Piezo Drive Circuit Power Reduction via D-Class Amplification
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Solution Overview
Problem
Existing liquid ejecting apparatuses, such as inkjet printers, face challenges in reducing power consumption while efficiently driving piezoelectric elements, as traditional amplification methods like linear and D-class amplification lead to increased power consumption and inefficiency.
Innovation Solution
A liquid ejecting apparatus with a drive circuit that utilizes a first and second pair of transistors, driven by different voltages, and integrated circuits to generate control signals, allowing for efficient power management and reduced area requirements on the circuit substrate, thereby minimizing power consumption and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linear amplification is used to drive piezoelectric elements, then sufficient current is provided to operate the piezoelectric elements, but power consumption increases and energy efficiency decreases
Solution Approach 1:
The patent changes the amplification method from linear amplification to D-class amplification, which uses pulse width modulation instead of continuous analog amplification. This parameter change in the amplification technique reduces power consumption while still providing sufficient current to drive the piezoelectric elements effectively.
Solution Approach 2:
D-class amplification uses periodic switching action through pulse width modulation, where the amplification circuit switches between on and off states rather than maintaining continuous conduction. This periodic action reduces power dissipation in the amplification circuit while delivering the required energy to the piezoelectric elements in controlled pulses.
2Use of energy by moving object
If D-class amplification is used to reduce power consumption, then energy efficiency improves, but power consumed by the low pass filter cannot be ignored
Solution Approach 1:
The patent extracts and removes the low pass filter component from the D-class amplification system. By eliminating this energy-consuming component, the system achieves further power consumption reduction while maintaining the benefits of D-class amplification's high energy efficiency.
Solution Approach 2:
The amplification circuit is designed to directly drive the piezoelectric elements without requiring additional filtering components. The circuit itself provides the necessary signal conditioning and drive capability, eliminating the need for separate power-consuming filtering stages.
3Ease of manufacture
If transistors are disposed far from the integrated circuit, then wiring is simplified, but circuit substrate area increases and wire resistance increases
Solution Approach 1:
The patent merges the transistor components with the integrated circuit by disposing them in close proximity and integrating their wiring. This consolidation reduces the overall circuit substrate area while maintaining manufacturing simplicity through unified layout design and reduced interconnect lengths.
Solution Approach 2:
The patent utilizes vertical stacking or multi-layer wiring approaches to accommodate transistors near the integrated circuit without increasing the planar footprint. By transitioning to three-dimensional spatial arrangement, the design reduces substrate area while maintaining wiring accessibility and managing complexity through vertical integration.
4Area of stationary object
If wire width is reduced to minimize circuit substrate area, then area is reduced, but resistance increases
Solution Approach 1:
By merging the transistor wiring with the integrated circuit wiring in a unified close-proximity layout, the patent reduces total wire length. This allows the use of narrower wires without increasing resistance, as the reduced length compensates for the reduced cross-sectional area, maintaining low power loss while minimizing substrate area.
Solution Approach 2:
The patent optimizes the wire geometry parameters by adjusting the length-to-width ratio. By reducing wire length through close component placement, the system can use narrower wires without increasing overall resistance, thus reducing substrate area while maintaining acceptable power loss levels.
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 power consumption and allows for efficient disposition of transistors near the integrated circuit, minimizing the circuit substrate area and securing wider wire widths, leading to improved energy efficiency and reduced resistance.
Implementation Method 1
An apparatus which uses a piezoelectric element (for example, a piezo element) is known as an ink jet printer which prints an image or a document by ejecting ink
Data Source
AI summary
A liquid ejecting apparatus includes an ejecting unit that includes a piezoelectric element and ejects liquid by driving the piezoelectric element; a first drive circuit that generates a drive signal; and a circuit substrate in which the first drive circuit is disposed. The first drive circuit includes a first integrated circuit having a shape which includes a first side and a second side. The first integrated circuit includes, a first power supply terminal; a second power supply terminal; a first output terminal; and a second output terminal. The first power supply terminal and the second power supply terminal are disposed along the first side. The first output terminal and the second output terminal are disposed along the second side.