Larry G Harris

US Patent:

6362612, Mar 26, 2002

Filed:

Jan 23, 2001

Appl. No.:

09/771517

Inventors:

Larry L. Harris - Austin TX 78725

International Classification:

G05F 304

US Classification:

323312, 323313, 323314, 327538

Abstract:

An improved bandgap voltage reference circuit for providing a stable reference output voltage, useful in circuits associated with power supply voltage operations as low as approximately 1. 3 Volts. The V generator is comprised of a pair of bipolar transistors operating at different current densities. Resistors in series with the transistors, in conjunction with an operational amplifier and current sources, produce a larger Voltage drop proportional to the V of the transistors. Output from the operational amplifier is connected to the base of a third bipolar transistor. The third bipolar transistor is provided as the bandgap voltage output device.

US Patent:

6879145, Apr 12, 2005

Filed:

Feb 15, 2002

Appl. No.:

10/076951

Inventors:

Larry L. Harris - Austin TX, US

International Classification:

G01R031/00

US Classification:

3241581

Abstract:

A voltage isolation buffer, comprising a pilot channel having a first Hall effect element and a data channel having a second Hall effect element is disclosed. The pilot channel is preferably AC coupled, and the data channel is preferably DC coupled. The voltage isolation buffer may comprise a means for calibration, which may be configurable to calibrate the voltage generated by the second Hall effect element based on the information from the first Hall effect element. A bi-directional voltage isolation buffer is also disclosed, comprising a first integrated circuit and a second integrated circuit. The first integrated circuit comprises a DC coupled Hall effect sensor and an AC coupled Hall effect sensor. The second integrated circuit comprises an AC coupled Hall effect sensor and a DC coupled Hall effect sensor. A method for transmitting data across a voltage isolation barrier is also disclosed comprising the steps of generating a first Hall voltage signal, AC coupling the first Hall voltage signal, generating a second Hall voltage signal, DC coupling the second Hall voltage signal, and calibrating the second Hall voltage signal, wherein the step of calibrating is controlled by the first Hall voltage signal.

US Patent:

7042208, May 9, 2006

Filed:

Mar 7, 2005

Appl. No.:

11/074353

Inventors:

Larry L. Harris - Austin TX, US

International Classification:

G01R 31/00

US Classification:

3241581

Abstract:

A voltage isolation buffer, including a pilot channel having a first Hall effect element and a data channel having a second Hall effect element is disclosed. The pilot channel is preferably AC coupled, and the data channel is preferably DC coupled. The voltage isolation buffer may include a calibration engine, which may be configurable to calibrate the voltage generated by the second Hall effect element based on the information from the first Hall effect element. A bi-directional voltage isolation buffer is also disclosed, including a first integrated circuit and a second integrated circuit. The first integrated circuit includes a DC coupled Hall effect sensor and an AC coupled Hall effect sensor. The second integrated circuit includes an AC coupled Hall effect sensor and a DC coupled Hall effect sensor. A method for transmitting data across a voltage isolation barrier is also disclosed including the steps of generating a first hall voltage signal, AC coupling the first Hall voltage signal, generating a second Hall voltage signal, DC coupling the second Hall voltage signal, and calibrating the second Hall voltage signal, wherein the step of calibrating is controlled by the first Hall voltage signal.

US Patent:

7477178, Jan 13, 2009

Filed:

Jun 30, 2007

Appl. No.:

11/772132

Inventors:

Prashanth Drakshapalli - Austin TX, US
Larry L. Harris - Austin TX, US

Assignee:

Cirrus Logic, Inc. - Austin TX

International Classification:

H03M 1/36

US Classification:

341159, 341155

Abstract:

A power-optimized analog-to-digital converter (ADC) input circuit provides for optimized power consumption versus performance. The first amplifier stage of the ADC is provided by a plurality of amplifiers that are selectably enabled to provide a particular bandwidth and noise performance level. The selection of the combination of enabled amplifiers may be made in conformity with the sample rate of the converter and the amplifiers may have evenly-weighted bias currents, or unevenly weighed bias currents and may be optimized for their particular use in combinations for bandwidth and 1/f noise corner performance. The outputs of the amplifiers are combined in a combiner circuit, which may be a discrete-time chopping amplifier that receives charges from a plurality of capacitors that sample each enabled amplifier output.

