Passive Pulse Modulation ADC With RC Filter for Low-Power Sampling
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Solution Overview
Problem
Conventional Pulse Modulation Analog to Digital Converters (ADCs) face challenges in reducing power consumption and circuit area, especially at higher frequencies, due to the use of active elements like operational amplifiers, which become less ideal and increase power consumption and circuit size.
Innovation Solution
The implementation of a Passive Pulse Modulation Analog to Digital Converter (PPMADC) using primarily passive elements, such as a passive continuous time filter and a comparator, which converts analog signals into pulse modulated digital signals through time-discrete irregular sampling, eliminating the need for active elements in the signal path and reducing power consumption and circuit area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If active elements like operational amplifiers are used in the modulator, then the ADC can perform signal integration and modulation, but power consumption and circuit area increase significantly
Solution Approach 1:
The patent removes active elements (operational amplifiers) from the modulator circuit, extracting only the essential passive components (resistors and capacitors) needed for the RC integrator function. This extraction eliminates the high power consumption and large area associated with active elements while preserving the core integration functionality through passive RC networks.
Solution Approach 2:
The patent replaces expensive, power-hungry active elements with inexpensive passive components. The passive RC integrator uses simple resistors and capacitors that consume minimal power and occupy small area, effectively substituting the 'expensive' operational amplifier with 'cheap' passive elements that achieve the same functional goal with much lower resource cost.
2Productivity
If operational amplifiers are used as integrators in the modulator, then signal processing can be performed, but the circuit size and power consumption increase
Solution Approach 1:
The patent substitutes the electronic active system (operational amplifier-based integrator) with a passive electromagnetic system (RC integrator). The operational amplifier, which requires power supply and active control, is replaced by a passive resistor-capacitor network that performs integration through natural RC time constants, eliminating the need for continuous power consumption while maintaining signal processing capability.
3Reliability
If active elements are used in the modulator, then acceptable performance characteristics can be maintained, but the circuit requires greater area and higher supply voltage
Solution Approach 1:
The patent changes the fundamental parameters of the integrator from active to passive implementation. By adjusting the resistance and capacitance values in the RC network, the same integration function is achieved with different physical parameters that result in smaller area and lower voltage requirements. The passive RC time constant (τ = RC) replaces the active amplifier gain-bandwidth product, enabling performance maintenance with reduced area and voltage.
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 PPMADC achieves high-resolution, high-bandwidth streaming with lower power consumption and smaller circuit area, enabling successful operation at frequencies of hundreds of megahertz in 100 nm technology or smaller, while maintaining minimal voltage domain signal processing and improved streaming capabilities.
Implementation Method 1
a passive continuous time filter having a first input receiving an analog signal and a second input receiving a feedback signal, the passive continuous time filter filtering and combining the signals received at the first and second inputs
Implementation Method 2
a comparator comparing an output signal from the passive continuous time filter with at least one reference voltage to produce a pulse modulated output signal
Data Source
AI summary
Exemplary implementations of electrical circuits and systems are disclosed, and methods for signal processing including sampling and quantizing of amplitude and band limited signals implemented through a Passive Pulse Modulation Analog to Digital Converter (PMADC).