A piezoelectric ceramic differential charge pump drive circuit and control method

Abstract

This invention discloses a piezoelectric ceramic differential charge pump drive circuit and control method, relating to the field of precision drive control for piezoelectric ceramics. A single-pole double-throw switch is connected to each end of a DC regulated power supply, providing switchable positive and negative reference voltages. A charge pump capacitor is also connected to a single-pole double-throw switch, switching between the DC regulated power supply and two high-voltage operational amplifiers. The charge pump capacitor is charged from the DC regulated power supply and then injects equal and opposite charges into the two piezoelectric ceramics connected to the high-voltage operational amplifiers, thus realizing the differential charge pump drive and control. This invention simplifies the charge drive circuit of a piezoelectric bicrystalline wafer, provides equal differential charges to the two piezoelectric ceramics, and significantly improves the control accuracy of the bending displacement of the piezoelectric bicrystalline wafer using charge drive technology.

Description

Technical Field

[0001] This invention relates to the field of precision drive control for piezoelectric ceramics, and specifically to a piezoelectric ceramic differential charge pump drive circuit and control method. Background Technology

[0002] In the field of precision drive control, piezoelectric ceramic actuators offer advantages such as high displacement resolution, large driving force, and fast response speed, making them the preferred solution for nanoscale precision drives. They are widely used in applications involving nanoscale positioning operations, such as semiconductor manufacturing, optical measurement, and biomedicine. Piezoelectric ceramic actuators utilize the inverse piezoelectric effect, inducing strain within the material by applying a driving voltage to the surface electrodes, thus generating the output displacement. However, a nonlinear relationship, including hysteresis and creep, exists between the driving voltage and the output displacement, severely limiting the displacement control accuracy of piezoelectric ceramic actuators.

[0003] Piezoelectric bicrystalline wafers are one of the most common types of piezoelectric ceramic actuators. They utilize the differential strain of the upper and lower piezoelectric wafers (e.g., the upper wafer elongates while the lower wafer shortens) to create bending deformation using the strain gradient. They are characterized by simple structure and large output displacement. However, since a piezoelectric bicrystalline wafer contains at least two piezoelectric wafers with different applied driving voltages, the upper and lower wafers require two separate high-voltage amplifiers, leading to high control difficulty and system cost. To reduce the complexity of the driving circuit, patent number US5233256 proposes differential driving with a single high-voltage amplifier through optimized electrode connections. However, the control accuracy of this method is limited due to the significant nonlinearity error inherent in voltage driving. To avoid the nonlinearity of piezoelectric driving, patent number CN110518829B proposes a charge-driven circuit for piezoelectric bicrystalline wafers, using a charge amplifier circuit instead of a voltage amplifier circuit to improve the nonlinear characteristics of piezoelectric driving. However, this method has strict proportional requirements for circuit parameters, and at low frequencies, it is equivalent to a conventional voltage amplifier circuit, limiting its practical effectiveness. Therefore, it is necessary to further combine the characteristics of piezoelectric bicrystalline wafers and charge-driven circuits to propose more effective differential charge-driven circuits and control methods. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a piezoelectric ceramic differential charge pump drive circuit and control method to solve the technical problems of complex drive circuits and poor control accuracy of piezoelectric bicrystalline wafers in the prior art.

[0005] This invention is achieved through the following technical solution:

[0006] A piezoelectric ceramic differential charge pump drive circuit, characterized in that it includes a DC regulated power source E, a single-pole double-throw switch S1, a single-pole double-throw switch S2, a single-pole double-throw switch S3, a single-pole double-throw switch S4, a charge pump capacitor Ci, a piezoelectric ceramic Cp1, a piezoelectric ceramic Cp2, a high-voltage operational amplifier A1, and a high-voltage operational amplifier A2.

[0007] The fixed ports of the single-pole double-throw switches S1 and S2 are respectively connected to the two ends of the DC regulated power supply E, and the switching ports of the single-pole double-throw switches S1 and S2 are respectively cross-connected to the two ends of the charge pump capacitor Ci. Through the synchronous switching of the single-pole double-throw switches S1 and S2, positive and negative reference voltages are provided to the charge pump capacitor Ci respectively.

[0008] The fixed ports of the single-pole double-throw switches S3 and S4 are respectively connected to the two ends of the charge pump capacitor Ci. One end of the switching port of the single-pole double-throw switches S3 and S4 is respectively connected to the two ends of the DC regulated power supply E, and the other end is respectively connected to the inverting terminals of the high-voltage operational amplifiers A1 and A2. Through the synchronous switching of the single-pole double-throw switches S3 and S4, the charge pump capacitor Ci is charged and discharged respectively.

