Frequency-Voltage Conversion Circuit for Leakage and Noise Stability
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Solution Overview
Problem
Frequency-voltage conversion circuits face challenges in maintaining a constant output voltage due to leakage currents and sinusoidal noise affecting constant current sources, leading to voltage fluctuations.
Innovation Solution
The frequency-voltage conversion circuit employs a configuration with multiple switches and capacitors, where switches alternately charge and discharge capacitors to prevent leakage currents and average sinusoidal noise fluctuations, ensuring a constant output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a frequency-voltage conversion circuit uses a constant current source, then it can generate output voltage according to frequency, but the output voltage fluctuates due to leakage current and sinusoidal noise
Solution Approach 1:
The patent divides the constant current source into multiple parallel constant current sources (first constant current source and second constant current source). Each source charges a separate capacitor during alternating half-cycles, segmenting the current path to prevent leakage current accumulation and reduce the impact of sinusoidal noise on the output voltage.
Solution Approach 2:
The patent employs periodic switching of MOS transistors to alternately connect the first and second constant current sources to the output capacitor. During positive half-cycles, the first current source charges the capacitor; during negative half-cycles, the second current source charges it. This periodic action averages out sinusoidal noise fluctuations and prevents leakage current from causing voltage drift.
2Reliability
If switches are added to alternately charge and discharge capacitors, then leakage currents are prevented and output voltage is stabilized, but device complexity increases
Solution Approach 1:
The MOS transistors in the circuit serve multiple functions: they act as switches for alternating current source connection, function as leakage prevention mechanisms, and enable periodic charging/discharging of capacitors. By making these components multi-functional, the patent reduces the need for additional dedicated components, thereby limiting the increase in device complexity while achieving voltage stabilization.
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 configuration effectively prevents leakage currents and stabilizes the output voltage even under sinusoidal noise conditions, maintaining a constant DC voltage.
Implementation Method 1
a first capacitor connected between the first switch and ground; a second capacitor connected between the fourth switch and the ground
Data Source
AI summary
A frequency-voltage conversion circuit includes a constant current source, a first switch connected to an output of the constant current source, a first capacitor connected between the first switch and ground, a second switch connected between a first node that is between the first switch and the first capacitor, and an output node, a third switch connected between the first node and the ground, a fourth switch connected to the output of the constant current source, a second capacitor connected between the fourth switch and the ground, a fifth switch connected between a second node that is between the fourth switch and the second capacitor, and the output node, and a sixth switch connected between the second node and the ground.