Charge-transfer switched-capacity filter
First Claim
1. A charge-transfer switched-capacity filter, comprising an amplifier associated with a network of resistances and capacities in which each resistance is formed by two MOS switches in series and with a capacity between the common point of these switches and ground;
- said capacities are formed by MOS technology and said MOS switches are formed by control electrodes adjacent the MOS capacities and from which they are separated by an oxide layer;
one plate of each capacity being formed by the semiconductor substrate on which it is integrated, and connection between two capacities whose plates are formed by the substrate are periodically connected by transfer of charges in the semiconductor substrate on which said two capacities are integrated, and results in the establishment of the same surface potential under said two capacities;
the other external to the substrate plate of at least one of the capacities receiving input voltage of the filter, and of at least another of the capacities receiving a DC voltage taken for reference.
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Accused Products
Abstract
A switched capacity filter having capacities formed by MOS technology on a semiconductor substrate. The connection between two capacities whose first plates are formed by the semiconductor substrate are periodically connected by providing transfer of charges in the substrate on which these two capacities are integrated. The external or other plate of each capacity receives, the input voltage, or a reference voltage, or the surface potential under another capacity which is provided by a reinjection and reading device formed from a diode and a voltage follower stage.
106 Citations
11 Claims
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1. A charge-transfer switched-capacity filter, comprising an amplifier associated with a network of resistances and capacities in which each resistance is formed by two MOS switches in series and with a capacity between the common point of these switches and ground;
- said capacities are formed by MOS technology and said MOS switches are formed by control electrodes adjacent the MOS capacities and from which they are separated by an oxide layer;
one plate of each capacity being formed by the semiconductor substrate on which it is integrated, and connection between two capacities whose plates are formed by the substrate are periodically connected by transfer of charges in the semiconductor substrate on which said two capacities are integrated, and results in the establishment of the same surface potential under said two capacities;
the other external to the substrate plate of at least one of the capacities receiving input voltage of the filter, and of at least another of the capacities receiving a DC voltage taken for reference. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- said capacities are formed by MOS technology and said MOS switches are formed by control electrodes adjacent the MOS capacities and from which they are separated by an oxide layer;
Specification