FPGA-based direct resistance and capacitance measurements

Arés, L.; Rodríguez-Andina, Juan J.; Fariña, José

doi:10.1109/iecon.2009.5415404

Cited by 5 publications

(7 citation statements)

References 8 publications

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“…2.1b, the μ C will be the digital system in charge of exciting and measuring the sensor without using either the signal conditioning circuit or the ADC. Other digital systems, such as fi eld programmable gate arrays (FPGA), have also been proposed to carry out such functions (Ares et al ., 2009;Vidal-Verd ú et al ., 2011), but a μ C seems more advisable because of its lower cost (say, $1) and lower power consumption (say, about 1 mA in active mode and less than 1 μ A in power-down mode).…”

Section: Microcontrollersmentioning

confidence: 99%

Direct interface circuits for sensors

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2014

Smart Sensors and Mems

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Section: Microcontrollersmentioning

confidence: 99%

Direct interface circuits for sensors

Reverter

2014

Smart Sensors and Mems

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“…The digital feedback introduces memory and the circuit is able to store a bit that indicates that a falling edge at the input has already been detected. This memory actually replaces the analog memory present in proposals with analog circuits with hysteresis, such as Trigger Schmitt buffers or the proposal in [ 7 ].…”

Section: Capture Modules On Fpgasmentioning

confidence: 99%

“…The proposal in [ 7 ] introduces hysteresis by implementing a block composed of an input buffer, an output buffer to add positive feedback, and two external resistors. Together with the

network

can both be the sensor) the resulting circuit is a relaxation oscillator whose output waveform, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…The resources in the FPGA allow digital circuits to be built that detect the first change of logical value at the input buffer when the input signal reaches the threshold. Instead of adding analog positive feedback [ 7 ], such feedback is implemented in digital circuits to achieve the memory of the hysteresis cycle. Moreover, smarter capture modules can be used to improve performance and precision.…”

Section: Introductionmentioning

confidence: 99%

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Smart Capture Modules for Direct Sensor-to-FPGA Interfaces

Oballe-Peinado

Vidal‐Verdú

Sánchez-Durán

et al. 2015

Sensors

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Direct sensor–digital device interfaces measure time dependent variables of simple circuits to implement analog-to-digital conversion. Field Programmable Gate Arrays (FPGAs) are devices whose hardware can be reconfigured to work in parallel. They usually do not have analog-to-digital converters, but have many general purpose I/O pins. Therefore, direct sensor-FPGA connection is a good choice in complex systems with many sensors because several capture modules can be implemented to perform parallel analog data acquisition. The possibility to work in parallel and with high frequency clock signals improves the bandwidth compared to sequential devices such as conventional microcontrollers. The price to pay is usually the resolution of measurements. This paper proposes capture modules implemented in an FPGA which are able to perform smart acquisition that filter noise and achieve high precision. A calibration technique is also proposed to improve accuracy. Resolutions of 12 effective number of bits are obtained for the reading of resistors in the range of an example piezoresistive tactile sensor.

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“…The signal conditioning circuit is only one capacitor in each column, which is also part of the circuit for AD conversion (for our case a time-to-digital conversion). This is carried out by using an FPGA as in [ 26 ] instead of microcontrollers [ 27 ]. This configuration, with some modifications, can be applied to other sensors (capacitive or inductive) that provide a time-modulated signal that can be directly measured in the digital domain [ 28 , 29 ].…”

Section: Introductionmentioning

confidence: 99%

Accuracy and Resolution Analysis of a Direct Resistive Sensor Array to FPGA Interface

Oballe-Peinado

Vidal‐Verdú

Sánchez-Durán

et al. 2016

Sensors

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Resistive sensor arrays are formed by a large number of individual sensors which are distributed in different ways. This paper proposes a direct connection between an FPGA and a resistive array distributed in M rows and N columns, without the need of analog-to-digital converters to obtain resistance values in the sensor and where the conditioning circuit is reduced to the use of a capacitor in each of the columns of the matrix. The circuit allows parallel measurements of the N resistors which form each of the rows of the array, eliminating the resistive crosstalk which is typical of these circuits. This is achieved by an addressing technique which does not require external elements to the FPGA. Although the typical resistive crosstalk between resistors which are measured simultaneously is eliminated, other elements that have an impact on the measurement of discharge times appear in the proposed architecture and, therefore, affect the uncertainty in resistance value measurements; these elements need to be studied. Finally, the performance of different calibration techniques is assessed experimentally on a discrete resistor array, obtaining for a new model of calibration, a maximum relative error of 0.066% in a range of resistor values which correspond to a tactile sensor.

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FPGA-based direct resistance and capacitance measurements

Cited by 5 publications

References 8 publications

Direct interface circuits for sensors

Direct interface circuits for sensors

Smart Capture Modules for Direct Sensor-to-FPGA Interfaces

Accuracy and Resolution Analysis of a Direct Resistive Sensor Array to FPGA Interface

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