System and apparatus for generating dynamic reference voltage in power constrained devices
OwnerRobert Bruce Ganton, Robert S Ballaminventors
Life of this patent
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Abstract
A simplified electronics approach to allow cost, size, and power consumption to be reduced while maintaining state of the art accuracy and reliability, key features for wireless medical devices/systems and industrial sensors alike. Extreme accuracy is achieved by innovative noise shaping and filtering introduced to the electrochemical sensor, before sampling by the analog to digital converter. Introduction of the noise and bias to the electrochemical sensor provides very low power biasing which is necessary to achieve overall reliable and very accurate bias for the electrochemical reaction cell.
Claims19
A circuit for measuring an output signal from an electronic sensor, comprising:
- a measurement output line from the electronic sensor coupled to a first input of an op amp;
- a reference signal line coupled to a second input to the op amp;
- a reference signal generator coupled to the reference signal line, the reference signal generator further comprising:
- a first GPIO pulse generator coupled to a first a first RC network;
- a reference ADC coupled to the reference signal line;
- a sampling ADC sampling an output of the op amp;
- and
- a processor constructed to activate the GPIO for a precise elapse time such that the first GPIO pulse signal charges the capacitor to about a target reference voltage.
A method of generating a reference voltage for an op amp that is coupled to an output of an electronic sensor, comprising:
- calculating an elapse time for a GPIO clock output to charge an RC network to about a target reference voltage;
- activating the GPIO for the elapse time to charge the RC network;
- measuring an output voltage from the RC network;
- comparing the measured output voltage to the target reference voltage;
- if the measure voltage is too high, then discharging the RC network for a short elapse time;
- if the measure voltage is too low, then charging the RC network for a short elapse time;
- and
- waiting a period of time and using an ADC to sample an output from the op amp over a sample period.
A method of generating a reference voltage on a reference voltage line for an op amp that is coupled to an output of an electronic sensor, comprising:
- calculating a first elapse time for a first GPIO clock output to charge a first RC network to about a target reference voltage;
- activating the first GPIO for the first elapse time to charge the first RC network, which is coupled to the reference voltage line;
- waiting a period of time and measuring the voltage on the reference voltage line;
- calculating, using the voltage measured on the reference voltage line, a second elapse time for a second GPIO clock output to charge a second RC network to about a the target reference voltage;
- activating the second GPIO for the second elapse time to charge the second RC network, which is coupled to the reference voltage line;
- and
- waiting a period of time and using an ADC to sample an output from the op amp over a sample period.
Dependencies are inferred from the claim text.