Fully Differential Chopper-Stabilized Multipath Current-Feedback Instrumentation Amplifier with R-2R DAC Offset Adjustment for Resistive Bridge Sensors

Abstract

A fully differential multipath current-feedback instrumentation amplifier (CFIA) for a resistive bridge sensor readout integrated circuit (IC) is proposed. To reduce the CFIA’s own offset and 1/f noise, a chopper stabilization technique is implemented. To attenuate the output ripple caused by chopper up-modulation, a ripple reduction loop (RRL) is employed. A multipath architecture is implemented to compensate for the notch in the chopping frequency band of the transfer function. To prevent performance degradation resulting from external offset, a 12-bit R-2R digital-to-analog converter (DAC) is employed. The proposed CFIA has an adjustable gain of 16–44 dB with 5-bit programmable resistors. The proposed resistive sensor readout IC is implemented in a 0.18 μm complementary metal-oxide-semiconductor (CMOS) process. The CFIA draws 169 μA currents from a 3.3 V supply. The simulated input-referred noise and noise efficiency factor (NEF) are 28.3 nV/√Hz and 14.2, respectively. The simulated common-mode rejection ratio (CMRR) is 162 dB, and the power supply rejection ratio (PSRR) is 112 dB.

A Chopper Stabilization Audio Instrumentation Amplifier for IoT Applications

“…From Equation (15), it is clear that the NEF parameter includes almost every performance shown in Table 1, namely the equivalent-input referred noise, the power consumption, the bandwidth and indirectly the PSRR (power-supply rejection ratio) and the CMRR (common-mode rejection ratio). In [18,19], the instrumentation amplifier has a high CMRR and high PSRR. However, it has also a high equivalentinput referred noise at list of about 18 nV/√Hz.…”

Chopping for over 50 MHz gain‐bandwidth product current sense amplifiers achieving input noise level of 8.5 nV/√Hz

“…However, the bandwidth was strictly limited by 200 Hz 10 . More recently, several very promising works have been published using more advanced semiconductor technologies and more complex design concepts in order to even further reduce input noise and offset, while also dealing with chopping‐related challenges 11–25 …”

“…10 More recently, several very promising works have been published using more advanced semiconductor technologies and more complex design concepts in order to even further reduce input noise and offset, while also dealing with chopping-related challenges. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] In general, one typically distinguishes between (1) pure or classical chopping as employed in this work, which is partially extended to nested chopping using several interleaved choppers 3,26 ; (2) chopper stabilization, which is a multipath amplifier approach utilizing a main amplifier and a nulling amplifier 27 ; and (3) analogous auto zeroing, for example, using switched capacitors. Although the basic principle of the latter is different, it is still related to this topic, since the inputs are switched and input offset is reduced.…”

A Modulation Method for Tunnel Magnetoresistance Current Sensors Noise Suppression

“…A capacitor-coupled chopping amplifier can effectively suppress noise, yet this approach may reduce the input impedance of the instrumentation amplifier to a certain degree [ 2 , 3 , 4 , 5 , 6 ]. Current feedback structures can fundamentally address this issue, with recent research focusing on chopping amplifiers based on these structures [ 7 , 8 , 9 , 10 ]. Within chopping technology, designing low-frequency low-pass filters presents increased complexity in CMOS circuits, leading to the rising trend of employing high-frequency ripple suppression loops as alternative solutions [ 11 ].…”