A single-line drive circuit enables identical actuator orientation.

Abstract

A drive circuit is described. The drive circuit includes a first piezoelectric actuator including one or more piezoelectric elements disposed between a first electrode and a second electrode. The first electrode is configured to be connected to a first ground at a first terminal, and the second electrode is configured to be connected to an amplifier at a second terminal. The drive circuit includes a second piezoelectric actuator including one or more piezoelectric elements disposed between the first electrode and the second electrode. The first electrode is configured to be connected to a control signal at the first terminal, and the second electrode is connected to a second ground at the second terminal. The first terminal of the first piezoelectric actuator and the first terminal of the second piezoelectric actuator are configured such that the first piezoelectric actuator and the second piezoelectric actuator are symmetrical and have the same polarity.

Description

Technical Field

[0001] The present disclosure relates to the field of piezoelectric actuators. More particularly, the present disclosure relates to improving the performance of piezoelectric actuators.

Background Art

[0002] As a type of information storage device, hard disk drives are well known. A hard disk drive generally includes one or more magnetic disks rotatably attached to a spindle and one or more actuator assemblies for positioning a magnetic transducer, i.e., a head, with respect to concentric data tracks on the magnetic media carrying surface of each disk.

[0003] With the advancement of personal computers, the recording density of hard disk drives has increased, so that data tracks are increasingly arranged at higher density on the disk and the tracks themselves have become physically narrower. As a result, it has become more difficult to maintain the transducer, i.e., the head, at an accurate track-following position for reading and writing. To cope with the more precise adjustments required in the positioning of magnetic heads, precision positioning actuators have been introduced. For such actuators, a single piezoelectric actuator assembly is generally used. The piezoelectric actuator forms part of a head gimbal assembly. The head gimbal assembly moves the head laterally with respect to the track to precisely position the head radially with respect to the track.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure relates to the field of piezoelectric actuators. More particularly, the present disclosure relates to improving the performance of piezoelectric actuators.

Means for Solving the Problems

[0005] A drive circuit is described. The drive circuit includes a first piezoelectric actuator, which includes one or more piezoelectric elements positioned between a first electrode and a second electrode. The first electrode is configured to be connected to a first ground at its first terminal, and the second electrode is configured to be connected to an amplifier at its second terminal. The drive circuit includes a second piezoelectric actuator, which includes one or more piezoelectric elements positioned between the first electrode and the second electrode. The first electrode is configured to be connected to a control signal at its first terminal, and the second electrode is connected to a second ground at its second terminal. The first terminal of the first piezoelectric actuator and the first terminal of the second piezoelectric actuator are configured to be symmetrical and have the same polarity.

[0006] In some examples of the drive circuit, the first piezoelectric actuator includes a first piezoelectric element, a second piezoelectric element, and a third piezoelectric element. The upper surface of the first piezoelectric element may be partially covered by a portion of the first electrode and a portion of the second electrode, with the second electrode covering more of the upper surface of the first piezoelectric element than the first electrode. The first and second piezoelectric elements are partially separated by the first electrode, which is connected to a first ground. The second and third piezoelectric elements may be partially separated by the second electrode. The lower surface of the third piezoelectric element may be partially covered by a portion of the first electrode and a portion of the second electrode, with the second electrode covering less of the lower surface of the third piezoelectric element than the first electrode.

[0007] In some examples of the drive circuit, the second piezoelectric actuator includes a first piezoelectric element, a second piezoelectric element, and a third piezoelectric element. The upper surface of the first piezoelectric element may be partially covered by a portion of the first electrode and a portion of the second electrode, with the second electrode covering more of the upper surface of the first piezoelectric element than the first electrode. The first and second piezoelectric elements are partially separated by the first electrode. The second and third piezoelectric elements may be partially separated by the second electrode. The lower surface of the third piezoelectric element may be partially covered by a portion of the first electrode and a portion of the second electrode, with the second electrode covering less of the lower surface of the third piezoelectric element than the first electrode.

