Ring Oscillator PLL Voltage Feedback for Supply Limit Control
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Solution Overview
Problem
Traditional PLL circuits face performance degradation when the supply voltage of a ring oscillator exceeds a predetermined value, leading to instability and inefficiency.
Innovation Solution
A phase locked loop circuit design incorporating a phase frequency detector, control circuit, charge pump, loop filter, voltage-controlled oscillator, frequency divider, and voltage detector, which generates control signals to regulate the supply voltage within acceptable limits by preventing excessive voltage through a protection circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the supply voltage of the ring oscillator is increased to improve oscillation performance, then the oscillation frequency and stability are improved, but the supply voltage exceeds the predetermined value causing performance degradation and potential damage
Solution Approach 1:
The patent implements a feedback mechanism where the voltage detector continuously monitors the supply voltage of the ring oscillator and feeds this information back to the control circuit. When the voltage exceeds the predetermined threshold, the control circuit adjusts the control signals to the charge pump to reduce the charging current, thereby lowering the supply voltage back to the acceptable range. This closed-loop feedback system ensures the supply voltage remains within safe limits while maintaining oscillation stability.
Solution Approach 2:
The patent introduces a voltage detector as an intermediary component between the supply voltage source and the ring oscillator. This intermediary monitors the supply voltage and generates detection signals that trigger the control circuit to intervene when voltage exceeds thresholds. The voltage detector acts as a mediator that prevents excessive voltage from reaching the ring oscillator by enabling timely control adjustments.
2Device complexity
If traditional voltage control methods are used without voltage monitoring, then the circuit structure is simpler, but the supply voltage cannot be maintained within acceptable ranges leading to performance degradation
Solution Approach 1:
The patent implements a self-service mechanism where the PLL circuit monitors and regulates its own supply voltage through the voltage detector and control circuit. The system automatically detects voltage deviations and adjusts control signals to maintain voltage within acceptable ranges without external intervention. This self-regulating capability ensures reliable voltage control while keeping the overall system integrated and cohesive.
Data Source
AI summary
A phase locked loop circuit includes a phase frequency detector, a control circuit, a charge pump, a loop filter, a supply circuit, a ring oscillator, a frequency divider and a voltage detector. The phase frequency detector generates a frequency-increasing signal and a frequency-decreasing signal according to a phase difference between an input signal and a feedback signal. The control circuit generates a first control signal and/or a second control signal according to the frequency-increasing signal and the frequency-decreasing signal. The charge pump generates a current signal according to the first control signal and/or the second control signal. The voltage detector monitors a supply voltage of the supply circuit, and controls the control circuit to generate only the second control signal so as to reduce the supply voltage if the supply voltage is greater than a high reference voltage.