Round-robin sensing device and method of use
A round-robin sensing device is disclosed. The round-robin sensing device comprises a MEMS device, wherein the MEMS device includes first and second sense electrodes. The round-robin sensing device also comprises a multiplexer coupled to the first and second sense electrodes, at least one sense amplifier coupled to the multiplexer, a demodulator coupled to the at least one sense amplifier, and an integrate and dump circuit coupled to the demodulator. Finally, the round-robin sensing device comprises an analog-to-digital converter (ADC) coupled to the de-multiplexer, wherein the multiplexer, the at least one sense amplifier and the demodulator provide a continuous time sense path during amplification that is resettable and wherein the integrate and dump circuit and the ADC provide a discrete time processing path.
1. A round-robin sensing device comprising:
a MEMS device; wherein the MEMS device includes first and second sense electrodes;
a multiplexer coupled to the first and second sense electrodes;
at least one sense amplifier coupled to the multiplexer;
a demodulator coupled to the at least one sense amplifier;
an integrate and dump circuit coupled to the demodulator; and
an analog-to-digital converter (ADC) coupled to a de-multiplexer; wherein the multiplexer, the at least one sense amplifier and the demodulator provide a continuous time sense path during amplification that is resettable and wherein the integrate and dump circuit and the ADC provide a discrete time processing path when switching between the first and second sense electrodes.
2. The round-robin sensing device of claim 1 , wherein the first sense electrode senses in a first axis and the second electrode senses in a second axis.
3. The round-robin sensing device of claim 1 , wherein the round-robin sensing device comprises a multi-axis gyroscope.
4. The round-robin sensing device of claim 3 , further comprising a drive system for driving the MEMS device.
5. The round-robin sensing device of claim 4 , further comprising a feed-through capacitor coupled to drive system and the at least one sense amplifier.
6. The round-robin sensing device of claim 1 , wherein the at least one sense amplifier comprises first and second sense amplifiers.
7. The round-robin sensing device of claim 6 , wherein the first sense amplifier includes a first operational amplifier coupled to the multiplexer, a first reset switch and a first feedback capacitor coupled in feedback relationship to the first operational amplifier.
8. The round-robin sensing device of claim 6 , wherein the second sense amplifier includes an input capacitor coupled to the first sense amplifier, a second operational amplifier coupled to the input capacitor, a second reset switch and a second feedback capacitor coupled in feedback relationship with the second operational amplifier.
9. The round-robin sensing device of claim 1 , wherein the integrate and dump circuit comprises:
an input de-multiplexer;
a first and a second integrator coupled to the input de-multiplexer; and
a multiplexer coupled to an output of the first and second integrators.
10. The round-robin sensing device of claim 9 , wherein each of the first and second integrators comprises:
a resistor coupled to the input de-multiplexer;
an operational amplifier coupled to the resistor;
a reset switch coupled in feedback relationship with the operational amplifier; and
a capacitor coupled in feedback relationship with the operational amplifier.
11. The round-robin sensing device of claim 9 , wherein the input de-multiplexer includes a resistor and each of the first and second integrators comprises:
an operational amplifier coupled to the input de-multiplexer;
a reset switch coupled in feedback relationship with the operational amplifier; and
a capacitor coupled in feedback relationship with the operational amplifier.
12. A round-robin sensing device comprising:
a MEMS device; wherein the MEMS device includes first and second sense electrodes;
a plurality of sense amplifiers adapted to be selectively coupled to the first and second sense electrodes;
a demodulator coupled to the plurality of sense amplifiers;
an integrate and dump circuit coupled to the demodulator; and
an analog-to-digital converter (ADC) coupled to a de-multiplexer; wherein the de-multiplexer, the plurality of sense amplifiers and the demodulator provide a continuous time sense path during amplification that is resettable and wherein the integrate and dump circuit and the ADC provide a discrete time processing path when switching between the first and second sense electrodes.
13. The round-robin sensing device of claim 12 , wherein the first sense electrode senses in a first axis and the second electrode senses in a second axis.
14. The round-robin sensing device of claim 12 , wherein the plurality of sense amplifiers comprises first and second sensor amplifiers.
15. The round-robin sensing device of claim 12 , wherein each of the plurality of sense amplifiers includes a first operational amplifier coupled to one of the first and second sense electrodes, a reset switch and a first feedback capacitor coupled in feedback relationship to the first operational amplifier.
16. The round-robin sensing device of claim 12 , wherein the round-robin sensing device comprises a multi-axis gyroscope.
17. The round-robin sensing device of claim 16 , further comprising a drive system for driving the MEMS device.
18. The round-robin sensing device of claim 17 , further comprising a feed-through capacitor coupled to drive system and the at least one sense amplifier.
19. The round-robin sensing device of claim 12 , wherein the integrate and dump circuit comprises:
an input de-multiplexer;
first and second integrators coupled to the input de-multiplexer; and
a multiplexer coupled to an output of the first and second integrators.
20. The round-robin sensing device of claim 19 , wherein each of the first and second integrators comprises:
a resistor coupled to the input de-multiplexer;
an operational amplifier coupled to the resistor;
a reset switch coupled in feedback relationship with the operational amplifier; and
a capacitor coupled in feedback relationship with the operational amplifier.
21. The round-robin sensing device of claim 19 , wherein the input de-multiplexer includes a resistor and each of the first and second integrators comprises:
an operational amplifier coupled to the input de-multiplexer;
a reset switch coupled in feedback relationship with the operational amplifier; and
a capacitor coupled in feedback relationship with the operational amplifier.