Capacitor Divider Gain Control for Switch Distortion Compensation
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Solution Overview
Problem
Amplifier circuits face voltage distortions due to nonlinearities in switches, particularly when implemented with N-type FETs, leading to unwanted distortion products and noise, especially when handling weak input signals.
Innovation Solution
The implementation of a capacitor voltage divider with programmable capacitor banks coupled to opposing terminals of a switch, which allows for selective adjustment of capacitances to control amplifier gain and counteract voltage distortions by maintaining a specific capacitance ratio to cancel out nonlinear resistance effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switch is used in the amplifier circuit to enable the capacitor voltage divider, then the gain adjustment capability is improved, but voltage distortions and noise increase due to switch nonlinearities
Solution Approach 1:
The patent applies preliminary anti-action by introducing a distortion compensation circuit that generates compensation signals in advance to counteract the nonlinear distortion introduced by the switch. The compensation circuit includes additional capacitors connected to the switch terminals that produce opposing distortion voltages, thereby canceling out the harmful nonlinear effects before they significantly degrade the signal quality.
Solution Approach 2:
The patent uses an intermediary approach by introducing compensation capacitors as mediator elements between the switch and the signal path. These compensation capacitors (C1 and C2) act as intermediary components that interact with the switch nonlinearities to generate compensating effects, reducing the direct harmful impact of switch distortion on the amplifier output.
2Adaptability or versatility
If the capacitor voltage divider is enabled to control gain, then the gain control range is improved, but distortion products increase due to switch nonlinearities
Solution Approach 1:
The compensation circuit is designed to generate anti-distortion signals in advance that preemptively counteract the distortion products generated by the switch. By configuring capacitors C1 and C2 with specific capacitance values, the circuit creates compensation voltages that oppose and cancel the nonlinear distortion components, allowing the voltage divider to operate across its full gain range without excessive distortion.
Solution Approach 2:
The patent applies parameter changes by adjusting the capacitance values of the compensation capacitors C1 and C2 to optimize distortion cancellation. The specific parameter relationship (C1/C2 ratio) is tuned to match the switch characteristics, dynamically adapting the compensation effect to maintain low distortion across different gain settings and operating conditions.
3Reliability
If N-type FETs are used for the switch, then the switch performance is improved, but nonlinear resistance effects and associated distortions worsen
Solution Approach 1:
The patent converts the harmful nonlinear resistance effect of the N-type FET switch into a beneficial compensation mechanism. By carefully selecting the capacitance values of C1 and C2, the circuit exploits the switch's nonlinear characteristics to generate compensation voltages that cancel the distortion, effectively transforming the problematic nonlinear behavior into a useful distortion-cancellation effect.
Solution Approach 2:
The compensation capacitors C1 and C2 serve as intermediary elements that mediate between the N-type FET switch and the signal path. These intermediaries interact with the switch's nonlinear resistance to produce linearizing effects, reducing the direct transmission of nonlinear distortion while preserving the switch's essential functionality for gain control.
Data Source
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AI summary
An amplifier circuit that includes a capacitor voltage divider that is selectively enabled with a switch. The circuit includes two capacitor banks where the banks are electrically coupled to opposing side terminals of the switch. When the capacitor voltage divider is not enabled, one bank is adjusted to control the gain of the amplifier. When the capacitor voltage divider is enabled, both banks are used to control the gain of the amplifier.