The development of electronic devices made amazing, all electronic and electrical equipment are identified using DC power. This power is rapidly cascade control from the old-fashioned way to small, lightweight, high efficiency switch mode transfers. This filter uses the power of the electrolytic capacitors, film capacitors, magnetic capacitors. With the use of switching power supply, the switching power supply noise, safety and legal requirements are stringent year by year. The capacitor performance requirements have changed a lot, not only to small, lightweight, but also to high temperature, high top performance, and high reliability. In this overview describes the power adapter electrolytic capacitors, film capacitors current situation and future development.
Aluminum electrolytic capacitor characteristics. Since toward switching DC power supply (later called the switching regulator) transfer and use of the power supply itself diversification requirements on the characteristics of aluminum electrolytic capacitors, there are big changes can be summarized the following five characteristics: (1) resistance high ripple voltage (2) temperature (3) long life (4) of high frequency (5) small
The original control power series aluminum electrolytic capacitors used in the above five have made progress, which feature also applies to switching regulators, switching regulators described below Used electrolytic capacitor characteristics.
Input smoothing capacitor due to the switching regulator itself requires miniaturization, the input smoothing circuit is also required to use an electrolytic capacitor small. And because an AC input from the commercial power supply, so that compared with the tandem control mode, the input voltage is high, the capacity of the capacitor is small, but due to the high impedance of the capacitor, the ripple voltage increases. As can be seen from the above I, R is increased, and because the area of miniaturization that A narrow, so that all heating elements are raising the temperature, as well as switching power supply unit itself is in a sealed enclosure majority state, both within temperature rises, the capacitor, without exception, in harsh environments, the insertion smoothing capacitor must be miniaturized, high ripple voltage, high temperature.
As a countermeasure, efforts to reduce the capacitor's equivalent Shenlian resistance, make their own heat control in a very small, but by improving the material, making the temperature range from the general increase to 105 ℃ 35 ℃ resulting higher allowable temperature range has expanded to the original two-fold. Japan's industrial production is guaranteed capacitor 105 ℃ and importance of the PK series allowable ripple voltage, and the same size to ensure 105 ℃ and the importance of small GM series, but each capacitor plant is adjusting product lines that refer to each company's product catalog.
