1. Why are capacitors important components for buck and boost converters?
Good engineering practice requires additional external capacitors to be placed at the input and output of all regulators. This is because capacitors not only help reduce voltage ripple and improve circuit reliability, but these components also increase efficiency compared to linear regulators. A well-designed power supply decoupling network will use capacitors of different types and materials, such as ceramic capacitors, aluminum capacitors and tantalum capacitors.
2. Advantages of using multilayer ceramic capacitors in converters
Choosing the right capacitor for your converter is a key factor in ensuring that the end product is as efficient, durable and reliable as possible. In such applications, multilayer ceramic capacitors (MLCCs) offer unique advantages because they can provide higher capacitance values with their single-element construction and multiple internal layers.
Multilayer ceramic capacitors (MLCCs) are typically used in buck or boost converters for the following functions:
- Optional input filters - MLCCs can be connected in parallel with bulk aluminum electrolytic or polymer capacitors for optimal filtering when the frequency is below 1MHz; MLCCs are ideal filters when the frequency is greater than 1MHz.
- Bypass capacitors - Eliminate voltage drops on the power supply by storing charge, which can be released when voltage spikes occur.
- Buffer capacitors - MLCCs help reduce ripple in the switching network.
- Output capacitors - Low capacitance (<1uF) ceramic capacitors can be used when the frequency is greater than 1MHz; aluminum electrolytic capacitors can be used when the frequency is less than 1MHz.
The use of multilayer ceramic capacitors (MLCC) in the above applications can help increase the ripple current rating of the converter, enhance filtering performance and extend service life. MLCCs are used in a wide range of applications, from simple topologies to more complex topologies.
3. Special considerations for high-reliability applications
For high reliability applications, such as power supplies for military drones, additional testing to meet military standards (MIL-STDS) is required. When selecting capacitors for high reliability applications, we need to test them to the strictest MIL-STD requirements - including burning in high voltage and high temperature environments - and subject them to 100% electrical testing to ensure compliance with stringent performance standards to ensure your components are safe for use in the most complex military and aerospace applications. use.
