Voltage Source Circuit Stabilization Under Low DC Bias
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Solution Overview
Problem
Conventional voltage source and current source circuits experience instability and deviation from ideal output levels when operated under lower DC bias, leading to unstable signal sources and noise generation, limiting their portability and full-swing output capabilities in modern electronic products.
Innovation Solution
The proposed solution involves a voltage source and current source circuit configuration that includes an amplifier, first and second current mirror circuits, a PMOS transistor, and an NMOS transistor, where the PMOS transistor acts as a source follower to adjust the amplifier output voltage, ensuring stability even under low DC bias conditions by duplicating driving currents and voltages through the current mirror circuits, thereby maintaining a stable reference voltage and current source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional voltage source and current source circuits are operated under lower DC bias to achieve lower power consumption, then power consumption is reduced, but the output voltage of the amplifier deviates from the ideal output voltage level, causing signal instability and noise
Solution Approach 1:
A source follower circuit is introduced as an intermediary between the amplifier and the current mirror circuit. This source follower acts as a buffer that isolates the amplifier from the load, preventing the amplifier's output voltage from being directly affected by the current mirror's current draw. The source follower's high input impedance and low output impedance characteristics allow it to maintain stable voltage levels even under low DC bias conditions, thereby resolving the contradiction between low power consumption and signal stability.
2Use of energy by moving object
If conventional voltage source and current source circuits are operated under lower DC bias, then power consumption is reduced, but the output voltage of the amplifier is too close to the DC bias, constraining the selection of configurations for fulfilling the requirements of the full-swing output voltage
Solution Approach 1:
The source follower circuit serves as a voltage buffer that decouples the amplifier's output stage from the current mirror's current requirements. This intermediary allows the amplifier to operate with a smaller voltage swing while the source follower maintains a stable output voltage, effectively extending the usable output voltage range and providing greater configuration flexibility under low DC bias conditions.
3Use of energy by moving object
If the amplifier output voltage is allowed to deviate from the ideal output point to achieve lower DC bias operation, then power consumption is reduced, but the signal source becomes unstable and noise increases
Solution Approach 1:
The source follower circuit acts as a noise-isolating intermediary between the amplifier and the rest of the circuit. By providing a high input impedance, it minimizes the loading effect on the amplifier, allowing the amplifier to operate at lower DC bias with reduced noise. The source follower's inherent voltage buffering capability maintains signal integrity while enabling energy-efficient operation.
Data Source
AI summary
The voltage source and current source circuits including an amplifier, a first current mirror circuit, a first PMOS transistor, a second current mirror circuit and a NMOS transistor are provided. The amplifier has a positive input terminal and a negative input terminal coupled to the source terminal of the NMOS transistor. The first current mirror circuit is coupled to a reference current and duplicates the reference current to the source terminal of the first PMOS transistor. The first PMOS transistor has a drain terminal, a gate terminal and a source terminal. The drain terminal of the NMOS transistor is coupled to the third current terminal, and the gate terminal of the NMOS transistor is coupled to the source terminal of the first PMOS transistor. The second current mirror circuit duplicates the current from the third current terminal.