Pipelined ADC Comparator Circuit With Switched-Capacitor Sampling
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Solution Overview
Problem
Analog-to-digital converters (ADCs) face challenges in efficiently generating digital signals due to the limitations of traditional comparators in terms of power consumption and clock distribution complexity.
Innovation Solution
A comparator design comprising a plurality of switches, a capacitor, an amplifier, and a latch is implemented, where the switches are composed of transistors (PMOS or NMOS) to sample input and reference signals, and the amplifier generates a digital signal by amplifying the difference voltage, thereby reducing power consumption and simplifying clock distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional comparators are used in ADCs, then digital signal generation can be achieved, but power consumption is high and clock distribution complexity increases
Solution Approach 1:
The comparator employs periodic switching actions through control signals (PH1, PH2) that alternately connect the capacitor to different voltage sources during sampling and comparison phases. This periodic operation enables the circuit to perform multiple functions at different time intervals, reducing the need for continuous operation of all components and thereby lowering overall power consumption while simplifying clock distribution requirements.
Solution Approach 2:
The capacitor serves multiple functions: it stores the sampled input voltage during the sampling phase, holds this voltage during the comparison phase, and enables differential comparison with the reference voltage. The switching network also performs both sampling and comparison functions by reconfiguring connections based on control signals. This multi-functionality reduces the number of dedicated components needed, simplifying the overall circuit architecture and clock distribution.
2Device complexity
If traditional comparators are used in ADCs, then digital signal generation can be achieved, but power consumption increases
Solution Approach 1:
The comparator circuit merges the sampling function and comparison function into a single integrated structure. The same capacitor and switching network are used for both sampling the input voltage and performing the differential comparison with the reference voltage, rather than using separate dedicated circuits for each function. This merging reduces the total number of active components that would otherwise need to operate continuously, thereby reducing power consumption while maintaining a relatively simple device structure.
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 comparator design enhances the efficiency of digital signal generation in ADCs by minimizing power consumption and simplifying clock distribution, improving the overall performance of ADCs.
Implementation Method 1
a capacitor (121, 122), wherein the capacitor (121, 122) is coupled to the at least one switch (111, 114)
Implementation Method 2
an amplifier (130), wherein the amplifier (130) is coupled to the capacitor (121, 122) for receiving a difference voltage between the input signal and the reference signal and amplifies the difference voltage during the second period
Data Source
AI summary
A comparator includes a plurality of switches, a capacitor, an amplifier, and a latch. The switches provide an input signal during a first period and provide a reference signal during a second period. A first switch among the switches is composed of a first transistor. The capacitor receives the input signal during the first period and receives the reference signal during the second period. The amplifier is coupled to the capacitor for receiving a difference voltage between the input signal and the reference signal and amplifies the difference voltage during the second period to generate an amplified result. The determining circuit provides a digital signal according to the amplified result.