Variable Feedback Gain Delta Modulator for Low-Power ADCs
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Solution Overview
Problem
Existing analog-to-digital converters, such as flash-type and sigma delta converters, face challenges in power consumption and implementation area due to fixed feedback gains in delta modulators, which limits their efficiency in wireless communication systems.
Innovation Solution
A delta modulator with a variable feedback gain is implemented using a capacitor group classified into first and second capacitor groups, and a switch group controlled by digital output signals, allowing adaptive adjustment of feedback gain based on clock signal frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a flash-type analog-to-digital converter is used, then operation speed is improved, but power consumption and implementation area increase
Solution Approach 1:
The patent applies dynamics by making the feedback gain variable rather than fixed. The delta modulator adjusts its feedback gain dynamically based on operating conditions, allowing it to optimize performance across different signal ranges. This dynamic adjustment enables the system to achieve high conversion speeds similar to flash-type converters while consuming less power, as the variable gain allows for more efficient operation in different phases.
Solution Approach 2:
The patent changes the parameter of feedback gain from a fixed value to a variable parameter. By implementing variable feedback gain through switched capacitor networks, the system can adapt its conversion characteristics to different operating conditions. This parameter change allows the converter to maintain high speed performance while reducing power consumption compared to traditional fixed-gain architectures.
2Speed
If a flash-type analog-to-digital converter is used, then operation speed is improved, but implementation area increases
Solution Approach 1:
The dynamic feedback gain adjustment allows the converter to achieve high-speed performance without requiring the large implementation area of flash-type converters. By dynamically optimizing the conversion process, the system maintains speed performance while using a more compact architecture.
Solution Approach 2:
By changing the feedback gain parameter dynamically, the patent enables a compact implementation that does not require the extensive comparator array of flash-type converters. The variable gain approach allows high-speed conversion in a smaller area by adapting the conversion characteristics rather than using a fixed, resource-intensive architecture.
3Use of energy by moving object
If a SAR-type analog-to-digital converter is used, then power consumption and implementation area are reduced, but operation speed decreases
Solution Approach 1:
The patent applies dynamics by implementing variable feedback gain that adapts during conversion phases. This dynamic adjustment enables the delta modulator to achieve faster operation compared to SAR-type converters while maintaining low power consumption. The system can optimize its conversion speed dynamically without sacrificing the power efficiency of sequential conversion architectures.
4Device complexity
If a fixed feedback gain of 1 is used in a delta modulator, then implementation is simplified, but adaptability to different operational conditions is limited
Solution Approach 1:
The patent makes the feedback gain dynamic rather than fixed at 1. By implementing variable feedback gain through switched capacitor networks controlled by digital output signals, the delta modulator can adapt to different operational conditions and signal characteristics. This dynamic approach maintains reasonable implementation complexity while significantly improving adaptability.
Solution Approach 2:
The patent changes the feedback gain from a fixed parameter to a variable parameter that can be adjusted based on operating conditions. This parameter change enables the system to adapt to different signal ranges and conversion requirements without requiring a completely different architecture, maintaining implementation feasibility while improving versatility.
Data Source
AI summary
A variable feedback gain delta modulator includes group of capacitors commonly connected to a first terminal and are respectively classified into a first capacitor group and a second capacitor group; a comparator for sequentially generating n-bit digital output signals based on a voltage of the first terminal; and a switch group including switches respectively connected to the capacitors, wherein the switches are respectively classified into a first switch group and a second switch group respectively connected to the first capacitor group and the second capacitor group, and the first switch group and the second switch group respectively operate according to a first control signal and a second control signal that are determined based on the n-bit digital output signals and the variable feedback gain.