[0009] The positive terminal of the piezoelectric ceramic Cp1 is connected to the inverting terminal of the high-voltage operational amplifier A1, and the negative terminal is connected to the output terminal of the high-voltage operational amplifier A1; the positive terminal of the piezoelectric ceramic Cp2 is connected to the inverting terminal of the high-voltage operational amplifier A2, and the negative terminal is connected to the output terminal of the high-voltage operational amplifier A2; the non-inverting terminals of the high-voltage operational amplifiers A1 and A2 are grounded.

[0010] To achieve the above objectives, in addition to the aforementioned piezoelectric ceramic differential charge pump drive circuit, this invention also provides a piezoelectric ceramic differential charge pump control method, comprising the following steps:

[0011] Step 1: The single-pole double-throw switches S1 and S2 are synchronously switched to connect with the charge pump capacitor Ci, and the DC regulated power supply E provides a positive reference voltage +E to the charge pump capacitor Ci.

[0012] Step 2: The single-pole double-throw switches S3 and S4 are synchronously switched and connected to the DC regulated power source E. The DC regulated power source E charges the two ends of the charge pump capacitor Ci, injecting positive charge +ΔQ and negative charge -ΔQ respectively. The charge amount ΔQ is expressed as:

[0013] ΔQ=E·Ci (1);

[0014] Step 3: The single-pole double-throw switches S3 and S4 are synchronously switched and connected to the inverting terminals of high-voltage operational amplifiers A1 and A2. The charge pump capacitor Ci discharges, and the positive charge +ΔQ stored at one end is injected into the piezoelectric ceramic Cp1, while the negative charge -ΔQ stored at the other end is injected into the piezoelectric ceramic Cp2.

[0015] Step 4: Repeat steps 2 and 3. The single-pole double-throw switches S3 and S4 switch back and forth between the DC regulated power source E and the high-voltage operational amplifiers A1 and A2. The charge pump capacitor Ci performs charging and discharging cycle operations. Positive charge +ΔQ is continuously injected into the piezoelectric ceramic Cp1, and the total charge of the piezoelectric ceramic Cp1 gradually increases, resulting in an increase in output displacement. Negative charge -ΔQ is continuously injected into the piezoelectric ceramic Cp2, and the total charge of the piezoelectric ceramic Cp2 gradually decreases, resulting in a decrease in output displacement.

[0016] Step 5: The single-pole double-throw switches S1 and S2 are synchronously switched to connect with the charge pump capacitor Ci, and the DC regulated power supply E provides a negative reference voltage -E for the charge pump capacitor Ci;

[0017] Step 6: The single-pole double-throw switches S3 and S4 are synchronously switched to connect to the DC regulated power supply E. The DC regulated power supply E charges the two ends of the charge pump capacitor Ci, injecting negative charge -ΔQ and positive charge +ΔQ respectively.

[0018] Step 7: The single-pole double-throw switches S3 and S4 are synchronously switched and connected to the inverting terminals of high-voltage operational amplifiers A1 and A2. The charge pump capacitor Ci discharges, and the negative charge -ΔQ stored at one end is injected into the piezoelectric ceramic Cp1, while the positive charge +ΔQ stored at the other end is injected into the piezoelectric ceramic Cp2.

[0019] Step 8: Repeat steps 6 and 7. The single-pole double-throw switches S3 and S4 switch back and forth between the DC regulated power source E and the high-voltage operational amplifiers A1 and A2. The charge pump capacitor Ci performs charging and discharging cycle operations. Negative charge -ΔQ is continuously injected into the piezoelectric ceramic Cp1, and the total charge of the piezoelectric ceramic Cp1 gradually decreases, resulting in a decrease in output displacement. Positive charge +ΔQ is continuously injected into the piezoelectric ceramic Cp2, and the total charge of the piezoelectric ceramic Cp2 gradually increases, resulting in an increase in output displacement.

[0020] Step 9: The single-pole double-throw switches S1 and S2 are synchronously switched to connect with the charge pump capacitor Ci, and the DC regulated power source E provides a positive reference voltage +E to the charge pump capacitor Ci.

