Vacuum Pump Interference Suppression for Reliable Accessory Detection
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Solution Overview
Problem
Vacuum pumps face interference issues during accessory recognition due to limited connection poles or data lines in standardized interfaces, preventing reliable automatic detection of both analog and digital signals, especially when the drive motor is operational.
Innovation Solution
A turbomolecular pump with an interface, controller, and interference suppression device that recognizes signal types and activates/deactivates the suppression device accordingly, using a standardized interface like micro-USB, allowing for reliable accessory recognition by distinguishing between analog and digital signals and suppressing interference effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a standardized interface with a common data line is used for both analog and digital signals, then manufacturing costs are reduced and flexibility is increased, but interference from pulse-width modulation prevents reliable automatic accessory detection
Solution Approach 1:
The patent applies the dynamics principle by making the data line's electrical characteristics changeable through a switching device. The switching device can alter the capacitance of the data line between two states: a first capacitance value when no accessory is connected, and a second capacitance value when an accessory is connected. This dynamic change in electrical characteristics enables the controller to detect accessory connection and distinguish between analog and digital accessories based on capacitance measurements, thereby achieving reliable automatic accessory detection while using a standardized interface.
2Reliability
If a permanently connected capacitor is used to suppress interference, then analog signal detection is improved, but digital signals are short-circuited and automatic accessory detection via digital data packets is prevented
Solution Approach 1:
The patent replaces the static permanently connected capacitor with a dynamic switching mechanism. The switching device selectively connects or disconnects the capacitor based on the detected accessory type. When an analog accessory is detected, the capacitor is connected to suppress interference. When a digital accessory is detected, the capacitor is disconnected to avoid short-circuiting digital signals. This dynamic adaptation resolves the contradiction between analog signal detection and digital accessory detection.
Solution Approach 2:
The patent changes the electrical parameters of the data line dynamically. The controller measures capacitance to detect accessory type, then changes the capacitance value by switching the capacitor in or out. This parameter change allows the system to optimize performance for different accessory types: high capacitance for analog signal suppression, low capacitance for digital signal integrity.
3Device complexity
If the data line capacitance remains constant, then circuit simplicity is maintained, but the system cannot distinguish between different accessory types during operation
Solution Approach 1:
The patent introduces a switching device that adds minimal complexity to the circuit while enabling dynamic capacitance adjustment. The switching device is controlled by the controller based on capacitance measurements, creating a simple feedback mechanism. This minimal added complexity enables the system to distinguish between different accessory types by measuring capacitance changes when accessories are connected, resolving the contradiction between circuit simplicity and accessory detection capability.
Data Source
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Figure 2A~2B
Figure 3A~3B
AI summary
A vacuum pump has an interface for connecting the vacuum pump to an accessory device, a controller that communicates with the interface, and an interference suppression device that is connected to the interface and the controller. The controller is configured to detect at least two different types of signal present at the vacuum pump's interface and to activate the interference suppression device depending on the detected type of signal present at the interface.