Active Power Filters Replace Passives In Switching Circuits

A family of integrated smart-power products provides active filtration with sharp attenuation of low frequencies (less than 200 Hz) in switching power conversion circuits used for telecommunication and test and measurement applications. The devices use an active semiconductor approach to filtering of low-frequency noise and ripple rather than the traditional passive component approach.The first products available are active capacitance types. The AXC-051 is a three-terminal power filter that offers a minimum of 30 dB of attenuation at 20 Hz. It's designed for supplies of -18V to -75V and up to a 5A load. The AXC-053 is a positive-supply version. Models AXC-101 and -102 are 20A versions designed for -8V to -72V and 0V to 28V, respectively.