Sensor signal conditioner

An ASIC chip circuit for temperature compensating, linearizing, and amplifying a transducer signal output for electronic instrumentation, comprising:

• a programmable gain instrument amplifier having an input for receiving a signal from a sensor;
• a comparator for comparing an amplifier output voltage of said programmable gain instrument amplifier to a desired output voltage value and providing a difference;
• a micro-controller for providing a gain and an offset based on said difference;
• a first digital-to-analog converter for providing said gain to said programmable gain instrument amplifier;
• a second digital-to-analog converter for providing said offset to said programmable gain instrument amplifier;
• an I/O pin;
• a mode switch for connecting said I/O pin to an input of said comparator for inputting said desired output voltage value in a programming mode and for connecting said I/O pin to said amplifier output in a user mode;
• a user/programming mode pin for controlling said mode switch;
• and
• a memory for storing a programming protocol and a plurality of programmed DAC adjustment values whereby, in said programming mode, said programming protocol is performed to store said plurality of programmed DAC adjustment values and, in said user mode, linearly fit said programmed DAC adjustment values to set trim values for temperature compensating and linearizing an amplifier output of said programmable gain instrument amplifier.

A mass-produced, temperature compensated, linearized, and amplified transducer comprising:

• a programmable gain instrument amplifier having an input connected to a sensor;
• a comparator for comparing an amplifier output voltage of said programmable gain instrument amplifier to a desired output voltage value and providing a difference;
• a micro-controller for providing a gain and an offset based on said difference;
• a first digital-to-analog converter for providing said gain to said programmable gain instrument amplifier;
• a second digital-to-analog converter for providing said offset to said programmable gain instrument amplifier;
• an I/O pin for providing connection to a voltage generator simultaneously with a second transducer;
• a mode switch for connecting said I/O pin to an input of said comparator for inputting said desired output voltage value in a programming mode and for connecting said I/O pin to said amplifier output in a user mode;
• a user/programming mode pin for controlling said mode switch;
• a memory for storing a programming protocol and a plurality of programmed DAC adjustment values;
• and
• a step indicator for indicating the currently processed step of said programming protocol whereby, in said programming mode, said programming protocol is performed while said second transducer is connected at said I/O pin and said programming protocol is performed to store said plurality of programmed DAC adjustment values and, in said user mode, linearly fit said programmed DAC adjustment values to set trim values for temperature compensating and linearizing an amplifier output of said programmable gain instrument amplifier.

An electronic instrumentation circuit for temperature compensating, linearizing, and amplifying a sensor signal output, comprising:

• a programmable gain instrument amplifier having an input connected to a sensor;
• a comparator for comparing an amplifier output voltage of said programmable gain instrument amplifier to a desired output voltage value and providing a difference;
• a micro-controller for providing a gain and an offset based on said difference;
• a temperature sensor for measuring a temperature of said sensor;
• a first analog-to-digital converter for providing a temperature input from said temperature sensor to said micro-controller;
• a second analog-to-digital converter for providing a digital value of said amplifier output voltage to said micro-controller;
• a first digital-to-analog converter for providing said gain to said programmable gain instrument amplifier;
• a second digital-to-analog converter for providing said offset to said programmable gain instrument amplifier;
• a high resolution digital-to-analog converter for providing a fine gain to said programmable gain instrument amplifier;
• a high resolution digital-to-analog converter for providing a fine offset to said programmable gain instrument amplifier;
• an I/O pin;
• a mode switch for connecting said I/O pin to an input of said comparator for inputting said desired output voltage value in a programming mode and for connecting said I/O pin to said amplifier output in a user mode;
• a user/programming mode pin for controlling said mode switch;
• a program set pin;
• a memory for storing a programming protocol wherein said memory is an EPROM, said EPROM being programmable within five seconds after a high voltage is applied to said program set pin;
• and
• a step indicator for indicating the currently processed step of said programming protocol whereby, in said programming mode, said programming protocol is performed to store a plurality of programmed DAC adjustment values and, in said user mode, linearly fit said programmed DAC adjustment values to set trim values for temperature compensating, and linearizing an amplifier output of said programmable gain instrument amplifier.

A method for temperature compensating, linearizing, and amplifying sensor signal output, comprising steps of:

• applying a signal for a sensor signal conditioner to enter a programming mode;
• connecting a programmable, precision voltage source to said sensor signal conditioner;
• setting a temperature for a sensor connected to said sensor signal conditioner;
• taking at least three different physical measurements from said sensor at said temperature;
• storing a plurality of programmed DAC adjustment values into a memory in said sensor signal conditioner;
• repeating said setting, taking, and storing steps for at least a second different temperature;
• applying an appropriate signal for said sensor signal conditioner to enter a user mode;
• and
• linearly fitting said plurality of programmed DAC adjustment values in said signal sensor conditioner.

A method for mass production of temperature compensated, linearized, and amplified transducers, comprising steps of:

• applying a common signal simultaneously to a plurality of sensor signal conditioners for each sensor signal conditioner to enter a programming mode;
• connecting a programmable, precision voltage source simultaneously to each of said plurality of sensor signal conditioners;
• setting a temperature for a plurality of sensors each of which is connected to one of said plurality of sensor signal conditioners;
• taking at least three different physical measurements from each of said plurality of sensors at said temperature;
• storing a plurality of programmed values into a memory in each of said plurality of sensor signal conditioners;
• repeating said setting, taking, and storing steps for at least a second different temperature;
• and
• applying a second common signal simultaneously to said plurality of sensor signal conditioners for each sensor signal conditioner to enter a user mode.