MEMS-based electrically isolated analog-to-digital converter

An isolated-ADC providing isolation between an analog input signal and a digital output signal, the isolated-ADC comprising:

• a microelectromechanical system (MEMS) including:
• a substrate;
• a beam element supported from the substrate for movement with respect to an axis relative to the substrate;
• a first actuator attached to the beam element, wherein the first actuator is capable of exerting a first force upon the beam element causing the beam element to move with respect to the axis, and wherein the first force is dependent upon the analog input signal provided to the isolated-ADC;
• a sensor communicating with the beam element to detect a change in position of the beam element and to produce a position signal indicative of the position of the beam element;
• and
• a second actuator attached to the beam element, wherein the second actuator is capable of exerting a second force upon the beam element based upon a first feedback signal;
• a comparator electrically coupled to the sensor, wherein the comparator generates a digital signal based upon a comparison of the position signal with a reference value representative of a reference position of the beam element;
• and
• a differentiator electrically coupled to the comparator, wherein the differentiator generates an intermediate signal related to a derivative of the digital signal;
• wherein the first feedback signal includes at least one of a first analog signal component based upon the intermediate signal and a second analog signal component based upon the digital signal;
• and
• wherein the digital output signal is further produced by a processing device within the isolated-ADC in dependence upon the digital signal, the digital output signal being an indication of, and electrically isolated from, the analog input signal.

An isolated-ADC providing isolation between an analog input signal and a digital output signal, the isolated-ADC comprising:

• a microelectromechanical system (MEMS) including:
• a substrate;
• a beam element supported from the substrate for movement with respect to an axis relative to the substrate;
• a first actuator attached to the beam element, wherein the first actuator is capable of exerting a first force upon the beam element causing the beam element to move with respect to the axis, and wherein the first force is dependent upon the analog input signal provided to the isolated-ADC;
• a sensor communicating with the beam element to detect a change in position of the beam element and to produce a position signal indicative of the position of the beam element;
• and
• a second actuator attached to the beam element, wherein the second actuator is capable of exerting a second force upon the beam element based upon a feedback signal;
• a set of comparators including at least first, second and third comparators that are each electrically coupled to the sensor,
• wherein the first comparator generates a first digital signal based upon a comparison of the position signal with a reference value representative of a reference position of the beam element;
• wherein the second comparator generates a second digital signal based upon a comparison of the position signal with a first offset value representative of a first reference position offset of the beam element;
• and
• wherein the third comparator generates a third digital signal based upon a comparison of the position signal with a second offset value representative of a second reference position offset of the beam element;
• a logical decision device coupled to the first, second and third comparators, wherein the logical decision device generates a feedback bitstream signal that is based on at least the first, second and third digital signals;
• and
• a digital-to-analog converter (DAC) electrically coupled between the second actuator and the logical decision device, wherein the DAC generates the feedback signal in dependence upon the feedback bitstream signal;
• wherein the digital output signal is further produced by the isolated-ADC in dependence upon at least one of the first, second and third digital signals, the digital output signal being an indication of, and electrically isolated from, the analog input signal.

An isolated-ADC providing isolation between an analog input signal and a digital output signal, the isolated-ADC comprising:

• a microelectromechanical system (MEMS) including:
• a substrate;
• a beam element supported from the substrate for movement with respect to an axis relative to the substrate;
• a first actuator attached to the beam element, wherein the first actuator is capable of exerting a first force upon the beam element causing the beam element to move with respect to the axis, and wherein the first force is dependent upon the analog input signal provided to the isolated-ADC;
• a sensor communicating with the beam element to detect a change in position of the beam element and to produce a position signal indicative of the position of the beam element;
• and
• a second actuator attached to the beam element, wherein the second actuator is capable of exerting a second force upon the beam element based upon a feedback signal;
• a differential amplifier electrically coupled to the sensor, wherein the differential amplifier generates two intermediate signals based upon a comparison of the position signal with a reference value representative of a reference position of the beam element;
• a comparator bias circuit including a comparator that receives the two intermediate signals and in response generates a digital signal;
• and
• a digital-to-analog converter (DAC) electrically coupled between the second actuator and the comparator bias circuit, wherein the DAC generates the feedback signal dependent upon the digital signal,
• wherein the digital output signal is further produced by the isolated-ADC in dependence upon the digital signal, the digital output signal being an indication of, and electrically isolated from, the analog input signal.

An isolated-ADC providing isolation between an analog input signal and a digital output signal, the isolated-ADC comprising:

• a microelectromechanical system (MEMS) including:
• a substrate;
• a beam element supported from the substrate for movement with respect to an axis relative to the substrate;
• a first actuator attached to the beam element, wherein the first actuator is capable of exerting a first force upon the beam element causing the beam element to move with respect to the axis, and wherein the first force is dependent upon the analog input signal provided to the isolated-ADC;
• a sensor communicating with the beam element to detect a change in position of the beam element and to produce a position signal indicative of the position of the beam element;
• a second actuator attached to the beam element, wherein the second actuator is capable of exerting a second force upon the beam element based upon a feedback signal;
• and
• a damping element coupled to the beam element, wherein the damping element tends to generate a third force when the beam element moves, the third force tending to counter the at least one of the first and second forces causing the movement;
• a first comparator electrically coupled to the sensor, wherein the first comparator generates a first digital signal based upon a comparison of the position signal with a reference value representative of a reference position of the beam element;
• and
• a digital-to-analog converter (DAC) electrically coupled between the first comparator and the second actuator, wherein the DAC generates the feedback signal in dependence upon the first digital signal;
• wherein the digital output signal is further produced by the isolated-ADC in dependence upon the first digital signal, the digital output signal being an indication of, and electrically isolated from, the analog input signal.

