupled to a last LED segment of the string of LEDs, and a fourth diode having a cathode coupled to the ripple capacitor and the anode of the third diode.

US Patent:

20170094733, Mar 30, 2017

Filed:

Sep 26, 2016

Appl. No.:

15/276253

Inventors:

- Chandler AZ, US
Scott Lynch - Half Moon Bay CA, US

Assignee:

Microchip Technology Incorporated - Chandler AZ

International Classification:

H05B 33/08

Abstract:

A sequential linear LED driver circuit is provided. The sequential linear LED driver circuit may include a plurality of current sinks, wherein each of the plurality of current sinks is configured to be coupled to a segment of a string of light-emitting diodes (LEDs), and a voltage divider that generates a plurality of reference voltages, wherein each of the plurality of reference voltages is applied to a respective current sink of the plurality of current sinks. The output of each current sink of the plurality of current sinks may be connected at a summing node.