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W.E. Ott

Bio: W.E. Ott is an academic researcher. The author has contributed to research in topics: Sense (electronics) & Settling time. The author has an hindex of 1, co-authored 1 publications receiving 20 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a thermal technique of rms measurement is described which uses the base-emitter junction of a bipolar transistor to sense the temperature change of a monolithic chip due to the power dissipation of a companion diffused resistor.
Abstract: A thermal technique of rms measurement is described which uses the base-emitter junction of a bipolar transistor to sense the temperature change of a monolithic chip due to the power dissipation of a companion diffused resistor. An analysis is presented which provides: 1) design equations for performing error compensation to minimize the nonlinearity of the rms-to-dc conversion, and 2) ac feedback network design to optimize the low frequency cutoff and settling time product. Resulting rms converters had midband accuracies of /spl plusmn/0.05 percent of full scale over a dynamic range of 30 dB, high frequency limits of 100 MHz for 2 percent accuracy, and settling times less than 1 s.

20 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a planar diaphragm structure and micromachined dielectric windows are used for thermal rms-dc conversion with a thermal efficiency greater than 7/spl deg/C/mW.
Abstract: This paper reports a monolithic rms-dc converter for measuring wideband rms signals. Two identical thermoelements for thermal rms-dc conversion are formed using planar diaphragm structures and micromachined dielectric windows. Each thermoelement consists of two polysilicon heaters and a thin-film temperature sensor located on a window and operated at constant temperature using on-chip control feedback circuitry. The thermoelements achieve a thermal efficiency greater than 7/spl deg/C/mW with a thermal time constant less than 5 ms. The on-chip control circuitry is realized using a standard 3 /spl mu/m p-well CMOS process with minor modifications for process compatibility with the dielectric window formation. This converter measures rms signals over a full scale range of 1 Vrms, handles crest factors in excess of 5, exhibits a typical nonlinearity of less than 1%, and achieves a 3 dB bandwidth greater than 20 MHz. >

30 citations

Journal ArticleDOI
TL;DR: In this article, an anisotropic undercut etch in conjunction with an electrochemical etch stop is used to form the thermal elements of the r.m.s. converter, which are suspended single-crystal silicon regions containing temperature-sensing diodes heated by polysilicon resistors.
Abstract: A high-frequency root-mean-square (r.m.s.) converter composed of two matched thermal elements and on-chip circuitry has been fabricated in a foundry CMOS process with post-process micromachining techniques. An anisotropic undercut etch in conjunction with an electrochemical etch stop is used to form the thermal elements of the r.m.s. converter, which are suspended single-crystal silicon regions containing temperature-sensing diodes heated by polysilicon resistors. One of the elements is heated by the a.c. signal, while an integrated continuous-time feedback network maintains a second element at the same temperature. The converter has a packaging-limited — 3 dB bandwidth of 415 MHz, an r.m.s. dynamic range of 53 dB, nonlinearity of 1%, a quiescent power dissipation under 1 mW, and occupies an area of approximately 400 μm × 400 μm. The thermoelements have a thermal resistance of up to 37 000 K W −1 in air. In addition to the r.m.s. converter itself, an improved wet etchant chemistry is presented. Ammonium persulfate, when added to tetramethyl ammonium hydroxide (TMAH) silicon etchant, improves the silicon etch rate and the (100) surface quality. This etch chemistry should be useful for a broad range of CMOS-compatible micromachining applications.

28 citations

Book ChapterDOI
01 Jan 2013
TL;DR: In this article, the authors proposed a sine wave excitation circuit for cold cathode fluorescent lamps (CCFLs) to achieve optimal current-to-light conversion in the lamp.
Abstract: Current generation portable computers and instruments utilize backlit LCDs (Liquid Crystal Displays). These displays have also appeared in applications ranging from medical equipment to automobiles, gas pumps and retail terminals. Cold Cathode Fluorescent Lamps (CCFLs) provide the highest available efficiency for backlighting the display. These lamps require high voltage AC to operate, mandating an efficient high voltage DC/AC converter. In addition to good efficiency, the converter should deliver the lamp drive in sine wave form. This is desirable to minimize RF emissions. Such emissions can cause interference with other devices, as well as degrading overall operating efficiency. The sine wave excitation also provides optimal current-to-light conversion in the lamp. The circuit should permit lamp control from zero to full brightness with no hysteresis or “pop-on,” and must also regulate lamp intensity vs power supply variations.

26 citations

Journal ArticleDOI
TL;DR: In this article, the 4-quadrant multiplier is presented, which consists of three diffused resistance heaters and arrays of Si-Al contact sensors, and its frequency response is suitable for many applications.
Abstract: A new type of thermal-function i.c. is presented: the 4-quadrant multiplier. The design consists of three diffused resistance heaters and arrays of Si-Al contact sensors. The multiplier is quite linear and its frequency response is suitable for many applications. The structure is extremely simple and compatible with usual i.c. technology.

19 citations

Journal ArticleDOI
TL;DR: In this article, a monolithic thermal sensor, a unique high-impedance attenuator, a precision sample-and-hold circuit, and a novel ac-error-correction technique have brought significant improvements in the accuracy of ac measurements.
Abstract: Development of a new monolithic thermal sensor, a unique high-impedance attenuator, a precision sample-and-hold circuit, and a novel ac-error-correction technique have brought significant improvements in the accuracy of ac measurements. A precision thermal truerms measurement system is described that offers a transfer stability of 25 parts/106 in the frequency band 40 Hz-kHz. A microprocessor-based system uses a nonvolatile memory for software calibration; this enhances dc, ac, and resistance measurement accuracy, including production and repair.

19 citations