Abstract: The thermal isolation of a thermally-trimmable resistor has a direct impact on temperature rise. It is possible to design the thermal isolation of the portions of a compound resistor to minimize or optimize the resistance variation of the overall compound resistor. The resistance variation of the overall compound resistor due to self-heating of its portions can be reduced or optimized, by designing different thermal isolation for each of the portions, such that compensation and/or optimization can occur. Furthermore, one can also design such different thermal isolation of the portions of a compound resistor to minimize resistance variation over a trim range of a compound resistor due to self-heating.

Abstract: Electro-thermal trimming of thermally-trimmable resistors is used to trim one or more of the plurality of resistors in or associated with an analog electric circuit. The TCR of each of a subset of a plurality of electro-thermally-trimmable resistors can be trimmed independently from the resistance in order to adjust the output parameter of an analog electric circuit without changing other parameters that would be affected by a change in resistance.

Abstract: A circuit for trimming a thermally-trimmable resistor, measuring a temperature coefficient of resistance of the thermally-trimmable resistor, and annealing a thermally-trimmable resistor post-trimming, the circuit comprising: a thermally-isolated area on a substrate housing the thermally-trimmable resistor; heating circuitry for applying a signal to a heating resistor; and a constant-power module adapted to maintain power dissipated in the heating resistor substantially constant over a duration of the signal by varying at least one parameter of the signal as a result of a change in resistance of the heating resistor during the signal.

Abstract: There is described a method and sub-circuit to measure temperature coefficients (coefficient of variation of a measurable parameter of the component), by using a thermally-isolated silicon micro-platform with a mass of mono-crystalline silicon suspended from it. The particular effectiveness of the measurement of temperature coefficient(s) stems from the influence of the mono-crystalline silicon mass in maintaining a substantially uniform temperature throughout the micro-platform. The measurement of temperature coefficient can be an absolute temperature coefficient of one or more components, or can be a relative temperature coefficient of two components, or can be relative temperature coefficients between more than two components.

Abstract: There is described a method for producing a packaged integrated circuit. The method comprises a first step of building an integrated circuit having a micro-structure suspended above a micro-cavity, and having a heating element on the micro-structure capable of heating itself and its immediate surroundings. A layer of protective material is then deposited on said micro-structure such that at least a top surface of the micro-structure and an opening of the micro-cavity is covered, wherein the protective material is in a solid state at room temperature and can protect the micro-structure during silicon wafer dicing procedures and subsequent packaging. The integrated circuit is packaged and an electric current is passed through the heating element such that a portion of the protective material is removed and an unobstructed volume is provided above and below the micro-structure.

Abstract: There is described a printed circuit board with a thermally trimmable component embedded therein. A layer of refractory insulating material is provided to provide mechanical support and chemical passivation for the thermally trimmable component. The component is trimmed by applying a sequence of heat pulses the a heating element, which could be the component itself or a separate element. A cavity may be burned in the substrate to provide thermal isolation for the thermally trimmable component.

Abstract: There is described a method for creating a thermally-isolated microstructure on a slab of mono-crystalline silicon which uses a hybrid dry-then-wet etch technique that when controlled, can produce microstructures without any silicon adhering underneath, microstructures having small masses of silicon adhering underneath, and microstructures that are still attached to the slab of mono-crystalline silicon via a waisted silicon body. When creating the microstructures with a waisted silicon body, the thermal isolation of the microstructure can be designed by controlling the depth of the etching and the size of the waist.

Abstract: There is described a method and sub-circuit to measure temperature coefficients (coefficient of variation of a measurable parameter of the component), by using a thermally-isolated silicon micro-platform with a mass of mono-crystalline silicon suspended from it. The particular effectiveness of the measurement of temperature coefficient(s) stems from the influence of the mono-crystalline silicon mass in maintaining a substantially uniform temperature throughout the micro-platform. The measurement of temperature coefficient can be an absolute temperature coefficient of one or more components, or can be a relative temperature coefficient of two components, or can be relative temperature coefficients between more than two components.

Abstract: There is provided a method and circuit for trimming a functional resistor on a thermally isolated micro-platform such that a second functional resistor on the same micro-platform remains substantially untrimmed; a method and circuit for providing and trimming a circuit such that at least two circuit elements of the circuit are subjected to a same operating environment and the operating environment is compensated for by distributing heat generated during operation of the circuit among the two circuit elements; a method and circuit for trimming a functional resistor on a thermally-isolated micro-platform such that a constant temperature distribution is obtained across the functional resistor; and a method and circuit for calculating a temperature coefficient of resistance of a functional resistor.

Abstract: There is provided a method and circuit for trimming a functional resistor on a thermally isolated micro-platform such that a second functional resistor on the same micro-platform remains substantially untrimmed; a method and circuit for providing and trimming a circuit such that at least two circuit elements of the circuit are subjected to a same operating environment and the operating environment is compensated for by distributing heat generated during operation of the circuit among the two circuit elements; a method and circuit for trimming a functional resistor on a thermally-isolated micro-platform such that a constant temperature distribution is obtained across the functional resistor; and a method and circuit for calculating a temperature coefficient of resistance of a functional resistor.

Abstract: There is provided a method and circuit for trimming a functional resistor on a thermally isolated micro-platform such that a second functional resistor on the same micro-platform remains substantially untrimmed; a method and circuit for providing and trimming a circuit such that at least two circuit elements of the circuit are subjected to a same operating environment and the operating environment is compensated for by distributing heat generated during operation of the circuit among the two circuit elements; a method and circuit for trimming a functional resistor on a thermally-isolated micro-platform such that a constant temperature distribution is obtained across the functional resistor; and a method and circuit for calculating a temperature coefficient of resistance of a functional resistor.

Abstract: There is provided a method and circuit for trimming a functional resistor on a thermally isolated micro-platform such that a second functional resistor on the same micro-platform remains substantially untrimmed; a method and circuit for providing and trimming a circuit such that at least two circuit elements of the circuit are subjected to a same operating environment and the operating environment is compensated for by distributing heat generated during operation of the circuit among the two circuit elements; a method and circuit for trimming a functional resistor on a thermally-isolated micro-platform such that a constant temperature distribution is obtained across the functional resistor; and a method and circuit for calculating a temperature coefficient of resistance of a functional resistor.

Abstract: This invention addresses a fundamental weakness in currently common microphones, and their applications in feedback for audio speaker systems. This limitation stems from the fundamental difficulties of typical membrane-type microphones in the frequency range 1-100 Hz. The self-noise of membrane-type microphones increases in this range approximately as 1/f, and membrane-type microphones are sensitive to parasitic inertial vibrations, which are usually very important in this frequency range. The removal of these limitations enables the use of such a sensor (APV sensor) for effective feedback in audio speakers, dramatically improving performance in the low-frequency range of 10-100 Hz. Without feedback, typical audio speakers suffer severe attenuation and/or distortion in this range.