Wenhua Yang, Age ~50Lexington, MA

Wenhua Yang Phones & Addresses

Lexington, MA

400 Sharpners Pond Rd, North Andover, MA 01845 (978) 685-2492

20 Westgate Dr, Woburn, MA 01801 (781) 932-2949

109 Saint Stephen St, Boston, MA 02115

Sunnyvale, CA

Malden, MA

Revere, MA

Troy, NY

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Mentions for Wenhua Yang

Publications

Us Patents

Ac Coupled Multistage High Gain Operational Amplifier

US Patent:
6756842, Jun 29, 2004
Filed:
May 8, 2002
Appl. No.:
10/141191
Inventors:
Iuri Mehr - North Andover MA
Lawrence A. Singer - Bedford MA
Wenhua Yang - North Andover MA
Assignee:
Analog Devices, Inc. - Norwood MA
International Classification:
H03F 102
US Classification:
330 9, 330 51, 330258
Abstract:
An a. c. coupled multistage high gain operational amplifier includes at least two gain stages, each having an input and an output; an a. c. coupling level shifting capacitance interconnecting the output of a first stage to the input of a second stage; and a charging circuit interconnecting with the a. c. coupling level shifting capacitance and the input of the second stage to charge the a. c. coupling level shifting capacitance in a track phase and to connect the a. c. coupling capacitance to the input of the second stage during a hold phase for dissociating the bias voltages of the stages.

Methods And Apparatus For Rotating A Thermometer Code

US Patent:
7692569, Apr 6, 2010
Filed:
Apr 3, 2008
Appl. No.:
12/080463
Inventors:
Wenhua Yang - North Andover MA,
Assignee:
Analog Devices, Inc. - Norwood MA
International Classification:
H03M 1/66
H03M 1/10
US Classification:
341144, 341143, 341155
Abstract:
In one aspect, an apparatus for data conversion is provided. The apparatus comprises a plurality of inputs whose values together define a thermometer code to be converted to an analog output signal on each of a plurality of successive time increments, a plurality of conversion elements, each configured to convert one of the values at the plurality of inputs into an output signal, a shift circuit having a plurality of outputs connected to the plurality of conversion elements, the shift circuit coupled between the plurality of inputs and the plurality of conversion elements, the shift circuit selectively providing the values at the plurality of inputs to the plurality of conversion elements on the plurality of outputs to apply a rotation on each of the plurality of successive time increments, the rotation being indicated by a rotation pointer, and a pointer circuit coupled to the shift circuit and adapted to generate the rotation pointer on each of the successive time increments based on the values at the plurality of outputs during a preceding time increment, the pointer circuit indicating to the shift circuit which of the values at the plurality of inputs are to be provided to which of the plurality of conversion elements on a current time increment.

Pseudo-Differential Active Rc Integrator

US Patent:
7714634, May 11, 2010
Filed:
Jan 30, 2008
Appl. No.:
12/011787
Inventors:
Wenhua Yang - Andover MA,
Assignee:
Analog Devices, Inc. - Norwood MA
International Classification:
G06F 7/64
US Classification:
327344, 327345
Abstract:
A pseudo-differential active RC integrator is described. The pseudo-differential active RC integrator includes a common-mode feedback sub-circuit to control the common-mode output signal of the integrator. The common-mode feedback subcircuit may be coupled to one or more virtual ground nodes of the pseudo-differential active RC integrator, and may include one or more transconductors.

Cross-Coupled Multipath Feedforward Operational Amplifiers

US Patent:
8536939, Sep 17, 2013
Filed:
Nov 9, 2011
Appl. No.:
13/292835
Inventors:
Hajime Shibata - Toronto,
Richard Schreier - Toronto,
Wenhua Yang - North Andover MA,
Assignee:
Analog Devices, Inc. - Norwood MA
International Classification:
H03F 3/68
US Classification:
330124R, 330310
Abstract:
An operational amplifier can include a plurality of amplifiers connected to form a plurality of amplification paths extending from an input terminal to an output terminal of the operational amplifier. An amplifier in one of the amplification paths can include an intrinsic amplification-transistor capacitance connected between a first amplifier input and a first amplifier output, and a cross-coupling capacitor connected between the first amplifier input and a second amplifier output. A plurality of the amplification paths can include series-connected amplifiers connected in parallel with the cross-coupled amplifier. The cross-coupling capacitor can have a capacitance value selected as a function of the intrinsic capacitance and a gain experienced between the amplifier inputs and outputs. The operational amplifier can include an AC coupling capacitor connected in series with the cross-coupled amplifier. The operational amplifier can be arranged in feedback configuration.

