Gang G Liu

US Patent:

6486643, Nov 26, 2002

Filed:

Aug 27, 2001

Appl. No.:

09/813078

Inventors:

Gang Liu - Novi MI

Assignee:

Analog Technologies, Inc. - Farmington Hills MI

International Classification:

G05F 159

US Classification:

323268, 323274, 323284

Abstract:

An H bridge regulating system for driving an electric load includes a linear output stage and switch mode output stage connected to opposite ends of the load. The linear output stage has a linear mode amplifier and a feedback circuit, and its amplifier generates a first output signal tied to one end of the load. This output voltage is passed through a conditioning resistor to an inverting input of the linear mode amplifier. The switch mode output stage has a switch mode amplifier and a feedback circuit, and its amplifier generates a second output signal tied to the other end of the load. Its voltage signal is passed through a second conditioning resistor to an inverting input of the switch mode amplifier. Other feedback circuit elements are also provided to create three distinct regions of operations for each of the amplifiers. Due to this novel arrangement for an H bridge circuit, and this novel method of operation involving three distinct regions of operation for the linear mode and switch mode output stages, very high power-saving energy efficiencies are achieved.

US Patent:

6636124, Oct 21, 2003

Filed:

Nov 30, 2001

Appl. No.:

10/000775

Inventors:

Gang Liu - Novi MI

Assignee:

Analog Technologies, Inc. - Sunnyvale CA

International Classification:

H03K 708

US Classification:

332109, 327172

Abstract:

A pulse width modulation (PWM) circuit has a PWM output signal that features accurate timing even in the face of interference imposed upon the control signal representative of the desired PWM duty cycle. The PWM circuit includes or has a first or switching section and a second or analog section. The second section has an operational amplifier with a summing circuit that sums two input signals, namely a triangular wave signal and the control input signal, and then amplifies the summed signal to produce a trapezoidal waveform output delivered to the second section. The first section features a two-input comparator that produces a PWM signal output with a fast transition in response to trapezoidal output fed as an input and compared to a stable reference signal. Due to the speed of the op amp, timing errors on the PWM output signal due to interference on the control signal are minimized.

US Patent:

6801557, Oct 5, 2004

Filed:

Apr 6, 2001

Appl. No.:

09/827764

Inventors:

Gang Liu - Novi MI 48375

International Classification:

H01S 300

US Classification:

372 3809, 372 3802, 372 3803, 372 3804, 372 3807

Abstract:

A laser driver for laser sensing system having two lasers on a single PCB, thermo-electric temperature control, rapid activation, and pulse power and duration safety tables embedded in the microprocessor controller.

US Patent:

6984969, Jan 10, 2006

Filed:

Mar 19, 2004

Appl. No.:

10/805459

Inventors:

Gang Liu - Sunnyvale CA, US
Joseph C. Buxton - Palo Alto CA, US

Assignee:

Analog Devices, Inc. - Norwood MA

International Classification:

G05F 1/40

US Classification:

323286, 323280, 323284, 323303

Abstract:

A voltage regulator includes a linear mode regulator having a high pass filter circuit connected between its output and an output node, and a switch mode regulator having an low pass filter circuit connected between its output and the same output node. The high pass filter passes high frequency AC current provided by the linear mode regulator to the output node and reduces the low frequency AC and DC currents to substantially zero, and the low pass filter prevents the high frequency AC current produced by the linear mode regulator from being drawn by the switch mode regulator and passes the low AC and DC currents provided by the switch mode regulator to the output node. Thus, the present regulator offers the high response speed and low noise of a linear mode regulator, and the high power efficiency and large continuous output current capability of a switch mode regulator.

US Patent:

7283345, Oct 16, 2007

Filed:

Jul 14, 2004

Appl. No.:

10/891713

Inventors:

Gang Liu - Sunnyvale CA, US

International Classification:

H02H 9/00

US Classification:

361118, 361 35

Abstract:

A printed circuit board trace coupling system for providing high voltage isolation includes a driving circuit, a coupling transformer including a printed circuit board trace, and a receiving circuit.

US Patent:

7948042, May 24, 2011

Filed:

Mar 3, 2009

Appl. No.:

12/397183

Inventors:

Chun Ning Lau - Diamond Bar CA, US
Gang Liu - Riverside CA, US
Jairo Velasco, Jr. - Riverside CA, US

Assignee:

The Regents of the University of California - Oakland CA

International Classification:

H01L 29/84

US Classification:

257415, 257417, 257419, 257E43002, 257E43003, 257E43007, 257E27005, 257E27046, 257E27064

Abstract:

A multi-level lithography processes for the fabrication of suspended structures are presented. The process is based on the differential exposure and developing conditions of several a plurality of resist layers, without harsher processes, such as etching of sacrificial layers or the use of hardmasks. These manufacturing processes are readily suited for use with systems that are chemically and/or mechanically sensitive, such as graphene. Graphene p-n-p junctions with suspended top gates formed through these processes exhibit high mobility and control of local doping density and type. This fabrication technique may be further extended to fabricate other types of suspended structures, such as local current carrying wires for inducing local magnetic fields, a point contact for local injection of current, and moving parts in microelectromechanical devices.

US Patent:

8050643, Nov 1, 2011

Filed:

May 9, 2008

Appl. No.:

12/118357

Inventors:

Songping Wu - Sunnyvale CA, US
Hua Qian - Fremont CA, US
Gang Liu - Fremont CA, US
King Chun Tsai - San Jose CA, US
Lawrence Tse - Fremont CA, US
Hui-Ling Lou - Sunnyvale CA, US

Assignee:

Marvell International Ltd. - Hamilton

International Classification:

H04B 7/00

US Classification:

4552341, 455254

Abstract:

In a method and system for controlling gain in an RF receiver, an RF signal is analyzed over different attack and decay windows, from which the receiver determines (1) if the signal is in an attack condition with dip values below a threshold level thus indicating a need for increasing signal gain, or (2) if the signal is in a decay condition with threshold values above a threshold level thus indicating a need for decreasing signal gain. The receiver applies attack and decay windows of different sizes and in an asynchronous manner to create a gain control scheme that is insensitive to transient effects such as channel interference and deep fading that affect the intensities of an in-band signal.

US Patent:

8571142, Oct 29, 2013

Filed:

Dec 1, 2011

Appl. No.:

13/309464

Inventors:

Songping Wu - Cupertino CA, US
Gang Liu - Fremont CA, US
Yonghua Song - Cupertino CA, US

Assignee:

Marvell International Ltd. - Hamilton

International Classification:

H04L 27/00
H03D 3/00
H04W 4/00
H04B 7/00
H04B 1/18
H04B 1/28
H04B 15/00

US Classification:

375326, 375324, 375322, 375316, 370330, 370329, 370328, 370310, 4551501, 455130, 4551641, 455333, 455323, 455313

Abstract:

Systems and methods for using non-crystal-based reference oscillators in the transmission and reception of frequency-modulated signals are disclosed. To protect against intrusion on neighboring designated frequency bands, guard bands, having a collective width greater than the total expected error based on the contribution of the frequency error from the non-crystal-based oscillators in the transmitter and/or receiver, can be designated. To protect against inter-channel interference within a designated frequency band, transmitters and receivers can include static sub-bandwidths wider than any possible total frequency error, such that it would be impossible for a transmitter or receiver to attempt to communicate on an unintended sub-band. The determination of the total possible frequency error can be determined dynamically based on the correlation between a received training sequence and a known pattern before or a communication session to avoid or correct for frequency offset or drift due to the use of non-crystal-based reference oscillators.