Sensor Circuit Trimming Terminal Elimination
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Solution Overview
Problem
Conventional sensor apparatuses have inefficient use of chip area due to a dedicated trimming signal input terminal that becomes unnecessary after trimming is completed, leading to suboptimal utilization of semiconductor integrated circuit space.
Innovation Solution
A sensor circuit with an illuminance sensor and proximity sensor that includes a writable nonvolatile memory for storing trimming data, allowing the elimination of a dedicated trimming signal input terminal and optimizing chip area usage by repurposing terminals for other functions such as drive, detection result output, communication protocol data input/output, and clock signal input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated trimming signal input terminal is provided for inputting trimming data, then trimming operation can be performed, but chip area usage efficiency deteriorates because the terminal is not used after trimming completes
Solution Approach 1:
The patent applies multi-functionality by enabling existing terminals (drive terminal, detection result output terminal, input/output terminal, or clock terminal) to serve dual purposes: during trimming mode, they input trimming data; during normal operation, they perform their original functions. This eliminates the need for a dedicated trimming terminal while preserving trimming capability, thus resolving the contradiction between trimming reliability and chip area efficiency
2Ease of manufacture
If a dedicated trimming signal input terminal is provided, then trimming can be performed externally, but device complexity increases due to additional terminal requirements
Solution Approach 1:
The patent reduces device complexity by making existing terminals multi-functional. The control circuit identifies trimming mode through specific signal patterns on existing terminals and routes trimming data accordingly. This approach maintains external trimming capability while avoiding the complexity of adding dedicated trimming terminals and their associated control logic
3Area of stationary object
If existing terminals are repurposed for trimming data input, then chip area usage improves, but terminal functionality complexity increases
Solution Approach 1:
The patent applies dynamics by making terminal functions dynamic rather than static. The control circuit determines the operational mode (trimming or normal) based on received signals and dynamically switches terminal functions accordingly. During trimming mode, terminals accept trimming data; during normal mode, they perform their original functions. This dynamic switching mechanism resolves the contradiction between chip area efficiency and terminal function management complexity
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 enhances the efficiency of chip area usage by eliminating the need for a dedicated trimming terminal, allowing for improved functionality and flexibility in sensor circuit design while maintaining sensitivity adjustments for both illuminance and proximity sensing.
Implementation Method 1
a writable nonvolatile memory in which trimming data for correcting an individual variation of a characteristic of the sensor circuit is to be written
Implementation Method 2
an illuminance sensor configured to detect illuminance of ambient light
Implementation Method 3
a proximity sensor configured to drive a light emitter, and to detect proximity of an object, based on an intensity of reflected light coming from the object on which light emitted from the light emitter is reflected
Data Source
AI summary
A sensor circuit includes an illuminance sensor to detect illuminance of ambient light; and a proximity sensor to drive a light emitter, and to detect proximity of an object, based on an intensity of light emitted by the emitter and reflected on the object. The sensor circuit further includes at least one terminal among: a drive terminal for driving the light emitter; a detection result output terminal used for outputting a detection result of one of the sensors; an input/output terminal used for inputting and outputting data compliant with a communication protocol; and a clock terminal used for inputting a clock signal compliant with the communication protocol, and a writable nonvolatile memory in which trimming data for correcting an individual variation of a characteristic of the sensor circuit is to be written. The trimming data input from at least one of the terminal is written in the memory.