Analog negative temperature coefficient (NTC) compensation
AssigneeBelimo Holding AG
InventorYoram Mottas
Life of this patent
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Abstract
A room operating unit (ROU) which is integral part of a HVAC system has an operating unit providing different functionalities, a device terminal and an analog sensor unit including an electrical circuit for determining room temperature. Depending on the construction of the device, self-heating effects caused by the heat generating components of the device may affect the result of the temperature measurement, i.e., the ambient temperature of the sensor unit may be higher than room temperature. Therefore, the sensor unit comprises a compensation circuit for correcting the temperature output by the sensor unit by eliminating self-heating effects.
Claims13
A device including at least one heat generating component, wherein the device has a temperature sensor unit having an electrical circuit comprising:
- a first resistor having a negative temperature coefficient and a first operation characteristic corresponding to a relation between the ambient temperature of the first resistor and a first electrical resistance of the first resistor;
- and
- a compensation circuit comprising at least a second resistor, wherein the compensation circuit has a second operation characteristic corresponding to a relation between the ambient temperature of the compensation circuit and a second electrical resistance of the compensation circuit;
- wherein the compensation circuit is configured to compensate a deviation, caused by self-heating effects of the device, of the measured first electrical resistance from the electrical resistance corresponding to a room temperature.
A method of determining a room temperature using an analog sensor unit in proximity to at least a component of a device generating heat, the method comprising:
- (a) determining a third electrical resistance defined as a combination of a first electrical resistance arranged in the device, and a second electrical resistance of a compensation circuit;
- (b) determining a temperature based on the third electrical resistance, wherein the determined temperature corresponds to the room temperature by compensating self-heating effects of the at least one component of the device.
Dependencies are inferred from the claim text.