Nec Electronics Corporation

Nec Electronics America, Inc.

Mitsutoshi Sugawara

Takeshi Nagahori

In an active hybrid transformer circuit connected to both transmit and receive sides, a current driver is connected to a transmission path circuit through a common connection point of a load resistor and a replica resistor while a replica driver is connected to the replica resistor of which another connection point is directly connected to the receive side. The replica driver may be formed by a DAC of a current output type. A current ratio of the replica driver and the current driver is selected at a predetermined value so as to prevent a transmit signal from leaking into the receive side.

Active hybrid transformer circuit having a replica driver

A voltage reference generating circuit for providing voltage references substantially less than the typical 1300 mV, with a controllable thermal coefficient. By forcing equal-valued currents through two semiconductor junctions having disparate junction areas, a voltage differential is developed, as is a current proportional to the voltage differential. The voltage differential, and a current proportional to the voltage differential, have positive thermal coefficients. A third semiconductor junction is biased from a third current source and bridged by a resistor pair so as to synthesize a Thevenin-equivalent voltage equivalent series resistance. The equivalent voltage has a negative thermal coefficient. By forcing a current that is equal to the proportional current through the equivalent resistance, a reference voltage, equal to the sum of the Thevenin-equivalent voltage plus the voltage drop across the Thevenin-equivalent resistance, is created.

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Santa Clara, CA, United States of America

Mitsutoshi Sugawara