Imaging Current-Source Ramp Control for Built-In Fault Detection
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Solution Overview
Problem
Existing imaging devices require external inspection devices to test current sources for malfunctions, which increases test time due to the influence of parasitic RC and other factors, making it desirable to detect malfunctions within the device without external aid.
Innovation Solution
An imaging device with a control unit that generates first-phase and second-phase ramp voltages using first and second group current sources, allowing for malfunction detection within the device without external inspection, thereby omitting the need for external devices and reducing test time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external inspection device is used to test current sources, then measurement accuracy can be improved, but test time increases due to parasitic RC influence
Solution Approach 1:
The patent extracts the malfunction detection function from the external inspection device and relocates it to the imaging device itself. By generating test signals internally and using the imaging device's own ADC and processing circuits to detect malfunctions, the system eliminates the need for external equipment, thereby removing parasitic RC influences and significantly reducing test time while maintaining measurement accuracy through the device's built-in measurement pathways
Solution Approach 2:
The imaging device performs self-diagnosis by using its own current sources, ADC, and processing circuits to detect malfunctions. The device generates test ramp voltages internally, compares them against expected values, and identifies malfunctioning current sources without requiring external inspection equipment,从而实现 self-service malfunction detection that eliminates external parasitic influences
2Reliability
If multiple current sources are tested individually using external inspection device, then each current source can be detected, but the test process becomes complex and time-consuming
Solution Approach 1:
The patent merges the malfunction detection function with the normal imaging processing circuits. The same ADC, signal processing circuits, and control logic used for normal operation are utilized to generate test ramp voltages and detect current source malfunctions. This integration eliminates the need for separate external inspection equipment and simplifies the test process while maintaining comprehensive malfunction detection capability for all current sources
Data Source
AI summary
An imaging device according to an embodiment of the present disclosure includes: a plurality of current sources including first group current sources and second group current sources; and a control unit that controls driving of the first group current sources to generate a first-phase ramp voltage and controls driving of the first group current sources and at least one current source of the second group current sources to generate a second-phase ramp voltage.