Self-Calibrated Voltage Regulator with Segmented Feedback Loop
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Solution Overview
Problem
Voltage regulators face challenges in maintaining a constant output voltage across varying load currents due to insufficient power supply rejection ratio (PSRR), leading to noise immunity issues in modern electronic devices.
Innovation Solution
A voltage regulator design incorporating a feedback circuit and a control loop with a variable resistor and operational amplifiers to adjust the feedback voltage independently of the output voltage, ensuring the regulated voltage remains constant by compensating for load current variations through a calibration loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional voltage regulator is used, then the output voltage can be maintained at a constant level, but the power supply rejection ratio (PSRR) is insufficient leading to noise immunity issues
Solution Approach 1:
The feedback circuit is segmented into two independent loops: a main feedback loop for voltage regulation and a calibration loop for PSRR optimization. The main feedback loop includes a first operational amplifier and first feedback network, while the calibration loop includes a second operational amplifier and second feedback network with a variable resistor. This segmentation allows each loop to be optimized independently, achieving high PSRR without excessive overall complexity.
Solution Approach 2:
The calibration loop automatically adjusts the variable resistor based on the output voltage detected by the second operational amplifier, enabling the system to self-optimize its PSRR performance. The calibration circuit monitors the output voltage and automatically modifies the feedback division ratio to compensate for noise, eliminating the need for external manual calibration while achieving superior noise immunity.
2Stability of the object's composition
If the feedback voltage is adjusted to compensate for load current variations, then the regulated voltage remains constant, but the adjustment must be independent of the output voltage
Solution Approach 1:
The control system is divided into two independent operational amplifiers with separate feedback networks. The first operational amplifier handles output voltage regulation through a main feedback loop, while the second operational amplifier handles load current compensation through a calibration loop with a variable resistor. This segmentation allows independent adjustment of feedback voltage without affecting output voltage stability.
Solution Approach 2:
The variable resistor in the calibration loop dynamically adjusts the feedback division ratio based on load conditions. The second operational amplifier detects output voltage variations and automatically modifies the feedback signal through the variable resistor, enabling adaptive compensation for load current variations while maintaining regulated voltage stability.
3Reliability
If a high PSRR is achieved across all frequencies, then power supply noise immunity is enhanced, but the circuit requires advanced calibration capabilities
Solution Approach 1:
The calibration loop automatically adjusts the variable resistor based on real-time output voltage detection by the second operational amplifier. This self-calibrating mechanism achieves high PSRR across all frequencies without requiring external manual calibration equipment or complex calibration procedures, simplifying manufacturing while maintaining superior noise immunity performance.
Solution Approach 2:
The calibration loop uses feedback from the second operational amplifier to continuously monitor output voltage and automatically adjust the variable resistor to optimize PSRR. This closed-loop feedback mechanism ensures high-frequency noise rejection is automatically maintained without requiring manual calibration, making the high-performance circuit easier to manufacture and implement.
Data Source
AI summary
A voltage regulator includes a driving circuit, a feedback circuit, first and second control circuits and a resistor. The driving circuit is coupled to an input node and an output node and generates an output voltage at the output node from an input voltage at the input node. The feedback circuit is coupled to the output node and generates a feedback voltage based on the output voltage. The first control circuit is coupled to the feedback circuit and the driving circuit to control the output voltage based on the feedback voltage. The resistor has opposite first and second terminals. The first terminal of the resistor is coupled to the output node. The second control circuit is coupled to the second terminal of the output stage resistor and the feedback circuit to control the feedback voltage based on a regulated voltage at the second terminal of the resistor.