Voltage-Controlled Semiconductor Inductor for Tunable RLC Circuits
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Solution Overview
Problem
Variable-capacitor RLC circuits have limited frequency range due to the constraints of variable capacitor adjustment, restricting the operational flexibility of electronic devices like radio receivers and cellular telephones.
Innovation Solution
A voltage-controlled inductor is introduced, comprising a conductor with inductive coils and semiconductor material doped to form diodes, where the depletion region dimensions change with voltage, allowing adjacent coils to be electrically shorted or isolated, thereby varying the inductance and extending the frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable capacitor is used to tune the RLC circuit, then the circuit can be adjusted over a range of frequencies, but the frequency range is limited by the capacitor's adjustment range
Solution Approach 1:
The patent changes the inductance parameter of the inductor by varying the reverse bias voltage applied to the pn junction. This voltage controls the depletion region width, which in turn controls the number of active turns in the inductor, thereby changing the inductance value and extending the frequency range of the RLC circuit.
Solution Approach 2:
The patent makes the inductor dynamically adjustable by applying a variable reverse bias voltage to the pn junction. This allows the inductance to be continuously tuned by changing the voltage, enabling dynamic frequency adjustment of the RLC circuit without mechanical moving parts.
2Adaptability or versatility
If the depletion region is used to electrically short adjacent coils, then the inductance can be varied, but the manufacturing precision is required for doping
Solution Approach 1:
The patent uses precise control of doping concentrations during manufacturing to create a pn junction with predictable depletion region characteristics. By carefully selecting dopant types and concentrations, the depletion region width can be precisely controlled at a given reverse bias voltage, enabling accurate inductance tuning.
Solution Approach 2:
The patent incorporates feedback mechanisms where the reverse bias voltage is adjusted based on the desired inductance value. The depletion region width responds to the applied voltage, and this relationship is used to achieve the target inductance through voltage control, compensating for manufacturing variations.
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 voltage-controlled inductor enables adjustable inductance over a wider range, enhancing the frequency tuning capabilities of RLC circuits and improving the performance of electronic devices by allowing more precise control over resonant frequencies.
Implementation Method 1
A voltage across the diode changes lengths of the first doped region, the second doped region and the depletion region, and adjacent coils in contact with at least one of the doped regions are electrically shorted, thereby varying the inductance of the inductor.
Data Source
AI summary
A voltage-controlled semiconductor inductor and method is provided. According to various embodiments, the voltage-controlled inductor includes a conductor configured with a number of inductive coils. The inductor also includes a semiconductor material having a contact with at least a portion of at least one of the coils. The semiconductor material is doped to form a diode with a first doped region of first conductivity type, a second doped region of second conductivity type, and a depletion region. A voltage across the diode changes lengths of the first doped region, the second doped region and the depletion region, and adjacent coils in contact with at least one of the doped regions are electrically shorted, thereby varying the inductance of the inductor. In various embodiments, the inductor is electrically connected to a resistor and a capacitor to provide a tunable RLC circuit. Other aspects and embodiments are provided herein.