Temperature Detector Circuit With Adaptive Sweep Range
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Solution Overview
Problem
Existing temperature detection systems in ink-jet printers face challenges with low responsiveness and reduced driving efficiency due to elongated sweep periods and phase lag in temperature detection, leading to potential thermal destruction of the driver IC.
Innovation Solution
A temperature detector system comprising a temperature sensor, reference signal generation circuit, level memory, control circuit, and comparator circuit, which dynamically adjusts the range of the reference signal to improve responsiveness and accuracy by optimizing the smoothing circuit's time constant and pulse signal patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a sweep range is always set to a constant wide temperature range, then temperature detection coverage is improved, but sweep period is elongated which lowers responsiveness in temperature detection
Solution Approach 1:
The patent applies dynamics by making the reference voltage sweep range variable rather than fixed. The control circuit dynamically adjusts the sweep range based on the operating temperature of the driver IC, narrowing the range when temperature is stable and expanding it when temperature changes are detected. This resolves the contradiction by adapting the sweep range to actual temperature conditions, maintaining wide coverage when needed while reducing sweep period during stable operation.
Solution Approach 2:
The patent changes the parameter of reference voltage sweep range from a constant value to a variable value that adapts to temperature conditions. By modifying the sweep range parameter based on detected temperature and its rate of change, the system achieves both wide temperature detection coverage and reduced sweep period, resolving the contradiction between adaptability and time loss.
2Reliability
If a detection temperature is set to a lower value in anticipation of sudden temperature rise, then thermal protection is improved, but driving efficiency decreases due to low-temperature operation
Solution Approach 1:
The patent implements feedback by continuously monitoring the temperature of the driver IC and using this information to adjust the reference voltage sweep range. The control circuit receives temperature feedback and dynamically modifies detection parameters, allowing the system to operate at optimal temperatures while maintaining protection capabilities. This resolves the contradiction by eliminating the need to preemptively lower detection temperature.
Solution Approach 2:
The patent applies preliminary action by detecting temperature trends and preparing the sweep range adjustment in advance of actual temperature changes. The control circuit monitors temperature rate of change and proactively adjusts the reference voltage sweep range before the driver IC reaches critical temperatures, maintaining both protection and efficiency.
3Measurement precision
If a time constant of the smoothing circuit is made larger to generate stable reference voltage, then temperature detection accuracy is improved, but phase lag increases which lowers responsiveness
Solution Approach 1:
The patent applies dynamics by making the reference voltage sweep range adaptive rather than fixed. By dynamically adjusting the sweep range based on actual temperature conditions and rate of change, the system achieves accurate temperature detection without requiring a large time constant, thereby reducing phase lag while maintaining detection precision.
Solution Approach 2:
The patent changes the parameter of reference voltage sweep range to resolve the contradiction between accuracy and responsiveness. By modifying sweep range parameters based on temperature conditions, the system achieves stable reference voltage generation with reduced phase lag, eliminating the need for a large smoothing circuit time constant.
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 system enhances temperature detection responsiveness while maintaining accuracy, preventing thermal destruction of the driver IC and improving driving efficiency by shortening detection time and reducing phase lag.
Implementation Method 1
an output signal of the temperature sensor changes in level in accordance with change in temperature of driver IC
Implementation Method 2
the comparator circuit compares a level of the reference signal and a level of the output signal
Data Source
AI summary
A temperature detector of the present invention includes a temperature sensor, a reference signal generation circuit, a level memory which rewritably stores therein a first signal level and a second signal level, a control circuit which controls the reference signal generation circuit so as to make a level of the reference signal change from the first signal level to the second signal level, a comparator circuit which compares the level of the reference signal and a level of the output signal, and a level rewriter which rewrites at least either one of the first signal level and the second signal level. When the level of the reference signal reaches the level of the output signal, the control circuit generates a detected temperature signal, and controls the level rewriter so as to change a range where a level of the reference signal changes.