Floated HV Supply Shielding for Low-Noise Ion Detector Bias
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Solution Overview
Problem
Conventional high-voltage power supply configurations in mass spectrometry systems suffer from noise coupling between floated and ground-referenced power supplies, leading to increased noise in ion detectors and degraded signal-to-noise ratios.
Innovation Solution
A high-voltage power supply system with a ground-referenced voltage power supply and a floated bias voltage power supply, featuring a floating shield and resistive elements in the return electrical path to reduce noise coupling, along with a Faraday shield and capacitive coupling to ground, which mitigates parasitic coupling and voltage ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a floated high-voltage power supply is electrically coupled to a ground-referenced power supply to bias the output voltage, then the bias voltage is provided to the ion detector, but current ripples flow from the secondary winding to the output capacitor, inducing ripple voltage and increasing noise
Solution Approach 1:
A resistive element is introduced as an intermediary component in the return electrical path between the floated bias power supply and the ground-referenced power supply. This resistor acts as a mediator that blocks the propagation of current ripples and noise while still allowing the DC bias voltage to pass through, thereby resolving the contradiction between providing bias voltage and preventing noise coupling
Solution Approach 2:
The harmful noise and ripple currents are extracted or removed from the return path by using the resistive element to impede their flow. The resistor selectively removes the AC ripple components from the circuit while maintaining the DC bias function, effectively separating the useful signal from the harmful noise
2Device complexity
If conventional power supply configurations are used to provide high voltage to ion detectors, then the system is simple to implement, but noise coupling occurs between power supplies, degrading signal-to-noise ratio
Solution Approach 1:
The resistive element serves as a noise isolation intermediary that minimally increases device complexity while dramatically improving signal-to-noise ratio. This simple component addition creates electrical isolation between the two power supplies, preventing noise coupling without requiring complex shielding or isolation circuits
Solution Approach 2:
The return path's electrical impedance is changed by adding the resistive element, transforming it from a low-impedance noise-conductive path to a high-impedance noise-blocking path. This parameter change in the return path impedance selectively blocks noise while maintaining the necessary DC bias current flow
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
Significantly reduces noise coupling between the power supplies, improving the performance of the high-voltage power supply system by minimizing ripple voltage and enhancing the signal-to-noise ratio in mass spectrometry systems.
Implementation Method 1
The floating shield can provide a low AC impedance path from the return electrical path of the floated voltage power supply to the ground
Implementation Method 2
The resistive element disposed in the return electrical path can be coupled in series with a capacitance associated with the floating shield so as to enhance impedance of the return electrical path
Implementation Method 3
The resistive element disposed in the return electrical path can be coupled in series with a capacitance associated with the floating shield
Implementation Method 4
In some embodiments, the Faraday shield can reduce the coupling by a factor in a range of about 2 to about 100
Implementation Method 5
In some embodiments, a Faraday shield is disposed in the transformer of the floated bias voltage power supply so as to reduce parasitic coupling between the secondary winding and the primary winding of the transformer
Data Source
AI summary
A high-voltage power supply system for a mass spectrometer comprises a ground-referenced power supply with a first transformer having a primary winding and a secondary winding, the primary winding is electrically coupled to a first source of AC power, and a floated bias voltage power supply with a second transformer having a primary winding and a secondary winding, the primary winding of the second transformer is electrically coupled to a second source of AC power. A return electrical path of the floated bias voltage power supply is electrically coupled to the ground-referenced power supply to bias an output voltage of the ground-referenced power supply. A floating shield is around the floating bias voltage power supply, and at least one resistive element is in the return electrical path of the floated bias voltage power supply to reduce noise coupled from the floated bias voltage power supply to the ground-referenced power supply.