[0008] In some examples of the drive circuit, the first piezoelectric actuator is configured to be driven in response to a control signal applied from an amplifier via a second terminal. In some examples of the drive circuit, the second piezoelectric actuator is configured to be driven in response to a control signal applied from an amplifier via a first terminal. In some examples, the drive circuit further includes a head slider. The head slider is precisely positioned radially by the first and second piezoelectric actuators having the same polarity and symmetry.

[0009] A suspension device is also provided. The suspension device includes a drive circuit including a first piezoelectric actuator, which includes one or more piezoelectric elements disposed between a first electrode and a second electrode. The first electrode is connected to a first ground at a first terminal, and the second electrode is connected to an amplifier at a second terminal. The drive circuit further includes a second piezoelectric actuator, which includes one or more piezoelectric elements disposed between the first electrode and the second electrode. The first electrode is connected to an amplifier at a first terminal, and the second electrode is connected to a second ground at a second terminal. The first terminal of the first piezoelectric actuator and the first terminal of the second piezoelectric actuator are arranged such that the first piezoelectric actuator and the second piezoelectric actuator have the same polarity and orientation.

[0010] Although several embodiments have been disclosed, further embodiments of this disclosure will become apparent to those skilled in the art from the following detailed description, which illustrates exemplary embodiments of this disclosure. Therefore, the drawings and detailed description should be considered illustrative and not restrictive in nature.

[0011] To illustrate how the above and other advantages and features of this disclosure are obtained, a more detailed explanation of the principles described above is given with reference to specific examples shown in the accompanying drawings. These drawings are merely illustrative of the embodiments of this disclosure and should not be construed as limiting its scope. The principles are described and explained in more specific and detail with reference to the following drawings. [Brief explanation of the drawing]

[0012] [Figure 1] A side cross-sectional view of a first piezoelectric actuator for a drive circuit, according to an example of the present disclosure. [Figure 2] A side cross-sectional view of a second piezoelectric actuator according to an example of the present disclosure. [Figure 3] A side cross-sectional view of a first piezoelectric actuator according to an example of the present disclosure. [Figure 4] A side cross-sectional view of a second piezoelectric actuator according to an example of the present disclosure. [Figure 5] A diagram showing a drive circuit architecture according to an example of this disclosure. [Figure 6] A side cross-sectional view of the first piezoelectric actuator of the drive circuit architecture shown in Figure 5, according to an example of this disclosure. [Figure 7] A side cross-sectional view of the second piezoelectric actuator of the drive circuit architecture shown in Figure 5, according to an example of this disclosure. [Figure 8] A graph of the PZT frequency response function of a suspension incorporating a drive circuit architecture, as shown in one example of this disclosure. [Figure 9] A graph of the PZT frequency response function of a suspension incorporating a drive circuit architecture, as shown in one example of this disclosure. [Figure 10] A table showing the stroke of a suspension incorporating a drive circuit according to one example of the foregoing disclosure, as described herein. [Figure 11] A graph comparing the PZT frequency response functions of the incorporated suspensions, based on simulations. [Modes for carrying out the invention]

[0013] Figure 1 shows a side cross-sectional view of a first piezoelectric actuator 120 having a first polarity. The first piezoelectric actuator 120 has a first electrode 112 configured to be connected to a first reference potential, for example, zero potential (ground, etc.). The first piezoelectric actuator 120 further has a second electrode 114 configured to be connected to a control signal 130. The first piezoelectric actuator 120 includes a first piezoelectric element 122, a second piezoelectric element 124, and a third piezoelectric element 126. The upper surface of the first piezoelectric element 122 is partially covered by a portion of the first electrode 112 and a portion of the second electrode 114. The second electrode 114 covers more of the upper surface of the first piezoelectric element 122 than the first electrode 112. The first piezoelectric element 122 and the second piezoelectric element 124 are partially separated by the first electrode 112. Also, the second piezoelectric element 124 and the third piezoelectric element 126 are partially separated by the second electrode 114. The lower surface of the third piezoelectric element 126 is partially covered by a portion of the first electrode 112 and a portion of the second electrode 114. The second electrode 114 covers less of the lower surface of the third piezoelectric element 126 than the first electrode 112.

