Multipoint digital temperature controller
First Claim
1. An electronic digital thermostat control unit for wide temperature range comprising:
- a linear temperature sensing element other than pn-junction sensing element;
a constant current source to drive the said linear temperature sensing element;
an analog-to-digital converter coupled to the output of the said linear temperature sensing element to produce a digital output;
a non-volatile memory storing calibration data;
a correcting circuit coupled to the analog-to-digital converter for correcting the digital output for sensitivity and offset values of the sensing element using the calibration data stored in the non-volatile memory and generating a corrected output;
at least one digital comparator having first and second inputs, the first input coupled to the corrected output from the correcting circuit and the second input coupled to a digital reference value, the digital comparator generating an output when the corrected output matches the digital reference value; and
a control latch having an input that is to set and/or reset in response to the output of digital comparator for actuating a load comprising a temperature correction device in a consumer/industrial product.
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Accused Products
Abstract
The present invention relates to an electronic digital thermostat control unit comprising a linear temperature sensing element (1) connected to an A-D converter (3), a sensitivityand offset correction circuit (4), digital comparators (5, 6), digital noise filters (7, 8), a control latch (9), an output drive and protection circuit (10) and a solid state switch (11) to produce the desired output with user input in either analogue form using a potentiometer (12) or a digital form using a switch with calibration and control data stored in a nonvolatile memory and a display unit (18) for displaying sensed or user set temperature. The invention further relates to the application of the said electronic digital thermostat in a multipoint temperature for the refrigerant and heating systems using a plurality of said electronic thermostat control units (40-44) with a logic circuit, central control unit (71), system timers and a starting relay circuit to provide application specific functions. The implementation is also shown in the form of an Application Specific Integrated Circuit (ASIC) (32) to provide reduced size and cost.
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Citations
29 Claims
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1. An electronic digital thermostat control unit for wide temperature range comprising:
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a linear temperature sensing element other than pn-junction sensing element;
a constant current source to drive the said linear temperature sensing element;
an analog-to-digital converter coupled to the output of the said linear temperature sensing element to produce a digital output;
a non-volatile memory storing calibration data;
a correcting circuit coupled to the analog-to-digital converter for correcting the digital output for sensitivity and offset values of the sensing element using the calibration data stored in the non-volatile memory and generating a corrected output;
at least one digital comparator having first and second inputs, the first input coupled to the corrected output from the correcting circuit and the second input coupled to a digital reference value, the digital comparator generating an output when the corrected output matches the digital reference value; and
a control latch having an input that is to set and/or reset in response to the output of digital comparator for actuating a load comprising a temperature correction device in a consumer/industrial product. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An electronic multi-point temperature control unit comprising:
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a plurality of electronic thermostat control units, each electronic thermostat control unit comprising;
a linear temperature sensing element;
a constant current source to drive the said linear temperature sensing element;
an analog-to-digital converter coupled to the output of the said linear temperature sensing element to produce a digital output;
a correcting circuit coupled to the analog-to-digital converter for correcting the digital output for sensitivity and offset values of the sensing element using the calibration data and generating a corrected output;
at least one digital comparator having first and second inputs, the first input coupled to the corrected output from the correcting circuit and the second input coupled to a digital reference value, the digital comparator generating an output when the corrected output matches the digital reference value;
a control latch having an input that is set and/or reset in response to the output of digital comparator for actuating a load comprising a temperature correction device in a consumer/industrial product;
a common non-volatile memory that stores reference values and calibration data for each control unit to control the temperature in a plurality of locations;
one or more output drive and protection circuits;
a logic circuit, the outputs from the control latches of each electronic thermostat control unit being connected to the logic circuit for selectively connecting the outputs to the one or more output drive and protection circuits based on data stored in the non-volatile memory;
a central control unit connected to each of the outputs from the control latches of the electronic thermostat control units and the inputs of the output drive and protection circuits for enabling or disabling the electronic thermostat control units and the output of said drive and protection circuits depending upon a combination of the output from the electronic thermostat control unit and user control input;
a system timer unit coupled to the central control unit for generating timing signals for enabling/disabling one or more of the said output drive and protection circuits during operation; and
a starting relay circuit coupled to the central control unit for providing signals to control one or more output drive and protection circuits when a load is to be switched on. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification