RF DAC Capacitor Modulation for High-Bandwidth Low-Power MIMO
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Solution Overview
Problem
Current digital to analog converters (DACs) in mobile communication devices face challenges in achieving high signal bandwidth, low current consumption, and Multiple Input, Multiple Output (MIMO) capability simultaneously.
Innovation Solution
A radio frequency digital to analog converter is designed with a capacitor arrangement and controller that combines in-phase and quadrature components with local oscillator signals to generate modulation signals, controlling switchable capacitor paths to produce a differential analog signal, enabling high bandwidth and efficiency while supporting MIMO applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional modulator types are used, then certain functions are achieved, but it is impossible to simultaneously achieve high signal bandwidth, low current consumption, and MIMO capability
Solution Approach 1:
The modulator is divided into multiple independent modulator units (first modulator unit, second modulator unit, etc.), each capable of processing one or more baseband signals. This segmentation allows the system to achieve MIMO capability by using multiple units while maintaining low current consumption in each individual unit, as each unit can be optimized independently for efficiency.
2Speed
If conventional modulator types are used, then certain functions are achieved, but it is impossible to simultaneously achieve high signal bandwidth, low current consumption, and MIMO capability
Solution Approach 1:
The modulator employs dynamic element selection where the number of active modulator units can be adjusted based on the required signal bandwidth and MIMO configuration. This dynamic operation allows the system to achieve high signal bandwidth when needed by activating more units, while reducing current consumption by activating fewer units when lower bandwidth is sufficient.
3Speed
If conventional modulator types are used, then certain functions are achieved, but it is impossible to simultaneously achieve high signal bandwidth, low current consumption, and MIMO capability
Solution Approach 1:
Each modulator unit is designed as a universal building block that can handle multiple baseband signals and support both single-stream and MIMO operations. This multi-functionality reduces overall device complexity compared to designing separate dedicated modulators for different functions, as the same unit architecture can be replicated and configured for various bandwidth and MIMO requirements.
Data Source
AI summary
A RF digital to analog converter has a first capacitor arrangement, a first common node, and a first controller. The first capacitor arrangement has multiple switchable capacitor paths arranged in parallel. Respective switchable capacitor paths have a switchable element and a capacitor coupled in series. The first common node is connected to the multiple switchable capacitor paths. The first controller receives a baseband signal having an in-phase component and a quadrature component, and a local oscillator (LO) signal having an in-phase LO signal and a quadrature LO signal. The first controller combines the in-phase component and the in-phase LO signal to obtain a first in-phase modulation signal and combines the quadrature component and the quadrature LO signal to obtain a first quadrature modulation signal. The first controller controls the multiple switchable capacitor paths of the first capacitor arrangement with the first in-phase modulation signal and/or the first quadrature modulation signal.