ANALOG MULTIPLYING CIRCUIT

Japanese Patent JP2740440

B2

PURPOSE: To enable high-linearity operation even under a low power supply voltage by providing first and second reference current generating circuits for controlling first and second differential amplifying circuits to which a first operation input signal to be a multiplying signal is impressed corresponding to the output of a third differential amplifying circuit.
CONSTITUTION: This circuit is provided with a first differential amplifying circuit I composed of a first differential pair Q1-Q2 and a first variable current source 101 so as to fetch a first differential input signal, second differential amplifying circuit II composed of a second differential pair Q3-Q4 and a second variable current source 102 so as to fetch the first differential input signal, and third differential amplifying circuit III equipped with first and second output terminals with mutually opposite phases so as to fetch a second differential input signal. Then, a reference current generating circuit IV is provided between the first output terminal and the first variable current source 101, and a second reference current generating circuit V is provided between the second output terminal and the second variable current source 102. Thus, the number of steps to longitudinally pile up transistors can be decreased to two steps while keeping a constant current operation.

WO/1996/041295	BIPOLAR ANALOG MULTIPLIERS FOR LOW VOLTAGE APPLICATIONS
JPS61876	MULTIPLYING CIRCUIT

Tsuneo Tsukahara
Ishikawa Masayuki

JP2079993A

April 15, 1998

January 14, 1993

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Nippon Telegraph and Telephone Corporation

G06G7/163; (IPC1-7): G06G7/163

JP333989A

Masataka Kobayashi

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