Electronic filter

About: Electronic filter is a research topic. Over the lifetime, 13207 publications have been published within this topic receiving 93063 citations. The topic is also known as: filter.

Small-capacitance nondissipative ripple filters for DC supplies

Abstract: Two configurations of ripple filters, one passive and one active, used to filter the output ripple of dc-to-dc converters and other power supplies are discussed. The passive one uses a small-microfarad capacitor and a mutual inductor; the active one uses these same components and, in addition, an operational amplifier. These filters have potential for spacecraft applications to enable the designer to use more reliable types of capacitors such as ceramic or mica instead of tantalum capacitors now commonly used in the conventional L -section or pure-capacitance filters requiring large-microfarad capacitance. The passive filter has achieved attenuation greater than 40 dB and the active filter greater than 50 dB. Both of these filters accomplished significant capacitance reduction when compared with an L -section filter for the same application.

A new parallel hybrid filter configuration minimizing active filter size

Abstract: Conventional parallel hybrid active filters suffer from the problem of heavy current ratings of devices used in the inverter. In general, this problem has been solved by adjusting the turn ratio of a matching transformer. However, adjusting the transformer to a high turn ratio may not be possible for high voltage power systems due to their requirements for high voltage insulation. In this paper, a new configuration is proposed for a parallel hybrid active filter. In the proposed hybrid active filter, the active filter is connected to the passive filter inductor in parallel through a matching transformer with the aim of reducing the current rating of the inverter. As a result, the fundamental component of the current flowing through the passive filter is divided by the parallel paths of two inductors located at the inverter side and passive filter side, respectively. Hence, the current rating of the inverter can be reduced. Additionally, a harmonic elimination method is suggested for the proposed active filter. Through computer simulations and experiment, we have verified the effectiveness of the proposed topology.

Vertically coupled microring resonator filter for integrated add/drop node

Abstract: The add/drop wavelength filter is an essential component in the new-generation photonic network. Microring resonator filters using high index contrast (HIC) optical waveguides are recently attracting attention as add/drop filters owing to their compactness, functionality such as dispersion compensation, and ease of filter synthesis. In particular, the vertically coupled microring resonator (VCMRR) filter is highly suited for the dense, large-scale integration of filter circuits. In this review, the fundamental characteristics advantageous to the add/drop filter nodes are introduced, and the recent progress in the development of vertically coupled microring resonator filters achieved mainly by the author's group is described.

Fully Integrated Buck Converter With Fourth-Order Low-Pass Filter

Abstract: Fully integrated buck converters are typically operated with a second-order LC low-pass filter and a switching frequency beyond 100 MHz. The motivation for such design choices is to reduce the size of passive components in the LC low-pass filter required for small output voltage ripple. However, in a buck converter with on-chip planar spiral inductors, a fourth-order filter can deliver better performance characteristics without area penalty. This paper presents a comparative study of a fourth-order LC low-pass filter versus a second-order LC low-pass filter with on-chip planar spiral inductors and on-chip capacitors. A fully integrated buck converter is then designed with a quasi-V 2 controller to demonstrate the benefits of a fourth-order LC low-pass filter. The prototype chip, which is implemented in a 65-nm CMOS process, produces a nominal voltage of 0.7 V from a 1-V supply. The fourth-order LC low-pass filter uses a total inductance of 1.8 nH and a total capacitance of 4 nF. Measurement results demonstrate fast transient response on the order of nanoseconds. A peak efficiency of 76.1% is achieved, and the output voltage ripple is kept below 15 mV over the entire range of load current from 40 to 180 mA.