[0014] Under the polarization direction shown in Figure 1, when a positive voltage is applied and the electric field is in the same direction as the polarization direction across the first electrode 112 and the second electrode 114, all three piezoelectric elements 122, 124, and 126 will extend in the longitudinal direction.

[0015] Figure 2 shows a side cross-sectional view of a second piezoelectric actuator 125 having a second polarity opposite to that of the first polarity. The second piezoelectric actuator 125 has a first electrode 116 configured to be connected to a first reference potential, for example, zero potential (second ground 180, etc.). The second piezoelectric actuator 125 further has a second electrode 118 connected to a control signal 130. The second piezoelectric actuator 125 includes a first piezoelectric element 132, a second piezoelectric element 134, and a third piezoelectric element 136. The upper surface of the first piezoelectric element 132 is partially covered by a portion of the first electrode 116 and a portion of the second electrode 118.

[0016] The second electrode 118 covers more of the upper surface of the first piezoelectric element 132 than the first electrode 116. The first piezoelectric element 132 and the second piezoelectric element 134 are partially separated by the first electrode 116. Also, the second piezoelectric element 134 and the third piezoelectric element 136 are partially separated by the second electrode 118. The lower surface of the third piezoelectric element 136 is partially covered by a part of the first electrode 116 and a part of the second electrode 118. The second electrode 118 covers less of the lower surface of the third piezoelectric element 136 than the first electrode 116.

[0017] When a positive voltage is applied under the polarization direction shown in FIG. 2, if the electric field is in the opposite direction to the polarization direction across the first electrode 116 and the second electrode 118, all three piezoelectric elements 132, 134, and 136 contract in the longitudinal direction.

[0018] FIG. 3 shows a side cross-sectional view of a first piezoelectric actuator 220 for a drive circuit. The first piezoelectric actuator 220 has a first electrode 212 configured to be connected to a first reference potential, for example, 0 volts (ground, etc.). The first piezoelectric actuator 220 further has a second electrode 214 connected to a control signal 230. The first piezoelectric actuator 220 includes a first piezoelectric element 222, a second piezoelectric element 224, and a third piezoelectric element 226. The upper surface of the first piezoelectric element 222 is partially covered by a part of the first electrode 212 and a part of the second electrode 214.

[0019] The second electrode 214 covers more of the upper surface of the first piezoelectric element 222 than the first electrode 212. The first piezoelectric element 222 and the second piezoelectric element 224 are partially separated by the first electrode 212. Also, the second piezoelectric element 224 and the third piezoelectric element 226 are partially separated by the second electrode 214. The lower surface of the third piezoelectric element 226 is partially covered by a part of the first electrode 212 and a part of the second electrode 214. The second electrode 214 covers less of the lower surface of the third piezoelectric element 226 than the first electrode 212.

[0020] Under the polarization direction shown in FIG. 3, when a positive voltage is applied and the electric field is in the same direction as the polarization direction across the first electrode 212 and the second electrode 214, all three piezoelectric elements 222, 224, and 226 extend in the longitudinal direction.

[0021] FIG. 4 shows a side cross-sectional view of the second piezoelectric actuator 225 of the drive circuit according to an example of the present disclosure. The second piezoelectric actuator 225 has a first electrode 216 connected to a first reference potential, for example, 0 V (ground, etc.). The second piezoelectric actuator 225 further has a second electrode 218 connected to a control signal 230. The second piezoelectric actuator 225 includes a first piezoelectric element 322, a second piezoelectric element 324, and a third piezoelectric element 326. The upper surface of the first piezoelectric element 322 is partially covered by a part of the first electrode 216 and a part of the second electrode 218.