[0021] The present invention has the following advantages over the prior art:

[0022] (1) The two ends of the charge pump capacitor Ci are connected to the inverting terminals of the high-voltage operational amplifiers A1 and A2 respectively, and are in a virtual ground state. Therefore, the charge pump capacitor Ci does not need to be connected to a common ground. By using a single DC regulated power source E in conjunction with single-pole double-throw switches S1 and S2, positive and negative reference voltages can be provided to the charge pump capacitor Ci, ensuring that the positive and negative charges injected into a single piezoelectric ceramic Cp1 or Cp2 are equal in amount ΔQ.

[0023] (2) The single-pole double-throw switches S3 and S4 are synchronously switched and connected to the inverting terminals of high-voltage operational amplifiers A1 and A2. The current flows out from the output terminal of high-voltage operational amplifier A1, passes through piezoelectric ceramic Cp1, charge pump capacitor Ci and piezoelectric ceramic Cp2, and flows into the output terminal of high-voltage operational amplifier A2. The positive charge injected by piezoelectric ceramic Cp1 and the negative charge injected by piezoelectric ceramic Cp2 are equal in charge amount ΔQ. The total charge of piezoelectric ceramic Cp1 increases by ΔQ, and the total charge of piezoelectric ceramic Cp2 decreases by ΔQ, thereby realizing differential charge pump drive. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the piezoelectric ceramic differential charge pump drive circuit of the present invention;

[0025] Figure 2 This is a flowchart of the piezoelectric ceramic differential charge pump control method of the present invention;

[0026] Figure 3 This is a schematic diagram of some signals during the drive control process of the piezoelectric ceramic differential charge pump of the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] like Figure 1 As shown, a piezoelectric ceramic differential charge pump drive circuit includes a DC regulated power source E, a single-pole double-throw switch S1, a single-pole double-throw switch S2, a single-pole double-throw switch S3, a single-pole double-throw switch S4, a charge pump capacitor Ci, piezoelectric ceramics Cp1 and Cp2, a high-voltage operational amplifier A1, and a high-voltage operational amplifier A2.

[0029] The fixed ports of the single-pole double-throw switches S1 and S2 are respectively connected to the two ends of the DC regulated power supply E, and the switching ports of the single-pole double-throw switches S1 and S2 are respectively cross-connected to the two ends of the charge pump capacitor Ci. Through the synchronous switching of the single-pole double-throw switches S1 and S2, positive and negative reference voltages are provided to the charge pump capacitor Ci respectively.

[0030] The fixed ports of the single-pole double-throw switches S3 and S4 are respectively connected to the two ends of the charge pump capacitor Ci. One end of the switching port of the single-pole double-throw switches S3 and S4 is respectively connected to the two ends of the DC regulated power supply E, and the other end is respectively connected to the inverting terminals of the high-voltage operational amplifiers A1 and A2. Through the synchronous switching of the single-pole double-throw switches S3 and S4, the charge pump capacitor Ci is charged and discharged respectively.

[0031] The positive terminal of the piezoelectric ceramic Cp1 is connected to the inverting terminal of the high-voltage operational amplifier A1, and the negative terminal is connected to the output terminal of the high-voltage operational amplifier A1; the positive terminal of the piezoelectric ceramic Cp2 is connected to the inverting terminal of the high-voltage operational amplifier A2, and the negative terminal is connected to the output terminal of the high-voltage operational amplifier A2; the non-inverting terminals of the high-voltage operational amplifiers A1 and A2 are grounded.

[0032] like Figure 1-3 As shown, based on the above-described piezoelectric ceramic differential charge pump drive circuit, the corresponding piezoelectric ceramic differential charge pump control method of the present invention includes the following steps:

[0033] In step S01, at time t0, the single-pole double-throw switches S1 and S2 are applied with a high level, synchronously switching upwards to connect with the charge pump capacitor Ci. The DC regulated source E provides a positive reference voltage +E to the charge pump capacitor Ci. The single-pole double-throw switches S3 and S4 are applied with a low level, synchronously switching to the right to connect with the inverting terminals of the high-voltage operational amplifiers A1 and A2. The initial charge of the piezoelectric ceramics Cp1 and Cp2 is zero.

[0034] In step S02, at time t1, the single-pole double-throw switches S3 and S4 are applied with a high level, synchronously switching to the left to connect with the DC regulated power source E. The DC regulated power source E charges the two ends of the charge pump capacitor Ci, injecting a positive charge +ΔQ into the upper end and a negative charge -ΔQ into the lower end. The charge amount ΔQ is expressed as:

[0035] ΔQ=E·Ci (1);

[0036] In step S03, at time t2, the single-pole double-throw switches S3 and S4 are applied with a low level, and synchronously switch to the right to connect with the inverting terminals of the high-voltage operational amplifiers A1 and A2. The charge pump capacitor Ci discharges, and the positive charge +ΔQ stored at the upper end is injected into the piezoelectric ceramic Cp1, and the negative charge -ΔQ stored at the lower end is injected into the piezoelectric ceramic Cp2.

