Liquid Ejecting 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 maintaining efficient operation of piezoelectric elements, particularly due to the energy inefficiencies in current drive signal amplification methods like linear and D-class amplifications.
Innovation Solution
A liquid ejecting apparatus with a drive circuit that utilizes a pair of transistors and an integrated circuit to generate drive signals from multiple voltage levels, optimizing the arrangement of components to reduce wire resistance and power consumption, and incorporating a gate driver to control the transistors efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If linear amplification is used to amplify the drive signal, then the piezoelectric element can be driven with sufficient current, but power consumption increases and energy efficiency decreases
Solution Approach 1:
The patent changes the amplification method from linear to D-class switching amplification, fundamentally altering the operating parameters. The drive circuit uses pulse width modulation to amplify the drive signal, switching between on and off states rather than linear amplification, thereby achieving high current output with improved energy efficiency
Solution Approach 2:
The patent replaces the linear amplification mechanism with a switching amplification mechanism using MOSFETs. The gate drivers control the switching transistors to operate in saturation and triode regions, substituting the continuous linear amplification process with discrete switching operations that reduce power loss
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 eliminates the low pass filter component from the D-class amplification system. By removing this energy-consuming component, the patent achieves further power reduction while maintaining the benefits of switching amplification efficiency
Solution Approach 2:
The switching transistors themselves perform the filtering function through their inherent switching characteristics and the capacitive nature of the piezoelectric element, eliminating the need for separate filtering components that consume power
3Area of stationary object
If the first pair of transistors and second pair of transistors are disposed closely to the integrated circuit, then the area of circuit substrate is reduced, but wire resistance may increase
Solution Approach 1:
The patent arranges the transistor pairs and integrated circuit terminals along one side of the integrated circuit in a linear configuration. This one-dimensional arrangement optimizes wire length and resistance while maintaining compact substrate area utilization
Solution Approach 2:
The patent applies different voltage levels (first voltage and second voltage higher than first voltage) to different transistor pairs, creating localized electrical environments. The difference voltage between the two voltages is applied to the second pair of transistors, optimizing performance while managing wire resistance through strategic voltage distribution
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 effectively reduces power consumption and minimizes the area of the circuit substrate, allowing for more efficient disposal of wires and improved noise resistance, thereby enhancing the overall efficiency of the liquid ejecting process.
Implementation Method 1
a piezoelectric element which is driven by a drive signal and ejects liquid by driving the piezoelectric element
Data Source
AI summary
A liquid ejecting apparatus includes an ejecting unit and a drive circuit that generates the drive signal in accordance with a first voltage and a second voltage. The drive circuit includes a first pair of transistors, a second pair of transistors, and an integrated circuit that includes a first terminal to which the first voltage is applied, a second terminal to which the second voltage is applied, a first output terminal group which outputs a first control signal group for controlling the first pair of transistors, and a second output terminal group which outputs a second control signal group for controlling the second pair of transistors. The first terminal, the second terminal, the first output terminal group, and the second output terminal group are arranged along one side of the integrated circuit. The second output terminal group is disposed between the first terminal and the second terminal.