DC Output Voltage Circuit Flat PSRR via Extraction
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Solution Overview
Problem
Existing DC output voltage circuits suffer from poor power supply rejection ratio (PSRR) across various frequency ranges due to their design limitations, such as reliance on amplifiers for feedback loops, which perform poorly with high-frequency noise, and diode-connected source followers, which perform poorly with low-frequency noise, making them unsuitable for multipurpose devices requiring diverse voltage and current formats.
Innovation Solution
The circuit design includes a transistor connected to a current source and a reference voltage circuit that maintains a substantially constant gate-to-source voltage, eliminating the need for feedback loops and diode-connected configurations, thereby achieving a flat PSRR across frequencies by using a current source and a reference voltage circuit with optional capacitance to stabilize the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an amplifier is used in the feedback loop, then the circuit can provide voltage regulation, but the PSRR deteriorates at higher frequencies
Solution Approach 1:
The patent removes the amplifier from the feedback loop entirely, extracting the problematic component that caused high-frequency PSRR degradation. The circuit achieves voltage regulation through a different mechanism that does not rely on amplification, thereby eliminating the high-frequency noise amplification issue while maintaining DC voltage regulation capability.
2Measurement precision
If a diode-connected source follower is used, then the circuit can provide voltage regulation, but the PSRR deteriorates at lower frequencies
Solution Approach 1:
The patent changes the operating parameters and configuration of the transistor circuit, moving away from the diode-connected source follower topology. By adjusting the circuit parameters and using a different transistor configuration with proper biasing, the circuit achieves voltage regulation while maintaining good low-frequency PSRR performance.
3Measurement precision
If feedback loops are used, then voltage regulation can be achieved, but the circuit complexity increases
Solution Approach 1:
The patent extracts and removes the feedback loop from the circuit design. Instead of using complex feedback mechanisms, the invention employs a simpler direct voltage regulation approach using properly biased transistors and current sources, thereby reducing circuit complexity while maintaining voltage regulation functionality.
Data Source
AI summary
The disclosed technology provides circuitry for providing a DC output voltage. In accordance with one aspect of the invention, the circuit includes a power connection and a transistor connected to the power connection. A current source coupled to the transistor causes the transistor to pass at least a minimum current. The transistor's gate-to-source voltage can vary based on the current that passes through it, so that the minimum current established by the current source corresponds to a particular gate-to-source voltage. A reference voltage circuit is coupled to the transistor and causes a substantially constant voltage to appear on the gate connection of the transistor. The transistor's source connection carries an output voltage that is based on the gate voltage and the transistor's gate-to-source voltage. In accordance with one aspect of the invention, the DC output voltage circuitry has a substantially flat PSRR across frequencies of interest.