Chin Ok Chang

US Patent:

6597842, Jul 22, 2003

Filed:

May 21, 2001

Appl. No.:

09/862146

Inventors:

Jyl Ren Dent - Rolling Heights CA
Amado Cordova - Venice CA
Ronald J. Michal - Wrightwood CA
Chin L. Chang - Walnut CA
Trong-Huang Lee - Walnut CA

Assignee:

Copley Networks, Inc. - City of Industry CA

International Classification:

G02B 642

US Classification:

385 39, 385 24, 385 33, 385 42, 359124, 359127, 359131

Abstract:

An optical interleaver. The interleaver is based upon the Mach Zender interferometer. At least one of the optical paths joining opposed couplers of the arrangement includes an optical image transfer element intermediate the ends of fibers associated with the couplers. In one embodiment, the optical image transfer element is a single imaging lens whereas, in another embodiment, the element consists of an aligned pair of collimating lenses. During fabrication, optical positioning stages support the optical image transfer element and fiber ends to permit ready adjustment of , the optical path length difference between the arms of the interleaver, to assure predetermined optical channel spacing of an input DWDM signal.

US Patent:

7443209, Oct 28, 2008

Filed:

Dec 18, 2003

Appl. No.:

10/540671

Inventors:

Chin Chang - Agoura Hills CA, US

Assignee:

Koninklijke Philips Electronics N.V. - Eindhoven

International Classification:

G11C 27/02

US Classification:

327 94, 327108, 327109, 315291, 323282

Abstract:

Improved stability in a regulator having a sample-and-hold. Coupling an input voltage to an input node of the sample-and-hold circuit is provided. Activating the sample-and hold circuit in response to the input voltage and sensing an output voltage at an output node coupled to the sample and hold circuit is also provided. Determining whether the input voltage at the input node is greater than the output voltage at the output node and providing a sample-and-hold function based on the determination are also provided. A regulation circuit is provided. A sample-and-hold circuit coupled to input and output nodes is also provided. The transfer function of the sample-and-hold circuit is pseudo-all-pass if the input voltage at the input node is greater than an output voltage at the output node and is a substantially constant signal if the input voltage at the input node is less than the output voltage at the output node.

US Patent:

7508182, Mar 24, 2009

Filed:

Oct 26, 2006

Appl. No.:

11/553434

Inventors:

Chin Chang - Agoura Hills CA, US

Assignee:

Semtech Corporation - Camarillo CA

International Classification:

G05F 1/575
G05F 1/618

US Classification:

323282

Abstract:

Methods and apparatuses are provided for monitoring an inductor output current delivered to a load by a power converter. For example, there is provided an apparatus comprising: at least one power switch operatively coupled to an input voltage source; an output inductor operatively coupled to the at least one power switch and to the load; and a current sensor operatively coupled to the output inductor, the current sensor providing a current sense signal corresponding to the inductor output current delivered to the load. In one embodiment, the current sensor comprises: a filter comprising a first resistor coupled in series with a first capacitor; and a second capacitor coupled in parallel with the first resistor, the first and second capacitors forming an AC voltage divider to increase the signal-to-noise ratio of the current sense signal.

US Patent:

7593567, Sep 22, 2009

Filed:

Dec 4, 2003

Appl. No.:

10/538202

Inventors:

Chin Chang - Agoura Hills CA, US

Assignee:

Koninklijke Philips Electronics N.V. - Eindhoven

International Classification:

G06K 9/00
H04N 3/14
H04N 5/335
H04N 9/04

US Classification:

382162, 382167, 348272, 348273

Abstract:

RGB filter set and color estimation performance for RGB LED color sensing is provided. A criteria function describing an error between desired color matching functions and a spectral response of an RGB filter set is constructed. RGB filter set response characteristics based on the criteria function are then determined. Finally, color estimation parameters for substantially optimal color estimation with the RGB filter set are determined based upon the determined RGB filter set response characteristics. Computer readable code for constructing a criteria function is provided. Computer readable code for determining RGB filter set response characteristics is also provided. Finally, computer readable code for determining color estimation parameters is provided.

US Patent:

8344703, Jan 1, 2013

Filed:

Mar 2, 2010

Appl. No.:

12/716173

Inventors:

Chin Chang - Agoura Hills CA, US
Veter Chang - Sijhih, TW

Assignee:

Semtech Corporation - Camarillo CA

International Classification:

H02J 7/00

US Classification:

320166, 323265, 323271

Abstract:

An apparatus and method of controlling power converters is achieved that produces high light-load efficiency and reduced output voltage ripple while maintaining quiet operation that is free from audible noise. The inventive method includes a variable on-time control circuit that is applicable to a wide variety of switching mode converters, including, but not limited to, boost converters, buck converters, buck-boost converters, single-ended primary inductor (SEPIC) converters, and other converter topologies, both isolated and non-isolated.

US Patent:

20020181830, Dec 5, 2002

Filed:

May 21, 2001

Appl. No.:

09/861910

Inventors:

Jyh Dent - Rolling Heights CA, US
Amado Cordova - Venice CA, US
Ronald Michal - Wrightwood CA, US
Chin Chang - Walnut CA, US
Trong-Huang Lee - Walnut CA, US

International Classification:

G02B006/26

US Classification:

385/015000

Abstract:

A method for forming an all-fiber, low-loss interleaver to obtain a predetermined optical channel spacing. The interleaver features at least one arm formed with and continuous between couplers of a Mach Zender type arrangement. The interleaver is formed by first analytically determining , the difference in optical lengths between the two optical paths between the couplers. The difference is then fine-tuned by the application of heat and tension to a jacket-stripped segment of the continuous fiber arm as a DWDM signal is observed at the output of the interleaver.

US Patent:

20030094906, May 22, 2003

Filed:

Dec 27, 2002

Appl. No.:

10/330951

Inventors:

Chin Chang - Agoura Hills CA, US
Gert Bruning - Sleepy Hollow NY, US

International Classification:

H05B037/02

US Classification:

315/2090CD, 315/224000

Abstract:

A fluorescent lamp having a capacitive coupling structure in the form of cylindrical ceramic tubes is packaged with an inverter circuit for driving the fluorescent lamp and supply nodes for applying a supply voltage to the inverter circuit. The inverter circuit can be a conventional inverter circuit, such as, for example, current-fed push-pull, voltage-fed push-pull, active clamped Flyback, and voltage-fed half-bridge inverter circuits.

US Patent:

20040120720, Jun 24, 2004

Filed:

Dec 24, 2002

Appl. No.:

10/329225

Inventors:

Chin Chang - Walnut CA, US
Amado Cordova - Venice CA, US

International Classification:

H04B010/00

US Classification:

398/139000, 398/135000

Abstract:

A fiber optic transceiver includes a VCSEL light source. The transceiver is adapted to communicate with existing LED-based transceivers to enable external electronic circuits to interact. The transceiver of the invention includes an InGaAs photodetector for receiving 1310 nm signals emitted from the LED light source of an existing transceiver. The existing transceiver typically includes an InGaAs photodetector characterized by distinct responsivities at 850 nm and at 1310 nm. This enables signals transmitted at 850 nm from the VCSEL light source of the transceiver to be detected by an existing LED-based transceiver, while the InGaAs photodetector of the transceiver of the invention is capable of receiving signals emitted from the LED light source.