Piezoelectric-based MEMS device with time-sharing actuation and sensing circuit arrangement

Abstract

Embodiments of the present disclosure relate to a piezoelectric-based MEMS device with a time-sharing actuation and sensing circuit device. The MEMS device includes a rotating body and a first piezoelectric actuator mechanically coupled to the rotating body. The first piezoelectric actuator is electrically coupled between a first signal node and a common voltage node. The second piezoelectric actuator is mechanically coupled to the rotating body and electrically coupled between a second signal node and a common voltage node. The control circuit device includes: a drive circuit configured to drive the first piezoelectric actuator and the second piezoelectric actuator; a sensing circuit configured to process sensing signals generated by the first piezoelectric actuator and the second piezoelectric actuator; and a multiplexing circuit. The multiplexing circuit is configured to alternate between connecting the sensing circuit to the second piezoelectric actuator while connecting the drive circuit to the first piezoelectric actuator and connecting the sensing circuit to the first piezoelectric actuator while connecting the drive circuit to the second piezoelectric actuator.

Description

Technical Field

[0001] The present disclosure relates to the field of micro-electromechanical systems (MEMS) devices, and, in particular, to MEMS devices that time-share between drive circuitry and sense circuitry using the same piezoelectric device having both actuator and sensor functionality. Background Art

[0002] Microelectromechanical systems (MEMS) devices, such as mirrors, are used in portable devices like virtual or augmented reality headsets, laser beam scanners, and distance measurement devices.

[0003] For example, Figure 1 is a schematic diagram of a laser beam scanner 9 comprising a light source 1, such as a laser source, generating a combined light beam 2 formed of three monochromatic light beams, each corresponding to a primary color, which monochromatic light beams pass through an optical system 3 and are deflected by a mirror device 5 (which may be a biaxial mirror or two uniaxial mirrors) towards an exit window 6. In the example shown, the mirror element 5 is uniaxial, controlled to rotate about a vertical axis A and a horizontal axis B. The rotation of the mirror device 5 about the vertical axis A produces a horizontal scan. If the mirror device 5 comprises a second uniaxial mirror rotatable about a horizontal axis B, or if the mirror device 5 is a biaxial mirror, the rotation of the mirror device 5 about a horizontal axis B orthogonal to the vertical axis A will produce a vertical scan.

[0004] See also Figure 2 , the rotation of the mirror device 5 about the vertical axis A (and the horizontal axis B, if the mirror device 5 is so capable) can be achieved by piezoelectric actuation, and the combination of horizontal and vertical scanning is used to reflect the combined light beam 2 through the exit window 6 in a scanning pattern 7, which, when perceived by the human eye, generates a visible image and video. If the light source emits invisible light, such as an infrared laser beam, the scanning pattern 7 will not be perceived by the human eye, but will still be expected to achieve the intended function. It is also noted that when the mirror device 5 is uniaxial, it is used to reflect light through the exit window 6 in a one-dimensional pattern.

[0005] In order to determine whether the generated scanning pattern 7 matches the expected and desired scanning pattern, the mirror arrangement 5 has one or more position sensors associated therewith which allow the amount of deflection of the mirror arrangement 5 along the vertical axis A (and the horizontal axis B, if the mirror arrangement 5 is capable of such deflection) in both positive and negative directions to be detected. The information provided by these sensors is used by the drive circuitry for actuating the piezoelectric device of the mirror arrangement 5, or by the control circuitry which instructs the drive circuitry, as feedback to adjust the drive of the mirror arrangement 5, thereby helping to ensure that the generated scanning pattern 7 matches the expected and desired scanning pattern.

[0006] However, the use of such dedicated sensors and the provision of pads and electrical connections associated with such sensors consumes space on the die that would preferably be used for other components, or simply eliminated to save costs or produce a smaller die. That said, as mentioned above, the feedback information provided by such sensors is expensive. Therefore, there is a need for further development of designs that provide for such sensing while consuming less space and reducing manufacturing costs. Summary of the invention

[0007] A microelectromechanical (MEMS) device is disclosed herein, including a rotating body and a piezoelectric actuator mechanically coupled to the rotating body, the piezoelectric actuator being electrically coupled between a signal node and a reference node. The MEMS device has a control circuit device, which includes: a mirror drive circuit device configured to generate a drive pulse for the piezoelectric actuator on the signal node, a sensing circuit device configured to receive a sensing signal from the piezoelectric actuator, and a multiplexing circuit. The multiplexing circuit is configured to couple the drive pulse generated for the piezoelectric actuator to the piezoelectric actuator during a first portion of a motion cycle to cause a deflection of the rotating body, and to couple the sensing signal received from the piezoelectric actuator to the sensing circuit device during a second portion of the motion cycle.

