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.

Electrical filter with adjustable RC product

Abstract: A continuous time electrical filter fabricated as an integrated circuit includes capacitors (CO,CN) and resistors (R1,R2). Since capacitors and resistors are difficult to integrate with accurately defined values a trimming circuit is provided which operates switches (S1-SN) to select appropriate ones of the capacitors (CN) to accurately define the cut-off frequency of the filter. The trimming circuit comprises a capacitor (TC2) which is charged through a resistor TR1 during a first period and which is discharged in incremental steps by a capacitor (TC1). The number of incremental steps is counted by a counter (11) and transferred to a register (13). The outputs (S1-SN) of the register control the switches (S1-SN). Instead of adjusting the value of the capacitors in the filter, the values of the resistors may be adjusted. If this is done a convenient procedure is to short out selected portions of the resistors. More than one capacitor or resistor may be adjusted using a single counter and register.

OTRA-Based Multi-Function Inverse Filter Configuration

Abstract: A new OTRA-based multifunction Inverse filter configuration is presented which is capable of realizing low pass, high pass and band pass filters using only two OTRAs and five to six passive elements. To the best knowledge of the authors, any inverse filter configuration using OTRAs has not been reported in the literature earlier. The effect of the major parasitics of the OTRAs and their effect on the performance filter have been investigated and measured through simulation results and Monte-Carlo analysis. The workability of the proposed circuits has been confirmed by SPICE simulations using CMOS-based-OTRA realizable in 0.18 µm CMOS technology. The proposed circuits are the only ones which provide simultaneously the following features: use of reasonable number of active elements (only 2), realizability of all the three basic filter functions, employment of all virtually grounded resistors and capacitors and tunability of all filter parameters (except gain factor, H_0 for inverse high pass). The centre/cut-off frequency of the various filter circuits lying in the vicinity of 1 MHz have been found to be realizable, which has been verified through SPICE simulation results and have been found to be in good agreement with the theoretical results.

Digital implementation of a new type of hybrid filter with simplified control strategy

Abstract: A new type of hybrid active filter to compensate harmonics of a nonlinear load is presented in this paper. The proposed topology of hybrid filter combines a shunt passive filter (PF) and a shunt active filter (AF). A series inductor between both the filters is introduced to create a harmonic voltage source at the input of nonlinear load. A diode bridge rectifier with R-C load is considered as a nonlinear load. An indirect current controlled voltage source inverter (ICC-VSI) is considered as an AF. A simple control algorithm based on proportional plus integral control of a self-supporting DC bus voltage of the shunt AF is implemented on a TMS320C31 DSP. The passive filter is tuned to compensate 5/sup th/ and 7/sup th/ harmonics, while the AF compensates the rest of harmonics of the load current. A laboratory prototype model of the proposed hybrid filter is developed and its performance is examined. Experimental results are given and discussed.

Self-excited oscillation type high power LED constant-current driving circuit

Abstract: The invention provides a self-oscillation type high power LED constant-current drive circuit with low cost, high reliability and stability and high drive efficiency, the circuit comprises a rectifier and filter circuit, a switching circuit, a steady voltage constant current output circuit, a transformer, a self-oscillation type pulse width modulation signals generating circuit and a current feedback obstruction circuit, wherein the rectifier and filter circuit accesses commercial power into rectification, changes the commercial power into direct current, and then outputs commercial power to the switching circuit to switch in a self-oscillation type with high frequency, then high frequency voltage of the steady voltage constant current output circuit is transformed into direct voltage through the transformer to drive the LED, simultaneously sampling current signals produces jam signals through the current feedback obstruction circuit to control the switching circuit to work, the circuit does not adopt any driving chips and only uses fewer common individual devices to form a self-oscillation type structure to drive the switching circuit and to combine current feedbacks, which realizes constant current driving of the high power LED

Clonal selection algorithm in power filter optimization

Abstract: Inspired by natural immune mechanisms, artificial immune optimization (AIO) methods have been successfully applied to deal with numerous challenging optimization problems with superior performances over classical optimization techniques. Clonal selection algorithm (CSA) is one of the most widely employed immune-based approaches for handling those optimization tasks. In this paper, the proposed CSA is used to search for the optimal parameters (values of inductor and capacitor) of a passive filter in the diode full-bridge rectifier. Simulation results demonstrate that the CSA-based approach can acquire the optimal LC parameters with certain given criteria for power filter design.