[0022] In contrast to the first piezoelectric actuator 220 of FIG. 3, the second electrode 218 covers less of the upper surface of the first piezoelectric element 322 than the first electrode 216. This is because the second piezoelectric actuator 225 is rotated 180° from the orientation of the second piezoelectric actuator 125 in FIG. 2. The first piezoelectric element 322 and the second piezoelectric element 324 are partially separated by the second electrode 218. Also, the second piezoelectric element 324 and the third piezoelectric element 326 are partially separated by the first electrode 216. The lower surface of the third piezoelectric element 326 is partially covered by a part of the first electrode 216 and a part of the second electrode 218. The second electrode 218 covers more of the lower surface of the third piezoelectric element 326 than the first electrode 216.

[0023] Under the polarization direction shown in FIG. 4, when a positive voltage is applied such that the electric field is in the opposite direction to the polarization direction across the first electrode 216 and the second electrode 218, all three piezoelectric elements 322, 324, and 326 contract in the longitudinal direction.

[0024] Figure 5 shows a drive circuit 500 according to an example of the present disclosure. The drive circuit 500 includes a first piezoelectric actuator 520 and a second piezoelectric actuator 525 configured to move a head slider 540 of a suspension for a hard disk drive. The first piezoelectric actuator 520 and the second piezoelectric actuator 525 are each electrically connected to the drive circuit 500. As a result, the first piezoelectric actuator 520 and the second piezoelectric actuator 525 operate in response to a control signal, which is an applied voltage applied to control a desired physical displacement of the head slider, using techniques including techniques well known in the prior art. This is described in detail below with reference to Figures 6 and 7.

[0025] The drive circuit 500 is configured to be incorporated into a suspension device for a hard disk drive, such as a head gimbal assembly. The first piezoelectric actuator 520 includes a first terminal 521 (i.e., a reference terminal) and a second terminal 523. The first piezoelectric actuator 520 is connected to a first ground contact 570 at the first terminal 521. The first piezoelectric actuator 520 is further connected to a control signal 530 at the second terminal 523. The second piezoelectric actuator 525 includes a first terminal 527 (e.g., a reference terminal) and a second terminal 529. The second piezoelectric actuator 525 is connected to a second ground contact 580 at the second terminal 529. The second piezoelectric actuator 525 is further connected to a control signal 530 at the first terminal 527. In other words, since the first terminal 527 and the second terminal 529 of the second piezoelectric actuator 525 are swapped, the first piezoelectric actuator 520 and the second piezoelectric actuator 525 have the same polarity and orientation. Furthermore, the active parts 528 and 538 are arranged symmetrically, as shown in Figures 6 and 7.

[0026] Figure 6 shows a side cross-sectional view of a first piezoelectric actuator 520 of a drive circuit architecture 500 according to an example of the present disclosure. The first piezoelectric actuator 520 has a first electrode 512 connected to a first reference potential, for example, zero potential (via a first ground contact 570, etc.). The first piezoelectric actuator 520 further has a second electrode 514 connected to a control signal 530. The first piezoelectric actuator 520 includes a first piezoelectric element 522, a second piezoelectric element 524, and a third piezoelectric element 526. The upper surface of the first piezoelectric element 522 is partially covered by a portion of the first electrode 512 and a portion of the second electrode 514.

[0027] The second electrode 514 covers more of the upper surface of the first piezoelectric element 522 than the first electrode 512. The first piezoelectric element 522 and the second piezoelectric element 524 are partially separated by the grounded first electrode 512. The second piezoelectric element 524 and the third piezoelectric element 526 are also partially separated by the second electrode 514. The lower surface of the third piezoelectric element 526 is partially covered by part of the first electrode 512 and part of the second electrode 514. The second electrode 514 covers less of the lower surface of the third piezoelectric element 526 than the grounded first electrode 512. The first piezoelectric actuator 520 has an active portion 528 which includes the portion of the first piezoelectric element 522 between the second electrode 514 and the first electrode 512, the portion of the second piezoelectric element 524 between the first electrode 512 and the second electrode 514, and the portion of the third piezoelectric element 526 between the second element 514 and the first element 512.