[0008] The sensing circuitry may include current-to-voltage conversion circuitry configured to convert the sensing signal into a voltage signal.

[0009] The control circuitry may further comprise processing circuitry configured to generate a control signal for the mirror drive circuitry in response to the sense signal, the control signal adjusting properties of the drive pulses for the piezoelectric actuator.

[0010] The semiconductor body may have a cavity defined therein, the rotating body being suspended over the cavity by the piezoelectric actuator.

[0011] The piezoelectric actuator may be formed from lead zirconate titanate (PZT) or doped lead zirconate titanate (PZT).

[0012] In another embodiment, the MEMS device may include: a rotating body; and a first plurality of piezoelectric actuators mechanically coupled to the rotating body, the first plurality of piezoelectric actuators being electrically coupled between a first signal node and a common voltage node. The MEMS device may also include a second plurality of piezoelectric actuators mechanically coupled to the rotating body, the second plurality of piezoelectric actuators being electrically coupled between a second signal node and a common voltage node. The MEMS device may have a control circuit device, which includes: a mirror drive circuit device, configured to alternately generate drive pulses for a first plurality of piezoelectric actuators on a first signal node and drive pulses for a second plurality of piezoelectric actuators on a second signal node; a sensing circuit device, configured to alternately receive sensing signals from the second plurality of piezoelectric actuators and sensing signals from the first plurality of piezoelectric actuators; a first multiplexing circuit, configured to couple the drive pulses generated for the second plurality of piezoelectric actuators to the second plurality of piezoelectric actuators, while the second multiplexing circuit couples the sensing signals received from the first plurality of piezoelectric actuators to the sensing circuit device, and the second multiplexing circuit may be configured to couple the drive pulses generated for the first plurality of piezoelectric actuators to the first plurality of piezoelectric actuators, while the first multiplexing circuit couples the sensing signals received from the second plurality of piezoelectric actuators to the sensing circuit device.

[0013] The first plurality of piezoelectric actuators may include a first pair of piezoelectric actuators mechanically coupled to opposite sides of the rotating body; and the second plurality of piezoelectric actuators may include a second pair of piezoelectric actuators also mechanically coupled to opposite sides of the rotating body.

[0014] The sensing circuitry may include current-to-voltage conversion circuitry that converts the sensing signal into a voltage signal.

[0015] The control circuit device may also include a processing circuit device, which is configured to generate a control signal for the mirror drive circuit device in response to the sensing signal, wherein the control signal adjusts the performance of the drive pulses for the first plurality of piezoelectric actuators and the drive pulses for the second plurality of piezoelectric actuators.

[0016] The control circuit device may further include a synchronization circuit device, which is configured to control the first multiplexing circuit and the second multiplexing circuit so as to achieve: the first multiplexing circuit couples the driving pulses generated for the second plurality of piezoelectric actuators to the second plurality of piezoelectric actuators, while the second multiplexing circuit couples the sensing signals received from the first plurality of piezoelectric actuators to the sensing circuit device, and the second multiplexing circuit couples the driving pulses generated for the first plurality of piezoelectric actuators to the first plurality of piezoelectric actuators, while the first multiplexing circuit couples the sensing signals received from the second plurality of piezoelectric actuators to the sensing circuit device.

[0017] The control circuitry may further comprise common mode voltage generating circuitry configured to generate a common mode voltage at the common voltage node.

[0018] The semiconductor body may have a cavity defined therein, and the rotating body may be suspended over the cavity by the first plurality of piezoelectric actuators and the second plurality of piezoelectric actuators.

[0019] The first plurality of piezoelectric actuators and the second plurality of piezoelectric actuators may be comprised of lead zirconate titanate (PZT) or doped lead zirconate titanate (PZT).

[0020] Aspects of the method described herein include electrically coupling a drive circuit device to a first plurality of piezoelectric actuators while electrically coupling a second plurality of piezoelectric actuators to a sensing circuit device during a first half cycle, and electrically coupling the drive circuit device to the second plurality of piezoelectric actuators while electrically coupling the first plurality of piezoelectric actuators to a sensing circuit device during a second half cycle.

