Switched-Capacitor Differential Conversion for Smaller PLL Circuits
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Solution Overview
Problem
The existing phase lock loop (PLL) systems require a large area on semiconductor dies due to the size of differential amplifiers used for differential-to-single ended signal conversion, leading to increased costs.
Innovation Solution
A differential-to-single ended signal conversion circuit that utilizes switched capacitors and a control circuit to convert differential signals to single ended signals without a current source or operational amplifier, reducing the circuit's area and cost by using capacitors and switches to charge and combine signal values with a reference voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a differential amplifier is used to convert differential signals to single ended signals, then signal conversion and amplification are achieved, but the circuit occupies a large area on the semiconductor die
Solution Approach 1:
The patent extracts the signal conversion function from the traditional differential amplifier and implements it separately using a dedicated conversion circuit with switches and capacitors. This separates the conversion function from amplification, allowing the conversion circuit to use fewer components and occupy less area while the amplifier handles only the amplification function.
Solution Approach 2:
The patent segments the signal processing function into distinct stages: differential-to-single-ended conversion is performed by a dedicated conversion circuit using switches and capacitors, while amplification is handled by a separate amplifier stage. This segmentation allows each circuit to be optimized independently, reducing the total area required.
2Power
If a differential amplifier is used for signal conversion, then signal amplification is achieved, but the circuit complexity and component count increase
Solution Approach 1:
The patent extracts the amplification function from the differential-to-single-ended conversion process. Instead of using a differential amplifier that performs both functions, the invention uses a separate amplifier that only performs amplification, while conversion is achieved through a simpler switch-capacitor circuit.
Solution Approach 2:
The patent segments the signal processing into distinct functional blocks: a conversion circuit using switches and capacitors for differential-to-single-ended conversion, and a separate amplifier for signal amplification. This segmentation reduces overall circuit complexity by allowing each block to use the minimum necessary components for its specific function.
Data Source
AI summary
In one embodiment, a differential to single ended conversion circuit is configured to convert a differential signal to a single ended signal without using an operational amplifier and without using a current source to charge a capacitor.