Sigma-Delta Converter Bandwidth Switching via Reference Voltage
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Solution Overview
Problem
Conventional sigma delta converters face challenges in efficiently handling multiple bandwidths due to conflicting hardware requirements for narrowband and broadband signals, leading to increased complexity and cost with large numbers of capacitors.
Innovation Solution
A method and apparatus that adjust the bandwidth mode of a sigma delta converter by varying the reference voltage, using switched-capacitor digital-to-analog converters with dynamic element matching, allowing the converter to operate in both narrowband and broadband modes without significant compromise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If large capacitors are used to achieve low switching noise and high dynamic range for narrowband signals, then noise performance is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements dynamic switching of capacitor configurations between parallel and series connections based on bandwidth mode. In narrowband mode, capacitors are connected in parallel to achieve low switching noise and high dynamic range. In broadband mode, capacitors are connected in series to enable high-speed operation. This dynamic reconfiguration allows the system to optimize noise performance when needed without permanently requiring large capacitor values.
Solution Approach 2:
The patent changes the effective capacitance parameter by reconfiguring capacitor connections between parallel and series arrangements. This parameter change allows the same physical capacitors to provide different effective capacitance values: larger effective capacitance for narrowband low-noise operation, and smaller effective capacitance for broadband high-speed operation, eliminating the need for multiple capacitor sets.
2Speed
If small capacitors are used to enable high-speed operation for broadband signals, then speed is improved, but dynamic range and noise performance deteriorate
Solution Approach 1:
The system dynamically reconfigures capacitor connections based on the required operating mode. When broadband high-speed operation is required, capacitors are connected in series to provide smaller effective capacitance values that enable faster charging and discharging. When narrowband operation is required, capacitors switch to parallel configuration to provide larger effective capacitance for low-noise performance.
Solution Approach 2:
The same set of capacitors serves multiple functions by being reconfigured between parallel and series connections. The capacitors can provide both the large capacitance needed for low-noise narrowband operation and the small capacitance needed for high-speed broadband operation, making the circuit multi-functional without requiring separate capacitor sets for each mode.
3Adaptability or versatility
If multiple capacitor configurations are used to handle different bandwidths, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent uses dynamic switching of capacitor connections controlled by bandwidth mode signals. The system can adapt between narrowband and broadband modes by reconfiguring the same physical capacitors into different connection patterns (parallel or series), providing adaptability without requiring separate capacitor sets for each bandwidth mode.
Solution Approach 2:
A single set of capacitors is designed to perform multiple functions by being reconfigured between parallel and series connections. This universal capacitor structure can handle both narrowband and broadband signals, eliminating the need for multiple dedicated capacitor sets and reducing overall device complexity while maintaining versatility.
4Object-affected harmful factors
If a receiver is designed for narrowband signals with high dynamic range requirements, then noise performance is improved, but speed and broadband capability are reduced
Solution Approach 1:
The receiver dynamically adjusts its capacitance configuration based on the signal type being processed. When processing narrowband signals, the system configures capacitors in parallel to achieve high dynamic range and low noise. When processing broadband signals requiring high speed, the system reconfigures capacitors in series to enable faster operation, thus adapting noise and speed characteristics to match the signal requirements.
Data Source
AI summary
A method and apparatus for adjusting a bandwidth of a sigma delta converter by adjusting a reference voltage provided to the sigma delta converter. The apparatus includes a switched capacitor digital-to-analog converter in the feedback loop of the sigma delta modulator. The sigma delta modulator determines the bandwidth mode of the converter and adjusts the reference voltage to deliver high performance functionality. In one embodiment, a multi-bit digital signal is received by the digital-to-analog converter. The reference voltage is provided to multiple capacitive circuits of the digital-to-analog converter and the capacitive circuits are activated and deactivated based on the multi-bit digital signal. The digital-to-analog converter, thus, provides a feedback analog signal using dynamic element matching.