[0021] The method may further include: during a first half cycle, using a driving circuit device to generate driving pulses for a first plurality of piezoelectric actuators, and using a sensing circuit device to detect the deflection of a rotating body mechanically coupled to the first plurality of piezoelectric actuators and a second plurality of piezoelectric actuators; and during a second half cycle, using a driving circuit device to generate driving pulses for a second plurality of piezoelectric actuators, and using a sensing circuit device to detect the deflection of the rotating body.

[0022] The method may further include adjusting drive pulses for the first plurality of piezoelectric actuators based on deflection of the rotating body during the first half cycle, and adjusting drive pulses for the second plurality of piezoelectric actuators based on deflection of the rotating body during the second half cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of a laser beam scanner of the prior art.

[0024] Figure 2 When Figure 1 A schematic diagram of a scanning pattern generated by a prior art laser beam scanner when scanning an incident light beam passing through an exit window.

[0025] Figure 3 is a block diagram of control circuitry and drive circuitry for a MEMS device as described herein.

[0026] Figure 4 A graph including a first driving signal and a second driving signal and a first sensing signal and a second sensing signal, Figure 3The control circuitry and the drive circuitry use these signals for driving the MEMS device and sensing the position of the MEMS device. DETAILED DESCRIPTION

[0027] The following disclosure enables those skilled in the art to make and use the subject matter disclosed herein. Without departing from the spirit and scope of the present disclosure, the general principles described herein may be applied to embodiments and applications other than those described in detail above. The present disclosure is not intended to be limited to the embodiments shown, but is intended to conform to the maximum scope consistent with the principles and features disclosed or suggested herein.

[0028] Reference now Figure 3 A microelectromechanical (MEMS) device 9 is depicted, comprising a MEMS mirror 10 and control circuitry 19 for the MEMS mirror 10. As will be described in detail below, the MEMS mirror 10 uses the same piezoelectric region as both an actuator and a position sensor. In some applications, the MEMS mirror may lack a dedicated position sensor.

[0029] More specifically, the MEMS mirror 10 is formed in a semiconductor body 21 and comprises a rotating body 11 which is covered with a reflective material and has a main extension in a horizontal plane XY and can rotate about a first symmetry axis X parallel to the horizontal plane XY. The second symmetry axis Y is orthogonal to the first symmetry axis X and defines the horizontal plane XY together with the first symmetry axis X.

[0030] More details of the MEMS mirror 10 will now be given, but it should be noted that the details of the MEMS mirror 10 shown and described are not intended to be limiting, and the techniques described herein can be applied to MEMS mirrors 10 having rotating bodies and / or reflective surfaces of any shape (e.g., circular, rectangular, etc.).

[0031] The rotating body 11 is suspended on a cavity 21 defined in a semiconductor body 26 and, in the embodiment shown, has a substantially elliptical shape in a horizontal plane XY, with the main axis arranged along a first axis of symmetry X. The rotating body 11 is elastically coupled to a fixing structure 38 defined in the same semiconductor body 26. In particular, the fixing structure 38 forms a frame in the horizontal plane XY, which delimits and surrounds the cavity 21 and furthermore has a first support element 35a and a second support element 35b which extend longitudinally along the first axis of symmetry X inside the cavity 21 starting from the same frame on opposite sides of the rotating body 11.

[0032] The rotating body 11 is supported by a first support element 35a and a second support element 35b, to which the rotating body 11 is elastically coupled by first and second elastic suspension elements 36a and 36b, which have high stiffness to move out of the horizontal plane XY (along an orthogonal axis Z, transverse to the horizontal plane XY) and to comply with torsion about a first axis X). The first and second elastic suspension elements 36a and 36b extend along a first symmetry axis X between the support element 35a and a first side of the rotating body 11 and between the support element 35b and a second side of the rotating body 11.

[0033] In the embodiment shown, the first elastic suspension element 36a and the second elastic suspension element 36b are of the folding type, i.e. they are formed by a plurality of arms having a longitudinal extension parallel to the first axis X, which are connected two by two at the ends by connecting elements having an extension parallel to the second horizontal axis Y. The first elastic suspension element 36a and the second elastic suspension element 36b couple the rotating body 11 to the fixed structure 38 so that it can rotate about the first axis X.

[0034] The drive arms 39a-39d contribute to connecting the rotating body 11 to the fixed structure 38. The drive arms 39a and 39d are arranged on opposite sides of the first axis X and symmetrically about the first axis X; similarly, the drive arms 39b and 39c are arranged on opposite sides of the first axis X and symmetrically about the first axis X. The drive arms 39a, 39d and the drive arms 39b, 39c are arranged on opposite sides of the second axis Y and symmetrically about the second axis Y. The drive arms 39a-39d each have a longitudinal extension parallel to the first axis X and parallel to the support elements 35a and 35b.