An isolated-ADC comprising:

• a microelectromechanical means for adding an analog input signal to a feedback signal and producing a position signal in response to the analog input and feedback signals;
• a means for generating a digital output signal based upon the position signal;
• and
• a means for generating the feedback signal based upon the position signal;
• wherein, the digital output signal is electrically isolated from the analog input signal.

A method of providing a digital output signal based upon an analog input signal, wherein the digital output signal is electrically isolated from the analog input signal, the method comprising:

• receiving the analog input signal at a first actuator of a microelectromechanical system (MEMS);
• receiving a feedback signal at a second actuator of the MEMS;
• generating movement of a beam element of the MEMS by way of the first and second actuators in response to the respective analog input and feedback signals;
• sensing a position of the beam element of the MEMS at a sensor of the MEMS;
• comparing the sensed position with a reference value;
• generating a first digital signal in response to the comparing of the position and the reference value, wherein the first digital signal is at a high level while the sensed position is determined to be greater than the reference value and at a low level while the sensed position is determined to be less than the reference value;
• generating, based upon the first digital signal, both the digital output signal and the feedback signal.

A method of providing a digital output signal based upon an analog input signal, wherein the digital output signal is electrically isolated from the analog input signal, the method comprising:

• receiving the analog input signal at a first actuator of a microelectromechanical system (MEMS);
• receiving a first feedback signal at a second actuator of the MEMS;
• generating movement of a beam element of the MEMS by way of the first and second actuators in response to the respective analog input and first feedback signals;
• sensing a position of the beam element of the MEMS at a sensor of the MEMS;
• comparing the sensed position with a reference value;
• generating a first digital signal in response to the comparing of the position and the reference value, wherein the first digital signal is at a high level while the sensed position is determined to be greater than the reference value and at a low level while the sensed position is determined to be less than the reference value;
• generating the digital output signal based upon the first digital signal;
• and
• differentiating the first digital signal to obtain an intermediate signal, wherein the first feedback signal is based upon at least one of the intermediate signal and the first digital signal.

A method of providing a digital output signal based upon an analog input signal, wherein the digital output signal is electrically isolated from the analog input signal, the method comprising:

• receiving the analog input signal at a first actuator of a microelectromechanical system (MEMS);
• receiving a feedback signal at a second actuator of the MEMS;
• generating movement of a beam element of the MEMS by way of the first and second actuators in response to the respective analog input and feedback signals;
• sensing a position of the beam element of the MEMS at a sensor of the MEMS;
• comparing the sensed position with a reference value and a plurality of offset values at a plurality of respective comparators;
• generating a first digital signal in response to the comparing of the position and the reference value and a plurality of additional digital signals in response to the comparing of the position with the plurality of offset values, respectively;
• generating the digital output signal based upon the first digital signal;
• processing at a logical decision device the first digital signal and the plurality of additional digital signals to obtain a feedback bitstream signal;
• generating the feedback signal from the feedback bitstream signal by way of a digital-to-analog converter (DAC).

A method of providing a digital output signal based upon an analog input signal, wherein the digital output signal is electrically isolated from the analog input signal, the method comprising:

• receiving the analog input signal at a first actuator of a microelectromechanical system (MEMS);
• receiving a feedback signal at a second actuator of the MEMS;
• generating movement of a beam element of the MEMS by way of the first and second actuators in response to the respective analog input and feedback signals;
• sensing a position of the beam element of the MEMS at a sensor of the MEMS;
• providing an indication of the sensed position and a reference value to a differential amplifier;
• providing two intermediate signals from the differential amplifier to a comparator bias circuit;
• generating a digital signal at the comparator bias circuit based upon the high and low output signals;
• and
• generating, based upon the digital signal, both the digital output signal and the feedback signal.

A method of providing a digital output signal based upon an analog input signal, wherein the digital output signal is electrically isolated from the analog input signal, the method comprising:

• receiving the analog input signal at a first actuator of a microelectromechanical system (MEMS);
• receiving a feedback signal at a second actuator of the MEMS;
• generating movement of a beam element of the MEMS by way of the first and second actuators in response to the respective analog input and feedback signals;
• damping the movement of the beam element of the MEMS by way of a damping element;
• sensing a position of the beam element of the MEMS at a sensor of the MEMS;
• comparing the sensed position with a reference value;
• generating a digital signal in response to the comparing of the position and the reference value, wherein the digital signal is at a high level while the sensed position is determined to be greater than the reference value and at a low level while the sensed position is determined to be less than the reference value;
• determining the digital output signal based upon the digital signal;
• and
• generating the feedback signal based upon the digital signal.