Piezoelectric Printhead Driving Circuit With Level-Shift Gate Control
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Solution Overview
Problem
Existing driving circuits for inkjet printers, such as those using piezoelectric elements, face instability issues due to insufficient current supply and voltage management, affecting the reliability and accuracy of ink ejection.
Innovation Solution
A driving circuit with a modulation circuit, amplification circuit, level shift circuit, and demodulation circuit is designed to generate and manage driving signals for piezoelectric elements, utilizing gate drivers, transistors, and capacitance elements to stabilize voltage levels and improve power management, including specific gate signal control and capacitance charging strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple amplification circuit is used to drive piezoelectric elements, then the device complexity is reduced, but the reliability of ink ejection deteriorates due to insufficient current supply and voltage management
Solution Approach 1:
The driving circuit is segmented into multiple functional modules: modulation circuit, amplification circuit, level shift circuit, and demodulation circuit. Each module performs a specific function in the signal processing chain, allowing complex operations to be distributed across simpler, specialized components that can be independently optimized and controlled.
Solution Approach 2:
The modulation circuit performs preliminary action by modulating the base driving signal before amplification. This pre-modulation prepares the signal with the required characteristics (frequency, amplitude, timing) so that the subsequent amplification and level shifting operations can efficiently produce the final driving signal without requiring complex real-time processing.
2Productivity
If the amplification circuit operates continuously, then the productivity of signal generation is improved, but the loss of energy increases due to switching losses and power consumption
Solution Approach 1:
The amplification circuit operates periodically rather than continuously. The gate drivers control the transistors to switch on and off in synchronization with the modulated signal, creating periodic current flow through the piezoelectric elements. This periodic operation maintains productivity by generating signals at the required rate while reducing energy loss by eliminating current flow during periods when no ejection is needed.
Solution Approach 2:
The useful action of driving the piezoelectric elements is maintained continuously at the required frequency, while non-useful current flow is eliminated. The level shift circuit ensures that the transistor gates are properly biased during switching transitions, maintaining continuous useful signal generation while minimizing energy-wasting switching losses through optimized gate control.
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 enhances the stability and reliability of the driving signal output, reducing switching losses and power consumption, and maintains stable ink ejection performance even with changes in ambient conditions or ink viscosity.
Implementation Method 1
Ink jet printers that include driving elements, such as piezoelectric elements, are known for printing images and documents by ejecting ink
Implementation Method 2
a first capacitance element that has one end electrically coupled to the first output point and the other end electrically coupled to the other end of the fourth transistor, and a second capacitance element
Data Source
AI summary
A driving circuit includes an amplification circuit configured to output an amplified modulation signal and a level shift circuit. The level shift circuit includes a second gate driver that outputs a third gate signal and a fourth gate signal, a third transistor that operates based on the third gate signal, and a fourth transistor that operates based on the fourth gate signal. The second gate driver outputs the third gate signal for controlling the third transistor to be conductive and the fourth gate signal for controlling the fourth transistor to be nonconductive in a second period in which a driving signal is fixed in a second potential that is higher than a first potential and lower than a third potential and the fourth gate signal for controlling the fourth transistor to be nonconductive.