Active Balun Circuit Without Wire-Wound Inductors
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Solution Overview
Problem
The increase in semiconductor chip area due to the inclusion of balun circuits with wire winding inductors in power amplifier circuits, which complicates the reduction of overall chip size and increases process costs.
Innovation Solution
An active balun circuit utilizing transistors and impedance elements, such as resistors, inductors, or capacitors, to achieve differential signal output without the need for wire winding inductors, thereby reducing chip area and process complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a balun is implemented using wire winding inductors in the power amplifier circuit, then the balun function is achieved, but the semiconductor chip area increases
Solution Approach 1:
The patent replaces wire winding inductors (mechanical component) with an active circuit implementation using transistors (Q1, Q2), resistors (R1, R2), and capacitors (C1, C2) to achieve the balun function. This substitution eliminates the need for physical wire windings and significantly reduces the chip area required for the balun circuit.
Solution Approach 2:
The patent changes the implementation approach from passive inductor-based balun to active transistor-based balun. By using transistors configured in a differential pair arrangement with appropriate biasing and impedance matching components, the circuit achieves balun functionality through active device characteristics rather than passive inductance, thereby reducing area.
2Reliability
If wire winding inductors are used in the balun circuit, then the balun performance is achieved, but the process complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces wire winding inductors (mechanical component) with an active circuit implementation using transistors (Q1, Q2), resistors (R1, R2), and capacitors (C1, C2) to achieve the balun function. This substitution eliminates the need for physical wire windings and significantly reduces the chip area required for the balun circuit.
Solution Approach 2:
The patent changes the implementation approach from passive inductor-based balun to active transistor-based balun. By using transistors configured in a differential pair arrangement with appropriate biasing and impedance matching components, the circuit achieves balun functionality through active device characteristics rather than passive inductance, thereby reducing area.
Data Source
AI summary
An active balun circuit includes first and second transistors having emitters electrically coupled to each other and configured to output differential signals and a circuit element coupled between the connection point of the emitter of the first transistor and the emitter of the second transistor and a reference potential. The impedance of the circuit element at a particular frequency of the input signal appears significantly larger than impedances at other frequencies. An input signal from an input terminal is inputted to the base of the first transistor. The reference potential is applied to the base of the second transistor. A supply voltage is applied to the collector of the first transistor and the collector of the second transistor. A signal from the collector of the first transistor and a signal from the collector of the second transistor are outputted as the differential signals.