[0028] Under the polarization direction shown in Figure 6, when a positive voltage is applied such that the electric field is in the same direction as the polarization direction across the first electrode 512 and the second electrode 514, all three piezoelectric elements 522, 524, and 526 will stretch in the longitudinal direction.

[0029] Figure 7 shows a side cross-sectional view of a second piezoelectric actuator 525 of a drive circuit 500 according to an example of the present disclosure. The second piezoelectric actuator 525 has a first electrode 516 connected to a control signal 530. The second piezoelectric actuator 525 further has a second electrode 518 connected to a first reference potential, for example, zero potential (via a second ground contact 580, etc.). The second piezoelectric actuator 525 includes a first piezoelectric element 532, a second piezoelectric element 534, and a third piezoelectric element 536. The upper surface of the first piezoelectric element 532 is partially covered by a portion of the first electrode 516 and a portion of the second electrode 518.

[0030] The grounded second electrode 518 covers more of the upper surface of the first piezoelectric element 532 than the first electrode 516. The first piezoelectric element 532 and the second piezoelectric element 534 are partially separated by the first electrode 516. The second piezoelectric element 534 and the third piezoelectric element 536 are also partially separated by the second electrode 518. The lower surface of the third piezoelectric element 536 is partially covered by a portion of the first electrode 516 and a portion of the second electrode 518. The second electrode 518 covers less of the lower surface of the third piezoelectric element 536 than the first electrode 516. The second piezoelectric actuator 525 has an active portion 538 that includes the portion of the piezoelectric element 532 between the second electrode 518 and the first electrode 516, the portion of the second piezoelectric element 534 between the first electrode 516 and the second electrode 518, and the portion of the third piezoelectric element 536 between the second element 518 and the first element 516.

[0031] Under the polarization direction shown in Figure 7, when a positive voltage is applied such that the electric field is in the opposite direction to the polarization direction across the first electrode 516 and the second electrode 518, all three piezoelectric elements 532, 534, and 536 contract longitudinally.

[0032] Returning to Figure 5, the first piezoelectric actuator 520 and the second piezoelectric actuator 525 are similarly polarized. Furthermore, since the structures of the first piezoelectric actuator 520 and the second piezoelectric actuator 525 are arranged in a symmetrical orientation, each structure has the same polarity. The first piezoelectric actuator 520 is configured to be driven in response to a control signal 530 applied via the second (input) terminal 523. Similarly, the second piezoelectric actuator 525 is configured to be driven in response to a control signal 530 applied via the first (input) terminal 527. The control signals control the mechanical deformation of the piezoelectric elements of the first piezoelectric actuator 520 and the second piezoelectric actuator 525, as described above. The identical polarity and symmetry of the first piezoelectric actuator 520 and the second piezoelectric actuator 525 allow for precise radial positioning of the head slider 540 with respect to direction 510. Furthermore, because the first piezoelectric actuator 520 and the second piezoelectric actuator 525 have the same polarity and symmetry, the sway mode gain and torsional mode gain sensitivity are improved compared to conventional systems using actuators with opposite orientations and asymmetrical active parts.

[0033] Figure 8 is a graph 600 of the PZT frequency response function (0 to 80 kHz) of a suspension incorporating the drive circuit according to some embodiments described herein, as simulated. Figure 9 is a graph 700 of the PZT frequency response function (0 to 30 kHz) of a suspension incorporating the drive circuit according to some embodiments described herein, as simulated. As shown in Figure 9, the suspension exhibits a torsional mode gain sensitivity of 1 dB and a sway mode gain sensitivity of 3 dB. Lower sway mode and torsional mode gain sensitivities increase the head positioning control loop bandwidth. This leads to both reduced data seek time and reduced vibration effects.

