Capacitors can be used in switching power supplies to reduce ripple noise, improve power supply stability and transient response, but there are many types of them, let’s take a look together.
The type of capacitor
Capacitors can be divided into chip capacitors and plug-in capacitors according to the package, ceramic capacitors, electrolytic capacitors, mica capacitors, etc. according to the medium, and fixed capacitors, semi-fixed capacitors, and variable capacitors according to the structure. In the switching power supply, we use ceramic capacitors, electrolytic capacitors and tantalum capacitors the most.
The key parameters of the capacitor
Understanding the intrinsic key parameters of the capacitor can quickly select the type and use it reliably. The key parameters of all capacitors are the same, including the capacitance value of the capacitor, the withstand voltage value of the capacitor, the ESR of the capacitor, the accuracy of the capacitor value, and the allowable operating temperature of the capacitor. range.
The characteristics of the capacitor itself
Ceramic capacitors have small capacitance, good high-frequency characteristics, wider operating temperature range, smaller ESR and smaller volume than electrolytic capacitors;
The electrolytic capacitor capacitance can be made larger, but the operating temperature range is narrow, the ESR is larger, and there is polarity;
Tantalum capacitors have the smallest ESR, and their capacitance is larger than ceramic capacitors. They have polarity, poor safety performance, and are easy to catch fire.
Understand the characteristics of the above three types of capacitors, and you can use them with ease.
The environment
The internal environment of the circuit includes frequency, voltage value, current value, the main role of the capacitor in the circuit, etc.; the type of capacitor can be determined according to the circuit frequency; the voltage value of the selected capacitor can be determined according to the voltage value; the main function in the circuit can be used Refer to the capacitance value of the selected capacitor; the external use environment of the circuit, including the ambient temperature of the product working, and the safety requirements, can be used as a reference for selecting the capacitor.
Post time: May-06-2021