Nested-Current-Mirror Amplifier Circuit for Full Input-Range Operation
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Solution Overview
Problem
Conventional amplifier circuits using a single type of input terminal are turned off in certain input voltage ranges, limiting their operational effectiveness across all input voltage ranges.
Innovation Solution
The use of a nested-current-mirror (NCM) structure with differential input terminals and current redistributors, including multiple current mirror circuits and switching elements, ensures continuous operation by redistributing current and maintaining transconductance across all input voltage ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional amplifier circuit uses only one type of input terminal, then the circuit structure is simple, but the amplifier is turned off in predetermined input voltage ranges and cannot perform desired operation in all input voltage ranges
Solution Approach 1:
The amplifier circuit is segmented into multiple differential pairs (first differential pair and second differential pair) with different input terminal types. Each differential pair is responsible for specific input voltage ranges, allowing the circuit to maintain operation across all voltage ranges while keeping each segment relatively simple.
Solution Approach 2:
The invention adds a new dimension to the circuit by introducing both p-type and n-type differential pairs, transitioning from a single-type input terminal to a multi-type configuration. This dimensional expansion enables the circuit to handle diverse input voltage ranges simultaneously.
2Reliability
If the amplifier circuit uses multiple differential pairs with different types, then the amplifier operates in all input voltage ranges, but the circuit complexity increases
Solution Approach 1:
The output currents from both the first and second differential pairs are merged through current mirror circuits and combined at a common output node. This merging approach allows the circuit to achieve continuous operation across all voltage ranges while consolidating the complexity into a unified output structure.
Solution Approach 2:
Current mirror circuits serve as intermediary elements that transfer and combine the output currents from different differential pairs. These intermediaries facilitate the integration of multiple signal paths without requiring complex direct connections between all components.
3Power
If current redistributor is added to redistribute current to differential input terminal, then transconductance is enhanced in all input voltage ranges, but the device complexity increases
Solution Approach 1:
The current redistributor implements a feedback mechanism by monitoring the output currents from the differential pairs and automatically redistributing bias currents to maintain optimal transconductance across all input voltage ranges. This feedback control enhances power efficiency without requiring manual intervention or complex external circuitry.
Solution Approach 2:
The current redistributor enables the amplifier circuit to self-adjust its bias current distribution based on the operating conditions. The circuit automatically redistributes currents to maintain high transconductance across all voltage ranges without external control, making the system self-sufficient and reducing overall complexity.
Data Source
AI summary
An amplifier circuit includes a differential input terminal, a first power supplier, an amplifier, and a current redistributor. A differential input terminal includes a first differential pair of a p-type and a second differential pair of an n-type, and receives an input voltage. A first power supplier supplies a bias current to the differential input terminal. An amplifier receives an output current of the first differential pair and an output current of the second differential pair, and applies an amplified current to an output node. A current redistributor receives the output current of the first differential pair and the output current of the second differential pair, and provides a redistribution current to the differential input terminal.