MEMS-based electrically isolated analog-to-digital converter
First Claim
1. 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 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 digital-to-analog converter (DAC) electrically coupled between the second actuator and the comparator, wherein the DAC generates the feedback signal at least in partial dependence upon the digital signal;
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.
7 Assignments
0 Petitions
Accused Products
Abstract
An isolated-ADC and a method for providing isolated analog-to-digital conversion are disclosed. The isolated-ADC includes a microelectromechanical system (MEMS), a comparator, and a digital-to-analog converter (DAC). The MEMS includes a beam element supported from a substrate for movement with respect to an axis, first and second actuators and a sensor. The first and second actuators are capable of exerting respective forces upon the beam element causing the beam element to move in response to analog input and feedback signals, respectively. The sensor detects changes in position of the beam element and produces a position signal indicative thereof. The comparator generates a digital signal based upon a comparison of the position signal with a reference value. Based on the digital signal, the DAC generates the feedback signal, and the isolated-ADC produces a digital output signal.
115 Citations
79 Claims
-
1. 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 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 digital-to-analog converter (DAC) electrically coupled between the second actuator and the comparator, wherein the DAC generates the feedback signal at least in partial dependence upon the digital signal;
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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
at least one of the actuators comprises more than one actuator element, and the sensor comprises more than one sensor element.
-
-
12. 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. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
an adder coupled to the differentiator and to the comparator, wherein the adder generates a sum signal that is the sum of the intermediate signal and a multiple of the digital signal; - and
a digital-to-analog converter (DAC) electrically coupled between the second actuator and the adder, wherein the DAC generates the feedback signal based upon the sum signal such that the feedback signal includes both the first analog signal component based upon the intermediate signal and the second analog signal component based upon the digital signal.
-
-
23. The isolated-ADC of claim 22, wherein the DAC is a two-bit DAC.
-
24. The isolated-ADC of claim 22, wherein the comparator, the differentiator, the adder, the DAC and the processing device are all implemented on a single application specific integrated circuit (ASIC) chip.
-
25. The isolated ADC of claim 12, further comprising
a first digital-to-analog converter (DAC) electrically coupled to the differentiator, wherein the first DAC converts the intermediate signal into the first analog signal component; - and
a second DAC electrically coupled to the comparator, wherein the second DAC converts the digital signal into the second analog signal component.
- and
-
26. The isolated ADC of claim 25, further comprising
an adder coupled between the second actuator and the first and second DACs, wherein the adder sums the first and second analog signal components to generate the first feedback signal such that the first feedback signal includes both the first and second analog signal components, and wherein each of the first and second DACs are single-bit DACs. -
27. The isolated ADC of claim 25, wherein the MEMS further includes a third actuator attached to the beam element, wherein the third actuator is capable of exerting a third force upon the beam element based upon a second feedback signal, wherein the first feedback signal is the first analog signal component and the second feedback signal is the second analog signal component, and wherein each of the first and second DACs are single-bit DACs.
-
28. 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. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
-
-
42. 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. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
at least one of the actuators comprises more than one actuator element, and the sensor comprises more than one sensor element.
-
-
51. The isolated-ADC of claim 42, wherein the beam element is a beam attached to the substrate for sliding motion along the axis, wherein the axis is parallel to an adjacent surface of the substrate, and wherein at least a portion of the beam element between the first actuator and the sensor is an electrical insulator to electrically isolate the first actuator from the sensor.
-
52. The isolated-ADC of claim 42, wherein the MEMS further includes a damping element.
-
53. The isolated-ADC of claim 42, wherein the differential amplifier, the comparator bias circuit, the DAC, and a processing device employed to generate the digital output signal are all implemented on an application specific integrated circuit (ASIC) chip.
-
54. 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. - View Dependent Claims (55, 56, 57)
second and third comparators that are each electrically coupled to the sensor, 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; and
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, wherein the feedback bitstream signal is provided to the DAC.
-
-
57. The isolated-ADC of claim 56, further comprising a differential amplifier and a comparator bias circuit that includes the comparator, wherein the differential amplifier is coupled between the sensor and the comparator bias circuit.
-
58. 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.
-
-
59. 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. - View Dependent Claims (60, 61, 62, 63, 64, 65, 66)
comparing the sensed position with a first offset value, and with a second offset value;
generating second and third digital signals in response to the comparing of the position with the first and second offset values, respectively, wherein the first, second and third digital signals are respectively at high levels while the sensed position is determined to be greater than the reference value, the first offset value and the second offset value, and wherein the first, second and third digital signals are respectively at low levels while the sensed position is determined to be less than the reference value, the first offset value and the second offset value;
processing at a logical decision device the first, second and third 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).
-
-
63. The method of claim 62, further comprising:
-
setting the first offset value equal to the position upon the occurrence of a period following a time at which the position changes from being below the reference value to being above the reference value; and
setting the second offset value equal to the position upon the occurrence of the first period following a time at which the position changes from being above the reference value to being below the reference value.
-
-
64. The method of claim 61, further comprising:
-
comparing the sensed position with a plurality of offset values at a plurality of respective comparators;
generating a plurality of additional digital signals in response to the comparing of the position with the plurality of offset values, respectively;
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).
-
-
65. The method of claim 61, wherein each of the first and second actuators is a Lorentz force motor, and wherein the sensor is selected from the group consisting of a capacitive sensor, a piezoelectric sensor, a photoelectric sensor, a resistive sensor, and an optical switching sensor.
-
66. The method of claim 61, wherein each of the first and second actuators is selected from the group consisting of:
- a Lorentz force motor, an electrostatic motor, a piezoelectric motor, a thermal-expansion motor, and a mechanical-displacement motor, and wherein the sensor is selected from the group consisting of a capacitive sensor, a piezoelectric sensor, a photoelectric sensor, a resistive sensor, and an optical switching sensor.
-
67. 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. - View Dependent Claims (68, 69, 70, 71)
-
-
72. 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).
-
-
73. 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. - View Dependent Claims (74, 75, 76)
-
-
77. 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. - View Dependent Claims (78, 79)
-
Specification