Logarithmic taper resistor with zero crossing changes
AssigneeDallas Semiconductor Corporation
InventorRichard William Ezell
Life of this patent
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Abstract
A digital potentiometer capable of being connected directly to an electronic switch is disclosed. The digital potentiometer for example may utilize a 64 step resistor array, which would then have 64 steps. Each of the steps have precise values so as to accurately attenuate a signal in logarithmic steps. The logarithmic resistor is connected to a gate device which in turn has a voltage source connected to it designed to provide the threshold or turn-on voltage for the device for each of the 64 steps and wiper points of the resistor array.
Claims10
A semi-conductor potentiometer which comprises:
- a resistor array comprised of a plurality of cells of resistors each having a resistive value wherein the arrangement of resistors and resistive value of the resistors varies from cell to cell;
- a plurality of gate devices for selecting a wiper point wherein there exists a wiper point for every cell and there exists a gate device for every wiper point adapted for selecting said wiper point;
- a multiplex control device which comprises a zero-crossing detector adapted for triggering potentiometer changes at or near a zero-crossing of a signal being amplified;
- and
- an interface device connected to the multiplexer control device adapted for interfacing said multiplex control device directly to an external switch without requiring a special circuit or CPU to provide an interface.
In an amplifier for amplifying a signal, a potentiometer comprising:
- a resistor array comprised of a plurality of cells of resistors, each of said plurality of cells of resistors having a total resistive value;
- a plurality of wiper points for separating each of said plurality of cells of resistors;
- means for selecting at least one of said plurality of wiper points;
- triggering means for triggering potentiometer changes at or near a zero-crossing of the signal being amplified;
- and
- an interface means connected to said triggering means, said interface means for interfacing said triggering means to an external switch.
In a system for amplifying a signal, a potentiometer comprising:
- a plurality of cells of resistors, each of said plurality of cells of resistors having a total resistive value;
- a plurality of wiper points, wherein each of said plurality of cells of resistors are connected by at least one of said plurality of wiper points;
- a plurality of gate devices for selecting at least one of said plurality of wiper points;
- a control for triggering potentiometer changes at or near a zero-crossing of the signal being amplified;
- and
- an interface connected to the control device.
Dependencies are inferred from the claim text.