US 7,009,442 B2 · Linear multiplier circuit

Abstract

A linear multiplier circuit comprises a first, a second, a third and a fourth transistor, each having a drain, a source, a gate and substantially an identity threshold voltage. Each of these four transistors operates with a fixed drain-to-source voltage applied between the drain and source, a gate-to-source voltage applied between the gate and source. The sources of the first and second transistors, and the drains of the third and fourth transistors are coupled to form the output terminal. The gate-to-source voltages of the first, second, third and fourth transistor are respectively the sum of the first and second input signals, an additionally introduced input signal, and the identity threshold voltage; the sum of the additionally introduced input signal and the identity threshold voltage; the sum of the first input signal, the additionally introduced input signal and the identity threshold voltage; and the sum of the second input signal, the additionally introduced input signal and the identity threshold voltage.

Claims15

Dependent claims

A linear multiplier circuit, receiving a first input signal and a second input signal, generating a current proportional to a product of the first and second input signals on an output terminal of the linear multiplier circuit, the linear multiplier circuit comprising:

a first transistor;
a second transistor;
a third transistor;
and
a fourth transistor;
wherein each of the first transistor, the second transistor, the third transistor and the fourth transistor has a drain, a source, a gate, and substantially an identity threshold voltage, and operates in a saturation mode with a substantially fixed drain-to-source voltage applied between the drain and source, a gate-to-source voltage applied between the gate and source;
wherein the sources of the first and second transistors, and the drains of the third and fourth transistors are coupled together, and the gate-to-source voltages of the first, second, third and fourth transistors are respectively a sum of the first input signal, the second input signal, an additional input signal and the threshold voltage, a sum of the additional input signal and the threshold voltage, a sum of the first input signal, the additional input signal and the threshold voltage, and a sum of the second input signal, the additional input signal and the threshold voltage.

4 more elements

an operation amplifier having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal is coupled for receiving a first voltage potential;
a first transistor having a drain receiving a second voltage potential, a source coupled to the second input terminal of the operation amplifier, and a gate receiving a sum of the first and the second input signals, an additional input signal, and an offset voltage;
a second transistor having a drain coupling with the source voltage potential, a source coupled to the second input terminal of the operation amplifier, and a gate receiving the additional input voltage and the offset voltage;
a third transistor having a drain coupled to the second input terminal of the operation amplifier, a source coupled to a reference voltage potential, and a gate receiving a sum of the first input signal, the additional input signal, and the offset voltage;
and
a fourth transistor having a drain coupled to the second input terminal of the operation amplifier, a source coupled to the reference voltage potential, and a gate receiving a sum of the second input signal, the additional input signal and the offset voltage.

3 more elements

A method for generating a product of a first input signal and a second input signal in a multiplier circuit, comprising:

generating a first current by using the first input signal, the second input signal, and an additional input signal;
generating a second current by using the additional input signal;
generating a third current by using the first input signal and the additional input signal;
generating a fourth current by using the second signal and the additional input signal;
and
generating a current proportional in magnitude to the product of the first and second input signals by using the first, second, third, and fourth currents.

3 more elements

Dependencies are inferred from the claim text.

Linear multiplier circuit

Life of this patent

Linear multiplier circuit

Life of this patent

Abstract

Claims15