US 5,581,211 AGranted

Squaring circuit capable of widening a range of an input voltage

AssigneeNEC Corporation

InventorKatsuji Kimura

Life of this patent

Estimating the term…

Loading patent…

Abstract

In a squaring circuit which responds to an input voltage to produce an output current and which is specified by a squaring characteristic between the input voltage and the output current, first, second, and third transistors are connected in common to a constant current source while the first and the second transistors are connected to input terminals for the input voltage and also connected in common to a single output terminal. The third transistor is connected to another output terminal and supplied with a d.c. voltage as a control signal. The output current appears between the output terminals as a differential output current. The squaring characteristic is kept even when the input voltage is widely varied. Each of the first through the third transistors may be either a bipolar transistor or a MOS transistor.

Claims17

Dependent claims

A squaring circuit having first and second input terminals and first and second output terminals and operable in response to an input voltage provided across said first and said second input terminals to produce an output current which is specified by a squaring characteristic in relation to said input voltage, said squaring circuit comprising:

a constant current source;
a d.c. voltage source for producing a d.c. voltage;
first and second transistors each having input electrodes connected to said first and said second input terminals, respectively, output electrodes connected in common to said first output terminal, and internal electrodes connected to said constant current source;
and
a third transistor which has an input electrode supplied with said d.c. voltage, an output electrode connected to said second output terminal, and an internal electrode connected to said constant current source;
said first through third transistors being connected to said constant current source in a triple tail cell configuration so as to produce said output current with said squaring characteristic;
said output current appearing through at least one of said first and said second output terminals.

4 more elements

Dependencies are inferred from the claim text.