Mixer-First RF Receiver Gain Control and Impedance Matching
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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 impedance matching and noise reduction.
Innovation Solution
The proposed RF receiver design incorporates a mixer-first topology with a passive mixer and a gain control circuit that adjusts impedance to maintain linearity without the need for transimpedance amplifiers, using a voltage step-up circuit and switchable impedance units to provide multiple gain settings and impedance matching, reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passive mixer with large size is used to minimize mixer switch impedance, then linearity is improved, but power consumption increases due to larger LO drivers
Solution Approach 1:
The patent extracts and removes the transimpedance amplifier from the conventional receiver architecture, replacing it with a passive mixer directly connected to a high-impedance amplifier. This eliminates the need for large LO drivers while maintaining linearity through the high-impedance connection that minimizes mixer switch impedance effects.
Solution Approach 2:
Instead of using a low-impedance TIA output to drive the mixer, the patent inverts the approach by using a high-impedance amplifier output to drive the passive mixer. This inversion allows the mixer to operate in a high-impedance environment, reducing the need for large mixer sizes and LO driver power consumption.
2Reliability
If a transimpedance amplifier with large current consumption is used to maintain low noise and low impedance, then noise performance is improved, but power consumption increases
Solution Approach 1:
The patent removes the transimpedance amplifier entirely from the signal path, replacing its function with a passive mixer directly connected to a high-impedance amplifier. This eliminates the large current consumption required by the TIA while maintaining noise performance through the passive mixing architecture and high-impedance connection.
Solution Approach 2:
The patent replaces the active TIA circuit with a passive mixing architecture. The passive mixer, combined with the high-impedance amplifier, substitutes the mechanical/electrical function of the TIA without requiring large currents, thereby reducing power consumption while maintaining the required noise and impedance characteristics.
3Reliability
If the mixer size is increased to reduce mixer switch impedance, then impedance matching is improved, but device area increases
Solution Approach 1:
The patent inverts the conventional approach by operating the passive mixer in a high-impedance environment rather than a low-impedance environment. This allows the use of smaller mixer sizes while maintaining impedance matching, as the high-impedance amplifier output naturally provides the required impedance without requiring large mixer devices.
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.