Multimode Receiver Translational Loop for Input Matching
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Solution Overview
Problem
Current RF receivers face challenges in tolerating strong out-of-band interference while maintaining low noise figure and power consumption, especially in multi-standard applications, due to limited TX-to-RX isolation and the need for multiple inductors and SAW filters.
Innovation Solution
A multimode receiver design featuring a transconductance amplifier, current mixer, low-pass filter, and transimpedance amplifier, with a translational loop using switches controlled by a local oscillator for adaptive gain modes and input matching, allowing for high gain and low gain operations with reduced noise and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SAW filter is added to suppress TX leakage, then out-of-band IIP3 is improved, but device complexity and size increase
Solution Approach 1:
The patent extracts and eliminates the SAW filter from the receiver architecture by implementing a translational loop that translates out-of-band interferers to baseband where they can be filtered by the existing low-pass filter, thereby maintaining IIP3 performance without the additional filter component
Solution Approach 2:
The patent introduces a translational loop as an intermediary mechanism that uses mixers and a local oscillator to translate out-of-band signals to baseband frequency, enabling the existing low-pass filter to perform the suppression function that would otherwise require a dedicated SAW filter
2Adaptability or versatility
If multiple inductors are used for different bands, then multi-standard application support is improved, but chip area increases
Solution Approach 1:
The patent implements a universal receiver architecture where a single set of inductors serves multiple frequency bands through the translational loop mechanism, which can translate different out-of-band frequencies to baseband regardless of the specific band configuration, eliminating the need for separate inductors for each standard
Solution Approach 2:
The patent employs dynamic frequency translation through the translational loop that can adapt to different band configurations by adjusting the local oscillator frequency, allowing the same physical inductors to effectively handle multiple standards without requiring additional components
3Reliability
If high gain mode is used to improve sensitivity, then noise figure is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic gain control where the receiver can switch between high gain and low gain modes based on signal conditions, allowing optimization of noise figure when needed while reducing power consumption during normal operation through the switchable gain stages in the translational loop
Data Source
AI summary
A multimode receiver has a transconductance amplifier having an input terminal and adapted to receive a voltage RF signal and to deliver a current RF signal. The amplifier has a current mixer coupled to the transconductance amplifier and adapted to receive the current RF signal, the current mixer being adapted to combine the current RF signal with a signal generated by a local oscillator, the mixer generating an intermediate frequency signal having a frequency that equals a combination of a frequency of the current RF signal and a frequency of the local oscillator. A low-pass filter is coupled to the mixer and is adapted to generate a low-pass current signal. A transimpedance amplifier is coupled to the low-pass filter and is adapted to receive the low-pass current signal, the transimpedance amplifier being adapted to generate an intermediate frequency voltage signal proportional with the low-pass current signal. A first switch is adapted to receive a signal proportional with the intermediate frequency voltage signal at a first end, a second end being coupled to the input terminal and a second switch is coupled between the input terminal and a reference terminal. The first and second switches are mutually exclusive in an ON state in a specific mode of operation of the multimode receiver.