[0034] Figure 10 is Table 800, showing simulated strokes of suspensions incorporating the drive circuits according to several embodiments described herein, compared to suspensions incorporating conventional techniques including asymmetric arrangement of the active parts and opposite actuator orientation. As shown in the table, suspensions incorporating drive circuits with actuators having the same orientation and symmetrical active parts, according to several embodiments described herein, exhibit a stroke of 10.05 nm / V. In contrast, suspensions incorporating asymmetric arrangement of the active parts of the actuators exhibit a stroke of 8.99 nm / V. Thus, suspensions incorporating drive circuits according to several embodiments described herein show an increase in stroke. In the example shown in Figure 10, the drive circuit according to the embodiment described herein shows an 11% increase in stroke compared to suspensions incorporating asymmetric arrangement and opposite actuator orientation.

[0035] Figure 11 is a graph 900 comparing the PZT frequency response function of a suspension incorporating the drive circuit 500, obtained from simulation, with the PZT frequency response function of a suspension incorporating conventional techniques, including asymmetric arrangement of the active parts and opposite actuator orientation. As shown in Figure 11, suspensions incorporating the drive circuit according to some embodiments described herein exhibit low sway-mode gain sensitivity and torsional-mode gain sensitivity.

[0036] The terms “generally,” “approximately,” “about,” “substantially,” and “coplanar” as used herein and in the claims allow for some degree of variation from any exact dimensions, measurements, and placements; therefore, it will be understood that these terms should be considered within the context of the description and operation of this disclosure.

[0037] It will be further understood that terms such as “upper,” “lower,” “upper,” and “downward” as used herein and in the claims are convenient terms indicating the spatial relationship of parts relative to one another, rather than any specific spatial or gravitational direction. Accordingly, these terms are intended to encompass the assembly of components, whether oriented in a particular orientation as shown in the drawings and described herein, upside down from that orientation, or in any other rotational deformation.

[0038] All features disclosed herein, including the claims, abstract, and drawings, and all steps in any disclosed method or process, may be combined in any combination, except for any combination in which at least part of such features and / or steps are mutually exclusive. Each feature disclosed herein, including the claims, abstract, and drawings, may be replaced by an alternative feature serving the same, equivalent, or similar purpose unless otherwise specified. Thus, unless otherwise specified, each disclosed feature is merely an example of a comprehensive set of equivalent or similar features.

[0039] It should be understood that the term “example” as used herein should not be construed to mean that only a single example having a single essential element or set of elements is presented. Similarly, it should be understood that the term “this disclosure” encompasses multiple distinct modifications, each of which may be construed as a distinct example. Although this disclosure has been described in detail with respect to preferred embodiments and their drawings, it should be apparent to those skilled in the art that various adaptations and modifications of this disclosure can be achieved without departing from the spirit and scope of this disclosure. Accordingly, it should be understood that the detailed description and accompanying drawings described above do not limit the scope of this disclosure, and the scope of this disclosure should be construed solely from the following claims and their appropriately interpreted legal equivalents.

Claims

1. A drive circuit for applying voltage to a plurality of piezoelectric actuators in the suspension of a disk drive, A first piezoelectric actuator comprising one or more piezoelectric elements disposed between a first electrode and a second electrode, wherein the first electrode is configured to be connected to a first ground at a first terminal, and the second electrode is configured to be connected to an amplifier at a second terminal, A second piezoelectric actuator comprising one or more piezoelectric elements disposed between a first electrode and a second electrode, wherein the first electrode is configured to be connected to a control signal at a first terminal, and the second electrode is connected to a second ground at a second terminal, A drive circuit in which the first terminal of the first piezoelectric actuator and the first terminal of the second piezoelectric actuator are configured such that the first piezoelectric actuator and the second piezoelectric actuator are symmetrical and have the same polarity.

