Wireless Receiver Gain Control for Stable RFIC Operating Points
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Solution Overview
Problem
The RFIC in GPS receivers experiences unstable gain variations due to process variations and circuit design, leading to poor performance, despite the use of external low noise amplifiers, as the programmable gain amplifier's operating points are often unacceptable.
Innovation Solution
A method and apparatus for automatic gain control in a wireless receiver that includes a programmable gain amplifier and a low noise amplifier, where a control circuit compares a gain code determined by a frequency signal with a predetermined code range and adjusts the gain of the low noise amplifier or mixer module to maintain the gain within the predetermined range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the predetermined total gain is set for the RFIC, then the gain structure is defined, but the gain variations due to process variation or circuit design cause poor operating points
Solution Approach 1:
The patent implements automatic gain control by monitoring the actual gain of the programmable gain amplifier and comparing it with the expected gain. When the gain code falls outside the predetermined range, the system automatically adjusts the gain of the low noise amplifier or mixer module to compensate for the deviation, thereby maintaining the predetermined total gain and ensuring acceptable operating points.
Solution Approach 2:
The system dynamically changes the gain parameters of the low noise amplifier or mixer module based on the measured gain code of the programmable gain amplifier. By adjusting these parameters in response to process variations, the system maintains the total gain within the desired range despite manufacturing tolerances and circuit design variations.
2Object-affected harmful factors
If an external low noise amplifier is coupled to the RFIC to reduce the whole noise figure, then the noise figure is improved, but the total gain of the RFIC is reduced and gain stability issues persist
Solution Approach 1:
The automatic gain control system continuously monitors the gain code and compares it with the predetermined range. When the external low noise amplifier is coupled to the RFIC, the system detects the gain deviation caused by the additional component and automatically adjusts the gain of the low noise amplifier or mixer module to compensate, thereby maintaining both the improved noise figure and the required gain stability.
3Power
If the gain of components operating at high frequency is increased to meet total gain requirements, then the total gain is achieved, but the operating points become unacceptable due to gain variations
Solution Approach 1:
The system monitors the actual gain code of the programmable gain amplifier and uses this feedback to determine whether adjustment is needed. When the gain code is outside the predetermined range, the control circuit automatically adjusts the gain of the low noise amplifier or mixer module, allowing the system to achieve the required total gain while maintaining acceptable operating points despite high-frequency component variations.
Data Source
AI summary
A wireless receiver with automatic gain control and a method for automatic gain control of a receiving circuit utilized in a wireless receiver are provided. The receiving circuit includes a programmable gain amplifier and a low noise amplifier, and the method includes: comparing a gain code of the programmable gain amplifier with a predetermined code range, wherein the gain code is determined by a frequency signal received through the low noise amplifier; and adjusting a gain of the low noise amplifier when the gain code is out of the predetermined code range.