System and apparatus for enabling low power wireless devices
OwnerRobert Bruce Ganton, Robert S Ballaminventors
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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. 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 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 operational amplifier (op amp);
- a drive noise generator coupled to a second input of the op amp, the drive noise generator for generating a reference voltage signal and further comprising:
- a first noise generator;
- and
- a drive noise detector coupled to the second input to measure the second input;
- a sampling ADC sampling an output of the op amp;
- and
- a processor using the measured second input to control the drive noise generator.
The circuit according to claim 8, wherein the controllable average output is a variable voltage.
A method for providing a variable reference voltage to an input of an operational amplifier, comprising:
- calculating a PWM/PDM signal to generate a target reference voltage using an RC network;
- connecting a PWM/PDM generator to the RC network and applying the calculated PWM/PDM signal to generate a reference voltage;
- waiting for the reference voltage to settle;
- measuring the reference voltage and comparing the measured voltage to the target reference voltage;
- adjusting the PWM/PDM signal until a measured voltage of the refence voltage is at the target reference voltage;
- turning off and disconnecting the PWM/PDM generator from the RC network;
- and
- waiting a period of time in a low power state.
A method for providing a variable reference voltage to an input of an operational amplifier, comprising:
- calculating a first PWM/PDM signal to generate a target reference voltage using a first RC network;
- connecting a first PWM/PDM generator to the first RC network and applying the first calculated PWM/PDM signal to generate a reference voltage;
- waiting a time period that is at least X times the time constant of the first RC network, where X is 3 or greater;
- turning off the first PWM/PDM generator and disconnecting it from the first RC network;
- turning on a second PWM/PDM generator and connecting it to a second RC network to adjust or maintain the reference voltage, the second RC network having a time constant at least Y times the time constant of the first RC network, where Y is 5 or greater,
- waiting a time period that is at least Z times the time constant of the second RC network, where Z is 0.5 or greater.
- turning off the second PWM/PDM generator and disconnecting it from the second RC network;
- and
- waiting a period of time in a low power state.
Dependencies are inferred from the claim text.