Timer Device Input Time Determination Circuit Noise Resistance
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Solution Overview
Problem
Existing timer ICs face reliability issues due to noise interference and the need for additional terminals when setting measurement times, especially in applications requiring high reliability, such as in vehicles, where spare terminals are limited.
Innovation Solution
A timer device that determines the input time of a predetermined signal and changes its measurement process without requiring a dedicated external terminal, using an input time determination circuit and a counting circuit to select whether to initialize or update the count value, allowing for flexible operation without additional terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dedicated external terminal is provided for selecting whether to incorporate a set value, then the timer IC can flexibly change measurement process, but the number of terminals increases and cost increases
Solution Approach 1:
The first external terminal is designed to serve multiple functions: it can input a predetermined signal for mode selection (single-shot vs. repeat mode) and also function as a general-purpose input terminal for timer operations. This multi-functionality eliminates the need for a dedicated mode-selection terminal, reducing the total terminal count while maintaining measurement process flexibility.
Solution Approach 2:
The patent combines the mode-selection function with the existing first external terminal by detecting the input time duration of signals received at this terminal. Instead of requiring a separate dedicated terminal for mode selection, the terminal's existing signal input capability is enhanced with temporal analysis functionality, merging two functions into one terminal.
2Device complexity
If serial interface terminals are used to write set value, then fewer terminals are needed and cost is reduced, but noise interference may cause incorrect setting and reliability decreases
Solution Approach 1:
The patent replaces the software-based serial writing mechanism with a hardware-based temporal detection mechanism. Instead of writing set values through serial interfaces susceptible to noise, the system uses the input time determination circuit to detect signal duration directly at the terminal, performing mode selection through hardware-level temporal analysis that is inherently more noise-resistant.
Solution Approach 2:
The input time determination circuit continuously monitors and determines the input time duration of signals at the first external terminal in advance, before the timer measurement process begins. This preliminary temporal analysis allows the system to pre-determine the operating mode based on signal characteristics, ensuring reliable mode selection before any measurement or counting operation starts.
3Adaptability or versatility
If set value is overwritten continuously, then measurement process can be updated, but unnecessary overwriting occurs when set value is not needed to change
Solution Approach 1:
The patent implements dynamic mode selection where the timer operates in different modes (single-shot or repeat) based on the detected signal duration at the first external terminal. The system adaptively changes its measurement process by detecting whether the input signal duration exceeds a predetermined threshold, allowing the timer to dynamically adjust its behavior without continuous overwriting of set values.
Solution Approach 2:
The input time determination circuit provides feedback about the signal duration to the counting circuit, enabling the system to automatically select the appropriate measurement mode. This feedback mechanism allows the timer to intelligently determine whether to incorporate a new set value or maintain the current measurement process, avoiding unnecessary overwrites and energy consumption.
Data Source
AI summary
A timer device includes a RES input terminal (first external terminal), an input time determination circuit that determines the time length relationship between an input time of a predetermined signal input to the RES input terminal and a given determination time, and a pre-settable down counter (counting circuit) that counts a given set value. The pre-settable down counter changes a process according to a determination result of the input time determination circuit.