Programmable Mixer Driver for Wideband Linearity Control
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Solution Overview
Problem
Frequency mixers face challenges in maintaining linearity and gain over a wide frequency range due to second-order non-linear distortion, particularly at lower oscillator signal frequencies, which affects the performance of radio frequency signal receivers and transmitters.
Innovation Solution
A circuit with a programmable driver and controller that adjusts the rise and fall times of the oscillator signal based on its frequency, using a variable drive strength to reduce distortion and improve linearity, while applying bias voltages to counter non-linearities, allowing the same frequency mixer to operate effectively across a wide range of frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a frequency mixer operates at lower oscillator signal frequencies, then power consumption is reduced, but second-order non-linear distortion increases and linearity deteriorates
Solution Approach 1:
The patent implements a programmable driver with variable drive strength that can be dynamically adjusted based on the oscillator signal frequency. The driver includes multiple stages with different drive strengths that are selectively enabled or disabled according to the operating frequency, allowing the system to optimize between power consumption and linearity requirements across different frequency ranges.
Solution Approach 2:
The patent changes the drive strength parameter of the programmable driver based on the oscillator signal frequency. By adjusting the drive strength parameter to have an inverse relationship with frequency (higher drive strength at lower frequencies, lower drive strength at higher frequencies), the system maintains optimal linearity while managing power consumption across the operating frequency range.
2Reliability
If the drive strength of the programmable driver is increased to improve linearity at lower frequencies, then power consumption increases
Solution Approach 1:
The programmable driver dynamically adjusts its drive strength based on the oscillator signal frequency. At lower frequencies where linearity is more critical, the driver enables additional stages to provide higher drive strength. At higher frequencies where power consumption is more concerning, the driver disables unnecessary stages to reduce power consumption while maintaining adequate linearity.
Solution Approach 2:
The system changes the drive strength parameter of the programmable driver according to the operating frequency. The controller monitors the oscillator frequency and programmatically adjusts the drive strength parameter, creating an adaptive system that optimizes the trade-off between linearity and power consumption for each operating condition.
3Reliability
If the rise time and fall time of the oscillator signal are reduced to improve linearity, then the drive strength must be increased which increases power consumption
Solution Approach 1:
The programmable driver provides dynamic control over the rise time and fall time of the oscillator signal by adjusting its drive strength. The controller selectively enables or disables driver stages based on the required rise/fall times for the current operating frequency, allowing the system to achieve optimal signal edges for linearity while minimizing power consumption by not always using maximum drive strength.
Data Source
AI summary
The disclosure relates to technology for shifting a frequency range of a signal. In one aspect, a circuit comprises a frequency mixer, a frequency synthesizer configured to generate an oscillator signal, a programmable driver, and a controller. The programmable driver is configured to receive the oscillator signal from the frequency synthesizer and to provide the oscillator signal to the oscillator input of the frequency mixer. The programmable driver is configured to have a variable drive strength. The controller is configured to control the drive strength of the programmable driver based on a frequency of the oscillator signal to adjust a rise time and a fall time of the oscillator signal at the oscillator input of the frequency mixer.