Variable Gain Amplifier Circuit Interleaved Signal Processing
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Solution Overview
Problem
Existing semiconductor integrated circuit devices with variable amplifier circuits face challenges in achieving uniform gain during interleave operations due to differences in capacity ratios, leading to potential fixed pattern noise, especially when fine gain control is required.
Innovation Solution
A variable gain amplifier circuit design where two input capacitors share a variable capacitor device as a feedback capacitor, allowing for synchronized interleaving of signal amplification to maintain gain uniformity during interleave operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two sets of input capacitors with different capacity ratios are used for interleave operation, then signal processing capability is improved, but gain uniformity deteriorates
Solution Approach 1:
The patent merges the feedback capacitor functions of two separate amplifier circuits by having both input capacitors share a common variable capacitor device as their feedback capacitor. This consolidation ensures that both amplifier circuits use the same capacity ratio, thereby maintaining gain uniformity while still enabling interleave operation for improved signal processing capability.
Solution Approach 2:
The variable capacitor device serves multiple functions simultaneously: it acts as the feedback capacitor for both the first and second amplifier circuits, and its capacitance can be varied to control the gain for both input signals. This multi-functionality ensures consistent gain characteristics across both interleaved signal paths.
2Adaptability or versatility
If separate variable capacitor devices are used for each amplifier circuit, then gain control flexibility is improved, but manufacturing precision deteriorates
Solution Approach 1:
Instead of using separate variable capacitor devices for each amplifier circuit, the patent combines them into a single shared variable capacitor device. This merging approach eliminates manufacturing variations between separate devices while maintaining the ability to independently control gains through the shared device's variable capacitance characteristic.
3Manufacturing precision
If capacity ratios are made identical for both input capacitors, then gain uniformity is improved, but device complexity increases
Solution Approach 1:
The patent reduces device complexity by merging the feedback capacitor components into a single shared variable capacitor device rather than using separate capacitors for each amplifier circuit. This consolidation achieves identical capacity ratios for both input capacitors (improving gain uniformity) while simultaneously reducing the overall number of components and simplifying the circuit configuration.
Data Source
AI summary
There is a need for providing a variable amplifier circuit suited for a semiconductor integrated circuit and a high-performance camera preprocessing LSI using the variable amplifier circuit. At first timing, a first input capacitor acquires a first signal. An amplifier circuit amplifies a second signal acquired to the second input capacitor according to a gain corresponding to a capacity ratio between the second input capacitor and a feedback capacitor composed of a variable capacitor device. At second timing, the second input capacitor acquires a second signal. The amplifier circuit amplifies the first signal according to a gain corresponding to a capacity ratio between the first input capacitor and the feedback capacitor. A variable gain amplifier circuit interleavingly amplifies the first signal and the second signal in synchronization with the first timing and the second timing.