Multi-band RF Receiver LNA Switching Circuit
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Solution Overview
Problem
Existing multi-band receivers face challenges in efficiently supporting multiple frequency bands due to large chip area occupation and unwanted noise from LC tank frequency responses, particularly in dual-band and triple-band configurations.
Innovation Solution
A multi-band receiver design incorporating a low-noise amplifier with a switching circuit and a tunable LC tank that dynamically adjusts impedance to support multiple frequencies, sharing a loading circuit and using a mixer to convert signals, thereby reducing common-mode noise and optimizing chip area usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple independent single-band receivers are established in a chip to support multi-band operation, then the receiver can simultaneously support multiple frequency bands (e.g., 900 MHz, 1800 MHz, 1900 MHz), but the chip area is substantially occupied
Solution Approach 1:
The patent combines multiple single-band receivers into a single integrated multi-band receiver architecture. The receiving unit includes multiple receiving circuits (first receiving circuit for 900 MHz, second receiving circuit for 1800 MHz, third receiving circuit for 1900 MHz) that share common components such as the local oscillator unit, mixing unit, and filtering unit. This merging approach enables multi-band support while significantly reducing chip area compared to using three independent single-band receivers.
Solution Approach 2:
The patent implements a universal receiver architecture where a single receiving unit can handle multiple frequency bands through configurable receiving circuits. The local oscillator unit can generate multiple local oscillating signals corresponding to different bands, and the mixing unit can process signals from any band through selective connection via switching circuits. This multi-functional design allows one receiver unit to replace multiple dedicated single-band receivers.
2Area of stationary object
If a single circuit is used to achieve multi-band reception, then chip area is reduced, but the LC tank frequency response produces unwanted noise when receiving signals at specific frequencies
Solution Approach 1:
The patent extracts and removes the problematic LC tank component from the receiver architecture. Instead of using an LC tank for frequency selection and signal processing, the invention employs multiple discrete receiving circuits with dedicated filtering for each frequency band. This extraction eliminates the unwanted noise generated by the LC tank's frequency response characteristics while maintaining the ability to receive signals at specific frequencies cleanly.
Solution Approach 2:
The patent introduces switching circuits as intermediaries between the receiving circuits and the mixing unit. These switching circuits selectively connect the appropriate receiving circuit to the mixing unit based on the desired frequency band, replacing the direct LC tank connection. This intermediary approach enables clean frequency selection without the noise artifacts introduced by LC tank resonance effects.
3Adaptability or versatility
If multiple receivers are established in a chip for multi-band operation, then all frequency bands can be received, but the device complexity increases substantially
Solution Approach 1:
The patent merges multiple receiving circuits into a unified receiver architecture where the local oscillator unit, mixing unit, and filtering unit are shared resources. The local oscillator unit generates multiple local oscillating signals that can be selectively used by different receiving circuits. The mixing unit processes signals from any band through selective connection. This merging reduces device complexity compared to having completely independent receivers for each band.
Solution Approach 2:
The patent implements dynamic switching capabilities within the receiver architecture. Switching circuits dynamically connect different receiving circuits to the mixing unit based on the currently desired frequency band. The local oscillator unit dynamically generates different local oscillating signals corresponding to different bands. This dynamic reconfiguration allows a single receiver unit to adaptively handle multiple bands without requiring static, dedicated hardware for each band, thereby reducing overall device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient signal amplification and noise reduction across multiple frequency bands, improving transmission quality and reducing chip area requirements, while allowing for easy expansion to support additional frequencies.
Implementation Method 1
a first inductor coupled to the second inductor through inductive coupling
Implementation Method 2
a mixer coupled to the low-noise amplifier for converting the amplified signal into an output signal
Implementation Method 3
a multi-band LC tank for providing a first impedance at the first frequency and a second impendence at the second frequency to remove a common-mode noise of the amplified signal
Data Source
AI summary
A multi-band receiver is disclosed. The multi-band receiver includes a low-noise amplifier (LNA) and a mixer. The LNA includes a switched receiving circuit, a loading circuit, and a switching circuit. The switched receiving circuit has a first receiving circuit for receiving a first signal corresponding to a first frequency, and a second receiving circuit for receiving a second signal corresponding to a second frequency. The loading circuit is utilized for providing a specific load to the switched receiving circuit. The switching circuit is used for controlling whether the first signal or the second signal is transferred to the loading circuit. The mixer is coupled to the low-noise amplifier for receiving an output signal generated from the LNA and for down-converting the output signal.