Image Sensor Readout Circuit Bonding Pad Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The operation of the first section of the readout circuit in image sensors is often disrupted by the operation of the second section due to fluctuations in the operating voltage and reference potential, particularly in pipeline architectures where different clock frequencies are used, leading to interference and signal disruptions.
Innovation Solution
Arranging bonding pads for supplying the operating voltage and reference potential between the first and second sections of the readout circuit, with separate bonding pads for each section to minimize interference, and using larger bonding wires with lower electrical resistance to dissipate pulse currents, thereby reducing the impact of one section's operation on the other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the first and second sections of the readout circuit share common bonding pads for power supply and reference potential, then the device complexity is reduced, but the operation of one section disrupts the other due to voltage fluctuations and current interference
Solution Approach 1:
The bonding pads are segmented into separate groups: first bonding pads connected exclusively to the first readout circuit section and second bonding pads connected exclusively to the second readout circuit section. This segmentation prevents current interference between sections while maintaining a relatively simple overall device structure.
Solution Approach 2:
Separate bonding pads act as intermediaries that isolate the power supply and reference potential connections for each readout circuit section. This intermediary structure prevents direct electrical interference between sections while still providing necessary power and reference connections.
2Reliability
If larger bonding wires with lower electrical resistance are used, then pulse currents are better dissipated and voltage stability improves, but the manufacturing complexity and cost increase
Solution Approach 1:
Larger bonding wires with lower electrical resistance are applied locally at the bonding pad connections where high current dissipation is critical, rather than throughout the entire circuit. This localized application provides voltage stability where needed while minimizing manufacturing complexity elsewhere.
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 arrangement provides extensive mutual shielding and decoupling of the two sections, preventing significant interference and maintaining stable voltage and reference potential, thus ensuring uninterrupted operation of both sections even at different clock frequencies.
Implementation Method 1
The bonding wires have a significantly larger cross-section than the conductors on the image sensor and therefore a significantly lower electrical resistance
Data Source
AI summary
The invention relates to an image sensor for electronic cameras, comprising a plurality of light-sensitive pixels for generating exposure-proportional signals and at least one readout circuit coupled to the pixels, the readout circuit having a first section and a second section connected downstream of the first section in a signal readout direction. The first section and the second section are each connected to the readout circuit via at least one bond pad provided for supplying an operating voltage and/or at least one bond pad provided for supplying a reference potential. At least some of the bond pads provided for supplying the readout circuit with the operating voltage and/or the reference potential are arranged between the first section and the second section of the readout circuit.