Current-Voltage Conversion Bias Circuit for Stable Linear Amplification
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Solution Overview
Problem
Current current feedback amplifiers require multiple bias circuits, leading to complex circuit configurations and increased parts, which complicates temperature stability and amplification linearity.
Innovation Solution
A current-voltage conversion circuit with a simplified configuration using a bias circuit composed of two capacitors and transistors, where the bias circuit is directly coupled between the emitters and collectors of NPN and PNP transistors, eliminating the need for multiple bias circuits and improving temperature stability by compensating for transistor temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple bias circuits are provided in current feedback amplifiers, then the transistors can be properly biased, but the circuit configuration becomes complicated and the number of parts increases
Solution Approach 1:
The patent merges multiple bias circuits into a single integrated bias circuit that uses two capacitors (one connected to the NPN transistor and one to the PNP transistor) to provide biasing for both transistors simultaneously. This single bias circuit replaces what would traditionally require separate bias circuits for each transistor, thereby reducing the number of parts while maintaining proper biasing functionality.
2Reliability
If multiple bias circuits are provided in current feedback amplifiers, then the transistors can be properly biased, but the number of parts increases
Solution Approach 1:
The patent combines multiple biasing functions into a single bias circuit structure that serves both the NPN and PNP transistors. By using two capacitors within one bias circuit configuration rather than separate bias circuits, the total number of parts is reduced while maintaining the necessary biasing for both transistors.
3Device complexity
If a simplified bias circuit is used, then the circuit configuration is simplified, but temperature stability may deteriorate
Solution Approach 1:
The patent applies different characteristics to different parts of the bias circuit by using two distinct capacitors - one connected to the NPN transistor and another to the PNP transistor. This allows each capacitor to be optimized for its specific transistor's temperature characteristics, with each capacitor providing localized temperature compensation tailored to its associated transistor while maintaining an overall simplified circuit structure.
Data Source
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AI summary
A current-voltage conversion circuit comprises: a first transistor provided in an input stage; a second transistor provided in the input stage and has polarity different from that of the first transistor; and a bias circuit. A first terminal of the first transistor and a first terminal of the second transistor are connected to an input terminal into which an input current is input, a second terminal of the first transistor is connected to a first predetermined potential, a second terminal of the second transistor is connected to a second predetermined potential, the bias circuit is connected between the control terminal of the first transistor and the control terminal of the second transistor.