2. The drive circuit according to claim 1, wherein the first piezoelectric actuator includes a first piezoelectric element, a second piezoelectric element, and a third piezoelectric element.

3. The drive circuit according to claim 2, wherein the upper surface of the first piezoelectric element is partially covered by a part of the first electrode and a part of the second electrode, and the second electrode covers more of the upper surface of the first piezoelectric element than the first electrode.

4. The drive circuit according to claim 2, wherein the first piezoelectric element and the second piezoelectric element are partially separated by the first electrode connected to the first ground.

5. The drive circuit according to claim 2, wherein the second piezoelectric element and the third piezoelectric element are partially separated by the second electrode.

6. The drive circuit according to claim 2, wherein the lower surface of the third piezoelectric element is partially covered by a part of the first electrode and a part of the second electrode, and the second electrode covers less of the lower surface of the third piezoelectric element than the first electrode.

7. The drive circuit according to claim 1, wherein the second piezoelectric actuator includes a first piezoelectric element, a second piezoelectric element, and a third piezoelectric element.

8. The drive circuit according to claim 7, wherein the upper surface of the first piezoelectric element is partially covered by a part of the first electrode and a part of the second electrode, and the second electrode covers more of the upper surface of the first piezoelectric element than the first electrode.

9. The drive circuit according to claim 7, wherein the first piezoelectric element and the second piezoelectric element are partially separated by the first electrode.

10. The drive circuit according to claim 7, wherein the second piezoelectric element and the third piezoelectric element are partially separated by the second electrode.

11. The drive circuit according to claim 7, wherein the lower surface of the third piezoelectric element is partially covered by a part of the first electrode and a part of the second electrode, and the second electrode covers less of the lower surface of the third piezoelectric element than the first electrode.

12. The drive circuit according to claim 1, wherein the first piezoelectric actuator is configured to be driven in response to the control signal applied via the second terminal.

13. The drive circuit according to claim 1, wherein the second piezoelectric actuator is configured to be driven in response to the control signal applied via the first terminal.

14. Equipped with a head slider, The drive circuit according to claim 1, wherein the head slider is precisely positioned radially by the first piezoelectric actuator and the second piezoelectric actuator, which are symmetrical and have the same polarity.

15. A suspension device, The suspension device includes a drive circuit for applying voltage to a plurality of piezoelectric actuators in the suspension device. The aforementioned drive circuit is A first piezoelectric actuator comprising one or more piezoelectric elements disposed between a first electrode and a second electrode, wherein the first electrode is configured to be connected to a first ground at a first terminal, and the second electrode is configured to be connected to a control signal at a second terminal, A second piezoelectric actuator comprising one or more piezoelectric elements disposed between a first electrode and a second electrode, wherein the first electrode is connected to a control signal at a first terminal and the second electrode is connected to a second ground at a second terminal, A suspension device in which the first terminal of the first piezoelectric actuator and the first terminal of the second piezoelectric actuator are configured such that the first piezoelectric actuator and the second piezoelectric actuator are symmetrical and have the same polarity.

16. The suspension device according to claim 15, wherein the first piezoelectric actuator includes a first piezoelectric element, a second piezoelectric element, and a third piezoelectric element.

17. The suspension device according to claim 15, wherein the second piezoelectric actuator includes a first piezoelectric element, a second piezoelectric element, and a third piezoelectric element.

18. The suspension device according to claim 15, wherein the first piezoelectric actuator is configured to be driven in response to the control signal applied via the second terminal.

19. The suspension device according to claim 15, wherein the second piezoelectric actuator is configured to be driven in response to the control signal applied via the first terminal.

20. Equipped with a head slider, The suspension device according to claim 15, wherein the head slider is precisely positioned radially by the first piezoelectric actuator and the second piezoelectric actuator, which are symmetrical and have the same polarity.

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