Maxim Integrated Products, Inc.

Philips Electronics North America Corporation

Behzad Shahi

Johan Hendrik Huijsing

Maarten Jeroen Fonderie

Frequency stabilization of chopper-stabilized amplifiers using multipath hybrid double-nested Miller compensation. The compensation may provide a desired 6 dB/oct roll off for both instrumentation amplifiers and operational amplifiers. Various embodiments are disclosed.

Frequency stabilization of chopper-stabilized amplifiers

Accurate voltage to current converters for rail-sensing current-feedback instrumentation amplifiers using folded cascode transistors. Embodiments using various degrees of cascoding, as well as using bootstrapped folded cascoded input transistors are disclosed. Circuits for sensing around the negative rail are disclosed, though circuits for sensing around the positive rail may be readily achieved by use of complementary devices.

Accurate voltage to current converters for rail-sensing current-feedback instrumentation amplifiers

Chopper chopper-stabilized instrumentation and operational amplifiers having ultra low offset. The instrumentation amplifiers use current-feedback, and include, in addition to a main chopper amplifier chain, a chopper stabilized loop for correcting for the offset of the input amplifiers for the input signal and for receiving the feedback of the output voltage sense signal. Additional loops, which may include offset compensation and autozeroing loops, may be added to compensate for offsets in the chopper stabilized loop for correcting for the offset of the input amplifiers. Similar compensation is disclosed for decreasing the offset in operational amplifiers.

Chopper chopper-stabilized instrumentation and operational amplifiers

Constant GM models and GM-controlled current-isolated indirect-feedback instrumentation amplifiers. The constant GM models provide a transconductance that is proportional to the inverse of a resistance in the constant GM model circuits over a wide range of common mode and differential mode inputs. Current-isolated indirect-feedback instrumentation amplifiers using constant GM models to track the common mode and differential inputs of, and provide the tail currents for, the differential input pair in the transconductance amplifiers greatly enhance the instrumentation amplifier performance in numerous ways.

GM-controlled current-isolated indirect-feedback instrumentation amplifier

A functional circuit such as an OP-amp has a differential output. A common mode signal at the differential output is adjusted by means of a common mode feedback circuit coupled between the differential output and the common mode adjustment input. The common mode feedback circuit contains IGFETs, each having a channel and a backgate, each connection of the differential output being coupled to the backgate of a respective one of the IGFETS. Thus the voltages at the outputs influence the current through the channel. The sum of the currents determines a feedback to the common mode control input.

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San Jose, CA, United States of America

Behzad Shahi