Piezoelectric Drive Circuit Isolation for Noise-Accurate Liquid Discharge
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Solution Overview
Problem
Liquid discharge apparatuses, such as ink jet printers, face challenges in achieving high discharge accuracy due to noise interference from high oscillation frequencies in Class D amplifiers used for piezoelectric elements, which affect the precision of ink droplet formation and printing quality.
Innovation Solution
The implementation of a triple-well structure in the integrated circuit device separates noise-sensitive components, reducing parasitic capacitance and noise interference, allowing for accurate modulation signal generation and precise voltage control of piezoelectric elements, thereby enhancing discharge accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Class D amplifier with high oscillation frequency (1 MHz to 8 MHz) is used to drive the piezoelectric element, then the discharge accuracy can be improved, but the system becomes more susceptible to noise interference
Solution Approach 1:
The integrated circuit device is divided into multiple isolated circuit blocks (modulation portion, feedback circuit, low-pass filter, etc.) using triple-well structures. This segmentation isolates noise-sensitive circuits from noise-generating circuits, allowing high oscillation frequency operation for improved discharge accuracy while preventing noise propagation throughout the system.
Solution Approach 2:
The patent extracts and isolates the adder circuit (which is highly sensitive to noise) into a separate circuit block surrounded by triple-well structures. This extraction removes the adder from the noise environment of other circuits, enabling accurate signal processing at high oscillation frequencies without degradation from noise interference.
2Reliability
If noise-sensitive circuits are isolated using triple-well structures, then parasitic capacitance is reduced and noise interference is minimized, but the device complexity increases
Solution Approach 1:
The patent uses triple-well structures to create vertical isolation layers between circuit blocks on the same semiconductor substrate. This three-dimensional isolation approach achieves noise reduction and parasitic capacitance minimization without requiring separate physical substrates or complex multi-layer packaging, thus improving signal integrity while controlling device complexity.
Solution Approach 2:
The triple-well structures act as intermediary isolation layers between different circuit blocks. These intermediate structures provide electrical isolation and reduce parasitic capacitance coupling, enabling reliable signal transmission in high-frequency operation while maintaining a relatively simple integrated circuit architecture.
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
This configuration improves the discharge accuracy of liquid droplets by minimizing noise interference, ensuring high-frequency signal integrity and maintaining power efficiency within the specified frequency range of 1 MHz to 8 MHz, thus enhancing printing quality and reliability.
Implementation Method 1
a piezoelectric element that is displaced by applying the drive signal
Implementation Method 2
separates noise-sensitive components, reducing parasitic capacitance and noise interference
Data Source
AI summary
A driving circuit for driving a capacitive load includes an integrated circuit device that includes a modulation portion which generates a modulation signal by pulse-modulating a source signal; a feedback circuit; a transistor that generates an amplified modulation signal which is obtained by amplifying the modulation signal; a low-pass filter that generates a drive signal by demodulating the amplified modulation signal; and a piezoelectric element that is displaced by applying the drive signal, wherein the feedback circuit generates a feedback signal on the basis of the drive signal, and feeds back the feedback signal to the modulation portion through a feedback terminal, the modulation portion includes a first circuit block and a second circuit block, and the integrated circuit device is configured to separate the first circuit block from the second circuit block by a triple-well structure.