Multi-Output-Resistance Switch Driver Circuits

US Patent:
8638156, Jan 28, 2014
Filed:
Aug 5, 2011
Appl. No.:
13/204505
Inventors:
Hajime Shibata - Toronto,
Wenhua Yang - North Andover MA,
David Alldred - Toronto,
Assignee:
Analog Devices, Inc. - Norwood MA
International Classification:
H03K 5/00
H03L 5/00
US Classification:
327308, 327552, 338 81 R
Abstract:
A switch circuit can include an impedance selection switch and a multi-output-resistance switch driver. The impedance selection switch can electrically connect an impedance to an input of an amplifier in response to a driver output signal, and include at least one transistor. The multi-output-impedance switch driver may provide the driver output signal to the switch, and have a first, relatively higher output resistance when providing a first logic state of the driver output signal to turn on the switch, and a second, relatively lower output resistance when providing a second logic state of the driver output signal to turn off the switch. The ratio of the first output resistance to the second output resistance can be greater than a selected predetermined ratio value.

Quadrature Bandpass Δσ Converter

US Patent:
7262726, Aug 28, 2007
Filed:
Jun 1, 2006
Appl. No.:
11/445413
Inventors:
Richard E. Schreier - North Andover MA,
Wenhua Yang - North Andover MA,
Hajime Shibata - North Andover MA,
Assignee:
Analog Devices, Inc. - Norwood MA
International Classification:
H03M 3/00
US Classification:
341143, 341155
Abstract:
An improved quadrature bandpass ΔΣ converter includes a loop filter, an ADC responsive to the loop filter, and a first feedback DAC responsive to the ADC; a first summing circuit is responsive to the first DAC and an analog input for providing an input to the loop filter; a second feedback DAC is responsive to the ADC for providing an input to the loop filter; the loop filter includes a plurality of signal resonators, at least one image resonator, a second summing circuit, and a feed forward circuit connecting at least two of the resonators to the second summing circuit for reducing the quantization noise from the ADC; the image resonator is responsive to the second DAC for reducing the image quantization noise.

Bootstrap Module For Multi-Stage Circuit

US Patent:
2003001, Jan 23, 2003
Filed:
Aug 17, 2001
Appl. No.:
09/932216
Inventors:
Wenhua Yang - North Andover MA,
International Classification:
H03K017/16
US Classification:
327/390000
Abstract:
A multi-stage circuit has a first stage and a second stage that both share a bootstrap module. More specifically, the first stage has an output switch, and the second stage has an input switch in communication with the output switch. The multi-stage circuit thus includes the bootstrap module in communication with both the output switch and the input switch. The bootstrap module is capable of applying a voltage to both the input and output switches, while the applied voltage ensures that the first and second switches remain in an on state at specified times.

Active Cascode Amplifier With An Amplitude Limiter

US Patent:
2003001, Jan 23, 2003
Filed:
Jul 17, 2001
Appl. No.:
09/907329
Inventors:
Wenhua Yang - North Andover MA,
International Classification:
H03F001/22
US Classification:
330/311000
Abstract:
An active cascode amplifier circuit which includes an active cascode amplifier and an amplitude limiter. The active cascode amplifier includes an input stage, an output stage and an auxiliary amplifier and receives in a voltage input signal and outputs a voltage output signal wherein the cascode amplifier amplifies the input voltage signal. The auxiliary amplifier is provided within the circuit to increase the gain of the cascode amplifier and has an associated output. When the input stage shuts off, due to a decrease in the input voltage signal, the amplitude limiter becomes active and holds the voltage at the output of the auxiliary amplifier to a preset voltage in order to decrease the recovery time for turning the output stage on when the input voltage increases and turns the input stage on.

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