CS242531B1 - Double capacitor with switched capacitor - Google Patents

Abstract

The purpose of the solution is to reduce the number of elements of a double capacitor with switched capacitors while maintaining a bilinear transformation. The above purpose is achieved by using an amplifier with two elements, a single capacitor and two switches. With these elements connected in the order of the output, a charge profile is achieved that corresponds to a bilinear transformation. A double capacitor with switched capacitors and a bilinear transformation is to take from a constant voltage source the charge Cu, —iZCu, 2Cu, —2Cu, 2Cu etc., in the process of switching a capacitor with a capacity C. This requirement is met by the circuit in the drawing, because the capacitor (3) connected to the input terminals takes a charge Cu from the source, after switching to the output (6) of the amplifier (1) it returns a double charge —2Cu under the influence of the amplifier with amplification of two, and after switching to the input terminals it takes a charge 2Cu again, which is then repeated by periodic switching of the switch. The invention can be used in the design of frequency filters with switched capacitors.

Description

The invention relates to a dual capacitor with a switching capacitor and a bilinear trainformation, in which the number of active elements, capacitors and switches is reduced by means of an amplifier with a gain of two.

Known types of double capacitors with switched capacitors and bilinear transformation have the disadvantages of having two operational amplifiers and a high number of capacitors and switches.

This drawback is overcome by the connection of a double stage capacitor of the invention. The essence of the connection is the use of a single amplifier, with amplification two, which allows the uncharged capacitor connected to the gate to draw a certain charge from the input voltage source and after switching the capacitor between the input and output of the amplifier returns to the source double charge. After switching the capacitor back to the gateway, a double charge is also taken from the source due to the flood, which is repeated in the perlodic switching of the capacitor. Such a charge pattern corresponds to a double capacitor with a bilinear trainformation.

The capacitor connected by one terminal to the amplifier input with amplification two, has a second terminal by means of two switches periodically switched between the common terminal and the amplifier output. By such a capacitor switching, a wild-type amplifier ensures that it is charged and discharged, which corresponds to a double capacitor with a bilinear trainformation. Said circuit arrangement achieves its desired function with a minimum number of elements used.

The attached drawing shows a double capacitor with a switched capacitor. The amplifier 1 with amplification two has a capacitor 3 connected to the input 2, which is alternately switched to the common terminal 5 and the output 6 of the amplifier 1 by means of an electronically switched switch 4.

Said circuit is used in frequency filters with switched capacitances. The double capacitor in many types of active filters reduces the number of synthetic elements and the described type of double capacitor represents an economical solution with a minimized number of elements used.

Claims (1)

SUBJECT Dual capacitor with switched capacitor, characterized in that a capacitor (3) is connected to the input (2) of the amplifier (1) with amplification, which is periodically switched to the common terminal (5j and the output (6) by means of a switch (4). ) amplifier (lj.