US Patent:

7750724, Jul 6, 2010

Filed:

Dec 20, 2007

Appl. No.:

11/962022

Inventors:

Thirumalai Rengachari - Austin TX, US
Kartik Nanda - Dallas TX, US
Larry L. Harris - Austin TX, US
John Paulos - Austin TX, US

Assignee:

Cirrus Logic, Inc. - Austin TX

International Classification:

G05F 1/10
G05F 3/02

US Classification:

327538, 327539, 323313

Abstract:

A temperature and process-stable magnetic field sensor bias current source provides improved performance in Hall effect sensor circuits. A switched-capacitor sensing element is used to sense either a reference current or the bias current directly. A current mirror may be used to generate the bias current from the reference current, and may include multiple current source transistors coupled through corresponding control transistors that are switched using a barrel shifter to reduce variations in the bias current due to process variation. The current mirror control may be provided via a chopper amplifier to reduce flicker noise and the current mirror control voltage may be held using a track/hold circuit during transitions of the chopper amplifier to further reduce noise due to the chopping action.

US Patent:

8222872, Jul 17, 2012

Filed:

Jun 26, 2009

Appl. No.:

12/493045

Inventors:

John L. Melanson - Austin TX, US
Mauro L. Gaetano - Austin TX, US
Larry L. Harris - Austin TX, US

Assignee:

Cirrus Logic, Inc. - Austin TX

International Classification:

G05F 1/613
H02M 7/162

US Classification:

323222, 323282, 363 61, 363 89

Abstract:

A auxiliary power supply having a selectable operating mode raises efficiency of a switched-power converter. By selectably controlling the input/output behavior of the auxiliary power supply receiving a voltage from an auxiliary winding of one of the power converter magnetic elements, more efficient operation of the auxiliary power supply over the full variation range of the input line voltage is achieved. By selecting the operating mode according to the relationship between the required auxiliary power supply output and the voltage available across the auxiliary winding under current operating conditions, the turns ratio of the auxiliary winding and other circuit parameters can be optimized for efficiency. Selection of the operating mode may be made by detecting the output or input voltage of the multiplier, and the selection may be performed under hysteretic control so that the variation in auxiliary power supply output voltage is reduced dynamically.

US Patent:

8536854, Sep 17, 2013

Filed:

Sep 30, 2010

Appl. No.:

12/894472

Inventors:

John L. Melanson - Austin TX, US
Prashanth Drakshapalli - Austin TX, US
Larry L. Harris - Austin TX, US

Assignee:

Cirrus Logic, Inc. - Austin TX

International Classification:

G05F 3/28

US Classification:

323316, 323313, 327539

Abstract:

An electronic reference-signal generation system includes a supply invariant bandgap reference system that generates one or more bandgap reference signals that are substantially unaffected by bulk error currents. In at least one embodiment, the bandgap reference generates a substantially invariant bandgap reference signals for a range of direct current (DC) supply voltages. Additionally, in at least one embodiment, the bandgap reference system provides substantially invariant bandgap reference signals when the supply voltage varies due to alternating current (AC) voltages. In at least one embodiment, the bandgap reference system generates a bandgap reference voltage VBG, a “proportional to absolute temperature” (PTAT) current (“i”) and a “zero dependency on absolute temperature” (ZTAT) current (“i”) that are substantially unaffected by variations in the supply voltage and unaffected by a bulk error current.

US Patent:

53390679, Aug 16, 1994

Filed:

May 7, 1993

Appl. No.:

8/060431

Inventors:

Larry L. Harris - Austin TX
Baker P. L. Scott - Austin TX

Assignee:

Crystal Semiconductor Corporation - Austin TX

International Classification:

H01C 114

US Classification:

338323

Abstract:

An apparatus and method is provided for dividing a voltage with a resistor voltage divider and for employing the voltage divider in an integrated circuit. The resistor voltage divider utilizes inaccessible compensation taps that are placed between nonlinearly spaced output taps. The compensation taps reduce the impact of tap resistance on the voltage divider transfer function. The number of inaccessible compensation taps placed between output taps is dependant upon a chosen tap density that is substantially maintained across the body of the resistor voltage divider. The resistor may be used in integrated circuits employing amplifiers, such as volume control circuitry.