Charge-Redistribution Sample-and-Hold Circuit for PGA-Free Signal Gain
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Solution Overview
Problem
Existing analog-to-digital conversion processes are inefficient due to the large circuit area and high power consumption of programmable gain amplifiers (PGAs), and further amplification is limited by the output swing of these circuits, which hampers the effectiveness of signal conversion.
Innovation Solution
A sample and hold circuit comprising a control circuit, input switches, and capacitor arrays that operate in sample and hold phases to amplify input signals through charge redistribution, allowing for increased signal strength by receiving input signals on top electrodes and reference signals on bottom electrodes, achieving signal amplification without the need for additional amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a programmable gain amplifier (PGA) is used to amplify the input analog signal, then the signal strength is increased, but the circuit area occupied and power consumption increase significantly
Solution Approach 1:
The patent merges the amplification function with the existing sample and hold circuit by utilizing the capacitor array to perform both signal sampling and amplification. The same capacitors that hold the signal are used to redistribute charge for amplification, eliminating the need for a separate PGA circuit and reducing overall circuit area.
Solution Approach 2:
The capacitor array in the sample and hold circuit is designed to serve multiple functions: signal sampling, signal holding, and signal amplification. By configuring the switches to connect the capacitors in different arrangements, the circuit can perform amplification without requiring dedicated amplifier components, thus reducing circuit area while maintaining amplification capability.
2Power
If a programmable gain amplifier (PGA) is used to amplify the input analog signal, then the signal strength is increased, but power consumption increases significantly
Solution Approach 1:
The sample and hold circuit performs amplification using its own existing components (capacitors and switches) without requiring external power-intensive amplifier circuits. The charge redistribution mechanism uses the stored signal energy itself to generate the amplified output, rather than consuming additional power from a separate amplification stage.
Solution Approach 2:
The patent changes the operational parameters of the capacitor array by reconfiguring the switch states to achieve different amplification factors. By changing the connection topology of the capacitors through switch control, the circuit can provide variable gain without the continuous power consumption associated with traditional PGA operation.
3Power
If further amplification is applied to the output of a PGA, then the signal strength is increased beyond PGA limitations, but additional circuit components and complexity are required
Solution Approach 1:
The patent combines the sample and hold function with the amplification function into a single integrated circuit block. The capacitor array and switch network that constitute the sample and hold circuit are reconfigured to perform amplification, eliminating the need for separate PGA and additional amplification stages, thus reducing overall circuit complexity.
Solution Approach 2:
The same switch network and capacitor array used for sampling and holding the signal are utilized to perform amplification. By programmably configuring the switch states, the circuit can achieve multiple amplification factors without adding dedicated amplifier components, thereby maintaining low circuit complexity while providing enhanced signal strength.
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
The proposed solution effectively amplifies input signals in a cost-effective manner, improving the efficacy of analog-to-digital conversion by doubling or increasing the signal strength, thus overcoming the limitations of traditional PGA-based systems.
Implementation Method 1
the first capacitors provide a first sample voltage on the top electrodes of the first capacitors by charge redistribution
Data Source
AI summary
Disclosed is a sample and hold circuit and method capable of amplifying an input signal. The method includes: in a sample phase, receiving a first (second) input signal with top electrodes of first (second) capacitors, and receiving the second (first) input signal with all bottom electrode(s) of at least a part of the first (second) capacitors; in a hold phase, stopping receiving the first (second) input signal with the top electrodes of the first (second) capacitors, and receiving a first (second) group of reference signals with the bottom electrodes of the first (second) capacitors, so that the first (second) capacitors provide a first (second) sample voltage on the top electrodes of the multiple first (second) capacitors through charge redistribution, wherein the first and second input signals are a pair of differential signals and they are opposite to each other.