Mixer-First RF Receiver Gain Control for Low-Power Linearity
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Solution Overview
Problem
Conventional RF receivers face challenges in achieving high linearity and low power consumption due to the large size and high power consumption of passive mixers and transimpedance amplifiers, which are necessary for low output impedance and noise reduction.
Innovation Solution
A radio frequency receiver design that incorporates a passive mixer, a gain control circuit, and an amplifier, where the passive mixer has high impedance configurations and a mixer-first topology, eliminating the need for transimpedance amplifiers and reducing power consumption by using a gain control circuit to adjust impedance and gain settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passive mixer with low output impedance is used to achieve high linearity, then the linearity of the receiver is improved, but the power consumption increases due to larger mixer size and larger LO drivers
Solution Approach 1:
The patent inverts the conventional approach by using a passive mixer with high output impedance instead of low output impedance. This inversion allows the use of smaller mixer sizes and smaller LO drivers, thereby reducing power consumption while maintaining acceptable linearity through the high impedance configuration
Solution Approach 2:
The patent changes the impedance parameter of the passive mixer from low to high output impedance. This parameter change fundamentally alters the mixer's interaction with the LNA, enabling reduced component sizes and lower power consumption while achieving the desired linearity performance
2Reliability
If a transimpedance amplifier is used to achieve low output impedance, then the linearity is improved, but the power consumption increases due to large current consumption
Solution Approach 1:
The patent extracts and removes the transimpedance amplifier from the receiver architecture. By eliminating this high power consumption component entirely and replacing it with a passive mixer configuration, the system achieves the desired low output impedance effect without the associated current consumption
Solution Approach 2:
The patent introduces a high impedance passive mixer as an intermediary between the LNA and the rest of the receiver chain. This intermediary component provides the necessary impedance transformation and signal conditioning without requiring the high current consumption of a transimpedance amplifier
3Reliability
If a larger mixer size is used to minimize mixer switch impedance, then the linearity is improved, but the device area increases and power consumption increases
Solution Approach 1:
The patent changes the impedance parameter of the passive mixer to high output impedance, which allows the use of smaller mixer sizes. This parameter change fundamentally alters the impedance transformation characteristics, enabling reduced device area while maintaining acceptable linearity performance
Data Source
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AI summary
A radio frequency receiver (100, 600, 900, 1000, 1100) is provided. The receiver (100, 600, 900, 1000, 1100) can be employed in a low power (or ultra-low power) receiver architecture to generate a baseband signal or an intermediate frequency signal. In addition, the receiver (100, 600, 900, 1000, 1100) includes capabilities of gain control to provide different gain settings as well as providing better/improved impedance matching control.