PA-Cap在滤波电路中的应用研究

Practical Applications of Chip Polymer Aluminum Electrolytic Capacitor in Filter Circuit

以微机开关电源的滤波电路(工作频率为64.5kHz)来研究PA-Cap(片式聚合物铝固体电容器)在实际电路中的应用情况。实验发现用实测容量28.6μF的PA-Cap代替实测容量为960μF的液体铝电解电容器,可以得到同样的滤波效果;甚至可以用60μF的PA-Cap代替原电路中的960μF的电容和350μH的电感也得到同样的滤波效果。如果用片式二氧化锰钽电解电容,则分别需要127μF和192μF。其主要原因是采用高电导率的聚合物作阴极的PA-Cap具有优异的阻抗频率特性。

A chip polymer aluminum electrolytic capacitor （PA-Cap） was put to use in the filter circuit of the switch power source of microcomputer, which operating frequency is about 64.5 kHz. It is found that the effect of filter of a PA-Cap of 28.6μF is equivalent to a traditional aluminum electrolytic capacitor of 960 μF. In a same π-shape filter circuit, a PA-Cap of 60μF can substitute the combination of a traditional aluminum electrolytic capacitor of 960μF and an inductor of 350μH. If a chip tantalum electrolytic capacitor was used, the capacitance must be 127 μF and 192 μF, respectively. All of the reasons are because the PA-Cap has an excellent impedance frequency characteristic.