Noise detection circuit

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This patent describes a noise detection circuit specifically for power supplies. The circuit is designed to detect and measure common mode (CM) noise signals, while suppressing differential mode (DM) noise signals. Notably, it works without requiring a connection to protective earth and can use common references such as circuit ground or neutral wire. The design leverages an impedance element and a filter to isolate and measure the CM noise, providing output suitable for active noise filtering systems. The solution is versatile and can be integrated with both passive and active noise filters and can be implemented using discrete or integrated circuit components.

Use CasesContent extracted from patent full text and abstract with AI.

• Monitoring and mitigating electromagnetic interference (EMI) in power supplies for electronic devices.
• Integration into active common mode noise filters to improve power supply performance and system electromagnetic compatibility.
• Incorporation into power supplies of household appliances, industrial machines, or consumer electronics to meet EMI regulatory standards.
• Use in switched-mode power supplies to actively measure and cancel CM noise.
• Adaptation in modular power supply designs where space savings and efficiency are critical.

BenefitsContent extracted from patent full text and abstract with AI.

• Enables accurate detection of common mode noise without requiring a protective earth connection, increasing versatility in different electrical systems.
• Reduces the spatial footprint on circuit boards compared to bulky transformer-based solutions.
• Enhances EMI performance and compliance with regulatory standards by enabling real-time CM noise monitoring and suppression.
• Facilitates integration with existing passive differential mode noise filters, optimizing component reuse and circuit efficiency.
• Improves the overall efficiency and compactness of power supply noise filtering designs, especially when implemented in integrated circuits.

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Patent Abstract

A noise detection circuit 100 for a power supply, the noise detection circuit 100 comprising: an impedance element 110 connected to a line 104 for carrying a power supply current having a noise signal component, the noise signal comprising a common mode noise signal and a differential mode noise signal; a filter element 112 coupled to the impedance element 110 and configured to suppress the differential mode noise signal in the noise detection circuit 110; and an evaluation circuit 140 coupled to the impedance element 110 or the filter element 112 and arranged to sense the common mode noise signal and provide an output representative of the common mode noise signal.