Why Do I Need a Vector Network Analyser?

Why Do I Need a Vector Network Analyser?

Vector Network Analyser Characterising a Switch-Mode Power Supply

A switched mode power supply (SMPS) is a type of power supply that uses switching technology to convert electrical power from one form to another. Various applications use these power supplies, ranging from small electronic devices to large industrial systems. One of the critical challenges in designing and testing SMPSs is characterising their performance regarding efficiency, stability, and electromagnetic compatibility (EMC). An engineer can use a vector network analyser (VNA), a powerful tool to accurately and efficiently characterise the performance of SMPSs.

One of the main benefits of using a VNA to characterise an SMPS is its ability to measure the power supply's small-signal stability. A VNA can measure an SMPS' stability by performing a frequency-domain analysis of the power supply's input and output impedance. This type of analysis can reveal necessary information about the power supply's stability, such as its phase margin and gain margin. By measuring the stability of an SMPS, designers can ensure that the power supply will operate reliably and avoid any potential problems, such as oscillations or instability.

Gain-Phase Measurement


Another benefit of using a VNA to characterise an SMPS is its ability to measure the power supply's efficiency. A VNA can be used to measure the efficiency of an SMPS by performing a frequency-domain analysis of the power supply's input and output voltage and current. This type of analysis can reveal necessary information about the power supply's efficiency, such as its power factor and total harmonic distortion. By measuring the efficiency of an SMPS, designers can ensure that the power supply is operating at optimal efficiency and reduce costs associated with power consumption.

Loop Gain Plot - Frequency Response


A VNA also can be used to measure the EMC performance of an SMPS. EMC management is essential for switch-mode power supplies because they can generate electromagnetic interference (EMI) that can interfere with other electronic devices. A VNA can measure the EMI generated by an SMPS by performing a frequency-domain analysis of the power supply's conducted and radiated emissions. This analysis can reveal necessary information about the power supply's EMC performance, such as emission levels and frequency bands. By measuring the EMC performance of an SMPS, designers can make sure that the power supply meets regulatory standards and doesn't cause any problems for other electronic devices.

In conclusion, Engineers can use a vector network analyser (VNA) as a powerful tool to accurately and efficiently characterise the performance of switched-mode power supplies (SMPS). By using a VNA to measure the SMPS's small-signal stability, efficiency, and electromagnetic compatibility (EMC) performance, designers can ensure that the power supply will operate reliably, efficiently and meet regulatory standards. Using a VNA can save time and money for the designer and the manufacturer.

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