[0037] In step S04, steps S02 and S03 are repeated until time t3. The single-pole double-throw switches S3 and S4 switch back and forth between the DC regulated power source E and the high-voltage operational amplifiers A1 and A2. The charge pump capacitor Ci is charged and discharged in a cycle. Positive charge +ΔQ is continuously injected into the piezoelectric ceramic Cp1, and the total charge of the piezoelectric ceramic Cp1 gradually increases, resulting in an increase in output displacement. Negative charge -ΔQ is continuously injected into the piezoelectric ceramic Cp2, and the total charge of the piezoelectric ceramic Cp2 gradually decreases, resulting in a decrease in output displacement.

[0038] In step S05, at time t3, the single-pole double-throw switches S1 and S2 are applied with a low level, synchronously switching downwards to connect with the charge pump capacitor Ci, and the DC regulated source E provides a negative reference voltage -E for the charge pump capacitor Ci; the single-pole double-throw switches S3 and S4 are applied with a low level, synchronously switching to the right to connect with the inverting terminals of the high-voltage operational amplifiers A1 and A2, the total charge of the piezoelectric ceramic Cp1 is +6ΔQ, and the total charge of the piezoelectric ceramic Cp2 is -6ΔQ;

[0039] In step S06, at time t4, the single-pole double-throw switches S3 and S4 are applied with a high level and synchronously switch to the left to connect with the DC regulated power source E. The DC regulated power source E charges the two ends of the charge pump capacitor Ci, injecting negative charge -ΔQ into the upper end and positive charge +ΔQ into the lower end.

[0040] In step S07, at time t5, the single-pole double-throw switches S3 and S4 are applied with a low level, and synchronously switch to the right to connect with the inverting terminals of the high-voltage operational amplifiers A1 and A2. The charge pump capacitor Ci discharges, and the negative charge -ΔQ stored at the upper end is injected into the piezoelectric ceramic Cp1, and the positive charge +ΔQ stored at the lower end is injected into the piezoelectric ceramic Cp2.

[0041] In step S08, steps S06 and S07 are repeated until time t6. The single-pole double-throw switches S3 and S4 switch back and forth between the DC regulated power source E and the high-voltage operational amplifiers A1 and A2. The charge pump capacitor Ci is charged and discharged in a cycle. Negative charge -ΔQ is continuously injected into the piezoelectric ceramic Cp1, and the total charge of the piezoelectric ceramic Cp1 gradually decreases, resulting in a decrease in output displacement. Positive charge +ΔQ is continuously injected into the piezoelectric ceramic Cp2, and the total charge of the piezoelectric ceramic Cp2 gradually increases, resulting in an increase in output displacement.

[0042] In step S09, at time t6, the single-pole double-throw switches S1 and S2 are applied with a high level, synchronously switching upwards to connect with the charge pump capacitor Ci, and the DC regulated source E provides a positive reference voltage +E for the charge pump capacitor Ci; the single-pole double-throw switches S3 and S4 are applied with a low level, synchronously switching to the right to connect with the inverting terminals of the high-voltage operational amplifiers A1 and A2, and the total charge of the piezoelectric ceramics Cp1 and Cp2 is zero.

[0043] By controlling the switching frequency and number of steps S04 and S08, the total charge of piezoelectric ceramics Cp1 and Cp2 can be precisely controlled to change according to the set curve, thereby achieving precise bending displacement output of the piezoelectric bicrystalline wafer.

