Liquid Ejection Drive Circuit With Selectable Current Sources
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Solution Overview
Problem
Existing liquid ejecting apparatuses face inefficiencies in power consumption due to the need for amplifying current in transistors, particularly when using a single pair of transistors with fixed power supply voltages.
Innovation Solution
A liquid ejecting apparatus that includes an analog signal generating unit, a charging transistor with a current source terminal, and a current source connector that selects from multiple current sources based on the voltage of the analog signal, allowing for the use of a suitable current source to reduce power consumption by switching between different voltage sources during charging and discharging operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pair of transistors with fixed power supply voltages is used, then the device complexity is reduced, but power consumption increases due to the need to amplify current in all operating conditions
Solution Approach 1:
The patent applies dynamics by making the power supply voltage to the transistors changeable rather than fixed. A voltage selection circuit dynamically selects between first and second power supply voltages based on the signal level, allowing the transistor operating conditions to adapt to different operating states, thereby reducing power consumption while maintaining adequate drive capability when needed
Solution Approach 2:
The patent changes the parameter of power supply voltage from a fixed value to a selectable variable. By providing multiple power supply voltage levels and selectively applying them based on signal conditions, the system optimizes the balance between drive capability and power consumption, addressing the contradiction between simple configuration and energy efficiency
2Use of energy by moving object
If multiple current sources are provided with different voltages, then power consumption is reduced by selecting suitable current sources, but the device complexity increases due to the need for switching between current sources
Solution Approach 1:
The voltage selection circuit serves multiple functions: it selects appropriate current sources based on signal level, controls the switching between different power supply voltages, and manages the overall power distribution to the transistor pairs. This multi-functionality reduces the need for separate control mechanisms, thereby limiting the increase in device complexity while achieving power savings through selective current source usage
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 achieves power saving by using a current source suitable for the voltage of the analog signal, suppressing power consumption in the charging transistor and improving reliability by ensuring charge supply even when the capacitor's charge is consumed.
Implementation Method 1
a charging transistor that amplifies a current of the analog signal while the element is charged, and pushes the amplified current toward the element
Implementation Method 2
a current source connector that selects at least one of a plurality of current sources according to a voltage of the analog signal, and connects the selected current source to the current source terminal
Data Source
AI summary
A liquid ejection apparatus includes an element that is charged and discharged so as to perform an operation to eject a liquid, an analog signal generating unit that generates an analog signal having a voltage change pattern for determining the operation of the element, a charging transistor that amplifies a current of the analog signal while the element is charged, and pushes the amplified current toward the element, the charging transistor having a current source terminal, to which a current source is connected, and a push terminal for pushing the current, and a current source connector that selects at least one current source from among a plurality of current sources according to a voltage of the analog signal, and connects the selected current source to the current source terminal.