Piezoelectric Drive System Single-Supply Bias Amplifier
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Solution Overview
Problem
Conventional piezoelectric actuators require a negative supply, leading to increased costs and limitations in applying arbitrary voltages to common electrodes, and can only drive with relatively positive voltages, restricting the correction of actuator characteristics.
Innovation Solution
A drive system comprising a waveform generating unit, driving amplifier, and bias amplifier, all coupled to a shared power supply and ground, allowing for driving with a single supply without a negative supply, enabling the application of relatively negative voltages to common electrodes and adjusting actuator characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a negative supply is added to drive the piezoelectric actuator, then the actuator can be driven with positive voltage from ground, but the cost increases substantially
Solution Approach 1:
Instead of applying positive voltage to the piezoelectric element while maintaining the other electrode at ground, the invention inverts the approach by applying negative voltage to the other electrode while maintaining the piezoelectric element electrode at ground potential. This allows the same driving effect to be achieved without requiring a negative supply for the main drive amplifier, thereby reducing cost while maintaining operational capability
Solution Approach 2:
The bias amplifier is designed to serve multiple functions: it applies the negative voltage to the common electrode, provides biasing for the driving amplifier, and enables the single-supply operation of the entire system. This multi-functionality eliminates the need for separate negative supply circuits, reducing overall system complexity and cost
2Device complexity
If a single supply is used without negative supply, then cost is reduced, but arbitrary voltages cannot be applied to common electrodes
Solution Approach 1:
The bias amplifier acts as an intermediary that generates the negative voltage needed for common electrode control from the single positive supply. This intermediary circuit enables the application of arbitrary voltages to common electrodes while maintaining single-supply operation, thus preserving voltage application flexibility without requiring a negative supply
3Device complexity
If a single supply is used without negative supply, then cost is reduced, but actuator characteristics cannot be corrected
Solution Approach 1:
The bias voltage applied to the common electrode is made dynamically adjustable rather than fixed. By controlling the bias amplifier's output voltage, the system can adaptively correct actuator characteristics such as hysteresis and nonlinearity in real-time, maintaining characteristic adjustment capability while operating from a single supply
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables driving with a single supply without substantial cost increases, allowing for flexible voltage application and characteristic adjustment of piezoelectric actuators, improving operational efficiency and cost-effectiveness.
Implementation Method 1
A piezoelectric element is known to exert a so-called inverse piezoelectric effect that when applied with voltage in a direction of electrodes, deforms, i.e., contracts in proportion to an electrical potential of the applied voltage
Data Source
AI summary
A drive system includes an actuator, a waveform generating unit, a driving amplifier, and a bias amplifier. The actuator includes a drive unit. The waveform generating unit generates a voltage waveform for driving the drive unit. The driving amplifier amplifies the voltage waveform so as to apply a voltage to the drive unit. The bias amplifier applies a bias voltage to the drive unit. The driving amplifier and the bias amplifier are coupled to a shared power supply and the ground. The output voltage of the bias amplifier is higher than the minimum output voltage of the driving amplifier.