Claims

1. A piezoelectric ceramic differential charge pump drive circuit, characterized in that: It includes a DC regulated power supply E, a single-pole double-throw switch S1, a single-pole double-throw switch S2, a single-pole double-throw switch S3, a single-pole double-throw switch S4, a charge pump capacitor Ci, a piezoelectric ceramic Cp1, a piezoelectric ceramic Cp2, a high-voltage operational amplifier A1, and a high-voltage operational amplifier A2; The fixed ports of the single-pole double-throw switches S1 and S2 are respectively connected to the two ends of the DC regulated power supply E, and the switching ports of the single-pole double-throw switches S1 and S2 are respectively cross-connected to the two ends of the charge pump capacitor Ci. Through the synchronous switching of the single-pole double-throw switches S1 and S2, positive and negative reference voltages are provided to the charge pump capacitor Ci respectively. The fixed ports of the single-pole double-throw switches S3 and S4 are respectively connected to the two ends of the charge pump capacitor Ci. One end of the switching port of the single-pole double-throw switches S3 and S4 is respectively connected to the two ends of the DC regulated power supply E, and the other end is respectively connected to the inverting terminals of the high-voltage operational amplifiers A1 and A2. Through the synchronous switching of the single-pole double-throw switches S3 and S4, the charge pump capacitor Ci is charged and discharged respectively. The positive terminal of the piezoelectric ceramic Cp1 is connected to the inverting terminal of the high-voltage operational amplifier A1, and the negative terminal is connected to the output terminal of the high-voltage operational amplifier A1; the positive terminal of the piezoelectric ceramic Cp2 is connected to the inverting terminal of the high-voltage operational amplifier A2, and the negative terminal is connected to the output terminal of the high-voltage operational amplifier A2; the non-inverting terminals of the high-voltage operational amplifiers A1 and A2 are grounded.

2. A control method for a piezoelectric ceramic differential charge pump, characterized in that: The method using the piezoelectric ceramic differential charge pump drive circuit according to claim 1 includes the following steps: Step 1: The single-pole double-throw switches S1 and S2 are synchronously switched to connect with the charge pump capacitor Ci, and the DC regulated power supply E provides a positive reference voltage +E to the charge pump capacitor Ci. Step 2: The single-pole double-throw switches S3 and S4 are synchronously switched and connected to the DC regulated power source E. The DC regulated power source E charges the two ends of the charge pump capacitor Ci, injecting positive charge +ΔQ and negative charge -ΔQ respectively, where ΔQ is represented as: ΔQ=E·Ci (1); Step 3: The single-pole double-throw switches S3 and S4 are synchronously switched and connected to the inverting terminals of high-voltage operational amplifiers A1 and A2. The charge pump capacitor Ci discharges, and the positive charge +ΔQ stored at one end is injected into the piezoelectric ceramic Cp1, while the negative charge -ΔQ stored at the other end is injected into the piezoelectric ceramic Cp2. Step 4: Repeat steps 2 and 3. The single-pole double-throw switches S3 and S4 switch back and forth between the DC regulated power source E and the high-voltage operational amplifiers A1 and A2. The charge pump capacitor Ci performs charging and discharging cycle operations. Positive charge +ΔQ is continuously injected into the piezoelectric ceramic Cp1, and the total charge of the piezoelectric ceramic Cp1 gradually increases, resulting in an increase in output displacement. Negative charge -ΔQ is continuously injected into the piezoelectric ceramic Cp2, and the total charge of the piezoelectric ceramic Cp2 gradually decreases, resulting in a decrease in output displacement. Step 5: The single-pole double-throw switches S1 and S2 are synchronously switched to connect with the charge pump capacitor Ci, and the DC regulated power supply E provides a negative reference voltage -E for the charge pump capacitor Ci; Step 6: The single-pole double-throw switches S3 and S4 are synchronously switched to connect to the DC regulated power supply E. The DC regulated power supply E charges the two ends of the charge pump capacitor Ci, injecting negative charge -ΔQ and positive charge +ΔQ respectively. Step 7: The single-pole double-throw switches S3 and S4 are synchronously switched and connected to the inverting terminals of high-voltage operational amplifiers A1 and A2. The charge pump capacitor Ci discharges, and the negative charge -ΔQ stored at one end is injected into the piezoelectric ceramic Cp1, while the positive charge +ΔQ stored at the other end is injected into the piezoelectric ceramic Cp2. Step 8: Repeat steps 6 and 7. The single-pole double-throw switches S3 and S4 switch back and forth between the DC regulated power source E and the high-voltage operational amplifiers A1 and A2. The charge pump capacitor Ci performs charging and discharging cycle operations. Negative charge -ΔQ is continuously injected into the piezoelectric ceramic Cp1, and the total charge of the piezoelectric ceramic Cp1 gradually decreases, resulting in a decrease in output displacement. Positive charge +ΔQ is continuously injected into the piezoelectric ceramic Cp2, and the total charge of the piezoelectric ceramic Cp2 gradually increases, resulting in an increase in output displacement. Step 9: The single-pole double-throw switches S1 and S2 are synchronously switched to connect with the charge pump capacitor Ci, and the DC regulated power source E provides a positive reference voltage +E to the charge pump capacitor Ci.

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