RF Power Detector Circuit With Non-Linearity Cancellation
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Solution Overview
Problem
Designing a satisfactory radio-frequency amplifier for electronic devices with wireless communications capabilities is challenging due to linearity degradation when power detection circuits are coupled to the amplifiers, affecting the amplifier's performance.
Innovation Solution
Incorporating non-linearity cancellation components, such as metal-oxide-semiconductor (MOS) capacitors, into the power detection circuit to mitigate non-linear effects and improve the third-order intercept point (IP3) of the radio-frequency amplifier, which enhances the amplifier's throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a power detection circuit is coupled to the output of a radio-frequency amplifier, then power detection capability is improved, but linearity of the amplifier deteriorates
Solution Approach 1:
The patent introduces non-linearity cancellation components (MOS capacitors) as intermediary elements between the power detection circuit and the radio-frequency amplifier. These capacitors generate compensating signals that cancel the non-linear effects introduced by the power detection circuit, thereby maintaining amplifier linearity while enabling power detection capability.
Solution Approach 2:
The non-linearity cancellation components perform preliminary anti-action by generating compensating signals before the non-linear distortion fully affects the amplifier output. The MOS capacitors are configured to produce inverse non-linearities that preemptively counteract the linearity degradation caused by the power detection circuit coupling.
2Stability of the object's composition
If non-linearity cancellation components are added to the power detection circuit, then linearity of the amplifier is improved, but device complexity increases
Solution Approach 1:
The patent utilizes parameter changes by exploiting the voltage-dependent capacitance characteristics of MOS capacitors. By changing the operating voltage conditions and biasing schemes, the non-linearity cancellation components dynamically adjust their capacitance values to compensate for non-linear effects across different power levels, achieving linearity improvement through parameter modulation rather than complex circuit topologies.
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 use of non-linearity cancellation components in the power detection circuit improves the linearity of radio-frequency amplifiers, specifically by reducing third-order intermodulation distortion, thereby enhancing the amplifier's performance and efficiency.
Implementation Method 1
a non-linearity cancellation component configured to generate a current that at least partially cancels a non-linear current associated with the input transistor. The non-linearity cancellation component can be a metal-oxide-semiconductor (MOS) capacitor
Data Source
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AI summary
Wireless circuitry can include a radio-frequency amplifier and a power detection circuit (70) coupled to an output of the radio-frequency amplifier. The power detection circuit (70) can include an input transistor (110), a biasing circuit (156, 158, 160) configured to output a bias voltage for the input transistor (110) and configured to track temperature and voltage variations, and a non-linearity cancellation component (150) configured to generate a current that at least partially cancels a non-linear current associated with the input transistor (110). The input transistor (110) may be an n-type transistor, and the non-linearity cancellation component (150) may be a p-type metal-oxide-semiconductor capacitor. The biasing circuit (156, 158, 160) can include n-type and p-type diode-connected bias transistors.