Capacitive Load Drive Circuit Multi-Stage Voltage Amplification
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Solution Overview
Problem
Current liquid ejecting apparatuses, such as ink jet printers using piezoelectric elements, face challenges in reducing power consumption despite advancements in class D amplification schemes.
Innovation Solution
A drive circuit configuration that further improves power consumption by using a multi-stage voltage amplification approach, where the drive signals are amplified in stages from 0 to 42 volts, reducing energy consumption compared to traditional class D amplification methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If class D amplification is used to amplify the source drive signal, then energy efficiency is improved compared to linear amplification, but power consumption can still be further reduced
Solution Approach 1:
The amplification process is segmented into multiple stages with different power supply voltages. The drive circuit includes first, second, and third amplifier circuits that operate at different voltage levels (first power supply voltage, second power supply voltage higher than first, and third power supply voltage higher than second). This segmentation allows the system to use higher voltages only when necessary for signal amplification while using lower voltages during idle or low-demand periods, thereby reducing overall power consumption while maintaining energy efficiency.
2Power
If class D amplification with switching between high-side and low-side transistors is used, then signal amplification is achieved, but circuit complexity increases due to the need for low-pass filters and switching operations
Solution Approach 1:
The invention extracts and eliminates the low-pass filter component from the class D amplification circuit. By using a different amplification approach that doesn't rely on pulse modulation and switching, the circuit avoids the need for low-pass filters to smooth the switching signals. This extraction of the unnecessary component simplifies the overall circuit design while maintaining the signal amplification capability.
Solution Approach 2:
Instead of using the conventional class D approach of switching between high-side and low-side transistors with pulse modulation, the invention inverts the approach by using direct voltage amplification through multiple amplifier stages with different power supply voltages. This inversion of the amplification methodology eliminates the switching operations and associated complexity while achieving the desired signal amplification.
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 proposed solution reduces power consumption and simplifies the circuit design by minimizing the need for low-pass filters and reducing switching operations, leading to more efficient ink ejection and improved performance in liquid ejecting apparatuses.
Implementation Method 1
an ejecting unit including a piezoelectric element which becomes displaced in accordance with a drive signal
Data Source
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AI summary
A drive circuit that outputs a drive signal through a node includes a circuit that amplifies a signal ain by using a ground Gnd and voltages VA and VB, and the circuit includes a first transistor pair, a second transistor pair, a feeder line 290g for the ground Gnd, a feeder line 290a to which the voltage VA is applied, a feeder line 290b the voltage VB is applied, and capacitors Cag and Cba, and the first transistor pair amplifies the signal ain within a range from the ground Gnd to the voltage VA, and the second transistor pair amplifies the signal ain within a range from the voltage VA to the voltage VB, and one end of the capacitor Cag is connected to the feeder line 290g, the other end of the capacitor Cag is connected to the feeder line 290a, one end of the capacitor Cba is connected to the feeder line 290a, and the other end of the capacitor Cba is connected to the feeder line 290b.