[0035] The drive arms 39a-39d each have a generally trapezoidal (or fin-like) shape, with a major side oriented parallel to the first axis X, with a minor side oriented parallel to the second axis Y, and are fixedly coupled to the frame of the fixed structure 38. Each drive arm 39a-39d is suspended on the cavity 21 and carries a corresponding piezoelectric region 12a-12d on its top surface opposite to the cavity 21. The piezoelectric regions 12a-12d may be formed of lead zirconate titanate (PZT) or doped lead zirconate titanate or other suitable piezoelectric material and have substantially the same extension in the horizontal plane XY as the drive arms 39a-39d.

[0036] Piezoelectric regions 12a and 12b are electrically connected by metal trace 22a between signal pad 23a and common mode voltage pad 24a, and piezoelectric regions 12c and 12d are electrically connected by metal trace 22b between signal pad 23b and common mode voltage pad 24b.

[0037] The control circuit device 19 includes a first analog multiplexer 17a electrically connected to the signal pad 23a and a second analog multiplexer 17b electrically connected to the signal pad 23b. The mirror driver circuit 14 receives input via a drive bus and provides a drive signal as an output to the analog multiplexers 17a and 17b. The transimpedance amplifier (e.g., a current-to-voltage converter) 13 receives the output from the analog multiplexers 17a and 17b as input and provides an output to the sense bus. The synchronization circuit 16 provides control signals to the analog multiplexers 17a and 17b and the mirror driver 14. The common mode voltage generation circuit 15 provides a common mode voltage to the common mode voltage pads 24a and 24b and the mirror driver 14 and the synchronization circuit 16.

[0038] See also Figure 4 , the operation of the MEMS device 9 will now be described. During a given time period Tmems, the drive signal will be alternately pulsed, and each pulse lasts for one-half of the given time period Tmems / 2. When the first drive signal is pulsed through the analog multiplexer 17b (in response to the control signal from the synchronization circuit 16) and fed to the piezoelectric regions 12c and 12d to drive the piezoelectric regions to cause the deflection of the rotating body 11 around the X-axis, the sensing signal is transmitted from the piezoelectric regions 12a and 12b to the sensing bus through the analog multiplexer 17a (in response to the control signal from the synchronization circuit 16); on the contrary, when the second drive signal is pulsed through the analog multiplexer 17a (in response to the control signal from the synchronization circuit 16) and fed to the piezoelectric regions 12a and 12b to drive the piezoelectric regions to cause the deflection of the rotating body 11, the sensing signal is transmitted from the piezoelectric regions 12c and 12d to the sensing bus through the analog multiplexer 17b (in response to the control signal from the synchronization circuit 16).

[0039] This operation may be attributed to: (1) the properties of the piezoelectric material, which changes shape (e.g., contracts) when a voltage is applied thereto and generates a voltage when there is a mechanical change in shape (e.g., when contracted due to external pressure), and (2) the timing of the piezoelectric regions 12a-12d by the control circuit device 19 (e.g., when a drive voltage is applied to the piezoelectric regions 12a and 12b, this in turn causes the rotating body 11 to deflect and the piezoelectric regions 12c and 12d to subsequently stretch, and a sensing signal is read from the piezoelectric regions 12c and 12d; and when a drive voltage is applied to the piezoelectric regions 12c and 12d, this in turn causes the rotating body 11 to deflect and the piezoelectric regions 12a and 12b to subsequently stretch, and a sensing signal is read from the piezoelectric regions 12a and 12b).

[0040] The sense signals are read by processing circuitry 25 and used as feedback for generating and adjusting control signals over the drive bus to the mirror driver 14, thereby allowing processing circuitry 25 to help ensure that the degree of deflection of the rotating body 11 in each direction matches the desired degree of deflection.

[0041] As can be understood from the above description, the MEMS device 9 provides the same feedback (sensing signals from the piezoelectric regions 12a-12d) as a prior art MEMS device that utilizes a dedicated position sensor, but does not use such a dedicated position sensor, saving space on the semiconductor body 21. This also reduces the number of pins and wiring conductors, further saving space.

