PLL Regulator Precharge Circuit for Fast Voltage Stabilization
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Solution Overview
Problem
Existing step-down regulator circuits in PLL systems face challenges in quickly stabilizing the voltage output, which leads to increased jitter and longer lock times for the phase-locked loop.
Innovation Solution
The proposed regulator circuit includes a feedback loop, a precharge circuit, and switches that allow the capacitor to be charged and connected to the feedback loop in a controlled manner, optimizing bandwidth and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an internal capacitor is added to the LDO regulator to remove high-frequency noise, then noise reduction is improved, but the high-frequency bandwidth is reduced and voltage stabilization time increases
Solution Approach 1:
The precharge circuit charges the capacitor to a predetermined voltage before the LDO regulator begins operation. This preliminary charging action ensures that when the regulator starts, the capacitor is already at the correct voltage level, eliminating the initial voltage stabilization delay that would normally occur. The system performs the capacitor charging action in advance, before it is strictly needed for noise filtering.
Solution Approach 2:
The circuit uses control switches to dynamically change the configuration of the capacitor during different operational phases. Initially, the capacitor is connected to the precharge circuit for charging; then, control switches transition the capacitor to its operational position in the feedback loop. This dynamic reconfiguration allows the system to optimize performance at different stages of operation.
2Object-affected harmful factors
If the LDO regulator bandwidth is reduced to improve noise filtering, then noise reduction is improved, but the voltage stabilization speed decreases
Solution Approach 1:
By precharging the capacitor before the LDO regulator operates, the system eliminates the initial transient response that would normally require time for the regulator to stabilize. The capacitor is already at the correct voltage when the regulator begins filtering noise, so the full bandwidth capability is available immediately without the usual startup delay.
Solution Approach 2:
The precharge circuit ensures that the capacitor maintains its charging continuity, being charged to the required voltage level before the regulator needs it. This continuous preparation of the capacitor ensures that the noise filtering function can operate at full effectiveness without interruption or delay, maintaining both noise reduction and fast response.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables faster stabilization of the regulated voltage, reducing the time needed to lock the phase of the output signal and improving the low-noise characteristic of the PLL system.
Implementation Method 1
a first capacitor; a precharge circuit connected to the feedback loop, and configured to charge the first capacitor with a second voltage which is based on a first voltage
Data Source
AI summary
An electronic device including: a regulator circuit configured to output a regulated voltage based on a reference voltage and a feedback voltage; and an oscillator configured to generate an output frequency signal based on a reference frequency signal and the regulated voltage output from the regulator circuit, wherein the regulator circuit includes: a feedback loop configured to output the regulated voltage based on a difference between the reference voltage and the feedback voltage; a first capacitor; a precharge circuit connected to the feedback loop, and configured to charge the first capacitor with a second voltage which is based on a first voltage; a first switch configured to connect the precharge circuit with the first capacitor; and a second switch configured to connect the first capacitor with the feedback loop.