Intersil Americas Inc.

Brian E Williams

John S Prentice

Paul J Godfrey

Embodiments of the present invention are related to circuits and methods for generating a reference current (Idc). In an embodiment, a voltage-to-current converter circuit is used to generate the reference current (Idc) in dependence on a reference voltage (Vref) and a precision resistor (R), wherein Idc=Vref/R. A capacitor (C) is used to shunt noise that couples into the voltage-to-current converter. A frequency dependent feedback network is used to compensate for instabilities introduced by the capacitor (C). The capacitor (C) can be used to shunt noise that couples into the voltage-to-current converter by connecting the capacitor (C) in parallel with the precision resistor (R). The frequency dependent feedback network can be used to compensate for instabilities introduced by the capacitor (C) by connecting the frequency dependent feedback network between a feedback terminal of an amplifier of the voltage-to-current converter circuit and a terminal of the capacitor (C).

Coupling tolerant precision current reference with high PSRR

An amplifier with common mode output control including a reference circuit, a current mirror input circuit, a differential current mirror, a summing junction, first and second feedback amplifiers, first and second feedback current mirrors, and a differential output circuit. The input circuit receives the differential input voltage and develops a differential input current having polarity currents that have a constant sum based on a reference signal. The differential current mirror mirrors the differential input current into first and second high impedance nodes. The feedback amplifiers and the feedback current mirrors generate feedback current into the high impedance nodes in response to variations of summing junction voltage and maintain a constant common mode current. The output circuit develops a differential output current based on the differential input current mirrored into the high impedance nodes. RC compensation is provided to compensate open loop gain and the common mode output current loop.

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Malabar, FL, United States of America

Brian E Williams