[0042] Although the above has been described with reference to a MEMS device 9 having four piezoelectric regions 12a-12d shown and described, it will be appreciated that there may be any number of piezoelectric regions of any shape and any layout (e.g., there may be only one piezoelectric region, or there may be multiple piezoelectric regions). In any case, the same principles apply, wherein the motion cycle of the MEMS device for each piezoelectric region is divided into a drive phase (during which the piezoelectric region is connected to a drive circuit) and a sense phase (during which the piezoelectric region is connected to a sense circuit), wherein it will be appreciated that where there are multiple piezoelectric regions, their drive phases and sense phases may be in phase or anti-phase with each other depending on their position around the rotating body.

[0043] It should also be understood that this time sharing and time division can be applied to other MEMS device types, such as electrostatically actuated MEMS devices. In this case, the motion cycle of the MEMS device is still divided into a drive phase (during which the drive circuit is connected to the stator or rotating body) and a sense phase (during which the sense circuit is connected to the fixed body or rotating body).

[0044] While the present disclosure has been described with respect to a limited number of embodiments, those skilled in the art having benefit of this disclosure will appreciate that other embodiments may be conceived without departing from the scope of the present disclosure as disclosed herein. Accordingly, the scope of the present disclosure shall be limited solely by the appended claims.

Claims

1. A micro-electromechanical (MEMS) device, comprising: Rotating body; a first plurality of piezoelectric actuators mechanically coupled to the rotating body, the first plurality of piezoelectric actuators being electrically coupled between a first signal node and a common voltage node; a second plurality of piezoelectric actuators mechanically coupled to the rotating body, the second plurality of piezoelectric actuators electrically coupled between a second signal node and a common voltage node; as well as A control circuit device comprising: a mirror drive circuit arrangement configured to alternately generate drive pulses for the first plurality of piezoelectric actuators on the first signal node and drive pulses for the second plurality of piezoelectric actuators on the second signal node; a sensing circuit arrangement configured to alternately receive sensing signals from the second plurality of piezoelectric actuators and sensing signals from the first plurality of piezoelectric actuators; a first multiplexing circuit configured to couple the drive pulses generated for the second plurality of piezoelectric actuators to the second plurality of piezoelectric actuators while the second multiplexing circuit couples sense signals received from the first plurality of piezoelectric actuators to the sense circuitry; and The second multiplexing circuit is configured to couple the drive pulses generated for the first plurality of piezoelectric actuators to the first plurality of piezoelectric actuators, while the first multiplexing circuit couples the sense signals received from the second plurality of piezoelectric actuators to the sense circuit device.

2. The MEMS device of claim 1 , wherein the first plurality of piezoelectric actuators comprises a first pair of piezoelectric actuators mechanically coupled to opposite sides of the rotating body; and wherein the second plurality of piezoelectric actuators comprises a second pair of piezoelectric actuators also mechanically coupled to opposite sides of the rotating body. 3 . The MEMS device of claim 1 , wherein the sensing circuitry comprises current-to-voltage conversion circuitry configured to convert the sensing signal into a voltage signal.

4. A MEMS device according to claim 1, wherein the control circuit device further includes a processing circuit device, and the processing circuit device is configured to generate a control signal for the mirror drive circuit device in response to the sensing signal, wherein the control signal adjusts the performance of the drive pulse for the first plurality of piezoelectric actuators and the performance of the drive pulse for the second plurality of piezoelectric actuators.

5. The MEMS device according to claim 1, wherein the control circuit device further includes a synchronization circuit device, which is configured to control the first multiplexing circuit and the second multiplexing circuit so as to achieve: the first multiplexing circuit couples the driving pulses generated for the second plurality of piezoelectric actuators to the second plurality of piezoelectric actuators, and at the same time the second multiplexing circuit couples the sensing signals received from the first plurality of piezoelectric actuators to the sensing circuit device, and the second multiplexing circuit couples the driving pulses generated for the first plurality of piezoelectric actuators to the first plurality of piezoelectric actuators, and at the same time the first multiplexing circuit couples the sensing signals received from the second plurality of piezoelectric actuators to the sensing circuit device. 6 . The MEMS device of claim 1 , wherein the control circuitry further comprises common-mode voltage generating circuitry configured to generate a common-mode voltage at the common voltage node. 7 . The MEMS device of claim 1 , further comprising a semiconductor body having a cavity defined therein, wherein the rotating body is suspended over the cavity by the first plurality of piezoelectric actuators and the second plurality of piezoelectric actuators.

8. The MEMS device of claim 1, wherein the first plurality of piezoelectric actuators and the second plurality of piezoelectric actuators are comprised of lead zirconate titanate (PZT) or doped lead zirconate titanate (PZT).

