Piezoelectric Driver Circuit for Haptic Feedback
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Solution Overview
Problem
Existing driver circuits for piezoelectric devices in buttons with short travel are energy-intensive, prone to defects, and lack efficient mechanisms for providing haptic feedback with minimal components.
Innovation Solution
A driver circuit with a comparator and operational amplifier, connected to a piezoelectric device, that reads and controls voltage changes to induce mechanical movement, allowing for haptic feedback with reduced energy consumption and fewer components, utilizing a half-bridge for energy reuse and voltage regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a piezoelectric device is used to provide haptic feedback in a button with short travel, then the button contributes less to the structural height and miniaturization is supported, but the haptic impression on actuation changes and existing circuits are energy-intensive and prone to defects
Solution Approach 1:
The patent combines the sensor circuit and driver circuit into a single integrated circuit with shared components. The operational amplifier serves dual purposes: it amplifies the piezoelectric sensor signal and simultaneously drives the piezoelectric actuator. This merging reduces the total number of components, minimizes energy consumption, and improves reliability by eliminating multiple connection points that could fail.
Solution Approach 2:
The operational amplifier is designed to perform multiple functions: it acts as a signal amplifier for the sensor output, a comparator for threshold detection, and a driver for the piezoelectric actuator. This multi-functionality reduces the need for separate dedicated circuits, thereby reducing energy consumption and improving overall system reliability.
2Ease of operation
If existing driver circuits are used with piezoelectric devices, then haptic feedback can be provided, but the circuits are energy-intensive and have higher risk of defects due to more components
Solution Approach 1:
The patent merges the sensor amplification function and actuator driving function into a single operational amplifier circuit. This eliminates the need for separate sensor circuitry and driver circuitry, significantly reducing energy consumption while maintaining full haptic feedback functionality.
Solution Approach 2:
The operational amplifier circuit automatically detects the piezoelectric device's state through its own output and uses this information to control its driving output. The circuit monitors the voltage across the piezoelectric device and adjusts its driving signal accordingly, enabling efficient energy usage without external control circuits.
3Adaptability or versatility
If existing driver circuits with multiple components are used, then piezoelectric devices can be controlled, but the service life is reduced due to higher susceptibility to defects
Solution Approach 1:
The patent integrates multiple circuit functions into a single operational amplifier, reducing the total number of components from potentially dozens to just one active component plus passive elements. Fewer components mean fewer potential failure points, directly extending the circuit's service life while maintaining full piezoelectric device control capability.
Solution Approach 2:
The patent uses a single operational amplifier that can be readily replaced if needed, rather than a complex multi-component circuit. This simplifies maintenance and extends effective service life through easy replacement, while the simplified design reduces susceptibility to defects during operation.
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 solution reduces the risk of circuit failure, increases service life, and enables efficient energy use by reutilizing electrical energy, while providing configurable haptic feedback with minimal components, enhancing the reliability and efficiency of button actuation.
Implementation Method 1
a piezoelectric device, connected with a button or as part of a button, may supply a user with haptic feedback
Implementation Method 2
If the piezoelectric device experiences a pressure in the stack direction (due to the button being pressed, on the inside of which the layer stack is mounted), the change in voltage induced at the electrodes by an associated change in length of the layer stack is a measure of the force with which the button is being pressed
Data Source
AI summary
A driver circuit is disclosed. In an embodiment a drive circuit includes a signal port with a first terminal and a second terminal, a first node and a second node, a comparator with an inverting input, a non-inverting input and an output and an operational amplifier with an inverting input, a non-inverting input and an output, wherein the first terminal is electrically conductively connected with the inverting input of the operational amplifier, wherein the second terminal is electrically conductively connected with the non-inverting input of the comparator, wherein the inverting input of the comparator is electrically conductively connected with the output of the operational amplifier, wherein the first node is electrically conductively connected with the output of the operational amplifier, wherein the inverting input of the comparator is electrically conductively connected with the inverting input of the operational amplifier, and wherein the second node is electrically conductively connected with the non-inverting input of the operational amplifier.