Piezoelectric Switch Actuation via Bias Voltage
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Solution Overview
Problem
Semiconductor-based switches suffer from high sub-threshold power consumption due to their always-present semiconductor channel, while MEMS or NEMS switches, including piezoelectric switches, face challenges in efficiently actuating and isolating electrical contacts.
Innovation Solution
A piezoelectric switching system with a bias voltage source applied to body electrodes, allowing for a lower actuation voltage and enabling the use of a switching voltage that exceeds the actuation voltage difference to close the gap between contact regions, minimizing power consumption and actuation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high voltage is applied across the semiconductor channel to overcome isolation, then the switch can conduct electrical signals, but power is dissipated across the switch even when off due to the always-present semiconductor channel
Solution Approach 1:
The patent removes the semiconductor channel entirely and replaces it with a physical air gap between contact regions. This extraction eliminates the always-present conduction path that causes sub-threshold power consumption in semiconductor switches, achieving zero power consumption in the off state while maintaining electrical isolation.
Solution Approach 2:
The patent replaces the electrical control mechanism of semiconductor switches with a mechanical actuation system. Piezoelectric actuators physically move contact regions to open or close the air gap, substituting electrical field control with mechanical displacement control to achieve switching functionality without a continuous semiconductor channel.
2Reliability
If a sufficiently high voltage is applied to actuate the piezoelectric material, then the air gap closes and the switch conducts, but the actuation voltage requirement increases system complexity
Solution Approach 1:
The patent introduces a bias voltage dimension to the control mechanism. By applying a DC bias voltage to pre-stress the piezoelectric material and a smaller AC switching voltage to modulate the gap closure, the system reduces the peak voltage requirement compared to applying the full actuation voltage directly, simplifying the voltage generation system.
Solution Approach 2:
The patent applies a bias voltage in advance to pre-position the piezoelectric actuators near their actuation point. This preliminary action reduces the additional voltage swing needed to close the air gap, lowering the peak switching voltage requirement and simplifying the overall voltage generation system.
3Loss of time
If the gap between contact regions is reduced to improve switching speed, then actuation time decreases, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs dynamically adjustable gap distances through piezoelectric actuation. Rather than relying on a fixed small gap that requires precise manufacturing, the system can adaptively adjust the gap size and closure speed through voltage control, tolerating broader manufacturing variations while maintaining fast switching performance.
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
The system achieves low sub-threshold power consumption and rapid actuation, with the ability to switch on in less than 1 μs, and can be configured for either positive- or negative-actuated operation without structural changes.
Implementation Method 1
a voltage is applied to the piezoelectric material of the switch, which causes the material to contort in shape, thereby closing the air gap
Implementation Method 2
A piezoelectric switching system with a bias voltage source applied to body electrodes, allowing for a lower actuation voltage
Data Source
AI summary
Systems and methods for operating piezoelectric switches are disclosed. A piezoelectric switching system includes a first actuator, a second actuator, and a bias voltage source. The first actuator has a first body electrode, a first gate electrode, and a first contact region. The second actuator has a second body electrode, a second gate electrode, and a second contact region. The first and second contact regions are separated by a gap. The bias voltage source applies a bias voltage to the body electrodes. The bias voltage is lower in magnitude than an actuation voltage for the switch. The gate electrodes receive a switching voltage. The switching voltage causes at least one of the first and second actuators to bend, thereby closing the gap such that the second contact region electrically contacts the first contact region. The difference between the switching voltage and the bias voltage exceeds the actuation voltage of the switch.