9. A method for operating a micro-electromechanical (MEMS) device, comprising: During a first half cycle, electrically coupling the drive circuitry to the first plurality of piezoelectric actuators while electrically coupling the second plurality of piezoelectric actuators to the sense circuitry; as well as During a second half cycle, the drive circuitry is electrically coupled to the second plurality of piezoelectric actuators while the first plurality of piezoelectric actuators are electrically coupled to the sensing circuitry.

10. The method according to claim 9, further comprising: generating drive pulses for the first plurality of piezoelectric actuators using the drive circuit arrangement during the first half cycle, and detecting deflection of a rotating body mechanically coupled to the first plurality of piezoelectric actuators and the second plurality of piezoelectric actuators using the sense circuit arrangement; as well as During the second half period, drive pulses for the second plurality of piezoelectric actuators are generated using the drive circuit arrangement, and deflection of the rotating body is detected using the sense circuit arrangement.

11. The method of claim 10, further comprising adjusting the drive pulses for the first plurality of piezoelectric actuators based on the deflection of the rotating body during the first half cycle, and adjusting the drive pulses for the second plurality of piezoelectric actuators based on the deflection of the rotating body during the second half cycle.

12. A micro-electromechanical (MEMS) device, comprising: Rotating body; a first piezoelectric actuator mechanically coupled to the rotating body, the first piezoelectric actuator being electrically coupled between a first signal node and a common voltage node; a second piezoelectric actuator mechanically coupled to the rotating body, the second piezoelectric actuator being electrically coupled between a second signal node and the common voltage node; as well as A control circuit device comprising: a driving circuit configured to drive the first piezoelectric actuator and the second piezoelectric actuator; a sensing circuit configured to process sensing signals generated by the first piezoelectric actuator and the second piezoelectric actuator; and A multiplexing circuit is configured to alternate between: connecting the drive circuit to the first piezoelectric actuator while connecting the sense circuit to the second piezoelectric actuator; and connecting the drive circuit to the second piezoelectric actuator while connecting the sense circuit to the first piezoelectric actuator. 13 . The MEMS device of claim 12 , wherein the first piezoelectric actuator and the second piezoelectric actuator are mechanically coupled on the same side of the rotating body but are opposite to each other about the axis of the rotating body. 14 . The MEMS device of claim 12 , wherein the sensing circuit comprises a current-to-voltage conversion circuit device configured to convert the sensing signal into a voltage signal.

15. The MEMS device of claim 12, wherein the control circuit device further comprises a processing circuit device, wherein the processing circuit device is configured to generate a control signal for the drive circuit in response to the sensing signal, wherein the control signal adjusts the performance of the drive circuit driving the first piezoelectric actuator and the second piezoelectric actuator. 16 . The MEMS device of claim 12 , wherein the first piezoelectric actuator and the second piezoelectric actuator are formed of lead zirconate titanate (PZT) or doped lead zirconate titanate (PZT).

17. A micro-electromechanical (MEMS) device, comprising: Rotating body; a piezoelectric actuator mechanically coupled to the rotating body, the piezoelectric actuator being electrically coupled between a signal node and a reference node; as well as A control circuit device comprising: a mirror drive circuit arrangement configured to generate a drive pulse for the piezoelectric actuator on the signal node; a sensing circuit device configured to receive a sensing signal from the piezoelectric actuator; and The multiplexing circuit is configured as: coupling the drive pulse generated for the piezoelectric actuator to the piezoelectric actuator during a first portion of a motion cycle to cause deflection of the rotating body; and The sense signal received from the piezoelectric actuator is coupled to the sense circuitry during a second portion of the motion cycle. 18 . The MEMS device of claim 17 , wherein the sensing circuitry comprises current-to-voltage conversion circuitry configured to convert the sensing signal into a voltage signal.

19. A MEMS device according to claim 17, wherein the control circuit device further includes a processing circuit device, and the processing circuit device is configured to generate a control signal for the mirror drive circuit device in response to the sensing signal, wherein the control signal adjusts the performance of the drive pulse for the piezoelectric actuator.

20. The MEMS device of claim 17, further comprising a semiconductor body having a cavity defined therein, wherein the rotating body is suspended above the cavity by the piezoelectric actuator.

21. The MEMS device of claim 17, wherein the piezoelectric actuator is comprised of lead zirconate titanate (PZT) or doped lead zirconate titanate (PZT).

Images