An Interfacing Scheme with Improved Bandwidth for Multi-Current-Output Sensors

The paper presents a simple interfacing electronics suitable for a sensor system, involving multiple current-output sensors. The proposed interface selects and processes the individual sensor nodes, and then efficiently estimates the sensor-current and/or their combination. The novel design of the interface, which comprises an improved current-sense circuit, a switching logic and multi-regiming signal conditioner, renders many meritorious features. The salient features include improved bandwidth, reduced effects of ADC resolution, as well as the ability to provide customized design as per user requirements. The methodology and performance evaluation of this interfacing scheme is described in the paper. The test results, using simulation as well as hardware-based tests on a four-sensor system, demonstrate the performance of the scheme. The maximum non-linearity for a range of (10 nA, 160 nA) is obtained as 0.184%. The improvement in bandwidth is about 9.9 kHz (factor of improvement = 100). The working of gain regimes is shown adequately for single as well as multiple current output sensing. This technique is useful for various instruments such as magnetic field sensors and photodiodes.