US 6,584,486 B1Granted

Method for mathematically processing two quantities in an electronic circuit

AssigneeAnadec GmbH

InventorsMarkus Helfenstein, Hans-Andrea Loeliger, Felix Lustenberger, Felix Tarköy

Life of this patent

Estimating the term…

Loading patent…

Abstract

The method serves to add at least two values by means of a circuit. Both input values and output values are represented in differential form, either as a pair of voltages or as a pair of currents. The circuit consists of four transistors; it has a pair of current inputs for one of the input values, a pair of voltage inputs for the other input value, and a pair of current outputs for the output value. The voltage between the two voltage inputs corresponds to the first input value; the quotient of the currents through the two current inputs corresponds to the exponential of the other input value; and the quotient of the currents through the two current outputs corresponds to the exponential of the sum of the two input values. Values represented by voltages are easily transformed into current representation, and vice versa. The method is suitable for a variety of applications and the circuit can be cascaded both with copies of itself and with other circuits.

Claims23

Dependent claims

A method for mathematically processing at least to values rx and ry in a combination circuit, which combination circuit comprises two current inputs Ex,0 and Ex,1 for the value rx, two voltage inputs Ey,0 and Ey,1 for the value ry, two current outputs A0 and A1 for a result rz, and four transistors T0,0, T0,1, T1,0, T1,1, wherein the sources or emitters of the transistors T0,0 and T0,1 are connected to the current input Ex,0, the sources or emitters of the transistors T1,0 and T1,1 to the current input Ex,1, the gates or bases of the transistors T0,0 and T1,0 to the voltage input Ey,0, the gates or bases of the transistors T0,1 and T1,1 to the voltage input Ey,1, the drain or collector of the transistor T0,0 to the current output A0, the drain or collector of the transistor T1,1 with the current output A1, and the drains or collectors of the transistors T0,1 and T1,0 to a reference potential providing a saturation or forward polarization, said method comprising the steps of

feeding two input currents Ixpx(0) and Ixpx(1) through the current inputs Ex,0 and Ex,1, wherein a quotient of said input currents is equal to erx,
applying an input voltage between said voltage inputs Ey,0 and Ey,1 proportional to ry, and
generating, with said-combination circuit, two output currents at the current outputs A0 and A1, wherein a quotient of said output currents is equal to erx+ry, and
deriving, from said output currents, a sum of the values rx and ry.

1 more element

Dependencies are inferred from the claim text.